Synthesis and SARs of novel lincomycin derivatives Part 5: Optimization of lincomycin analogs exhibiting potent antibacterial activities by chemical modification at the 6- and 7-positions

Article abstract of DOI:10.1038/ja.2017.114

In order to modify lincomycin at the C-6 and C-7 positions, we prepared target molecules, which have substituted pipecolinic acid at the 6-amino group and a para-substituted phenylthio group at the C-7 position, in application of palladium-catalyzed cross-coupling as a key reaction. As the result of structure-activity relationship (SAR) studies at the 6-position, analogs possessing 4′-cis-(cyclopropylmethyl)piperidine showed significantly strong antibacterial activities against Streptococcus pneumoniae and Streptococcus pyogenes with an erm gene. On the basis of SAR, we further synthesized novel analogs possessing 4′-cis-(cyclopropylmethyl)piperidine by transformation of a C-7 substituent. Consequently, novel derivatives possessing a para-heteroaromatic-phenylthio group at the C-7 position exhibited significantly strong activities against S. pneumoniae and S. pyogenes with an erm gene even when compared with those of telithromycin. Finally, in vivo efficacy of selected two derivatives was evaluated in a rat pulmonary infection model with resistant S. pneumoniae with erm + mef genes. One of them exhibited strong and constant in vivo efficacy in this model, and both compounds showed strong in vivo efficacy against resistant S. pneumoniae with a mef gene.

Full text of DOI:10.1038/ja.2017.114

The Journal of Antibiotics (2017), 1–20
2017 Japan Antibiotics Research Association All rights reserved 0021-8820/17
www.nature.com/ja
&
ORIGINAL ARTICLE
Synthesis and SARs of novel lincomycin derivatives
Part 5: optimization of lincomycin analogs exhibiting
potent antibacterial activities by chemical modification
at the 6- and 7-positions
Yoshinari Wakiyama1, Ko Kumura1, Eijiro Umemura1, Satomi Masaki1, Kazutaka Ueda1, Yasuo Sato1,
Yoko Hirai1, Yoshio Hayashi2 and Keiichi Ajito1
In order to modify lincomycin at the C-6 and C-7 positions, we prepared target molecules, which have substituted pipecolinic acid at
the 6-amino group and a para-substituted phenylthio group at the C-7 position, in application of palladium-catalyzed cross-coupling
as a key reaction. As the result of structure-activity relationship (SAR) studies at the 6-position, analogs possessing 4′-cis-
(cyclopropylmethyl)piperidine showed significantly strong antibacterial activities against Streptococcus pneumoniae and
Streptococcus pyogenes with an erm gene. On the basis of SAR, we further synthesized novel analogs possessing 4′-cis-
(cyclopropylmethyl)piperidine by transformation of a C-7 substituent. Consequently, novel derivatives possessing a para-
heteroaromatic-phenylthio group at the C-7 position exhibited significantly strong activities against S. pneumoniae and S. pyogenes
with an erm gene even when compared with those of telithromycin. Finally, in vivo efficacy of selected two derivatives was evaluated
in a rat pulmonary infection model with resistant S. pneumoniae with erm + mef genes. One of them exhibited strong and constant
in vivo efficacy in this model, and both compounds showed strong in vivo efficacy against resistant S. pneumoniae with a mef gene.
The Journal of Antibiotics advance online publication, 1 November 2017; doi:10.1038/ja.2017.114
INTRODUCTION
As an overview, CLDM exhibits the following positive characters: (1)
Macrolide antibiotics have antibacterial activities against S. pneumo- availability in p.o. and i.v. administrations (switch therapy is possible),
niae, S. pyogenes, Haemophilus influenzae, Moraxella catarrhalis, (2) good distributions to the tissue and cells, (3) suppression19 of toxin
Mycoplasma pneumoniae and Neisseria gonorrhoeae, and have an production by streptococcal strains and (4) expected reasonable
acceptable safety profile as oral antibiotics. Consequently, macrolides production cost of its derivatives compared with that of ketolides
have widely been used in clinical sites for bacterial respiratory with a complex chemical structure. Thus, LCM derivatives might be
infections. Recently, macrolide resistant bacteria with an erm gene clinically more valuable than ketolide antibiotics, if they are effective
have markedly increased.1–3 Clarithromycin4 and azithromycin5,6 are against Gram-positive pathogens with an erm gene.
not effective against S. pneumoniae and S. pyogenes with an erm gene
Chemical modifications at the C-7 position of LCM were reported
and have low sensitivity against S. pneumoniae with a mef gene by several research groups.17,18,20-32 However, none of those com-
(Figure 1 and Table 1). Although telithromycin (TEL)7 exhibits pounds showed antibacterial activities against resistant Gram-positive
effective activities against S. pneumoniae with erm and/or mef genes, pathogens with an erm gene. On the other hand, we reported that
its activities are influenced by a mef gene. A serious liver damage8,9 and novel LCM derivatives modified at the C-7 position possessed
loss of consciousness10,11 were reported as side effects of TEL and antibacterial activities against resistant bacteria with an erm
medication with TEL was discontinued in Japan. Novel azalides gene.33–43 In particular, compound 1 (Wakiyama et al.40) (Figure 1)
reported by Miura et al.12,13 are also effective against the above and its analogues (possessing a ‘1-methylpiperidin-3-yl’ or ‘1-methyl-
resistant pathogens, but these analogs are still under research process. 1,2,5,6-tetrahydropyridin-3-yl’ moiety instead of a ‘pyrimidin-5-yl’
Development of an oral antibiotic possessing potent antibacterial moiety in compound 1) had significantly potent antibacterial activities
activities and an acceptable safety profile is strongly desired in clinical against resistant bacteria with an erm gene.
sites for respiratory infections.
Chemical modification at the C-6 position of LCM and/or CLDM
Lincomycin (LCM)14–17 and clindamycin (CLDM)18 are effective was also performed by several research groups.17,24,44–54 The C-6 side
against clinically isolated pathogens with a mef gene, but they are not chain, originally 1′-N-methyl-4′-trans-n-propylproline, has the follow-
effective against resistant bacteria with an erm gene (Figure 1, Table 1). ing characters: (1) diastereoisomers with 2′,4′-trans configuration were
1Pharmaceutical Research Center, Meiji Seika Pharma Co., Ltd, Yokohama, Japan and 2Department of Medicinal Chemistry, Tokyo University of Pharmacy and Life Sciences 1,
Tokyo, Japan
Correspondence: Dr K Ajito, Pharmaceutical Research Center, Meiji Seika Pharma Co., Ltd. 760 Morooka-cho, Kohoku-ku, Yokohama 222-8567, Japan.
Received 20 May 2017; revised 15 August 2017; accepted 24 August 2017

Synthesis and SARs of novel lincomycin derivatives Part 5
Y Wakiyama et al
2
O
Me
N
Me
HO
Me
Me
N
Me
Me
N
OMe
Me
OH
HO
Me
OH
Me
NMe2
Me
OH
Me
N
Me
NMe2
Me
HO
O
O
O
HO
O
O
O
O
N
Me
O
O
Me
OMe
Me
Me
Me
Me
OMe
O
O
OMe
Me
Me
Me
Me
OH
Me
O
OH
NMe2
Me
O
O
Me
O
O
Me
HO
O
O
Clarithromycin (CAM)
Me
Azithromycin (AZM)
Me
O
O
Me
4'
O Me
2'
Telithromycin (TEL)
7
Me
O
1'
N
N
N
H
HN
H
HO
SMe
R4
Me
HO
OH
Me
4'
4'
O Me
O Me
O Me
2'
R2
R1
O
2'
S
7
R3
O
VIC-105403
N
HN
HO
N
HN
HO
N
HN
H
HO
Me
Me
H
H
H
O
SMe
SMe
SMe
HO
OH
HO
OH
HO
OH
Lincomycin (LCM): R1 = OH; R2 = H
Clindamycin (CLDM): R1 = H; R2 = Cl
Pirlimycin: R3 = Cl; R4 = H
VIC-105555: R3 = R4 = Me
1
Figure 1 Chemical structures of macrolide derivatives and lincomycin/clindamycin derivatives.
Table 1 Antibacterial activities (MIC, μg ml− 1) of CAM, AZM, LCM, CLDM, VIC-105555, TEL and previously reported lincomycin derivative 1
Test organisma
Characteristics
CAM
AZM
LCM
CLDM
VIC-105555
TEL
1
S. pneumoniae DP1 TypeI
S. pneumoniae-2
S. pneumoniae-3
S. pneumoniae-4
S. pneumoniae-5
S. pneumoniae-6
S. pneumoniae-7
S. pneumoniae-8
S. pneumoniae-9
S. pyogenes Cook
S. pyogenes-2
Susceptible
Susceptible
0.03
0.03
0.015
4128
4128
4128
4128
4128
0.5
0.06
0.03
0.03
4128
4128
4128
4128
4128
0.5
1
1
0.06
0.12
0.06
4128
4128
4128
128
128
0.12
0.06
128
0.12
16
0.03
0.06
0.03
4128
4128
4128
128
⩽ 0.008
⩽ 0.008
⩽ 0.008
0.5
⩽ 0.008
⩽ 0.008
⩽ 0.008
0.5
Susceptible
0.25
4128
4128
4128
128
128
1
ermAM methylase (c)
ermAM methylase (c)
ermAM methylase (c) + mefE
ermAM methylase (i)
ermAM methylase (i)
mefE efflux
2
1
1
2
0.03
0.03
0.06
⩽ 0.008
16
0.25
0.25
⩽ 0.008
⩽ 0.008
0.5
128
0.015
0.06
4128
0.06
32
susceptible
0.015
4128
8
0.06
4128
8
0.12
4128
0.25
8
ermAM methylase (c)
mefE efflux
S. pyogenes-3
0.25
0.5
0.015
4
H. influenzae
Susceptible
2
0.25
1
H. influenzae-2
H. influenzae-3
H. influenzae-4
Susceptible
4
16
8
16
2
2
Susceptible
8
2
16
16
32
1
8
⊿acr
0.5
0.5
4
1
2
0.25
0.06
Abbreviations: AZM, azithromycin; c, constitutive; CAM, clarithromycin; CLDM, clindamycin; I, inducible Gray shading strains are target strains; LCM, lincomycin; TEL, telithromycin.
Gray shading strains are target strains.
aAll strains except standard organisms were clinically isolated.
more potent than cis isomers; (2) 1′-N-demethylclindamycin was twice introduction of hetero atoms to the 4′-side chain essentially lost
as active in vitro against Sarcina lutea as CLDM, but 1′-N-demethyl- activity;17,21,47 and (5) VIC-105403 (Lewis et al.24) (Figure 1) had
lincomycin was about one twentieth as active as LCM;21,44–45 (3) as for potent activities compared with CLDM.
As another background information on chemical modifications at
the C-6, azetidine,48–51 piperidine48,49,52–54 and azepane analogs48,49
chain length (H, Me to octyl) at the 4′-position of LCM, the hexyl
analog showed maximum in vitro antibacterial activity;21,46 (4)
The Journal of Antibiotics

Synthesis and SARs of novel lincomycin derivatives Part 5
Y Wakiyama et al
3
R
R
R
R
were synthesized accompanied with modifications at the C-7. Regard-
ing azetidine derivatives, 3′-trans-cyclobutylethyl CLDM derivative
showed significant antibacterial activities against sensitive S. pneumo-
niae compared with CLDM, but 3′-trans-cyclopropylmethyl, 3′-trans-
n-propyl and 3′-trans-n-butyl analogs exhibited similar potency as
CLDM. As a piperidine derivative, 4′-cis-ethyl CLDM analog, pirli-
mycin, is used in mastitis therapy for cattle in the European countries
and United States. On the other hand, VIC-105555 (Figure 1) was
selected as a candidate, which exhibited preferable pharmacokinetics
and characteristic in vitro antibacterial activities against methicillin-
resistant Staphylococcus aureus (MRSA) and Enterococcus faecalis.
Furthermore, azepane-type CLDM analogs were also synthesized and
4'
ref48, 55
2' CO2H
CO H
CO2H
+
2
N
N
N
N
Boc
Boc
Boc
2: R = nPr
( )-5: R = nPr
( )-6: R = nBu
( )-7: R = iBu
1:1, enantio mixture
3: R = nBu
4: R = iBu
Me
d
a
b, c
CN
CO2H
N
N
N
N
8
9
10
11
5′-(3-fluorobutyl) analog was 32 times as active (MIC: 0.25 μg ml− 1
against H. influenzae as CLDM (MIC: 8 μg ml− 1).48
)
4'
g
2' CO2H
CO2Bn
e, f
None of the C-6-modified compounds were disclosed to possess
activities against Gram-positive-resistant bacteria with an erm gene.
We reported that novel (7S)-substituted analogs42 modified at the N-1′
and C-4′ positions in a proline moiety had potent activities against
Gram-positive-resistant bacteria with an erm gene. We further pursued
modifications of LCM with a combination manner at the C-6 and C-7
positions in order to generate novel LCM derivatives exhibiting as
strong antibacterial activities as TEL. Then, we synthesized novel (7S)-
substituted analogs attached with piperidine or azepane instead of
pyrrolidine (a part of proline) at the C-6 position. We have found
three representative molecules so far and we chose a ‘pyrimidin-5-yl’-
phenyl derivative (1) (Figure 1) as a C-7 side chain for optimization of
a C-6 moiety, because a ‘1-methylpiperidin-3-yl’ moiety has a chiral
center (anxiety for relatively complex production) and a ‘1-methyl-
1,2,5,6-tetrahydropyridin-3-yl’ moiety has an isolated double bond
(anxiety for potential instability).
CO2Bn
+
N
N
N
Boc
Boc
14
Boc
13
(
)-12
h
CO2H
13
N
Boc
15
Me
Me
5'
2'
i
CO2Me
CO2H
N
N
Ns
1648
Ns
17
Scheme 1 Synthesis of substituted piperidines and 2,3,6,7-tetrahydro-1H-
azepine. Conditions: (a) bromocyclopropane, lithium diisopropylamide, THF,
− 78 °C, 1 h; (b) m-chloroperoxybenzoic acid (mCPBA), CH2Cl2, 0 °C to r.t.,
1 h; (c) TMSCN, Me2NCOCl, CH2Cl2, 20 °C 40 min, then r.t.,17 h; (d) 5 N
NaOH, MeOH, 50 °C, 8 h; (e) H2, PtO2, AcOH, r.t., 24 h; (f) Boc2O, 2 N
i
NaOH, dioxane, r.t., 15 h; (g) BnBr, Pr2NEt, CH3CN, r.t., 48 h; (h) H2, Pd/
C, MeOH, r.t., 1 h; (i) LiOH·H2O, dioxane:H2O = 4:1, r.t. 5 h.
RESULTS AND DISCUSSION
Synthesis of the substituted piperidines and 2,3,6,7-tetrahydro-1H-
azepine
Syntheses of substituted piperidines and 2,3,6,7-tetrahydro-1H-azepine
are shown in Scheme 1. Substituted piperidines ( )-5-7 and 2,3,6,7-
tetrahydro-1H-azepine 16 were synthesized by methods reported by
Shuman et al.55 and Lewis et al.48 Compound ( )-12 was prepared
from 4-methylpyridine (8) in improved reaction conditions based on
reported methods48,55 shown in Scheme 1. It was reported that
hydrogenation of disubstituted pyridine in the presence of PtO2
resulted in a racemate of cis-products as major products by Lewis
et al.48 Going back in time, Shuman et al.55 proved that 2,4-
disubstituted piperidine prepared from disubstituted pyridine by
hydrogenation had cis-configuration by NOE experiments. At the
beginning of this research, we used ( )-cis-carboxylic acids 5-7 and
12, but later on we could separate ( )-12 into each cis-enantiomer for
efficient synthetic study. Carboxylic acid ( )-12 was protected by a
benzyl group for the purpose of optical resolution by HPLC and both
enantiomers were purified by chiral column chromatography to obtain
a desired compound 13. Stereochemistry of compounds 13 and 14 was
assigned as following. Pirlimycin and VIC-105555 are reported as
representative LCM derivatives possessing a substituted piperidine
moiety (Figure 1). Absolute stereochemistry of pirlimycin was clarified
by X-ray crystallographic studies.49 Absolute stereochemistry of
VIC-105555 was reported by Vicuron at 44th Interscience Conference
on Antimicrobial Agents and Chemotherapy.54 Both compounds have
2′-β-4′-β-configuration and they showed remarkable polarity (lower Rf
value) and stronger potency compared with the corresponding 2′-α-4′-
2′-β-4′-β-configuration for a polar product. The benzyl group in 13
was removed by hydrogenolysis to give a key intermediate 15. A seven-
membered intermediate (17) was prepared by basic hydrolysis of 16.
Synthesis of key intermediates 30–33 and 39
Syntheses of key intermediates 30–33 and 39 are shown in Scheme
2. Diastereomeric mixtures 18–21 and compound 34 were
synthesized by coupling of compounds ( )-5-7, ( )-12 and 17
with MTL, respectively. MTL was prepared by a reported
method.56 Although each isomer was almost one to one mixture
except 17 when the coupling reactions were completed, precipita-
tion process gave 2′-β-4′-β-rich cis-isomers. As ‘Experimental
procedure’ reported, ratio of diastereoisomeric mixture was
difference for each compound. Tetra-O-trimethylsilylation of
mixtures 18–21 and regioselective deprotection of the 7-O-TMS
group followed by silica gel column chromatography finally gave
single compounds 22–2548,57 as 2′-β-4′-β-pure cis-isomers.
Methanesulfonylation of the 7-OH group and then SN2 reaction
by potassium thioacetate gave compounds 26-29. Key intermedi-
ates 30-3333–35,37–38,40,42 were prepared by deprotections of all
TMS groups and an acetyl group. On the other hand, the Ns group
of compound 34 was deprotected by 4-bromobenzenethiol under
the basic condition, and then the olefin group was reduced by
α-diastereoisomer, respectively. When we coupled a substituted hydrogenation to give an azepane intermediate 35 (stereochem-
pipecolic acid with methyl α-thiolincosaminide (MTL), we assigned istry at the C-5′ position is not assigned). An amino group of 35
The Journal of Antibiotics

Synthesis and SARs of novel lincomycin derivatives Part 5
Y Wakiyama et al
4
R
4'
R
R
R
2', 4'-cis
O
Me
O
Me
7
O
HN
HO
Me
O
Me
7
OH
O
OH
O
SH
O
R
4'
SAc
O
2', 4'-cis
2'
N
HN
HO
N
HN
H
TMSO
N
N
HN
H
TMSO
b, c
SMe
d, e
SMe
a
f, g
SMe
Boc
Boc
Boc
Boc
H
H
CO2H
2'
SMe
N
Me
Boc
OH
O
HO
18: R = nPr
OH
TMSO
22: R = nPr
OTMS
HO
OH
TMSO
26: R = nPr
OTMS
H2N
HO
( )-5: R = nPr
H
30: R = nPr
31: R = nBu
32: R = iBu
( )-6: R = nBu
( )-7: R = iBu
SMe
19: R = nBu
20: R = iBu
23: R = nBu
24: R = iBu
27: R = nBu
28: R = iBu
HO
OH
MTL
( )-12: R = cPrCH2
21: R = cPrCH2
25: R = cPrCH2
29: R = cPrCH2
33: R = cPrCH2
5'
Me
Me
a
Me
h, i
Me
O
HN
HO
Me
O
Me
O Me
2'
OH
O
OH
O
OH
O
CO2H
HN
HO
HN
HO
N
N
NH
N
j
Boc
Ns
Ns
H
H
H
SMe
SMe
SMe
17
+
HO
OH
HO
OH
HO
OH
MTL
34
35
36
Me
Me
Me
O
Me
O
Me
O
HN
HO
Me
OH
O
SAc
SH
f, g
d, e
HN
HN
H
TMSO
b, c
N
N
Boc
N
Boc
TMSO
Boc
H
O
H
O
SMe
SMe
SMe
TMSO
OTMS
TMSO
38
OTMS
HO
OH
37
39
Scheme 2 Synthesis of key intermediates 30 to 33 and 39. Conditions: (a) N,N′-dicyclohexylcarbodiimide (DCC) or EDC·HCl, HOBt, DMF, r.t., 6–20 h; (b)
TMSCl, HMDS, pyridine, r.t., 20 min–1 h; (c) 6 N AcOH or 2 N AcOH, MeOH, r.t., 40 min–6 h; (d) MsCl, NEt3, CH2Cl2, 0 °C to r.t., 1 h; (e) AcSK, DMF, 80 °
C, 1.5–3 h; (f) 1 N HCl, MeOH, r.t. or 0 °C, 5–100 min; (g) NaOMe, MeOH, r.t., 15 min–3 h; (h) 4-bromobenzenethiol, Cs2CO3, DMF, r.t., 2 h; (i) H2 (0.95
MPa), Pd/C, MeOH, 40 °C, 70 h; (j) Boc2O, LiOH·H2O, dioxane:H2O = 1:1, r.t. 3 h.
was protected by a Boc group to give 36, and a key intermediate coupling reaction of 56 with enantio-pure 15 provided desired 57 with
39 was synthesized from 36 by the similar procedures as described all carbon’s framework. Deprotection of the Boc group finally gave 58
for the preparation of 30.
and its reductive N-methylation provided compound 59.
Synthesis of novel (7S)-4-(pyrimidin-5-yl)phenylthio LCM
derivatives possessing piperidine or azepane as the C-6 side chain
Synthesis of novel 4′-cis-(cyclopropylmethyl)piperidine LCM
derivatives possessing a 4-substituted phenylthio group at the C-7
Syntheses of novel (7S)-4-(pyrimidin-5-yl)phenylthio LCM derivatives position
Syntheses of novel 4′-cis-(cyclopropylmethyl)piperidine LCM deriva-
possessing piperidine or azepane as the C-6 side chain are
shown in Scheme 3. Compounds 40-43 and 48 were synthesized
from key intermediates 30-33 and 39 by palladium-catalyzed
tives possessing a 4-substituted phenylthio group at the C-7 position
are shown in Scheme 5. Compounds 60, 61 and 63-65 were
synthesized from the key intermediate 33 by palladium-catalyzed
cross-coupling reaction with the corresponding 4-substituted phenyl
bromides. Reduction of 61 afforded saturated N-methylpiperidine 62
as a mixture of diastereoisomers at an N-methylpiperidine ring. The
first half of desired compounds 66, 68, 70, 72, 74 and 77 were
prepared by deprotection of a Boc group and their free secondary
amine was methylated by reductive alkylation to give the second half
of desired compounds 67, 69, 71, 73, 75 and 78, respectively.
Compound 76 was also synthesized from 47 with the similar
procedure. We confirmed that compound 76 derived from compound
33 had 4′-cis-stereochemistry by ROESY experiments. As the above, 4′-
cis-stereochemistry of compound 12 was assigned.
cross-coupling
reaction
with
5-(4-bromophenyl)pyrimidine,
respectively.33-35,38,40,42,58, The Boc group of 40-43 and 48 was finally
removed with TFA to give desired compounds 44-47 and 49.
Synthesis of divergent intermediate 54 and novel LCM derivatives
possessing a 4-(2-(dimethylamino)ethyl)phenylthio group at the
C-7 position
Because we had to develop a more divergent synthetic route than those
exemplified in Schemes 2 and 3, we decided to apply the next key
intermediate 54. Syntheses of divergent intermediate 54 and novel
LCM derivatives possessing a 4-(2-(dimethylamino)ethyl)phenylthio
group at the C-7 position are shown in Scheme 4. Compound 5059
was synthesized by trifluoroacetylation of an amino group of MTL,
and tetra-O-trimethylsilylation of all OH groups of 50 gave compound
51. Divergent intermediate 54 was synthesized from 51 by the similar
SAR analysis of C-6 modified and (7S)-7-(4-(pyrimidin-5-yl)phenyl)
thio-substituted LCM derivatives 44-47 and 49
procedures as described for preparation of 30. Palladium-catalyzed We reported potent antibacterial activities of 1 possessing the (7S)-(4-
cross-coupling reaction of 54 with 2-(4-bromophenyl)-N,N-dimethy- (pyrimidin-5-yl)phenyl)thio group at the C-7 position. For the
lethanamine gave 55, which was hydrolyzed in the presence of phase purpose of generating novel compounds possessing more potent
transfer catalyst under the basic condition to give diamine 56. A antibacterial activities against resistant Gram-positive pathogens with
The Journal of Antibiotics

Synthesis and SARs of novel lincomycin derivatives Part 5
Y Wakiyama et al
5
N
N
N
N
b
R
R
R
O Me
7
O Me
O Me
S
SH
O
S
6
N
HN
N
HN
H
HO
N
HN
H
HO
a
H
Boc
Boc
H
O
O
HO
SMe
SMe
SMe
HO
OH
HO
OH
HO
OH
30: R = nPr
31: R = nBu
32: R = iBu
40: R = nPr
41: R = nBu
42: R = iBu
44: R = nPr
45: R = nBu
46: R = iBu
N
N
33: R = cPrCH2
43: R = cPrCH2
47: R = cPrCH2
N
N
Me
Me
Me
b
O Me
O Me
O Me
7
S
SH
O
S
a
6
HN
HO
HN
HO
N
HN
N
N
Boc
Boc
H
H
O
H
H
HO
O
SMe
SMe
SMe
HO
OH
HO
OH
HO
OH
39
48
49
Scheme 3 Synthesis of novel (7S)-4-(pyrimidin-5-yl)phenylthio LCM derivatives possessing piperidine or azepane as the C-6 side chain. Conditions: (a) 5-(4-
i
bromophenyl)pyrimidine, Pd2(dba)3, Xantphos, Pr2NEt, dioxane, reflux, 2-6 h; (b) TFA, CH2Cl2, − 20 °C to r.t., 1.5–6 h.
O Me
O Me
O Me
O Me
NMe2
F3C
OH
O
F3C
OR
O
F3C
SAc
O
F3C
SH
O
HN
H
HO
HN
HN
HN
H
HO
c, d, e
SMe
a
f, g
SMe
H
H
SMe
TMSO
TMSO
SMe
h
O Me
F3C
S
HO
OH
TMSO
OTMS
TMSO
53
OTMS
HO
OH
HN
H
HO
O
50
51: R = TMS
52: R = H
54
b
SMe
HO
OH
NMe2
NMe2
NMe2
NMe2
55
O Me
O Me
O Me
Me
S
S
S
S
i
j
k
l
N
HN
H
HO
N
HN
H
HO
N
HN
H
HO
H2N
HO
H
Me
Boc
O
O
O
H
O
SMe
SMe
SMe
SMe
HO
OH
HO
OH
HO
OH
HO
OH
56
57
58
59
Scheme 4 Synthesis of divergent intermediate 54 and novel LCM derivatives possessing a 4-(2-(dimethylamino)ethyl)phenylthio group at the C-7 position.
Conditions: (a) TMSCl, HMDS, pyridine, r.t., 1 h; (b) 6 N AcOH, MeOH, r.t., 15 min; (c) MsCl, NEt3, CHCl3, r.t., 1 h; (d) AcSK, DMF, 80 °C, 1.5 h; (e)
TMSCl, HMDS, pyridine, r.t., 3 h; (f) 1 N HCl, MeOH, r.t., 10 min; (g) NaOMe, MeOH, r.t., 15 min; (h) 2-(4-bromophenyl)-N, N-dimethylethanamine, Pd2
i
(dba)3, Xantphos, Pr2NEt, dioxane, reflux, 17 h; (i) 20% aq. KOH, N-benzyl-N, N, N-triethylammonium bromide, r.t., 4 h; (j) 15, EDC·HCl, HOBt, DMF, r.t.,
5.5 h; (k) TFA, CH2Cl2, 0 °C, 3.5 h; (l) 36% HCHO, NaBH(OAc)3, AcOH, MeOH, r.t., 1 h.
an erm gene, we performed an SAR analysis of C-6-modified and (7S)- resistant S. pneumoniae with an erm gene than 1. However, its
7-(4-(pyrimidin-5-yl)phenyl)thio-substituted LCM derivatives 44–47 antibacterial activity against resistant S. pneumoniae with both erm and
and 49 (Table 2). According to our reported SAR studies, (7S) mef genes (S. pneumoniae-6) was not sufficient (MIC: 1 μg ml−1).
stereochemistry was selected among all novel derivatives.40 Compound Because there were a couple of reports21,42,46 stating that elongation
44, which possesses n-propyl-piperidine instead of n-propyl-pyrroli- of a side chain in a piperidine ring enhanced antibacterial activity,
dine as the C-6 side chain, showed stronger activities against we synthesized alternative derivatives with a longer carbon chain
The Journal of Antibiotics

Synthesis and SARs of novel lincomycin derivatives Part 5
Y Wakiyama et al
6
R
R
R
4'
O Me
O Me
2'
O Me
O Me
SH
O
S
S
S
N
HN
H
HO
N
HN
HO
HN
H
HO
N
HN
H
HO
N
a
c
d
Boc
Boc
H
Me
H
O
O
O
SMe
SMe
SMe
SMe
HO
OH
HO
OH
HO
OH
HO
OH
33
(43), 60, 63, 64, 65
(47), 66, 68, 70, 72, 74, 77
67, 69, 71, 73, 75, 76, 78
61
b
62
N
N
N
N
N
MeN
MeN
S
N
R =
N
N
60, 66, 67
61, 68, 69
62, 70, 71
63, 72, 73
64, 74, 75
(43), (47), 76
65, 77, 78
Scheme 5 Synthesis of novel 4′-cis-(cyclopropylmethyl)piperidine LCM derivatives possessing an aliphatic- or aromatic-phenylthio group at the C-7
position. Conditions: (a) the corresponding 4-substituted phenylbromides Pd2(dba)3, Xantphos, iPr2NEt, dioxane, reflux, 4–5 h; (b)
4-methylbenzenesulfonohydrazide, toluene, reflux, 5.5 h; (c) TFA, CH2Cl2, − 20 °C to r.t., 0.5–5 h; (d) 36% HCHO, NaBH(OAc)3, AcOH, MeOH, r.t., 0.5–2 h.
Table 2 Antibacterial activities (MIC, μg ml− 1) of novel lincomycin derivatives modified at the C-6 position
Test organisma
Characteristics
TEL
NT
NT
NT
NT
Abbreviations: c, constitutive; i, inducible; NT, not tested; TEL, telithromycin.
Gray shading strains are target strains.
aAll strains except standard organisms were clinically isolated.
or a branched side chain. However, antibacterial activities of compounds Antibacterial activities of novel LCM derivatives 58, 59 and 66–71
possessing an aliphatic amine at the para-position of phenylthio
group at the C-7 position
45 and 46 were not improved. On the other hand, both compounds 47
and 49 possessing a 4′-cis-(cyclopropylmethyl)piperidine-2-carbonyl and
5′-n-propylazepane-2-carbonyl group at the C-6 position exhibited
potent antibacterial activities against resistant S. pneumoniae with erm
gene. Because the cyclopropylmethyl analog (47) especially exhibited
stronger activities against Gram-positive pathogens with an erm gene
even compared with TEL, we chose a 4′-cis-cyclopropylmethyl moiety as
the C-6 side chain for further medicinal chemistry.
For the purpose of accumulating detail information of SAR on (7S)-7-
(4-substituted-phenylthio) LCM derivatives with a 4′-cis-(cyclopropyl-
methyl)piperidine moiety, we synthesized novel derivatives possessing
various substituents at the C-7 position with a set of R2 = both ‘N-H’
and ‘N-Me’ analogs (Table 3). Consequently, compounds 58, 66 and
68–71 showed potent antibacterial activities against target pathogens
The Journal of Antibiotics

Synthesis and SARs of novel lincomycin derivatives Part 5
Y Wakiyama et al
7
Table 3 Antibacterial activities (MIC, μg ml− 1) of novel lincomycin derivatives modified at the C-7 position with an aliphatic moiety
Test organisma
Characheristics
TEL
NT
NT
NT
NT
Abbreviations: c, constitutive; i, inducible; NT, not tested; TEL, telithromycin.
Gray shading strains are target strains.
aAll strains except standard organisms were clinically isolated.
with an erm gene and their activities were relatively stronger even modification at the C-6 position (the proline moiety) and the C-7
when compared with those of TEL. In addition, antibacterial activity position. These derivatives were also effective against resistant
of all compounds against S. pyogenes with an erm gene was M. pneumoniae.
significantly potent than that of TEL. We confirmed that combination
In vitro antibacterial activity (sensitivity distribution analysis) of
selected compounds against sixty clinical isolates of S. pneumoniae
We evaluated the antibacterial activity of compounds 47, 68, 72, 76, 77
and TEL against 60 clinical isolates of S. pneumoniae including
susceptible strains and resistant strains with erm and/or mef genes
for sensitivity distribution analysis (Figure 2). MIC90 values of five
novel LCM derivatives (0.06–0.125 μg ml− 1) were relatively smaller
of chemical modifications with the 4′-cis-(cyclopropylmethyl)piper-
idine group at the C-6 position and an aliphatic amine to the para-
position of a phenylthio group at the C-7 position was important to
enhance antibacterial activities against S. pneumoniae and S. pyogenes
with an erm gene.
Antibacterial activities of novel LCM derivatives 47 and 72–78
possessing an aromatic amine at the para-position of a phenylthio than that of TEL (0.25 μg ml− 1). Notably, 47 and 72 were significantly
group at the C-7 position
potent among tested compounds. These results reflect MIC values in
Table 4 and it was suggested that these derivatives would also be
effective against S. pneumoniae in clinical sites.
In order to expand possibilities of the combination modification at
both the C-6 and C-7 positions, we synthesized novel derivatives
possessing various aromatic amines as a substituent on the phenyl
group with a set of both ‘N-H’ and ‘N-Me’ analogs (Table 4). All their
antibacterial activities against target Gram-positive pathogens with an
erm gene were also relatively stronger than those of TEL. To be more
precise, compounds 47 and 72 showed potent activities in ‘N-H’
analogs and compound 76 exhibited the strongest activities among all
‘N-Me’ analogs in this article. As pharmacokinetic property must be
different between ‘N-H’ and ‘N-Me’ analogs, it is important to select
these two types of analogs for further development. Furthermore,
antimicrobial activity of compounds 72, 47 and 77 against
H. influenzae was relatively strong among all LCM derivatives we
reported, and their potency was stronger than that of clarithromycin
and catching up with that of TEL. We also investigated antibacterial
activity against M. pneumoniae (Table 4), because resistant M.
pneumoniae is causing problems for respiratory infections in clinical
sites. All evaluated compounds including 47 and 76 had significant
antibacterial activity against resistant M. pneumoniae, which TEL was
In vivo efficacy of 47 and 76 (subcutaneous administration) in rat
pulmonary infection model with resistant S. pneumoniae with erm
+ mef genes and a mef gene
We finally investigated the in vivo efficacy of selected compounds in
rat pulmonary infection model with resistant S. pneumoniae with erm
+ mef genes. Among derivatives reported in this study, in vitro
activities of compounds 47 and 72 are rather strong (Figure 2). On the
other hand, we had to clarify in vivo efficacy in the set of ‘N-H’ and
‘N-Me’ in the piperidine moiety (to evaluate ‘72 and 73’ or ‘47 and
76’). As in vitro activities of 73 were slightly weaker than those of 76,
we decided to select the set of compounds 47 and 76 for in vivo
evaluation. Compound 72 had weak hemolytic activity and thus
compound 72 might not be appropriate for further evaluation.
Compounds 47, 76 and TEL were subcutaneously administered
(10 mg kg− 1) to rats at 2 h after bacterial infection, and in vivo
efficacies are shown in Figure 3a. Compound 47 exhibited strong
not effective against. We could generate several novel LCM derivatives in vivo efficacy (3 log reduction or more) against resistant S.
exhibiting very strong antibacterial activities against resistant Gram- pneumoniae with erm + mef genes and its efficacy was constant (small
positive pathogens with erm and/or mef genes by combination s.d. value) compared with that of TEL (o2 log reduction). For our
The Journal of Antibiotics

Synthesis and SARs of novel lincomycin derivatives Part 5
Y Wakiyama et al
8
Table 4 Antibacterial activities (MIC, μg ml− 1) of optimized novel lincomycin derivatives modified at the C-7 position with an aromatic moiety
Test organisma
Characheristics
TEL
NT
NT
NT
NT
NT
NT
NT
NT
NT
NT
Abbreviations: c, constitutive; i, inducible; NT, not tested; TEL, telithromycin.
Gray shading strains are target strains.
aAll strains except standard organisms were clinically isolated.
100.0
80.0
60.0
analogs possessing 4′-cis-(cyclopropylmethyl)piperidine by transfor-
mation of a C-7 substituent. Consequently, compounds 47, 68, 72, 76
and 77 (Figure 4) exhibited significantly strong activities against S.
pneumoniae and S. pyogenes with an erm gene even when compared
with those of TEL. Then, the in vitro antibacterial activities of
compounds 47, 68, 72, 76, 77 and TEL were evaluated (sensitivity
distribution analysis) against 60 clinical isolates of S. pneumoniae
containing sensitive bacteria and resistant bacteria with erm and/or mef
genes. As a result, compounds 47 and 72 showed relatively strong
activities than that of TEL. Finally, the in vivo efficacy of compound 47
and its 1′-N-Me-derivative 76 was evaluated in the rat pulmonary
infection model (subcutaneous administration) with resistant S.
pneumoniae with erm + mef genes. Compound 47 exhibited strong
and constant in vivo efficacy. Moreover, compounds 47 and 76
showed strong in vivo efficacy against resistant S. pneumoniae with a
mef gene. These two compounds are under consideration toward next
developing stage.
47
72
77
68
40.0
20.0
0.0
76
TEL
(µg ml-1)
Figure 2 In vitro antibacterial activity (sensitivity distribution) of compounds
47, 68, 72, 76, 77 and TEL against 60 clinical isolates of S. pneumoniae.
references, we also evaluated in vivo efficacy of those by subcutaneous
administration (3 mg kg− 1) to rats at 2 h after bacterial infection with
S. pneumoniae with a mef gene, because resistant strains with a mef
gene have increased in the US.60 As a result shown in Figure 3b, 47
and 76 had significantly strong in vivo efficacy as expected on the basis
of in vitro evaluation. In vivo efficacy of 76 (5 log reduction) was very
constant (0 s.d. value) compared with that of TEL. Clinical efficacy of
these novel LCM derivatives is expected from the above fundamental
experimental data.
EXPERIMENTAL PROCEDURE
General methods
1H NMR spectra were measured with a BRUKER Ascend 400 NMR spectro-
meter (BRUKER Corporation, Coventry, UK) for 400 MHz, JEOL JNM-GSX
400 NMR spectrometer (JEOL Ltd, Tokyo, Japan) for 400 MHz or a Varian
Gemini 300 NMR spectrometer (Varian Inc., Palo Alto, CA, USA) for 300 MHz
in CDCl3 or CD3OD. TMS (0 p.p.m.) in CDCl3 or CD3OD was used as an
internal reference standard. Mass spectra were obtained on a JEOL JMS-700
mass spectrometer (JEOL Ltd) or Agilent Technologies 6530-Q-TOF–LC/MS
mass spectrometer (Agilent Technologies, Santa Clara, CA, USA). The optical
rotations were recorded with Jasco P-2300 digital polarimeter (JASCO
Corporation, Tokyo, Japan). Column chromatography was performed with
silica gel (Wakogel C200, Wako Pure Chemical Industries Ltd, Osaka, Japan).
Preparative TLC was performed with silica gel (Merck, Darmstadt, Germany:
CONCLUSION
As the result of SAR studies at the 6-position of 44–47 and 49,
compound 47 possessing 4′-cis-(cyclopropylmethyl)piperidine showed
significantly strong antibacterial activities against S. pneumoniae and S.
pyogenes with an erm gene. On the basis of SAR, we synthesized novel TLC plates Silica gel 60 F254). All organic extracts were dried over anhydrous
The Journal of Antibiotics

Synthesis and SARs of novel lincomycin derivatives Part 5
Y Wakiyama et al
9
8
7
6
5
4
3
2
1
0
8
7
6
5
4
3
2
1
0
Control
47
76
TEL
Control
47
76
TEL
Figure 3 (a) In vivo efficacy of 47 and 76 in a rat pulmonary infection model with S. pneumoniae MSC06856 (erm + mef). (b) In vivo efficacy of 47 and 76
in a rat pulmonary infection model with S. pneumoniae MSC6729 (mef). Comparison of the efficacy of novel lincomycin derivatives 47 and 76 in a rat
pulmonary neutropenic infection model with S. pneumoniae MSC06856 (erm + mef) and S. pneumoniae MSC06729 (mef). Three rats per group were
rendered neutropenic and 106 CFU per rat of S. pneumoniae MSC06856 or S. pneumoniae MSC06729 was injected into the lung, followed by s.c.
administration of the test compounds at 2 h after infection. The mean log10 CFU per lung recovered from the infected lung after 24 h is shown. Error bars
represent the s.d.
N
MeN
N
N
N
S
N
N
N
O Me
O Me
O Me
O Me
O Me
S
S
S
S
S
N
HN
H
N
HN
H
N
HN
H
N
HN
H
N
HN
H
H
H
Me
H
O
O
O
O
H
O
HO
SMe
HO
SMe
HO
SMe
HO
SMe
HO
SMe
HO
OH
HO
OH
HO
OH
HO
OH
HO
OH
47
68
72
76
77
Figure 4 Structures of novel lincomycin derivatives possessing strong in vitro antibacterial activity.
MgSO4 and the solvent was removed with a rotary evaporator under reduced 0.54–0.66 (m, 2 H), 0.90–1.02 (m, 1 H), 2.54 (d, J = 7.1 Hz, 2 H), 7.11–7.24
pressure.
(m, 2 H), 8.08–8.18 (m, 2 H).
To a solution of 4-(cyclopropylmethyl)pyridine N-oxide (30.7 g) in CH2Cl2
(350 ml) were added trimethylsilanecarbonitrile (30.6 ml, 0.229 mmol) and
dimethylcarbamic chloride (7.03 ml, 76.3 mmol) at room temperature. Then,
dimethylcarbamic chloride (7.03 ml, 76.3 mmol) was added in two portions
after 20 min interval to the mixture at 20 °C. The mixture was stirred at room
temperature for 17 h. The solution was added to 10% aqueous K2CO3. The
desired compound was extracted with CH2Cl2 and then the organic phase was
dried over Na2SO4, filtrated and concentrated under reduced pressure. The
resulting residue was purified by silica gel column chromatography (hexane to
hexane/ethyl acetate= 17/3) to obtain the title compound (25.5 g, 84% in 2
steps) as a colorless oil. EI–MS m/z 158 (M)+ as C10H10N2; 1H NMR
(400 MHz, CDCl3) δ 0.22–0.28 (m, 2 H), 0.60–0.70 (m, 2 H), 0.92–1.06 (m,
1 H), 2.61 (d, J = 7.1 Hz, 2 H), 7.41–7.46 (m, 1 H), 7.64 (br dd, J = 1.7, 0.7 Hz,
1 H), 8.55–8.64 (m, 1 H).
4-(Cyclopropylmethyl)pyridine (9)
To a solution of 8 (19.0 g, 204 mmol) in THF (136 ml) at −78 °C was added
2.0 M lithium diisopropylamide in tetrahydrofuran (THF) solution (204 ml,
408 mmol) and then was stirred in argon atmosphere at −40 °C for 20 min.
The mixture was cooled to − 78 °C. Then, bromocyclopropane (16.3 ml,
204 mmol) was added with dropwise to the solution. After stirring for 1 h,
the solution was poured into saturated aqueous NH4Cl. The desired compound
was extracted with ethyl acetate, was washed with brine and then the organic
phase was dried over Na2SO4, filtrated and concentrated under reduced
pressure. The resulting residue was purified by distillation under reduced
pressure (84 °C/8 mm Hg) to obtain the title compound (13.8 g, 51%) as
colorless oil. Fast atom bombardment (FAB)–MS m/z 134 (M+H)+ as C9H11N;
1H NMR (400 MHz, CDCl3) δ 0.18–0.26 (m, 2 H), 0.54–0.62 (m, 2 H), 0.93–
1.05 (m, 1 H), 2.54 (d, J =7.1 Hz, 2 H), 7.17–7.23 (m, 2 H), 8.47–8.53
(m, 2 H).
4-(Cyclopropylmethyl)picolinic acid (11)
To a solution of 10 (25.5 g, 161 mmol) in MeOH (300 ml) was added 5 M
aqueous NaOH (250 ml) and stirred at 50 °C for 8 h. The mixture was cooled
down to 0 °C, added to 5 M aqueous HCl (250 ml) at 0 °C and then
concentrated under reduced pressure to remove MeOH. The solution was
adjusted at pH 3 by 1 M aqueous HCl, extracted with CHCl3 (500 ml)-
isopropanol (150 ml) and then the organic phase was dried over Na2SO4,
filtrated and concentrated under reduced pressure to obtain the title compound
(27.6 g, 97%) as a colorless solid. FAB–MS m/z 178 (M+H)+ as C10H11NO2; 1H
4-(Cyclopropylmethyl)picolinonitrile (10)
To a solution of 9 (25.5 g, 191 mmol) in CH2Cl2 (300 ml) at 0 °C was added
m-chloroperoxybenzoic acid (50.8 g, 191 mmol) and stirred at room tempera-
ture for 1 h. To the mixture was added Na2S2O3 solution (75 g in 150 ml of
H2O). The solution was added to mixture of saturated aqueous NaHCO3
(500 ml), saturated aqueous K2CO3 (40 ml) and CHCl3 (500 ml). The organic
phase was separated and then further extracted twice with CHCl3 (500 ml)-
isopropanol (100 ml), the organic phase was dried over Na2SO4, filtrated and NMR (400 MHz, CDCl3) δ 0.22-0.30 (m, 2 H), 0.60–0.67 (m, 2 H), 0.95–1.11
concentrated under reduced pressure to obtain 4-(cyclopropylmethyl)pyridine (m, 1 H), 2.68 (d, J = 7.1 Hz, 2 H), 7.48–7.54 (m, 1 H), 8.15-8.20 (m, 1 H),
1
N-oxide (30.7 g as crude). H NMR (400 MHz, CDCl3) δ 0.15–0.26 (m, 2 H), 8.58 (d, J = 5.1 Hz, 1 H).
The Journal of Antibiotics

Synthesis and SARs of novel lincomycin derivatives Part 5
Y Wakiyama et al
10
N-(tert-Butoxycarbonyl)-4-(cyclopropylmethyl)piperidine-2-
carboxylic acid (( )-12)
(2S, Z)-1-(2-Nitrophenylsulfonyl)-5-n-propyl-2, 3, 6, 7-tetrahydro-
1H-azepine-2-carboxylic acid (17)
To a solution of 11 (6.90 g, 38.9 mmol) in AcOH (62 ml) was added PtO2
(442 mg) and then vigorously stirred in hydrogen atmosphere at room
temperature for 24 h. The mixture was filtrated with celite and concentrated
under reduced pressure to obtain 4-(cyclopropylmethyl)piperidine-2-carboxylic
acid (5.3 g as crude). For the qualified analytical purpose, the above crude
compound was purified by reverse-phase column chromatography (0.1%
aqueous TFA/CH3CN= 90/10 to 10/90) to obtain the highly purified 4-
(cyclopropylmethyl)piperidine-2-carboxylic acid TFA salt as a colorless solid.
To a solution of 16 (72 mg, 0.19 mmol) in 1,4-dioxane (0.8 ml)-H2O (0.2 ml)
was added LiOH·H2O (23.7 mg, 0.56 mmol) and then stirred at room
temperature for 5 h. The mixture was diluted with H2O, washed with Et2O.
The aqueous phase was adjusted at pH 3 by citric acid. The desired compound
was extracted with ethyl acetate and then the organic phase was dried over
Na2SO4, filtrated and concentrated under reduced pressure to obtain the title
compound (70 mg as crude). This crude compound including a trace amount
of citric acid could not be purified. ESI–MS m/z 369 (M+H)+ as C16H20N2O6S;
1H NMR (400 MHz, CD3OD) δ 0.73 (t, J = 7.4 Hz, 3 H), 1.16–1.31 (m, 2 H),
1.73–1.82 (m, 2 H), 2.15–2.26 (m, 2 H), 2.41–2.51 (m, 1 H), 2.62–2.70 (m, 1
H), 3.42 (ddd, J = 14.5, 7.8, 5.2 Hz, 1 H), 3.72 (dt, J = 14.6, 4.7 Hz, 1 H), 4.71
(dd, J = 7.1, 3.7 Hz, 1 H), 5.37 (t, J = 6.5 Hz, 1 H), 7.56–7.71 (m, 3 H), 7.95-
8.03 (m, 1 H).
1
ESI–MS m/z 184 (M+H)+ as C10H17NO2; H NMR (400 MHz, D2O) δ −0.08
to 0.02 (m, 2 H), 0.31–0.41 (m, 2 H), 0.58–0.72 (m, 1 H), 1.10–1.43 (m, 4 H),
1.71–1.85 (m, 1 H), 1.92–2.03 (m, 1 H), 2.35–2.45 (m, 1 H), 2.91–3.03 (m, 1
H), 3.39–3.48 (m, 1 H), 3.85–3.94 (m, 1 H).
To a solution of the above disubstituted piperidine (5.3 g) in 1,4-dioxane
(100 ml) were added 2 M aqueous NaOH (74.0 ml, 148 mmol) and di-tert-butyl
dicarbonate (14.3 ml, 62.2 mmol) and then stirred at room temperature for
15 h. The mixture was concentrated under reduced pressure to remove 1,4-
dioxane. The solution was adjusted at pH 8 by1 M aqueous NaOH. Then, to the
aqueous phase was added H2O, washed with Et2O, adjusted at pH 4 by 1 M
aqueous HCl, extracted with ethyl acetate and then the organic phase was dried
over Na2SO4, filtrated and concentrated under reduced pressure to obtain the
title compound (10.5 g, 96% in 2 steps) as a racemate of cis-isomers as a
colorless solid. It was reported that hydrogenation of disubstituted pyridine in
the presence of PtO2 resulted in an approximately 1:1 mixture of two isomeric
cis-products by Birkenmeyer et al.49 1H NMR (400 MHz, CDCl3) δ −0.04 to
0.08 (m, 2 H), 0.36–0.50 (m, 2 H), 0.60–0.73 (m, 1 H), 1.12–1.32 (m, 2 H),
1.35–1.55 (m, 1 H), 1.45 (s, 9 H), 1.66–1.89 (m, 3 H), 2.02–2.15 (m, 1 H),
3.55–3.60 (m, 2 H), 4.22–4.35 (m, 1 H).
Mixture 18 of methyl 6-N-((2′S, 4′R)-1′-N-(tert-butoxycarbonyl)-4′-
(n-propyl)piperidine-2′-carbonyl)-α-thiolincosaminide and methyl
6-N-((2′R, 4′S)-1′-N-(tert-butoxycarbonyl)-4′-(n-propyl)piperidine-
2′-carbonyl)-α-thiolincosaminide
To a solution of ( )-5 (11.7 g, 43.1 mmol) in DMF (100 ml) were added 1-
hydroxybenzotriazole (7.55 g, 55.8 mmol), N,N′-dicyclohexylcarbodiimide
(10.7 g, 51.9 mmol) and MTL (14.2 g, 56.1 mmol) and stirred at room
temperature for 12 h. To the mixture was added H2O and then the solution
was filtrated, and ethyl acetate and saturated aqueous NaHCO3 were added to
the filtrate. The desired compound was extracted with ethyl acetate, extracted
with CHCl3 and then the organic phase was dried over Na2SO4, filtrated and
concentrated under reduced pressure. The resulting residue was purified by
silica gel column chromatography (hexane/ethyl acetate= 50/50 to ethyl acetate,
then ethyl acetate to ethyl acetate/ MeOH=90/10) to obtain 6-N-(N′-(tert-
butoxycarbonyl)-4′-(n-propyl)piperidine-2′-carbonyl)-α-thiolincosaminide
(18.5 g, 84.9%, (2′S, 4′R) isomer:(2′R, 4′S) isomer= ca. 50:50) as a colorless
solid. To this colorless solid was added ethyl acetate, and insoluble matter was
filtrated off and ethyl acetate solution was concentrated under reduced pressure
to obtain the mixture 18 (13.5 g, 20% de ((2′S, 4′R) : (2′R, 4′S) = 60:40)) as a
colorless solid.
2-Benzyl (2S, 4R)-N-(tert-butyl)-4-(cyclopropylmethyl)piperidine-
1,2-dicarboxylate (13) 2-Benzyl (2R, 4S)-N-(tert-butyl)-4-
(cyclopropylmethyl)piperidine-1,2-dicarboxylate (14)
To a solution of ( )-12 (113 mg, 0.399 mmol) in CH3CN (1 ml) were added
diisopropylethylamine (0.104 ml, 0.599 mmol) and benzylbromide (0.652 ml,
0.439 mmol), and then stirred at room temperature for 48 h. The solution was
added to saturated aqueous NaHCO3. The desired compound was extracted
with ethyl acetate and then the organic phase was dried over Na2SO4, filtrated
and concentrated under reduced pressure. The resulting residue was purified by
preparative TLC (hexane/ethyl acetate= 5/1) to obtain 2-benzyl N-(tert-butyl)
4-(cyclopropylmethyl)piperidine-1,2-dicarboxylate (133 mg, 89.3%) as a color-
less oil. The above colorless oil (32.0 g) was further purified by column
chromatography (Chiralpak AD-H, n-hexane/IPA = 98/2) to obtain 13 (11.1 g,
35%) and 14 (11.0 g, 34%) as a colorless solid both. These enantiomers could
be independently analyzed by the following condition: Chiralpak AD-H,
0.46 cm I.D ×25 cm, n-hexane/IPA = 98/2, 1.0 ml min− 1, 40 ºC, 208 nm. 13:
Mixture 19 of methyl 6-N-((2′S, 4′R)-1′-N-(tert-butoxycarbonyl)-4′-
(n-butyl)piperidine-2′-carbonyl)-α-thiolincosaminide and methyl 6-
N-((2′R, 4′S)-1′-N-(tert-butoxycarbonyl)-4′-(n-butyl)piperidine-2′-
carbonyl)-α-thiolincosaminide
Compound
( )-6 (12.6 g, 44.2 mmol), 1-hydroxybenzotriazole (7.77 g,
57.5 mmol), N,N′-dicyclohexylcarbodiimide (11.0 g, 53.3 mmol) and MTL
(14.6 g, 57.5 mmol) in DMF (120 ml) were treated for 20 h according to the
similar procedure as described for the preparation of mixture 18 to afford 6-N-
(1′-N-(tert-butoxycarbonyl)-4′-(n-butyl)piperidine-2′-carbonyl)-α-thiolincosa-
minide (20.0 g, 87%, (2′S, 4′R) isomer:(2′R, 4′S) isomer= ca. 50:50) as a
colorless solid. To this colorless solid (14.53 g) was added ethyl acetate, and
insoluble matter was filtrated off and ethyl acetate solution was concentrated
under reduced pressure to obtain the mixture 19 (8.15 g, 80% de ((2′S, 4′R) :
(2′R, 4′S) =90:10)) as a colorless solid.
[α]D − 24.8° (c 0.65, CHCl3); ESI–MS m/z 374 (M+H)+ as C22H31NO4; 1H
27
NMR (400 MHz, CDCl3) δ −0.12 to −0.02 (m, 2 H), 0.32–0.44 (m, 2 H), 0.52–
0.66 (m, 1 H), 0.99–1.18 (m, 2 H), 1.30–1.50 (m, 1 H), 1.41 (s, 9 H), 1.69–1.88
(m, 3 H), 2.04 (ddd, J = 13.5, 6.5, 4.6 Hz, 1 H), 3.08–3.70 (m, 2 H), 4.38 (t,
26
J = 6.3 Hz, 1 H), 5.08–5.23 (m, 2 H), 7.27–7.42 (m, 5 H). 14: [α]D +24.2° (c
1.03, CHCl3); ESI–MS m/z 374 (M+H)+ as C22H31NO4. Compound 14 showed
Mixture 20 of methyl 6-N-((2′S, 4′R)-1′-N-(tert-butoxycarbonyl)-4′-
(i-butyl)piperidine-2′-carbonyl)-α-thiolincosaminide and methyl 6-
N-((2′R, 4′S)-1′-N-(tert-butoxycarbonyl)-4′-(i-butyl)piperidine-2′-
carbonyl)-α-thiolincosaminide
To a solution of ( )-7 (6.00 g, 21.0 mmol) in DMF (57 ml) were added 1-
hydroxybenzotriazole (2.84 g, 21.0 mmol), N,N′-dicyclohexylcarbodiimide
(5.20 g, 25.2 mmol) and MTL (5.40 g, 21.3 mmol), and stirred at room
temperature for 6 h. To the mixture were added H2O and ethyl acetate, and
then the mixture was filtrated. The desired compound was extracted with ethyl
acetate, washed with saturated aqueous KHCO3 and then the organic phase was
dried over MgSO4, filtrated and concentrated under reduced pressure. To the
resulting residue was added ethyl acetate, and insoluble matter was filtrated off
and ethyl acetate solution was concentrated under reduced pressure. To the
1
the exactly same H NMR spectrum with that of 13.
(2S, 4R)- N-(tert-Butoxycarbonyl)-4-(cyclopropylmethyl)piperidine-
2-carboxylic acid (15)
To a solution of 13 (1.51 g, 4.04 mmol) in MeOH (45 ml) was added Pd/C
(0.166 g) and then vigorously stirred in hydrogen atmosphere at room
temperature for 1 h. The mixture was filtrated with celite and concentrated
under reduced pressure to obtain the title compound (1.15 g, quant) as a
colorless solid. [α]D − 16.3° (c 0.40, MeOH); ESI–MS m/z 284 (M+H)+ as
27
C15H25NO4; time-of-flight (TOF)–ESI–HR-MS (M− H)− calcd for
C15H25NO4: 282.1705, found: 282.1718 ; Compound 15 showed the exactly
1
same H NMR spectrum with that of ( )-12.
The Journal of Antibiotics

Synthesis and SARs of novel lincomycin derivatives Part 5
Y Wakiyama et al
11
resulting residue was added toluene, and insoluble matter was filtrated off and Methyl 6-N-((2′S, 4′R)-1′-N-(tert-butoxycarbonyl)-4′-(i-butyl)
toluene solution was concentrated under reduced pressure to obtain the
mixture 20 (5.7 g, 90% de ((2′S, 4′R) : (2′R, 4′S) = 95:5)) as a colorless solid.
piperidine-2′-carbonyl)-2,3,4-tris-O-(trimethylsilyl)-α-
thiolincosaminide (24)
Mixture 20 (5.70 g, 10.9 mmol, 90% de ((2′S, 4′R) : (2′R, 4′S) = 95:5),
trimethylchlorosilane (13.2 ml, 103.6 mmol) and hexamethyldisilazane
(21.7 ml, 104 mmol) in pyridine (21 ml) were treated for 1 h according to
the similar procedure as described for the preparation of 22, and then the crude
compound and 6 N acetic acid (2.4 ml) in MeOH (61 ml) were treated for 6 h
according to the similar procedure as described for the preparation of 22 to
afford 24 (7.25 g, 90% (95% based on (2′S, 4′R) isomer) in 2 steps from
mixture 20) as a colorless solid. ESI–MS m/z 737 (M+H)+ as C33H68N2O8SSi3;
1H NMR (400 MHz, CD3OD) δ 0.14 (s, 9 H), 0.16 (s, 9 H), 0.20 (s, 9 H), 0.88
(d, J = 6.5 Hz, 6 H), 1.08–1.33 (m, 3 H), 1.17 (d, J = 6.4 Hz, 3 H), 1.46 (s, 9 H),
1.53–1.73 (m, 3 H), 1.77–1.88 (m, 1 H), 1.92–2.01 (m, 1 H), 2.05 (s, 3 H),
3.44–3.58 (m, 2 H), 3.74 (dd, J = 9.6, 2.6 Hz, 1 H), 3.78–3.88 (m, 1 H), 4.05–
4.17 (m, 3 H), 4.23–4.32 (m, 2 H), 5.17 (d, J = 5.4 Hz, 1 H).
Mixture 21 of methyl 6-N-((2′S, 4′R)-1′-N-(tert-butoxycarbonyl)-4′-
(cyclopropylmethyl)piperidine-2′-carbonyl)-α-thiolincosaminide
and methyl 6-N-((2′R, 4′S)-1′-N-(tert-butoxycarbonyl)-4′-
(cyclopropylmethyl)piperidine-2′-carbonyl)-α-thiolincosaminide
Compound ( )-12 (44.2 g, 156 mmol), 1-hydroxybenzotriazole monohydrate
(28.6 g, 187 mmol), N,N′-dicyclohexylcarbodiimide (35.8 g, 174 mmol) and
MTL (47.4 g, 187 mmol) in DMF (300 ml) were treated for 13 h. To the
mixture were added ethyl acetate and acetone, and then the solution was
filtrated and concentrated under reduced pressure. To the resulting residue
were added ethyl acetate, and the organic layer was washed with saturated
aqueous NaHCO3 and saturated aqueous NaCl, and then filtrated and
concentrated under reduced pressure. To the resulting residue was added ethyl
acetate, and insoluble matter was filtrated off and ethyl acetate solution was
concentrated under reduced pressure. To the resulting residue was added
toluene, and insoluble matter was filtrated off and toluene solution was
concentrated under reduced pressure to obtain the mixture 21 (36 g, 80% de
((2′S, 4′R) : (2′R, 4′S) = 90:10)) as a colorless solid. FAB–MS m/z 519 (M+H)+
as C24H42N2O8S.
Methyl 6-N-((2′S, 4′R)-1′-N-(tert-butoxycarbonyl)-4′-
(cyclopropylmethyl)piperidine-2′-carbonyl)-2,3,4-tris-O-
(trimethylsilyl)-α-thiolincosaminide (25)
Mixture 21 (35.0 g, 67.5 mmol, 80% de ((2′S, 4′R) : (2′R, 4′S) = 90:10),
trimethylchlorosilane (43.1 ml, 337 mmol) and hexamethyldisilazane
(70.6 ml, 337 mmol) in pyridine (130 ml) were treated for 1 h according to
the similar procedure as described for the preparation of 22, and then the crude
compound and 6 N acetic acid (16.9 ml) in MeOH (350 ml) were treated for
140 min according to the similar procedure as described for the preparation of
22 to afford 25 (30.6 g, 62% (69% based on (2′S, 4′R) isomer) in 2 steps from
mixture 21) as a colorless solid. FAB–MS m/z 735 (M+H)+ as C33H66N2O8SSi3;
1H NMR (400 MHz, CD3OD) δ −0.04 to 0.04 (m, 2 H), 0.13 (s, 9 H), 0.16 (s, 9
H), 0.20 (s, 9 H), 0.40–0.49 (m, 2 H), 0.65–0.78 (m, 1 H), 1.17 (d, J = 6.2 Hz, 3
H), 1.17–1.35 (m, 2 H), 1.34–1.47 (m, 1 H), 1.47 (s, 9 H), 1.64–1.91 (m, 3 H),
1.98–2.10 (m, 1 H), 2.05 (s, 3 H), 3.40–3.66 (m, 2 H), 3.75 (dd, J = 9.7, 2.6 Hz,
1 H), 3.76–3.85 (m, 1 H), 4.12 (dd, J = 9.7, 5.4 Hz, 1 H), 4.13–4.19 (m, 1 H),
4.20–4.35 (m, 3 H), 5.18 (d, J = 5.4 Hz, 1 H).
Methyl 6-N-((2′S, 4′R)-1′-N-(tert-butoxycarbonyl)-4′-(n-propyl)
piperidine-2′-carbonyl)-2,3,4-tris-O-(trimethylsilyl)-α-
thiolincosaminide (22)
To a solution of mixture 18 (13.5 g, 26.6 mmol, 20% de ((2′S, 4′R) : (2′R, 4′
S) = 60:40)) in pyridine (50 ml) were added trimethylchlorosilane (17.0 ml,
133 mmol) and hexamethyldisilazane (27.9 ml, 133 mmol), and stirred at room
temperature for 40 min, then the solution was added to saturated aqueous
NaHCO3. The desired compound was extracted with ethyl acetate, washed with
saturated aqueous NaCl and then the organic phase was dried over Na2SO4,
filtrated and concentrated under reduced pressure. To the resulting residue
were added methanol (138 ml) and 6 N acetic acid (5.8 ml), and stirred at room
temperature for 2.5 h. The mixture was added to saturated aqueous NaHCO3
and concentrated under reduced pressure to remove MeOH. The desired
compound was extracted with ethyl acetate, and then the organic phase was
dried over Na2SO4, filtrated and concentrated under reduced pressure. The
resulting residue was purified by silica gel column chromatography (hexane/
ethyl acetate= 19/1 to 3/1) to obtain the title compound (9.28 g, 48% (80%
based on (2′S, 4′R) isomer) in 2 steps from mixture 18) as a colorless solid.
ESI–MS m/z 723 (M+H)+ as C32H66N2O8SSi3; 1H NMR (400 MHz, CD3OD) δ
0.14 (s, 9 H), 0.16 (s, 9 H), 0.20 (s, 9 H), 0.90 (t, J = 7.0 Hz, 3 H), 1.16 (d,
J = 6.2 Hz, 3 H), 1.22-1.39 (m, 4 H), 1.40–1.49 (m, 1 H), 1.46 (s, 9 H), 1.52–
1.74 (m, 2 H), 1.75–1.87 (m, 1 H), 1.90–2.01 (m, 1 H), 2.04 (s, 3 H), 3.41–3.61
(m, 2 H), 3.75 (dd, J = 9.6, 2.5 Hz, 1 H), 3.78–3.87 (m, 1 H), 4.07–4.20 (m, 3
H), 4.23–4.32 (m, 2 H), 5.17 (d, J =5.4 Hz, 1 H).
Methyl (7S)-7-acetylthio-6-N-((2′S, 4′R)-1′-N-(tert-
butoxycarbonyl)-4′-(n-propyl)piperidine-2′-carbonyl)-7-deoxy-
2,3,4-tris-O-(trimethylsilyl)-α-thiolincosaminide (26)
To a solution of 22 (500 mg, 0.69 mmol) in CH2Cl2 (2 ml) at 0 °C were added
Et3N (291 μl, 2.08 mmol) and methanesulfonyl chloride (107 μl, 1.38 mmol),
and stirred at room temperature for 1 h. The mixture was added to saturated
aqueous NaHCO3, extracted with ethyl acetate, dried over Na2SO4 and
concentrated under reduced pressure to obtain methyl 6-N-((2′S, 4′R)-1′-N-
(tert-butoxycarbonyl)-4′-(n-propyl)piperidine-2′-carbonyl)-7-O-methanesulfo-
nyl-2,3,4-tris-O-(trimethylsilyl)-α-thiolincosaminide as
a crude compound
(530 mg). To a solution of this crude compound (530 mg) in DMF (3.0 ml)
was added AcSK (396 mg, 3.47 mmol) and stirred at 80 °C for 2 h. The mixture
was added to saturated aqueous NaHCO3, then extracted with ethyl acetate,
washed with 10% aqueous NaCl, dried over Na2SO4, filtrated and concentrated
under reduced pressure. The resulting residue was purified by silica gel column
chromatography (hexane to hexane/ethyl acetate= 85/15) to obtain the title
compound (357 mg, 66% in 2 steps from 22) as a colorless solid. FAB–MS m/z
781 (M+H)+ as C34H68N2O8S2Si3; 1H NMR (400 MHz, CDCl3) δ 0.126 (s, 9
H), 0.13 (s, 9 H), 0.18 (s, 9 H), 0.88 (t, J =6.9 Hz, 3 H), 1.10–1.21 (m, 1 H),
1.23–1.38 (m, 4 H), 1.35 (d, J = 6.8 Hz, 3 H), 1.42–1.60 (m, 2 H), 1.49 (s, 9 H),
1.80–1.94 (m, 1 H), 1.95–2.08 (m, 1 H), 1.99 (s, 3 H), 2.29 (s, 3 H), 3.00–3.18
(m, 1 H), 3.57 (dd, J = 9.5, 2.2 Hz, 1 H), 3.63-3.83 (m, 2 H), 3.87–4.04 (m, 2
H), 4.13 (dd, J = 9.5, 5.6 Hz, 1 H), 4.22–4.33 (m, 1 H), 4.50–4.62 (m, 1 H),
5.15 (d, J = 5.6 Hz, 1 H), 6.04–6.37 (m, 1 H).
Methyl 6-N-((2′S, 4′R)-1′-N-(tert-butoxycarbonyl)-4′-(n-butyl)
piperidine-2′-carbonyl)-2,3,4-tris-O-(trimethylsilyl)-α-
thiolincosaminide (23)
Mixture 19 (8.15g, 15.7 mmol, 80% de ((2′S, 4′R) : (2′R, 4′S) = 90:10),
trimethylchlorosilane (100 ml, 78.3 mmol) and hexamethyldisilazane
(16.4 ml, 78.3 mmol) in pyridine (30 ml) were treated for 20 min according
to the similar procedure as described for the preparation of 22, and then the
crude compound and 6 N acetic acid (3.4 ml) in MeOH (88 ml) were treated
for 40 min according to the similar procedure as described for the preparation
of 22 to afford 23 (8.20 g, 71% (79% based on (2′S, 4′R) isomer) in 2 steps
from mixture 19) as
a
colorless solid. ESI–MS m/z 737 (M+H)+ as
C33H68N2O8SSi3; 1H NMR (400 MHz, CDCl3) δ 0.14 (s, 18 H), 0.19 (s, 9
H), 0.82-0.93 (m, 3 H), 1.16 (d, J = 6.6 Hz, 3 H), 1.18–1.36 (m, 7 H), 1.38–1.55
(m, 2 H), 1.46 (s, 9 H), 1.77–1.89 (m, 1 H), 2.00–2.10 (m, 1 H), 2.06 (s, 3 H),
2.90–3.03 (m, 1 H), 3.30–3.54 (m, 2 H), 3.60 (dd, J = 9.6, 2.6 Hz, 1 H), 3.85–
3.92 (m, 1 H), 3.94–4.07 (m, 2 H), 4.07–4.17 (m, 1 H), 4.26–4.40 (m, 1 H), Compound 23 (1.01 g, 1.37 mmol), Et3N (490 μl, 3.48 mmol) and methane-
5.17 (d, J = 5.4 Hz, 1 H), 6.32 (br d, J = 9.0 Hz, 1 H). sulfonyl chloride (220 μl, 2.79 mmol) in CH2Cl2 (20 ml) at 0 °C were treated
Methyl (7S)-7-acetylthio-6-N-((2′S, 4′R)-1′-N-(tert-
butoxycarbonyl)-4′-(n-butyl)piperidine-2′-carbonyl)-7-deoxy-2,3,4-
tris-O-(trimethylsilyl)-α-thiolincosaminide (27)
The Journal of Antibiotics

Synthesis and SARs of novel lincomycin derivatives Part 5
Y Wakiyama et al
12
for 1 h according to the similar procedure as described for the preparation of Methyl (7S)-6-N-((2′S, 4′R)-1′-N-(tert-butoxycarbonyl)-4′-(n-butyl)
26, and then a crude mesylate (1.17 g) and AcSK (992 mg, 8.68 mmol) in DMF
piperidine-2′-carbonyl)-7-deoxy-7-mercapto-α-thiolincosaminide
(13 ml) at 80 °C were treated for 3 h according to the similar procedure as
(31)
described for the preparation of 26 to afford 27 (565 mg, 52% in 2 steps from
23) as a colorless solid. FAB–MS m/z 795 (M+H)+ as C35H70N2O8S2Si3; 1H
NMR (400 MHz, CDCl3) δ 0.11 (s, 9 H), 0.12 (s, 9 H), 0.17 (s, 9 H), 0.78–0.95
(m, 3 H), 1.07–1.32 (m, 7 H), 1.34 (d, J = 6.9 Hz, 3 H), 1.38–1.60 (m, 2 H),
1.48 (s, 9 H), 1.78–1.95 (m, 1 H), 1.95–2.11 (m, 1 H), 1.97 (s, 3 H), 2.27 (s, 3
H), 3.00–3.18 (m, 1 H), 3.54 (dd, J = 9.6, 2.2 Hz, 1 H), 3.62–3.85 (m, 2 H),
3.85–4.05 (m, 2 H), 4.06–4.16 (m, 1 H), 4.21-4.31 (m, 1 H), 4.50–4.62 (m, 1
H), 5.14 (d, J = 5.5 Hz, 1 H), 6.05–6.48 (m, 1 H).
To a solution of 27 (565 mg, 0.711 mmol) in MeOH (5.6 ml) was added 1 N
HCl (5.6 ml) and stirred at room temperature for 100 min. The mixture was
added to 8% aqueous NaHCO3, extracted with ethyl acetate, washed with 25%
aqueous NaCl, dried over Na2SO4 and concentrated under reduced pressure.
The resulting residue was purified by silica gel column chromatography
(CHCl3/MeOH = 30/1) to obtain methyl (7S)-7-acetylthio-6-N-((2′S, 4′R)-1′-
N-(tert-butoxycarbonyl)-4′-(n-butyl)piperidine-2′-carbonyl)-7-deoxy-α-thiolin-
cosaminide (378 mg, 91.8%) as a colorless solid. To a solution of this
intermediate (378 mg, 0.652 mmol) in MeOH (4 ml) was added NaOMe
(115 mg, 2.02 mmol) and stirred at room temperature for 3 h. The mixture was
added to 8% aqueous NaHCO3, extracted with ethyl acetate, washed with 25%
aqueous NaCl, dried over Na2SO4 and concentrated under reduced pressure.
The resulting residue was purified by silica gel column chromatography
(CHCl3/MeOH = 40/1) to obtain the title compound (373 mg, quant) as a
colorless solid. ESI–MS m/z 537 (M+H)+ as C24H44N2O7S2; 1H NMR
(400 MHz, CD3OD) δ 0.87–0.95 (m, 3 H), 1.23-1.40 (m, 7 H), 1.30 (br d,
J = 7.2 Hz, 3 H), 1.46 (s, 9 H), 1.50–1.65 (m, 2 H), 1.77–1.89 (m, 1 H), 1.96–
2.06 (m, 1 H), 2.15 (s, 3 H), 3.42–3.60 (m, 2 H), 3.45 (dq, J =7.1, 2.3 Hz, 1 H),
3.54 (dd, J = 10.3, 3.4 Hz, 1 H), 3.94–4.00 (m, 1 H), 4.06 (dd, J = 10.1, 5.6 Hz, 1
Methyl (7S)-7-acetylthio-6-N-((2′S, 4′R)-1′-N-(tert-
butoxycarbonyl)-4′-(i-butyl)piperidine-2′-carbonyl)-7-deoxy-2,3,4-
tris-O-(trimethylsilyl)-α-thiolincosaminide (28)
Compound 24 (1.01 g, 1.37 mmol), Et3N (930 μl, 6.85 mmol) and methane-
sulfonyl chloride (210 μl, 2.74 mmol) in CH2Cl2 (20 ml) at 0 °C were treated
for 1 h according to the similar procedure as described for the preparation of
26, and then the crude mesylate (1.17 g) and AcSK (470 mg, 4.11 mmol) in
DMF (6 ml) at 80 °C were treated for 3 h according to the similar procedure as
described for the preparation of 26 to afford 28 (598 mg, 55% in 2 steps from
24) as a colorless solid.
H), 4.10–4.26 (m,
2 H), 4.32 (dd, J =9.8, 2.3 Hz, 1 H), 5.24 (d,
J = 5.6 Hz, 1 H).
Methyl (7S)-7-acetylthio-6-N-((2′S, 4′R)-1′-N-(tert-
butoxycarbonyl)-4′-(cyclopropylmethyl)piperidine-2′-carbonyl)-7-
deoxy-2,3,4-tris-O-(trimethylsilyl)-α-thiolincosaminide (29)
Compound 25 (7.40 g, 10.1 mmol), Et3N (4.24 ml, 30.3 mmol) and methane-
sulfonyl chloride (1.56 ml, 20.2 mmol) in CHCl3 (70 ml) at 0 °C were treated
and then the solution was stirred at room temperature for 1 h according to the
similar procedure as described for the preparation of 26 and then, the crude
mesylate and AcSK (5.76 g, 50.5 mmol) in DMF (75 ml) at 80 °C were treated
for 1.5 h according to the similar procedure as described for the preparation of
26 to afford 29 (4.30 g, 54% in 2 steps from 25) as a colorless solid. ESI–MS m/
Methyl (7S)-6-N-((2′S, 4′R)-1′-N-(tert-butoxycarbonyl)-4′-(i-butyl)
piperidine-2′-carbonyl)-7-deoxy-7-mercapto-α-thiolincosaminide
(32)
To a solution of 28 (565 mg, 0.711 mmol) in MeOH (5.6 ml) was added 5 N
HCl (0.3 ml) and stirred at room temperature for 30 min. The mixture was
added to 8% aqueous NaHCO3, extracted with ethyl acetate, washed with 25%
aqueous NaCl, dried over Na2SO4 and concentrated under reduced pressure to
obtain methyl (7S)-7-acetylthio-6-N-((2′S, 4′R)-1′-N-(tert-butoxycarbonyl)-4′-
(i-butyl)piperidine-2′-carbonyl)-7-deoxy-α-thiolincosaminide (410 mg) as
a
1
z 793 (M+H)+ as C35H68N2O8S2Si3; H NMR (400 MHz, CDCl3) δ − 0.05 to
crude compound. Then, the crude compound (410 mg) in MeOH (13 ml)
was added and 5 N NaOMe (430 μl, 2.15 mmol) in MeOH at room temperature
were treated for 1 h according to the similar procedure as described for the
preparation of 31 to afford 32 (362 mg, 88% in 2 steps from 28) as a colorless
solid. ESI–MS m/z 537 (M+H)+ as C24H44N2O7S2; 1H NMR (400 MHz,
CD3OD) δ 0.89 (d, J = 2.8 Hz, 3 H), 0.90 (d, J = 2.9 Hz, 3 H), 1.12–1.27 (m, 3
H), 1.30 (d, J = 7.1 Hz, 3 H), 1.46 (s, 9 H), 1.49–1.60 (m, 1 H), 1.60–1.74 (m, 2
H), 1.75–1.88 (m, 1 H), 1.95–2.04 (m, 1 H), 2.15 (s, 3 H), 3.40–3.59 (m, 2 H),
3.45 (dq, J = 7.1, 2.3 Hz, 1 H), 3.54 (dd, J = 10.2, 3.4 Hz, 1 H), 3.93–4.02 (m, 1
H), 4.06 (dd, J = 10.2, 5.6 Hz, 1 H), 4.11–4.26 (m, 2 H), 4.32 (dd, J = 9.8,
2.3 Hz, 1 H), 5.25 (d, J =5.6 Hz, 1 H).
0.03 (m, 2 H), 0.125 (s, 9 H), 0.131 (s, 9 H), 0.18 (s, 9 H), 0.38–0.45 (m, 2 H),
0.60-0.73 (m, 1 H), 1.17–1.29 (m, 3 H), 1.35 (d, J = 6.8 Hz, 3 H), 1.50 (s, 9 H),
1.59–1.72 (m, 2 H), 1.86–1.97 (m, 1 H), 2.00 (s, 3 H), 2.06–2.14 (m, 1 H), 2.29
(s, 3 H), 3.03–3.18 (m, 1 H), 3.58 (dd, J = 9.6, 2.3 Hz, 1 H), 3.67–3.84 (m, 2
H), 3.88–4.02 (m, 2 H), 4.12 (dd, J = 9.5, 5.4 Hz, 1 H), 4.30–4.38 (m, 1 H),
4.52–4.60 (m, 1 H), 5.16 (d, J = 5.4 Hz, 1 H), 6.10–6.45 (m, 1 H).
Methyl (7S)-6-N-((2′S, 4′R)-1′-N-(tert-butoxycarbonyl)-4′-(n-
propyl)piperidine-2′-carbonyl)-7-deoxy-7-mercapto-α-
thiolincosaminide (30)
To a solution of 26 (341 mg, 0.436 mmol) in MeOH (4 ml) was added 1 N HCl
(2.5 ml) and stirred at room temperature for 5 min. The mixture was added to
saturated aqueous NaHCO3, concentrated under reduced pressure to remove
MeOH until half volume, extracted with ethyl acetate, dried over Na2SO4 and
concentrated under reduced pressure to obtain methyl (7S)-7-acetylthio-6-N-
((2′S, 4′R)-1′-N-(tert-butoxycarbonyl)-4′-(n-propyl)piperidine-2′-carbonyl)-7-
deoxy-α-thiolincosaminide (246.5 mg, quant) as a colorless solid. To a solution
of this intermediate (244 mg, 0.432 mmol) in MeOH (2.5 ml) was added 28%
NaOMe/MeOH solution (251 μl, 1.30 mmol), stirred at room temperature for
20 min. The mixture was added to a saturated aqueous NH4Cl, extracted with
ethyl acetate, washed with saturated aqueous NaHCO3, dried over Na2SO4 and
concentrated under reduced pressure. The resulting residue was purified by
silica gel column chromatography (hexane to hexane/ethyl acetate= 96/4) to
obtain the title compound (234 mg, 96%) as a colorless solid. ESI–MS m/z 523
(M+H)+ as C23H42N2O7S2; 1H NMR (400 MHz, CD3OD) δ 0.92 (t, J = 7.0 Hz,
3 H), 1.24–1.41 (m, 5 H), 1.30 (d, J = 7.0 Hz, 3 H), 1.46 (s, 9 H), 1.52–1.64 (m,
2 H), 1.77–1.90 (m, 1 H), 1.94–2.06 (m, 1 H), 2.15 (s, 3 H), 3.40–3.64 (m, 2
H), 3.46 (dq, J =7.0, 2.4 Hz, 1 H), 3.54 (dd, J = 10.3, 3.4 Hz, 1 H), 3.94–4.01
(m, 1 H), 4.06 (dd, J =10.3, 5.6 Hz, 1 H), 4.18–4.26 (m, 2 H), 4.32 (dd, J = 9.8,
2.4 Hz, 1 H), 5.25 (d, J = 5.6 Hz, 1 H).
Methyl (7S)-6-N-((2′S, 4′R)-1′-N-(tert-butoxycarbonyl)-4′-
(cyclopropylmethyl)piperidine-2′-carbonyl)-7-deoxy-7-mercapto-α-
thiolincosaminide (33)
To a solution of 29 (5.20 g, 6.55 mmol) in MeOH (70 ml) was added 1 N HCl
(26.2 ml) and stirred at room temperature for 5 min. The mixture was added to
10% aqueous NaHCO3 and then concentrated under reduced pressure until
half volume to remove MeOH, extracted with ethyl acetate, washed with 25%
aqueous NaCl, dried over Na2SO4 and concentrated under reduced pressure to
obtain methyl (7S)-7-acetylthio-6-N-((2′S, 4′R)-1′-N-(tert-butoxycarbonyl)-4′-
(cyclopropylmethyl)piperidine-2′-carbonyl)-7-deoxy-α-thiolincosaminide
(4.70 g) as a crude compound. Then, the crude compound (4.70 g) and 28%
NaOMe/MeOH solution (3.79 ml, 1.06 mmol) in MeOH (38 ml) at room
temperature were treated for 15 min according to the similar procedure as
described for the preparation of 30 to afford 33 (3.45 g, 99% in 2 steps from
29) as a colorless solid. FAB–MS m/z 535 (M+H)+ as C24H42N2O7S2; 1H NMR
(400 MHz, CD3OD) δ 0.01–0.06 (m, 2 H), 0.39–0.49 (m, 2 H), 0.63–0.78 (m, 1
H), 1.16–1.28 (m, 2 H), 1.30 (d, J = 7.1 Hz, 3 H), 1.34–1.43 (m, 1 H), 1.47 (s, 9
H), 1.55–1.76 (m, 2 H), 1.82–1.93 (m, 1 H), 2.05–2.14 (m, 1 H), 2.15 (s, 3 H),
3.40–3.66 (m, 2 H), 3.45 (dq, J = 7.1, 2.4 Hz, 1 H), 3.54 (dd, J = 10.3, 3.4 Hz, 1
The Journal of Antibiotics

Synthesis and SARs of novel lincomycin derivatives Part 5
Y Wakiyama et al
13
H), 3.94–4.01 (m, 1 H), 4.06 (dd, J =10.3, 5.6 Hz, 1 H), 4.13–4.25 (m, 2 H), Methyl 6-N-((2′S)-1′-N-(tert-butoxycarbonyl)-5′-n-propylazepane-
4.32 (dd, J = 9.7, 2.4 Hz, 1 H), 5.25 (d, J =5.6 Hz, 1 H).
2-carbonyl)-2,3,4-tris-O-(trimethylsilyl)-α-thiolincosaminide (37)
(stereochemistry at the C-5′ position is not assigned)
Methyl 6-N-((2′S, Z)-1′-N-(2′′-nitrophenylsulfonyl)-5′-n-propyl-
Compound 36 (894.0 mg, 1.72 mmol), trimethylchlorosilane (1.09 ml,
2′,3′,6′,7′-tetrahydro-1H-azepine-2′-carbonyl)-α-thiolincosaminide
(34)
8.59 mmol) and hexamethyldisilazane (1.80 ml, 8.59 mmol) in pyridine
(10 ml) were treated for 30 min according to the similar procedure as described
for the preparation of 22, and then the crude fully protected intermediate and
2 N acetic acid (2.23 ml) in MeOH (36 ml) were stirred at room temperature
for 1 h. The mixture was added to saturated aqueous NaHCO3, extracted with
ethyl acetate and then the organic phase was dried over Na2SO4, filtrated and
concentrated under reduced pressure to afford 37 as a crude compound.
To a solution of 17 (481.5 mg, 1.31 mmol) in DMF (5 ml) were added 1-
hydroxybenzotriazole (265.0 mg, 1.96 mmol), 1-ethyl-3-(3-dimethylaminopro-
pyl)carbodiimide hydrochloride (375.8 mg, 1.96 mmol) and MTL (496.8 mg,
1.96 mmol), and stirred at room temperature for 14 h. To the mixture were
added ethyl acetate and saturated aqueous NaHCO3. The desired compound
was extracted with ethyl acetate, washed with H2O and then the organic phase
was dried over Na2SO4, filtrated and concentrated under reduced pressure. The
resulting residue was purified by silica gel column chromatography (CHCl3/
MeOH = 50/1 to 30/1) to obtain the title compound (660 mg, 84%) as a
colorless solid. FAB–MS m/z 604 (M+H)+ as C25H37N3O10S2; 1H NMR
(400 MHz, CD3OD) δ 0.83 (t, J = 7.3 Hz, 3 H), 1.15 (d, J = 6.3 Hz, 3 H),
1.25–1.37 (m, 2 H), 1.08 (br t, J =7.4 Hz, 2 H), 2.05 (s, 3 H), 2.23–2.56 (m, 3
H), 2.68–2.80 (m, 1 H), 3.58 (dd, J =10.2, 3.4 Hz, 1 H), 3.73–3.88 (m, 3 H),
4.02–4.12 (m, 3 H), 4.36–4.41 (m, 1 H), 4.74 (dd, J = 8.0, 3.7 Hz, 1 H), 5.22 (d,
J = 5.6 Hz, 1 H), 5.39 (br t, J =6.3 Hz, 1 H), 7.74–7.86 (m, 3 H), 8.09–8.17
(m, 1 H).
Methyl (7S)-7-acetylthio-6-N-((2′S)-1′-N-(tert-butoxycarbonyl)-5′-
n-propylazepane-2-carbonyl)-7-deoxy-2,3,4-tris-O-(trimethylsilyl)-
α-thiolincosaminide (38) (stereochemistry at the C-5′ position is
not assigned)
Crude 37, Et3N (1.20 ml, 8.58 mmol) and methanesulfonyl chloride (0.53 ml,
6.9 mmol) in CHCl3 (20 ml) were treated at room temperature for 1 h
according to the similar procedure as described for the preparation of 26,
and then the crude mesylate and AcSK (1.19 g, 10.4 mmol) in DMF (9.8 ml) at
80 °C were treated for 2 h according to the similar procedure as described for
the preparation of 26 to afford 38 (768.6 mg, 56% in 4 steps from 36) as a
colorless solid. FAB–MS m/z 795 (M+H)+ as C35H70N2O8S2Si3.
Methyl 6-N-((2′S)-5′-n-propylazepane-2′-carbonyl)-α-
thiolincosaminide (35) (stereochemistry at the C-5′ position is not
assigned)
Methyl 6-N-((2′S)-1′-N-(tert-butoxycarbonyl)-5′-n-propylazepane-
2-carbonyl)-(7S)-7-mercapto-α-thiolincosaminide (39)
(stereochemistry at the C-5′ position is not assigned)
To a solution of 34 (1.15 g, 1.90 mmol) in DMF (10 ml) at 0 °C were added 4-
bromobenzenethiol (721 mg, 3.81 mmol) and cesium carbonate (1.25 g,
3.84 mmol), and then stirred at room temperature for 2 h. The mixture was
concentrated under reduced pressure. The resulting residue was purified by
silica gel column chromatography (hexane to hexane/ethyl acetate= 50/50, then
CHCl3/CH3OH/28% aq NH4OH= 20/1/0.1) to obtain methyl 6-N-((2′S, Z)-
5′-n-propyl-2′,3′,6′,7′-tetrahydro-1H-azepine-2′-carbonyl)-α-thiolincosaminide
(649.1 mg, 81.4%) as a colorless solid. To this intermediate (649.1 mg,
1.55 mmol) in MeOH (30 ml) was added Pd/C (324 mg) and then vigorously
stirred in hydrogen atmosphere of 0.95 MPa at 40 °C for 3.5 h. The mixture
was filtrated off with celite and the mother liquor was concentrated under
reduced pressure. To the resulting residue were added Pd/C (324 mg) and
MeOH (30 ml), and then the mixture was vigorously stirred in hydrogen
atmosphere of 0.95 MPa at 40 °C for 65 h. The mixture was filtrated with celite
and concentrated under reduced pressure to obtain the title compound
(560 mg, 86%) as a colorless solid. FAB–MS m/z 421 (M+H)+ as C19H36N2O6S;
TOF–ESI–HR-MS (M+H)+ calcd for C19H36N2O6S: 421.2372, found: 421.2370;
1H NMR (400 MHz, CD3OD) δ 0.90 (t, J = 7.2 Hz, 3 H), 1.18 (d, J = 6.6 Hz, 3
H), 1.20–1.48 (m, 7 H), 1.59–1.71 (m, 1 H), 1.77–1.88 (m, 1 H), 1.93–2.04 (m,
2 H), 2.08 (s, 3 H), 2.73–2.84 (m, 1 H), 3.03 (ddd, J = 13.8, 5.5, 2.1 Hz, 1 H),
3.53–3.62 (m, 2 H), 3.94–4.05 (m, 2 H), 4.10 (dd, J = 10.2, 5.6 Hz, 1 H), 4.15–
4.20 (m, 1 H), 4.22–4.26 (m, 1 H), 5.24 (d, J = 5.4 Hz, 1 H).
To a solution of 38 (768.6 mg, 0.966 mmol) in MeOH (16 ml) at 0 °C was
added 1 N HCl (1.6 ml) and then the mixture was stirred at 0 °C for 30 min.
The mixture was concentrated under reduced pressure to obtain methyl (7S)-7-
acetylthio-6-N-((2′S)-1′-N-(tert-butoxycarbonyl)-5′-n-propylazepane-2-carbo-
nyl)-7-deoxy-α-thiolincosaminide as a crude compound and then, the crude
intermediate and 28% NaOMe/MeOH soultion (0.238 ml, 0.966 mmol) in
MeOH (16 ml) at room temperature were treated for 30 min according to the
similar procedure as described for the preparation of 30 to afford 39 (170 mg,
33% in 2 steps from 38) as a colorless solid. ESI–MS m/z 537 (M+H)+ as
C24H44N2O7S2; TOF–ESI–HR-MS (M+H)+ calcd for C24H44N2O7S2: 537.2668,
1
found: 537.2668; H NMR (400 MHz, CD3OD) δ 0.92 (br t, J =6.6 Hz, 3 H),
1.20–1.80 (m, 12 H), 1.48 (s, 9 H), 1.88–2.07 (m, 2 H), 2.15 (s, 3 H), 3.38–3.74
(m, 4 H), 3.76–3.94 (m, 1 H), 4.00–4.12 (m, 2 H), 4.23–4.34 (m, 1 H), 4.36–
4.56 (m, 1 H), 5.24 (d, J = 5.6 Hz, 1 H).
Methyl (7S)-6-N-((2′S, 4′R)-1′-N-(tert-butoxycarbonyl)-4′-(n-
propyl)piperidine-2′-carbonyl)-7-deoxy-7-(4-(pyrimidin-5-yl)
phenylthio)-α-thiolincosaminide (40)
To a solution of 5-(4-bromophenyl)pyrimidine (103.4 mg, 0.440 mmol), 4,5-
bis(diphenylphosphino)-9,9-dimethylxanthene
(Xantphos)
(18.8 mg,
0.0315 mmol) and tris(dibenzylideneacetone)dipalladium(0) (Pd2(dba)3)
(13.4 mg, 0.0146 mmol) in 1,4-dioxane (2.0 ml) were added compound 30
(152.1 mg, 0.291 mmol) and N,N-diisopropylethylamine (0.100 ml,
0.576 mmol), and refluxed for 6 h. The mixture was filtrated by either
Chromatodisc (0.45 μm) (Kurabo Industries Ltd, Osaka, Japan) or celite,
concentrated under reduced pressure. The resulting residue was purified by
silica gel column chromatography (CHCl3/MeOH/28% aq NH4OH= 10/1/0.1)
to obtain the title compound (163.0 mg, 83%) as an off white solid. FAB–MS
m/z 677 (M+H)+ as C33H48N4O7S2.
Methyl 6-N-((2′S)-1′-N-(tert-butoxycarbonyl)-5′-n-propylazepane-
2-carbonyl)-α-thiolincosaminide (36) (stereochemistry at the C-5′
position is not assigned)
To a solution of 35 (560 mg, 1.34 mmol) in 1,4-dioxane (10 ml)-H2O (10 ml)
were added LiOH·H2O (84.0 mg, 2.00 mmol) and di-tert-butyl dicarbonate
(0.37 ml, 1.6 mmol), and then stirred at room temperature for 3 h. The
mixture was added to saturated aqueous NaHCO3, extracted with ethyl acetate
and then the organic phase was dried over Na2SO4, filtrated and concentrated
under reduced pressure. The resulting residue was purified by silica gel column
chromatography (CHCl3/CH3OH/28% aq NH4OH= 20/1/0.1) to obtain the
title compound (483.3 mg, 70%) as a colorless solid. ESI–MS m/z 521 (M+H)+
as C24H44N2O8S; 1H NMR (400 MHz, CD3OD) δ 0.85–0.96 (m, 3 H), 1.12–
1.38 (m, 7 H), 1.47 (s, 9 H), 1.50–1.65 (m, 4 H), 1.66–1.80 (m, 1 H), 1.84–2.14
(m, 2 H), 2.07 (s, 3 H), 3.43–3.55 (m, 2 H), 3.59 (dd, J = 10.1, 3.3 Hz, 1 H),
Methyl (7S)-6-N-((2′S, 4′R)-1′-N-(tert-butoxycarbonyl)-4′-(n-butyl)
piperidine-2′-carbonyl)-7-deoxy-7-(4-(pyrimidin-5-yl)phenylthio)-
α-thiolincosaminide (41)
Compound 31 (150.1 mg, 0.280 mmol), 5-(4-bromophenyl)pyrimidine
(99.3 mg, 0.422 mmol), Xantphos (17.3 mg, 0.029 mmol), Pd2(dba)3
3.75–3.90 (m, 1 H), 3.98–4.18 (m, 3 H), 4.26–4.45 (m, 2 H), 5.24 (d, (13.4 mg, 0.0146 mmol) and N,N-diisopropylethylamine (97.0 μl, 0.559 mmol)
J = 5.6 Hz, 1 H). in 1,4-dioxane (2.0 ml) were treated for 6 h according to the similar procedure
The Journal of Antibiotics

Synthesis and SARs of novel lincomycin derivatives Part 5
Y Wakiyama et al
14
1
as described for the preparation of 40 to afford 41 (150.8 mg, 78%) as a
ESI–HR-MS (M+H)+ calcd for C29H42N4O5S2: 591.2675, found: 591.2674; H
colorless solid.
NMR (400 MHz, CD3OD) δ 0.91 (d, J = 5.7 Hz, 3 H), 0.90 (d, J = 5.7 Hz, 3 H),
1.08–1.20 (m, 3 H), 1.36 (d, J = 7.0 Hz, 3 H), 1.64–1.82 (m, 4 H), 1.93 (s, 3 H),
2.03–2.12 (m, 1 H), 2.76-2.86 (m, 1 H), 3.21–3.28 (m, 1 H), 3.51–3.61 (m, 2
H), 3.89 (br dd, J = 3.2, 0.8 Hz, 1 H), 3.93 (dq, J = 7.0, 2.4 Hz, 1 H), 4.09 (dd,
J = 10.2, 5.6 Hz, 1 H), 4.45 (br dd, J = 10.0, 0.8 Hz, 1 H), 4.63 (dd, J = 10.0,
2.4 Hz, 1 H), 5.27 (d, J = 5.6 Hz, 1 H), 7.52–7.57 (m, 2 H), 7.66–7.71 (m, 2 H),
9.06 (s, 2 H), 9.11 (s, 1 H).
Methyl (7S)-6-N-((2′S, 4′R)-1′-N-(tert-butoxycarbonyl)-4′-(i-butyl)
piperidine-2′-carbonyl)-7-deoxy-7-(4-(pyrimidin-5-yl)phenylthio)-
α-thiolincosaminide (42)
Compound 32 (100 mg, 0.186 mmol), 5-(4-bromophenyl)pyrimidine
(50.0 mg, 0.213 mmol), Xantphos (10.0 mg, 0.0173 mmol), Pd2(dba)3
(10.0 mg, 0.0109 mmol) and N,N-diisopropylethylamine (60.0 μl, 0.353 mmol)
in 1,4-dioxane (1.3 ml) were treated for 6 h according to the similar procedure
as described for the preparation of 40 to afford 42 (105.0 mg, 82%) as a
colorless solid.
Methyl (7S)-6-N-((2′S, 4′R)-4′-(cyclopropylmethyl)piperidine-2′-
carbonyl)-7-deoxy-7-(4-(pyrimidin-5-yl)phenylthio)-α-
thiolincosaminide (47)
Compound 43 (1.63 g, 2.36 mmol) and 2,2,2-trifluoroacetic acid (3.5 ml) in
CH2Cl2 (32 ml) were treated at − 20 °C for 20 min, and then treated room
temperature for 5.5 h according to the similar procedure as described for the
preparation of 44 to afford 47 (1.12 g, 81%) as a colorless solid. [α]D24 +86.1°
(c 0.25, MeOH); ESI–MS m/z 589 (M+H)+ as C29H40N4O5S2; TOF–ESI–HR-
MS (M+H)+ calcd for C29H40N4O5S2: 589.2518, found: 589.2517; IR
(KBr) cm− 1 1046, 1078, 1415, 1508, 1602, 1653, 1671, 1698, 2338, 2360,
3001, 3347 and 3690 cm− 1; 1H NMR (400 MHz, CD3OD) δ − 0.01 to 0.08 (m,
2 H), 0.43–0.52 (m, 2 H), 0.67–0.78 (m, 1 H), 1.14–1.23 (m, 1 H), 1.24–1.40
(m, 3 H), 1.36 (d, J = 6.8 Hz, 3 H), 1.75-1.89 (m, 1 H), 1.90–2.00 (m, 1 H),
1.93 (s, 3 H), 2.28–2.37 (m, 1 H), 2.96 (dt, J = 13.1, 3.0 Hz, 1 H), 3.33–3.40 (m,
1 H), 3.59 (dd, J = 10.2, 3.1 Hz, 1 H), 3.75 (dd, J = 12.4, 3.0 Hz, 1 H), 3.90 (br
dd, J =3.1, 0.8 Hz, 1 H), 3.93 (dq, J = 6.8, 2.5 Hz, 1 H), 4.10 (dd, J = 10.2,
5.6 Hz, 1 H), 4.46 (br dd, J = 10.0, 0.8 Hz, 1 H), 4.65 (dd, J = 10.0, 2.5 Hz, 1
H), 5.28 (d, J = 5.6 Hz, 1 H), 7.51–7.57 (m, 2 H), 7.65–7.73 (m, 2 H), 9.06 (s, 2
H), 9.11 (s, 1 H); 13C NMR (100 MHz, CD3OD) δ 5.1, 9.2, 13.8, 20.7, 33.8,
38.2, 38.8, 43.5, 44.8, 46.4, 53.8, 61.1, 69.6, 69.9, 71.0, 72.1, 90.2,128.6, 131.7,
133.0, 135.3, 138.6, 155.9, 157.9 and 176.5.
Methyl (7S)-6-N-((2′S, 4′R)-1′-N-(tert-butoxycarbonyl)-4′-
(cyclopropylmethyl)piperidine-2′-carbonyl)-7-deoxy-7-(4-
(pyrimidin-5-yl)phenylthio)-α-thiolincosaminide (43)
Compound 33 (1.35 g, 2.52 mmol), 5-(4-bromophenyl)pyrimidine (771 mg,
3.28 mmol), Xantphos (151 mg, 0.253 mmol), Pd2(dba)3 (117 mg,
0.128 mmol) and N,N-diisopropylethylamine (0.875 ml, 5.04 mmol) in 1,4-
dioxane (20 ml) were treated for 6 h according to the similar procedure as
described for the preparation of 40 to afford 43 (1.63 g, 93%) as an off white
solid. ESI–MS m/z 689 (M+H)+ as C34H48N4O7S2.
Methyl (7S)-6-N-((2′S, 4′R)-4′-(n-propyl)piperidine-2′-carbonyl)-7-
deoxy-7-(4-(pyrimidin-5-yl)phenylthio)-α-thiolincosaminide (44)
To a solution of 40 (163 mg, 0.241 mmol) in CH2Cl2 (3.3 ml) at −20 °C was
added 2,2,2-trifluoroacetic acid (0.36 ml) and then the solution was stirred at
room temperature for 4 h. The solution was concentrated under reduced
pressure. The resulting residue was purified by preparative TLC (CHCl3/
MeOH/28% aq NH4OH=9/2/0.2) to obtain the title compound (122.8 mg,
22
88%) as a colorless solid. [α]D +85.2° (c 1.02, MeOH); ESI–MS m/z 577 (M
Methyl (7S)-6-N-((2′S)-1′-N-(tert-butoxycarbonyl)-5′-n-
propylazepane-2-carbonyl)-7-deoxy-7-(4-(pyrimidin-5-yl)
phenylthio)-α-thiolincosaminide (48) (stereochemistry at the C-5′
position is not assigned)
Compound 39 (15.0 mg, 0.0279 mmol), 5-(4-bromophenyl)pyrimidine
(13.1 mg, 0.0558 mmol), Xantphos (3.2 mg, 5.58 μmol), Pd2(dba)3 (5.1 mg,
5.6 μmol) and N,N-diisopropylethylamine (10.0 μl, 0.0558 mmol) in 1,4-
dioxane (0.2 ml) were treated for 2 h according to the similar procedure as
described for the preparation of 40 to afford 48 (17.0 mg, 88%) as a colorless
solid. ESI–MS m/z 691 (M+H)+ as C34H50N4O7S2.
+H)+ as C28H40N4O5S2; TOF–ESI–HR-MS (M+H)+ calcd for C28H40N4O5S2:
577.2518, found: 577.2516; 1H NMR (400 MHz, CD3OD) δ 0.90 (t, J = 7.3 Hz,
3 H), 1.02–1.15 (m, 2 H), 1.20–1.29 (m, 2 H), 1.31–1.42 (m, 2 H), 1.35 (d,
J = 6.8 Hz, 3 H), 1.49–1.63 (m, 1 H), 1.68–1.77 (m, 1 H), 1.93 (s, 3 H), 1.96–
2.05 (m, 1 H), 3.19 (dt, J = 10.9, 2.0 Hz, 1 H), 3.15-3.23 (m, 1 H), 3.40 (dd,
J = 11.9, 2.8 Hz, 1 H), 3.58 (dd, J = 10.3, 3.3 Hz, 1 H), 3.88 (br dd, J = 3.3,
0.8 Hz, 1 H), 3.93 (dq, J =6.8, 2.4 Hz, 1 H), 4.09 (dd, J = 10.3, 5.5 Hz, 1 H),
4.44 (br dd, J = 10.0, 0.8 Hz, 1 H), 4.61 (dd, J = 10.0, 2.4 Hz, 1 H), 5.27 (d,
J = 5.5 Hz, 1 H), 7.52–7.58 (m, 2 H), 7.66–7.71 (m, 2 H), 9.06 (s, 2 H), 9.11
(s, 1 H).
Methyl (7S)-6-N-((2′S)-5′-n-propylazepane-2-carbonyl)-7-deoxy-7-
(4-(pyrimidin-5-yl)phenylthio)-α-thiolincosaminide (49)
Methyl (7S)-6-N-((2′S, 4′R)-4′-(n-butyl)piperidine-2′-carbonyl)-7-
deoxy-7-(4-(pyrimidin-5-yl)phenylthio)-α-thiolincosaminide (45)
Compound 41 (150.8 mg, 0.218 mmol) and 2,2,2-trifluoroacetic acid (0.33 ml)
in CH2Cl2 (3.0 ml) were treated at − 20 °C for 10 min and then treated room
temperature for 2.5 h according to the similar procedure as described for the
(stereochemistry at the C-5′ position is not assigned)
Compound 48 (15.0 mg, 0.0217 mmol) and 2,2,2-trifluoroacetic acid (0.3 ml)
were treated at 0 °C for 20 min and then treated room temperature for 1 h
according to the similar procedure as described for the preparation of 44 to
23
preparation of 44 to afford 45 (102.6 mg, 80%) as a colorless solid. [α]D
24
+81.2° (c 0.78, MeOH); ESI–MS m/z 591 (M+H)+ as C29H42N4O5S2; TOF–
afford 49 (10.0 mg, 78%) as a colorless solid. [α]D +82.9° (c 0.84, MeOH);
ESI–MS m/z 591 (M+H)+ as C29H42N4O5S2; TOF–ESI–HR-MS (M+H)+ calcd
for C29H42N4O5S2: 591.2675, found: 591.2667; 1H NMR (400 MHz, CD3OD) δ
0.91 (t, J = 7.1 Hz, 3 H), 1.21–1.45 (m, 5 H), 1.37 (d, J = 6.8 Hz, 3 H), 1.45–
1.55 (m, 1 H), 1.55–1.68 (m, 1 H), 1.80–1.91 (m, 1 H), 1.92–2.01 (m, 1 H),
1.94 (s, 3 H), 2.07–2.22 (m, 2 H), 2.98–3.08 (m, 1 H), 3.32–3.39 (m, 1 H), 3.60
(dd, J = 10.2, 3.3 Hz, 1 H), 3.90 (dd, J = 3.3, 0.8 Hz, 1 H), 3.95 (dq, J = 6.8,
1
ESI–HR-MS (M+H)+ calcd for C29H42N4O5S2: 591.2675, found: 591.2669; H
NMR (400 MHz, CD3OD) δ 0.85–0.96 (m, 3 H), 1.09–1.22 (m, 2 H), 1.23–1.41
(m, 6 H), 1.36 (d, J = 6.8 Hz, 3 H), 1.51–1.66 (m, 1 H), 1.74–1.84 (m, 1 H),
1.93 (s, 3 H), 2.04-2.12 (m, 1 H), 2.78 (dt, J = 12.9, 2.8 Hz, 1 H), 3.21–3.29 (m,
1 H), 3.52 (dd, J =12.1, 2.9 Hz, 1 H), 3.58 (dd, J = 10.2, 3.3 Hz, 1 H), 3.89 (br
dd, J = 3.3, 0.8 Hz, 1 H), 3.93 (dq, J = 6.8, 2.5 Hz, 1 H), 4.09 (dd, J = 10.2,
5.6 Hz, 1 H), 4.45 (br dd, J = 10.0, 0.8 Hz, 1 H), 4.63 (dd, J = 10.0, 2.5 Hz, 1 2.4 Hz, 1 H), 3.98 (dd, J = 6.4, 5.1 Hz, 1 H), 4.10 (dd, J = 10.2, 5.6 Hz, 1 H),
H), 5.27 (d, J = 5.6 Hz, 1 H), 7.51–7.58 (m, 2 H), 7.65–7.72 (m, 2 H), 9.06 (s, 2 4.46 (dd, J = 10.0, 0.8 Hz, 1 H), 4.64 (dd, J = 10.0, 2.4 Hz, 1 H), 5.29 (d,
H), 9.11 (s, 1 H).
J = 5.6 Hz, 1 H), 7.52–7.59 (m, 2 H), 7.65–7.74 (m, 2 H), 9.07 (s, 2 H), 9.12
(s, 1 H).
Methyl (7S)-6-N-((2′S, 4′R)-4′-(i-butyl)piperidine-2′-carbonyl)-7-
deoxy-7-(4-(pyrimidin-5-yl)phenylthio)-α-thiolincosaminide (46)
Compound 42 (100 mg, 0.145 mmol) and 2,2,2-trifluoroacetic acid (0.50 ml)
Methyl 6-N-(2,2,2-trifluoroacetyl)-2,3,4,7-tetrakis-O-
(trimethylsilyl)-α-thiolincosaminide (51)
were treated at 0 °C for 1 h according to the similar procedure as described for Compound 50 (6.88 g, 19.7 mmol), trimethylchlorosilane (12.6 ml, 98.5 mmol)
24
the preparation of 44 to afford 46 (55.0 mg, 64%) as a colorless solid. [α]D
and hexamethyldisilazane (20.6 ml, 98.5 mmol) in pyridine (40 ml) were
+93.9° (c 0.83, MeOH); ESI–MS m/z 591 (M+H)+ as C29H42N4O5S2; TOF– treated at room temperature for 1 h according to the similar procedure as
The Journal of Antibiotics

Synthesis and SARs of novel lincomycin derivatives Part 5
Y Wakiyama et al
15
described for the preparation of 22 to afford 51 (8.87 g, 71%) as a colorless Methyl (7S)-7-deoxy-7-((4-(2-dimethylaminoethyl)phenyl)thio-6-N-
solid. FAB–MS m/z 638 (M+H)+ as C23H50F3NO6SSi4.
(2,2,2-trifluoroacetyl)-α-thiolincosaminide (55)
Compound 54 (3.44 g, 9.42 mmol), 2-(4-bromophenyl)-N,N-dimethylethana-
mine (3.22 g, 14.1 mmol), Xantphos (544.8 mg, 0.942 mmol), Pd2(dba)3
(431.1 mg, 0.471 mmol) and N,N-diisopropylethylamine (3.28 ml, 18.8 mmol)
Methyl 6-N-(2,2,2-trifluoroacetyl)-2,3,4-tris-O-(trimethylsilyl)-α-
thiolincosaminide (52)
in 1,4-dioxane (37 ml) were treated for 17 h according to the similar procedure
as described for the preparation of 40 to afford 55 (3.85 g, 80%) as a colorless
solid. FAB–MS m/z 513 (M+H)+ as C21H31F3N2O5S2; 1H NMR (400 MHz,
CD3OD) δ 1.27 (d, J = 6.9 Hz, 3 H), 2.01 (s, 3 H), 2.36 (s, 6 H), 2.58-2.68 (m, 2
H), 2.74-2.84 (m, 2 H), 3.59 (dd, J = 10.3, 3.2 Hz, 1 H), 3.76 (dq, J = 6.9,
2.8 Hz, 1 H), 3.87-3.92 (m, 1 H), 4.09 (dd, J = 10.3, 5.6 Hz, 1 H), 4.59 (dd,
J = 9.4, 0.7 Hz, 1 H), 4.64 (dd, J = 9.4, 2.8 Hz, 1 H), 5.28 (d, J = 5.6 Hz, 1 H),
7.16–7.22 (m, 2 H), 7.33-7.39 (m, 2 H).
To a solution of compound 51 (8.87 g, 13.9 mmol) in MeOH (65 ml) was
added 6 N acetic acid (4.17 ml) and stirred at room temperature for 15 min.
The mixture was added to saturated aqueous NaHCO3 and concentrated under
reduced pressure to remove MeOH. The desired compound was extracted with
ethyl acetate, and then the organic phase was dried over Na2SO4, filtrated and
concentrated under reduced pressure. The resulting residue was purified by
silica gel column chromatography (hexane/ethyl acetate= 95/5 to 80/20) to
obtain the title compound (7.21 g, 91% in 2 steps) as a colorless solid. ESI–MS
1
m/z 566 (M+H)+ as C20H42F3NO6SSi3; H NMR (400 MHz, CD3OD) δ 0.133
Methyl (7S)-7-deoxy-7-((4-(2-dimethylaminoethyl)phenyl)thio-α-
thiolincosaminide (56)
(s, 9 H), 0.134 (s, 9 H), 0.14 (s, 9 H), 1.13 (d, J = 6.5 Hz, 3 H), 2.06 (s, 3 H),
3.66 (dd, J = 9.6, 2.4 Hz, 1 H), 3.92 (d, J = 2.4 Hz, 1 H), 4.04 (dq, J = 6.5,
4.5 Hz, 1 H), 4.14 (dd, J = 9.6, 5.5 Hz, 1 H), 4.19 (d, J = 9.6 Hz, 1 H), 4.40 (dd,
J = 9.6, 4.5 Hz, 1 H), 5.21 (d, J =5.5 Hz, 1 H).
To a solution of 55 (3.85 g, 7.51 mmol) in CH2Cl2 (73 ml) were added N-
benzyl-N, N, N-triethylammonium bromide (171.1 mg, 0.751 mmol) and 20%
aqueous potassium hydroxide (5.1 ml), stirred at room temperature for 4 h. To
a solution of mixture was added 1 N HCl to adjust at pH 7 and then the
solution was concentrated under reduced pressure. The resulting residue was
diluted with MeOH, filtrated, and concentrated under reduced pressure. The
resulting residue was purified by silica gel column chromatography (CHCl3/
MeOH/28% aq NH4OH= 20/1/0.1 to 10/1/0.1) to obtain the title compound
(2.94 g, 94%) as off white solid. 1H NMR (400 MHz, CD3OD) δ 1.41 (d,
J = 7.1 Hz, 3 H), 1.92 (s, 3 H), 2.30 (s, 6 H), 2.51–2.59 (m, 2 H), 2.73–2.81 (m,
2 H), 3.20 (dd, J =8.8, 2.7 Hz, 1 H), 3.59 (dd, J = 10.3, 3.4 Hz, 1 H), 3.63 (dq,
J = 7.1, 2.7 Hz, 1 H), 4.04–4.13 (m, 2 H), 4.23 (dd, J = 8.8, 1.2 Hz, 1 H), 5.22
(d, J = 5.8 Hz, 1 H), 7.14–7.20 (m, 2 H), 7.31–7.37 (m, 2 H).
Methyl (7S)-7-acetylthio-7-deoxy-6-N-(2,2,2-trifluoroacetyl)-2,3,4-
tris-O-(trimethylsilyl)-α-thiolincosaminide (53)
Compound 52 (4.42 g, 7.82 mmol), Et3N (21.8 ml, 15.6 mmol) and methane-
sulfonyl chloride (1.21 ml, 15.6 mmol) in CHCl3 (20 ml) were treated at room
temperature for 1 h according to the similar procedure as described for the
preparation of 26 to afford methyl 7-O-methaneslufonyl-6-N-(2,2,2-trifluor-
oacetyl)-2,3,4-tris-O-(trimethylsilyl)-α-thiolincosaminide (5.46 g, quant) as a
colorless solid. To a solution of this mesylate (5.46 g, 7.82 mmol) in DMF
(40 ml) was added AcSK (2.68 g, 23.4 mmol) and stirred at 80 °C for 1.5 h. The
mixture was concentrated under reduced pressure, diluted with ethyl acetate
and saturated aqueous NaHCO3, and extracted with ethyl acetate. The organic
phase was dried over Na2SO4, filtrated and concentrated under reduced
pressure. To the resulting residue were added pyridine (16 ml), trimethyl-
chlorosilane (6.35 ml, 50.0 mmol) and hexamethyldisilazane (10.5 ml,
50.0 mmol), and stirred at room temperature for 3 h. The mixture was added
to saturated aqueous NaHCO3, extracted with ethyl acetate and then the
organic phase was dried over Na2SO4, filtrated and concentrated under reduced
pressure. The resulting residue was purified by silica gel column chromato-
graphy (hexane to hexane/ethyl acetate= 10/1) to obtain the title compound
Methyl (7S)-6-N-((2′S, 4′R)-1′-N-(tert-butoxycarbonyl)-4′-
(cyclopropylmethyl)piperidine-2′-carbonyl)-7-deoxy-7-((4-(2-
dimethylaminoethyl)phenyl)thio-α-thiolincosaminide (57)
Compound 15 (1.15 g, 4.04 mmol), 56 (2.02 g, 4.85 mmol), 1-
hydroxybenzotriazole (0.819 g, 6.06 mmol) and 1-ethyl-3-(3-dimethylamino-
propyl)carbodiimide hydrochloride (1.16 g, 6.06 mmol) in DMF (20 ml) were
treated for 5.5 h according to the similar procedure as described for the
preparation of 34 to afford the title compound (2.00 g, 73%) as a colorless
solid. ESI–MS m/z 682 (M+H)+ as C34H55N3O7S2.
Methyl (7S)-6-N-((2′S, 4′R)-4′-(cyclopropylmethyl)piperidine-2′-
carbonyl)-7-deoxy-7-((4-(2-dimethylaminoethyl)phenyl)thio-α-
thiolincosaminide (58)
(2.88 g) as
a crude compound. The crude compound (306.3 mg) was
suspended in hexane, and then the solid was filtered, washed with hexane to
obtain the title compound (129 mg, 25% in 3 steps) as a colorless solid. As
compound 53 is partially soluble in hexane, a yield of the third step was low.
Compound 57 (2.00 g, 2.93 mmol) and 2,2,2-trifluoroacetic acid (3.25 ml) in
CH2Cl2 (5.0 ml) were treated at 0 °C for 3.5 h according to the similar
procedure as described for the preparation of 44 to afford 58 (1.69 g, 99%) as a
1
ESI–MS m/z 624 (M+H)+ as C22H44F3NO6S2Si3; H NMR (400 MHz, CDCl3)
δ 0.15 (s, 9 H), 0.16 (s, 9 H), 0.22 (s, 9 H), 1.41 (d, J = 7.1 Hz, 3 H), 2.01 (s, 3
H), 2.33 (s, 3 H), 3.65 (dd, J = 9.5, 2.7 Hz, 1 H), 3.76–3.86 (m, 1 H), 3.97–4.04
(m, 1 H), 4.10 (dd, J = 9.5, 5.4 Hz, 1 H), 4.14–4.21 (m, 1 H), 4.34-4.44 (m, 1
H), 5.18 (d, J = 5.4 Hz, 1 H), 7.20 (br dd, J = 9.5 Hz, 1 H).
colorless solid. [α]D +101.3° (c 0.65, MeOH); ESI–MS m/z 582 (M+H)+ as
23
C29H47N3O5S2; TOF–ESI–HR-MS (M+H)+ calcd for C29H47N3O5S2: 582.3035,
found: 582.3032; 1H NMR (400 MHz, CD3OD) δ −0.02 to 0.06 (m, 2 H),
0.40–0.50 (m, 2 H), 0.67–0.78 (m, 1 H), 1.02–1.25 (m, 4 H), 1.25 (d,
J = 7.0 Hz, 3 H), 1.60–1.74 (m, 1 H), 1.75–1.84 (m, 1 H), 1.97 (s, 3 H), 2.04–
2.12 (m, 1 H), 2.31 (s, 6 H), 2.52–2.61 (m, 2 H), 2.62–2.72 (m, 1 H), 2.73–2.81
(m, 2 H), 3.13–3.21 (m, 1 H), 3.34 (dd, J = 11.8, 2.9 Hz, 1 H), 3.56 (dd,
J = 10.3, 3.3 Hz, 1 H), 3.76 (dq, J = 7.0, 2.4 Hz, 1 H), 3.85 (dd, J = 3.3, 0.8 Hz, 1
H), 4.08 (dd, J = 10.3, 5.6 Hz, 1 H), 4.40 (dd, J = 9.9, 0.8 Hz, 1 H), 4.52 (dd,
J = 9.9, 2.4 Hz, 1 H), 5.25 (d, J =5.6 Hz, 1 H), 7.15–7.19 (m, 2 H), 7.29–7.41
(m, 2 H).
Methyl (7S)-7-deoxy-7-mercapto-6-N-(2,2,2-trifluoroacetyl)-α-
thiolincosaminide (54)
Compound 53 (2.83 g, 4.54 mmol) and 1 N HCl (18.1 ml) in MeOH (30 ml)
were treated at room temperature for 10 min according to the similar
procedure as described for the preparation of 30, and then the crude
intermediate and 28% NaOMe/MeOH solution (2.63 ml, 8.68 mmol) in
MeOH (25 ml) at room temperature were treated for 15 min according to
the similar procedure as described for the preparation of 30 to afford 54
(1.65 g, 99% in 2 steps from 53) as a colorless solid. ESI–MS m/z 366 (M+H)+
Methyl (7S)-6-N-((2′S, 4′R)-4′-(cyclopropylmethyl)-1′-N-
methylpiperidine-2′-carbonyl)-7-deoxy-7-((4-(2-
dimethylaminoethyl)phenyl)thio-α-thiolincosaminide (59)
To a solution of 58 (1.19 g, 2.04 mmol) in MeOH (21 ml) were added 36%
aqueous HCHO (0.51 ml, 6.12 mmol), AcOH (0.35 ml, 6.12 mmol) and NaBH
(OAc)3 (2.59 g, 12.2 mmol), and stirred at room temperature for 1 h. The
mixture was diluted with ethyl acetate and saturated aqueous NaHCO3,
1
as C11H18F3NO5S2; H NMR (400 MHz, CD3OD) δ 1.29 (d, J =7.0 Hz, 3 H),
2.16 (s, 3 H), 3.45 (dq, J = 7.0, 2.2 Hz, 1 H), 3.54 (dd, J = 10.2, 3.2 Hz, 1 H),
3.82 (dd, J = 3.2, 1.0 Hz, 1 H), 4.08 (dd, J = 10.2, 5.6 Hz, 1 H), 4.39 (dd, J = 9.9,
1.0 Hz, 1 H), 4.55 (dd, J = 9.9, 2.2 Hz, 1 H), 5.26 (d, J = 5.6 Hz, 1 H).
The Journal of Antibiotics

Synthesis and SARs of novel lincomycin derivatives Part 5
Y Wakiyama et al
16
extracted with ethyl acetate/MeOH = 5/1. The organic phase was dried over Methyl (7S)-6-N-((2′S, 4′R)-1′-N-(tert-butoxycarbonyl)-4′-
Na2SO4, filtrated and concentrated under reduced pressure. The resulting
(cyclopropylmethyl)piperidine-2′-carbonyl)-7-deoxy-7-(4-(pyrazin-
residue was purified by silica gel column chromatography (CHCl3/MeOH/28%
2-yl)phenylthio)-α-thiolincosaminide (64)
aq NH4OH= 20/1/0.1) to obtain the title compound (1.10 g, 91%) as a
Compound 33 (80 mg, 0.147 mmol), 2-(4-bromophenyl)pyrazine (50.0 mg,
0.213 mmol), Xantphos (10 mg, 0.0173 mmol), Pd2(dba)3 (10 mg,
0.0109 mmol) and N,N-diisopropylethylamine (60 μl, 0.35 mmol) in 1,4-
dioxane (1.5 ml) were treated for 4 h according to the similar procedure as
described for the preparation of 40 to afford 64 as a crude compound.
colorless solid. [α]D +88.4° (c 1.58, MeOH); ESI–MS m/z 596 (M+H)+ as
22
C30H49N3O5S2; TOF–ESI–HR-MS (M+H)+ calcd for C30H49N3O5S2: 596.3192,
found: 596.3188; 1H NMR (400 MHz, CD3OD) δ −0.05 to 0.06 (m, 2 H),
0.38–0.49 (m, 2 H), 0.63–0.76 (m, 1 H), 1.13–1.38 (m, 4 H), 1.27 (d,
J = 7.0 Hz, 3 H), 1.40–1.57 (m, 1 H), 1.75–1.84 (m, 1 H), 1.92–2.10 (m, 1 H),
1.99 (s, 3 H), 2.10–2.21 (m, 1 H), 2.26 (s, 3 H), 2.41 (s, 6 H), 2.60–2.73 (m, 3
H), 2.77–2.86 (m, 2 H), 2.92–3.02 (m, 1 H), 3.58 (dd, J =10.1, 3.2 Hz, 1 H),
3.75–3.85 (m, 2 H), 4.10 (dd, J =10.1, 5.6 Hz, 1 H), 4.41 (br dd, J = 9.8, 0.6 Hz,
1 H), 4.54 (dd, J = 9.8, 2.6 Hz, 1 H), 5.27 (d, J = 5.6 Hz, 1 H), 7.16–7.23 (m, 2
H), 7.33–7.39 (m, 2 H).
Methyl (7S)-6-N-((2′S, 4′R)-1′-N-(tert-butoxycarbonyl)-4′-
(cyclopropylmethyl)piperidine-2′-carbonyl)-7-deoxy-7-(4-(1,2,3-
thiadiazol-4-yl)phenylthio)-α-thiolincosaminide (65)
Compound 33 (80.0 mg, 0.147 mmol), 4-(4-bromophenyl)-1,2,3-thiadiazole
(50 mg, 0.207 mmol), Xantphos (10 mg, 0.0173 mmol), Pd2(dba)3 (10 mg,
0.011 mmol) and N,N-diisopropylethylamine (60 μl, 0.35 mmol) in 1,4-diox-
ane (1.5 ml) were treated for 4 h according to the similar procedure as
described for the preparation of 40 to afford 65 as a crude compound. ESI–MS
m/z 695 (M+H)+ as C32H46N4O7S3.
Methyl (7S)-6-N-((2′S, 4′R)-1′-N-(tert-butoxycarbonyl)-4′-
(cyclopropylmethyl)piperidine-2′-carbonyl)-7-deoxy-7-(4-
(pyrrolidin-1-ylmethyl)phenylthio)-α-thiolincosaminide (60)
Compound 33 (40.2 mg, 0.0739 mmol), 1-(4-bromobenzyl)pyrrolidine
(64.6 mg, 0.269 mmol), Xantphos (4.6 mg, 0.0077 mmol), Pd2(dba)3 (4.0 mg,
4.3 μmol) and N,N-diisopropylethylamine (38.5 μl, 0.22 mmol) in 1,4-dioxane
(1 ml) were treated for 4 h according to the similar procedure as described for
the preparation of 40 to afford 60 (41.4 mg, 81%) as a colorless solid. FAB–MS
m/z 694 (M+H)+ as C35H55N3O7S2.
Methyl (7S)-6-N-((2′S, 4′R)-4′-(cyclopropylmethyl)piperidine-2′-
carbonyl)-7-deoxy-7-(4-(pyrrolidin-1-ylmethyl)phenylthio)-α-
thiolincosaminide (66)
Compound 60 (41.4 mg, 0.0597 mmol) and 2,2,2-trifluoroacetic acid (0.09 ml)
in CH2Cl2 (0.9 ml) were treated at − 20 °C for 5 min and then treated at room
temperature for 5 h according to the similar procedure as described for the
preparation of 44 to afford 66 (28.8 mg, 81%) as a colorless solid. [α]D23 +68.9°
(c 0.20, MeOH); ESI–MS m/z 594 (M+H)+ as C30H47N3O5S2; TOF–ESI–HR-
MS (M+H)+ calcd for C30H47N3O5S2: 594.3035, found: 594.3031; 1H NMR
(400 MHz, CD3OD) δ − 0.01 to 0.06 (m, 2 H), 0.39–0.50 (m, 2 H), 0.66–0.79
(m, 1 H), 1.02-1.26 (m, 4 H), 1.28 (d, J = 6.8 Hz, 3 H), 1.60–1.74 (m, 1 H),
1.74–1.87 (m, 5 H), 1.93 (s, 3 H), 2.05–2.17 (m, 1 H), 2.49–2.60 (m, 4 H),
2.62–2.74 (m, 1 H), 3.12–3.24 (m, 1 H), 3.37 (dd, J = 11.8, 2.8 Hz, 1 H), 3.57
(dd, J = 10.2, 3.3Hz, 1 H), 3.63 (s, 2 H), 3.81 (dq, J = 6.8, 2.3 Hz, 1 H), 3.86 (br
dd, J = 3.3, 0.7 Hz, 1 H), 4.08 (dd, J = 10.2, 5.6 Hz, 1 H), 4.38–4.46 (m, 1 H),
Methyl (7S)-6-N-((2′S, 4′R)-1′-N-(tert-butoxycarbonyl)-4′-
(cyclopropylmethyl)piperidine-2′-carbonyl)-7-deoxy-7-(4-(1-
methyl-1,2,5,6-tetrahydropyridin-3-yl)phenylthio)-α-
thiolincosaminide (61)
Compound 33 (222.4 mg, 0.416 mmol), 3-(4-bromophenyl)-1-methyl-1,2,5,6-
tetrahydropyridine (125.6 mg, 0.498 mmol), Xantphos (25.8 mg, 0.043 mmol),
Pd2(dba)3 (19.4 mg, 0.021 mmol) and N,N-diisopropylethylamine (144 μl, 4.55 (dd, J = 10.1, 2.3 Hz, 1 H), 5.26 (d, J = 5.6 Hz, 1 H), 7.26–7.32 (m, 2 H),
7.34–7.39 (m, 2 H).
0.83 mmol) in 1,4-dioxane (3.5 ml) were treated for 5 h according to the
similar procedure as described for the preparation of 40 to afford 61 (251.9 mg,
86%) as a colorless solid. ESI–MS m/z 706 (M+H)+ as C36H55N3O7S2.
Methyl (7S)-6-N-((2′S, 4′R)-4′-(cyclopropylmethyl)-1′-N-
methylpiperidine-2′-carbonyl)-7-deoxy-7-(4-(pyrrolidin-1-ylmethyl)
phenylthio)-α-thiolincosaminide (67)
Compound 66 (16.4 mg, 0.0276 mmol), 36% aqueous formaldehyde (21 μl,
0.28 mmol), AcOH (16 μl, 0.28 mmol) and NaBH(OAc)3 (61.4 mg,
0.281 mmol) in MeOH (1.0 ml) were treated at room temperature for 2 h
according to the similar procedure as described for the preparation of 59 to
Methyl (7S)-6-N-((2′S, 4′R)-1′-N-(tert-butoxycarbonyl)-4′-
(cyclopropylmethyl)piperidine-2′-carbonyl)-7-deoxy-7-(4-(1-
methylpiperidin-3-yl)phenylthio)-α-thiolincosaminide (62) (a
diastereo mixture at an N-methylpiperidine ring)
To a solution of 61 (201.7 mg, 0.286 mmol) in toluene (10 ml) was added 4-
methylbenzenesulfonohydrazide (1.10 g, 5.72 mmol) at room temperature and
then refluxed for 3 h. To the mixture was further added 4-
methylbenzenesulfonohydrazide (1.09 g, 5.70 mmol) and then stirred for
2.5 h under the reflux condition. The solution was added to 1 N NaOH,
extracted with ethyl acetate. The organic phase was dried over Na2SO4, filtrated
and concentrated under reduced pressure. The resulting residue was purified by
preparative TLC (CHCl3/MeOH/28% aq NH4OH= 10/1/0.1) to obtain the title
compound (27.7 mg, 14%) as a colorless solid. ESI–MS m/z 708 (M+H)+ as
C36H57N3O7S2.
22
afford 67 (14.7 mg, 88%) as a colorless solid. [α]D +65.9° (c 0.11, MeOH);
ESI–MS m/z 608 (M+H)+ as C31H49N3O5S2; TOF–ESI–HR-MS (M+H)+ calcd
for C31H49N3O5S2: 608.3192, found: 608.3187; 1H NMR (400 MHz, CD3OD) δ
−0.05 to 0.07 (m, 2 H), 0.37–0.51 (m, 2 H), 0.64–0.78 (m, 1 H), 1.10–1.22 (m,
2 H), 1.23–1.39 (m, 2 H), 1.30 (d, J =6.8 Hz, 3 H), 1.41–1.58 (m, 1 H), 1.73–
1.88 (m, 5 H), 1.91–2.01 (m, 1 H), 1.95 (s, 3 H), 2.07–2.19 (m, 1 H), 2.56 (s, 3
H), 2.53–2.66 (m, 5 H), 2.92–3.01 (m, 1 H), 3.57 (dd, J = 10.2, 3.2 Hz, 1 H),
3.65 (s, 2 H), 3.79–3.89 (m, 2 H), 4.10 (dd, J =10.2, 5.6 Hz, 1 H), 4.37–4.44
(m, 1 H), 4.56 (dd, J = 9.9, 2.6 Hz, 1 H), 5.26 (d, J = 5.6 Hz, 1 H), 7.26-7.33 (m,
2 H), 7.35–7.43 (m, 2 H).
Methyl (7S)-6-N-((2′S, 4′R)-4′-(cyclopropylmethyl)piperidine-2′-
carbonyl)-7-deoxy-7-(4-(1-methyl-1,2,5,6-tetrahydropyridin-3-yl)
phenylthio)-α-thiolincosaminide (68)
Compound 61 (26.6 mg, 0.37 mmol) and 2,2,2-trifluoroacetic acid (60 μl) in
CH2Cl2 (0.6 ml) were treated at − 20 °C for 20 min and then treated room
temperature for 4 h according to the similar procedure as described for the
preparation of 44 to afford 68 (21.5 mg, 94%) as a colorless solid. [α]D22 +91.4°
(c 1.82, MeOH); ESI–MS m/z 606 (M+H)+ as C31H47N3O5S2; TOF–ESI–HR-
MS (M+H)+ calcd for C31H47N3O5S2: 606.3035, found: 606.3012; 1H NMR
(400 MHz, CD3OD) δ − 0.07–0.03 (m, 2 H), 0.38–0.48 (m, 2 H), 0.62–0.75 (m,
Methyl (7S)-6-N-((2′S, 4′R)-1′-N-(tert-butoxycarbonyl)-4′-
(cyclopropylmethyl)piperidine-2′-carbonyl)-7-deoxy-7-(4-(pyridin-
3-yl)phenylthio)-α-thiolincosaminide (63)
Compound 33 (30.0 mg, 0.0561 mmol), 3-(4-iodophenyl)pyridine (18.9 mg,
0.0673 mmol), Xantphos (7.8 mg, 0.0135 mmol), Pd2(dba)3 (5.1 mg, 5.6 μmol)
and N,N-diisopropylethylamine (19.5 μl, 0.112 mmol) in 1,4-dioxane (0.5 ml)
were treated for 5 h according to the similar procedure as described for the
preparation of 40 to afford 63 (39.3 mg as crude).
The Journal of Antibiotics

Synthesis and SARs of novel lincomycin derivatives Part 5
Y Wakiyama et al
17
1 H), 1.07–1.25 (m, 4 H), 1.25 (d, J = 6.8 Hz, 3 H), 1.63–1.78 (m, 1 H), 1.78– Methyl (7S)-6-N-((2′S, 4′R)-4′-(cyclopropylmethyl)piperidine-2′-
1.87 (m, 1 H), 1.90 (s, 3 H), 2.10–2.19 (m, 1 H), 2.33–2.41 (m, 2 H), 2.44 (s, 3
carbonyl)-7-deoxy-7-(4-(pyridin-3-yl)phenylthio)-α-
H), 2.66 (t, J = 5.9 Hz, 2 H), 2.80 (dt, J = 12.9, 2.7 Hz, 1 H), 3.21–3.39 (m, 1
H), 3.32–3.38 (m, 2 H), 3.53–3.62 (m, 2 H), 3.80 (dq, J = 6.8, 2.4 Hz, 1 H), 3.89
(dd, J = 3.2, 0.7 Hz, 1 H), 4.09 (dd, J = 10.3, 5.6 Hz, 1 H), 4.43 (dd, J = 10.0,
thiolincosaminide (72)
Compound 63 (39.3 mg, 0.0571 mmol) and 2,2,2-trifluoroacetic acid (0.5 ml)
in CH2Cl2 (0.1 ml) were treated at 0 °C for 1 h according to the similar
0.7 Hz, 1 H), 4.57 (dd, J = 10.0, 2.4 Hz, 1 H), 5.27 (d, J = 5.6 Hz, 1 H), 6.17– procedure as described for the preparation of 44 to afford 72 (17.2 mg, 52% in
2 steps from 33) as a colorless solid. [α]D23 +92.4° (c 1.12, MeOH); ESI–MS m/
6.23 (m, 1 H), 7.29–7.40 (m, 4 H).
z 588 (M+H)+ as C30H41N3O5S2; TOF–ESI–HR-MS (M+H)+ calcd for
C30H41N3O5S2: 588.2566, found: 588.2560; 1H NMR (400 MHz, CD3OD) δ
Methyl (7S)-6-N-((2′S, 4′R)-4′-(cyclopropylmethyl)-1′-N-
− 0.04 to 0.05 (m, 2 H), 0.39–0.49 (m, 2 H), 0.65–0.76 (m, 1 H), 1.09–1.25 (m,
methylpiperidine-2′-carbonyl)-7-deoxy-7-(4-(1-methyl-1,2,5,6-
4 H), 1.35 (d, J =7.0 Hz, 3 H), 1.65–1.79 (m, 1 H), 1.79–1.88 (m, 1 H), 1.95 (s,
tetrahydropyridin-3-yl)phenylthio)-α-thiolincosaminide (69)
3 H), 2.10–2.20 (m, 1 H), 3.23 (dt, J =10.9, 1.9 Hz, 1 H), 3.18–3.27 (m, 1 H),
Compound 68 (38.4 mg, 0.0634 mmol), 36% aqueous formaldehyde (48.0 μl,
3.49 (dd, J = 12.0, 2.9 Hz, 1 H), 3.59 (dd, J = 10.2, 3.4 Hz, 1 H), 3.86–3.95 (m, 2
0.645 mmol), AcOH (36.5 μl, 0.638 mmol) and NaBH(OAc)3 (141.2 mg,
0.633 mmol) in MeOH (2.2 ml) were treated at room temperature for 1 h
H), 4.10 (dd, J = 10.2, 5.6 Hz, 1 H), 4.45 (br dd, J = 9.9, 0.7 Hz, 1 H), 4.61 (dd,
J = 9.9, 2.4 Hz, 1 H), 5.28 (d, J = 5.6 Hz, 1 H), 7.46-7.55 (m, 3 H), 7.58-7.66
(m, 2 H), 8.07 (ddd, J =7.9, 2.3, 1.5 Hz, 1 H), 8.50 (dd, J = 4.9, 1.5 Hz, 1 H),
8.79 (dd, J = 2.3, 0.8 Hz, 1 H).
according to the similar procedure as described for the preparation of 59 to
afford 69 (36.0 mg, 92%) as an off white solid. [α]D23 +67.4° (c 2.48, MeOH);
ESI–MS m/z 620 (M+H)+ as C32H49N3O5S2; TOF–ESI–HR-MS (M+H)+ calcd
for C32H49N3O5S2: 620.3192, found: 620.3187; 1H NMR (400 MHz, CD3OD) δ
Methyl (7S)-6-N-((2′S, 4′R)-4′-(cyclopropylmethyl)-1′-N-
−0.05 to 0.06 (m, 2 H), 0.38-0.49 (m, 2 H), 0.63–0.76 (m, 1 H), 1.10–1.23 (m,
methylpiperidine-2′-carbonyl)-7-deoxy-7-(4-(pyridin-3-yl)
2 H), 1.24–1.43 (m, 2 H), 1.30 (d, J = 7.0 Hz, 3 H), 1.52–1.67 (m, 1 H), 1.81–
phenylthio)-α-thiolincosaminide (73)
1.90 (m, 1 H), 1.94 (s, 3 H), 2.00–2.09 (m, 1 H), 2.31–2.46 (m, 1 H), 2.41 (s, 3
Compound 72 (20.0 mg, 0.034 mmol), 36% aqueous formaldehyde (25 μl,
H), 2.46–2.56 (m, 2 H), 2.69 (s, 3 H), 2.90–3.00 (m, 3 H), 3.06–3.15 (m, 1 H),
0.34 mmol), AcOH (19 μl, 0.30 mmol) and NaBH(OAc)3 (18 mg, 0.08 mmol)
3.59 (dd, J = 10.2, 3.2 Hz, 1 H), 3.62–3.69 (m, 2 H), 3.78–3.87 (m, 2 H), 4.10
in MeOH (2.2 ml) were treated at 0 °C for 1 h according to the similar
(dd, J = 10.2, 5.6 Hz, 1 H), 4.43 (dd, J = 9.9, 0.6 Hz, 1 H), 4.59 (dd, J = 9.9,
2.6 Hz, 1 H), 5.26 (d, J = 5.6 Hz, 1 H), 6.23–6.29 (m, 1 H), 7.32–7.42 (m, 4 H).
procedure as described for the preparation of 59 to afford 73 (20.0 mg, 98%) as
a colorless solid. [α]D +57.4° (c 0.28, MeOH); ESI–MS m/z 602 (M+H)+ as
24
C31H43N3O5S2; TOF–ESI–HR-MS (M+H)+ calcd for C31H43N3O5S2: 602.2722,
found: 602.2714; 1H NMR (400 MHz, CD3OD) δ −0.05 to 0.05 (m, 2 H),
0.38–0.48 (m, 2 H), 0.62–0.74 (m, 1 H), 1.07–1.43 (m, 4 H), 1.37 (d,
J = 7.0 Hz, 3 H), 1.54–1.69 (m, 1 H), 1.83–1.92 (m, 1 H), 1.96 (s, 3 H), 2.03–
2.11 (m, 1 H), 2.40–2.55 (m, 1 H), 2.47 (s, 3 H), 2.98–3.08 (m, 1 H), 3.10–3.20
(m, 1 H), 3.59 (dd, J = 10.3, 3.3 Hz, 1 H), 3.85 (br dd, J = 3.2, 0.9 Hz, 1 H),
3.91 (dq, J =6.9, 2.6 Hz, 1 H), 4.10 (dd, J = 10.2, 5.6 Hz, 1 H), 4.46 (br dd,
J = 9.9, 0.7 Hz, 1 H), 4.64 (dd, J = 9.9, 2.6 Hz, 1 H), 5.27 (d, J = 5.5 Hz, 1 H),
7.50–7.56 (m, 2 H), 7.51 (ddd, J = 8.0, 4.9, 0.8 Hz, 1 H), 7.60–7.67 (m, 2 H),
8.08 (ddd, J = 8.0, 2.3, 1.5 Hz, 1 H), 8.51 (dd, J = 4.9, 1.5 Hz, 1 H), 8.79 (br dd,
J = 2.3, 0.8 Hz, 1 H).
Methyl (7S)-6-N-((2′S, 4′R)-4′-(cyclopropylmethyl)piperidine-2′-
carbonyl)-7-deoxy-7-(4-(1-methylpiperidin-3-yl)phenylthio)-α-
thiolincosaminide (70) (a diastero mixture at an N-
methylpiperidine ring)
Compound 62 (6.9 mg, 9.75 μmol) and 2,2,2-trifluoroacetic acid (20 μl) in
CH2Cl2 (0.2 ml) were treated at − 20 °C for 20 min, and then treated room
temperature for 4 h according to the similar procedure as described for the
preparation of 44 to afford 70 (4.5 mg, 76%) as a colorless solid. [α]D23 +81.6°
(c 0.65, MeOH); ESI–MS m/z 608 (M+H)+ as C31H49N3O5S2; TOF–ESI–HR-
MS (M+H)+ calcd for C31H49N3O5S2: 608.3192, found: 608.3175; 1H NMR
(400 MHz,CD3OD) δ − 0.06–0.04 (m, 2 H), 0.37–0.47 (m, 2 H), 0.60–0.75 (m,
1 H), 1.08–1.28 (m, 4 H), 1.22 (d, J = 6.9 Hz, 3 H), 1.38–1.52 (m, 1 H), 1.63–
1.78 (m, 2 H), 1.78–1.89 (m, 3 H), 1.90 (s, 3 H), 2.12–2.24 (m, 3 H), 2.37 (s, 3
H), 2.72–2.83 (m, 2 H), 2.94–3.04 (m, 2 H), 3.18–3.26 (m, 1 H), 3.46–3.56 (m,
2 H), 3.73 (dq, J = 6.9, 2.3 Hz, 1 H), 3.79–3.85 (m, 1 H), 4.03 (dd, J = 10.2,
5.6 Hz, 1 H), 4.37 (m, 1 H), 4.50 (dd, J = 9.9, 2.3 Hz, 1 H), 5.21 (d, J = 5.6 Hz,
1 H), 7.12-7.19 (m, 2 H), 7.28-7.34 (m, 2 H).
Methyl (7S)-6-N-((2′S, 4′R)-4′-(cyclopropylmethyl)piperidine-2′-
carbonyl)-7-deoxy-7-(4-(pyrazin-2-yl)phenylthio)-α-
thiolincosaminide (74)
Compound 64 (crude) and 2,2,2-trifluoroacetic acid (0.5 ml) were treated at
0 °C for 30 min according to the similar procedure as described for
the preparation of 44 to afford 74 (41.1 mg, 48% in 2 steps from 33) as a
colorless solid. [α]D +78.5° (c 1.20, MeOH); ESI–MS m/z 589 (M+H)+
22
as C29H40N4O5S2; TOF–ESI–HR-MS (M+H)+ calcd for C29H40N4O5S2:
589.2518, found: 589.2514; 1H NMR (400 MHz, CD3OD) δ − 0.03 to
0.04 (m, 2 H), 0.40–0.48 (m, 2 H), 0.64–0.75 (m, 1 H), 1.09–1.27 (m, 4 H),
1.38 (d, J = 6.9 Hz, 3 H), 1.65–1.78 (m, 1 H), 1.79–1.87 (m, 1 H), 1.91
(s, 3 H), 2.10–2.18 (m, 1 H), 2.70–2.81 (m, 1 H), 3.19–3.26 (m, 1 H), 3.49
(dd, J = 12.0, 2.9 Hz, 1 H), 3.59 (dd, J = 10.2, 3.2 Hz, 1 H), 3.89 (dd, J = 3.2,
0.8 Hz, 1 H), 3.94 (dq, J =6.9, 2.4 Hz, 1 H), 4.10 (dd, J = 10.2, 5.6 Hz, 1 H),
Methyl (7S)-6-N-((2′S, 4′R)-4′-(cyclopropylmethyl)-1’-N-
methylpiperidine-2′-carbonyl)-7-deoxy-7-(4-(1-methylpiperidin-3-yl)
phenylthio)-α-thiolincosaminide (71) (a diastero mixture at an N-
methylpiperidine ring)
Compound 70 (9.4 mg, 0.016 mmol), 36% aqueous formaldehyde (12 μl,
0.16 mmol), AcOH (9.0 μl, 0.16 mmol) and NaBH(OAc)3 (37.1 mg,
0.166 mmol) in MeOH (0.6 ml) were treated at room temperature for 1.5 h
according to the similar procedure as described for the preparation of 59 to
4.45 (dd, J = 10.0, 0.8 Hz,
1
H), 4.63 (dd, J = 10.0, 2.4 Hz,
H), 7.48-7.55 (m, H), 7.99-8.06 (m,
H), 8.64 (dd, J = 2.6, 1.5 Hz,
1
2
H),
H),
5.28 (d, J = 5.6 Hz,
8.50 (d, J = 2.6 Hz,
(d, J = 1.5 Hz, 1 H).
1
2
22
afford 71 (9.4 mg, 98%) as a colorless solid. [α]D +70.1° (c 0.15, MeOH);
1
1
H), 9.08
ESI–MS m/z 622 (M+H)+ as C32H51N3O5S2; TOF–ESI–HR-MS (M+H)+ calcd
for C32H51N3O5S2: 622.3348, found: 622.3342; 1H NMR (400 MHz, CD3OD) δ
−0.28 to − 0.16 (m, 2 H), 0.29–0.39 (m, 2 H), 0.55–0.67 (m, 1 H), 1.04–1.14
(m, 2 H), 1.15–1.31 (m, 2 H), 1.19 (d, J =6.8 Hz, 3 H), 1.38–1.57 (m, 2 H),
1.65–1.78 (m, 2 H), 1.79–1.89 (m, 2 H), 1.86 (s, 3 H), 1.89–1.97 (m, 1 H),
2.09–2.20 (m, 1 H), 2.23 (s, 3 H), 2.32–2.45 (m, 2 H), 2.47 (s, 3 H), 2.65 (br
dd, J =11.5, 2.4 Hz, 1 H), 2.73–2.84 (m, 1 H), 2.90–2.97 (m, 1 H), 3.05–3.15
(m, 2 H), 3.48 (dd, J = 10.2, 3.2 Hz, 1 H), 3.64–3.76 (m, 2 H), 4.00 (dd,
J = 10.2, 5.6 Hz, 1 H), 4.30 (d, J = 9.8 Hz, 1 H), 4.46 (dd, J = 9.8, 2.6 Hz, 1 H),
5.16 (d, J = 5.6 Hz, 1 H), 7.09-7.16 (m, 2 H), 7.25-7.34 (m, 2 H).
Methyl (7S)-6-N-((2′S, 4′R)-4′-(cyclopropylmethyl)-1′-N-
methylpiperidine-2′-carbonyl)-7-deoxy-7-(4-(pyrazin-2-yl)
phenylthio)-α-thiolincosaminide (75)
Compound 74 (31.0 mg, 0.050 mmol), 36% aqueous formaldehyde (12 μl,
0.15 mmol), AcOH (17 μl, 0.30 mmol) and NaBH(OAc)3 (31.6 mg,
0.15 mmol) in MeOH (0.5 ml) were treated at room temperature for 30 min
according to the similar procedure as described for the preparation of 59 to
25
afford 75 (28.4 mg, 94%) as a colorless solid. [α]D +72.4° (c 0.64, MeOH);
The Journal of Antibiotics

Synthesis and SARs of novel lincomycin derivatives Part 5
Y Wakiyama et al
18
ESI–MS m/z 603 (M+H)+ as C30H42N4O5S2; TOF–ESI–HR-MS (M+H)+ calcd H), 3.10–3.19 (m, 2 H), 3.51 (dd, J = 10.2, 3.2 Hz, 1 H), 3.77 (br dd, J = 3.2,
for C30H42N4O5S2: 603.2675, found: 603.2672; 1H NMR (400 MHz, CD3OD) δ
0.9 Hz, 1 H), 3.84 (dq, J = 7.0, 2.6 Hz, 1 H), 4.01 (dd, J = 10.2, 5.6 Hz, 1 H),
− 0.06 to 0.04 (m, 2 H), 0.37–0.47 (m, 2 H), 0.60–0.74 (m, 1 H), 1.08–1.22 (m,
2 H), 1.25–1.38 (m, 2 H), 1.39 (d, J = 7.0 Hz, 3 H), 1.46–1.60 (m, 1 H), 1.78–
1.85 (m, 1 H), 1.92 (s, 3 H), 1.95–2.02 (m, 1 H), 2.20–2.30 (m, 1 H), 2.34 (s, 3
H), 2.77 (br dd, J = 11.4, 2.1 Hz, 1 H), 2.99–3.07 (m, 1 H), 3.59 (dd, J = 10.2,
3.2 Hz, 1 H), 3.85 (dd, J = 3.2, 0.6 Hz, 1 H), 3.96 (dq, J = 6.9, 2.6 Hz, 1 H), 4.11
(dd, J = 10.2, 5.6 Hz, 1 H), 4.45 (br dd, J =9.9, 0.6 Hz, 1 H), 4.64 (dd, J = 9.9,
2.6 Hz, 1 H), 5.27 (d, J = 5.6 Hz, 1 H), 7.50–7.56 (m, 2 H), 8.01–8.07 (m, 2 H),
4.40 (br dd, J = 9.9, 0.9 Hz, 1 H), 4.57 (dd, J =9.9, 2.6 Hz, 1 H), 5.18 (d,
J = 5.6 Hz, 1 H), 7.42–7.49 (m, 2 H), 7.93-7.99 (m, 2 H), 9.14 (s, 1 H).
In vitro antibacterial activity
MIC (μg/ml) was determined by the agar dilution method, which was described
in Clinical and Laboratory Standards Institute (M07-07 in 2006). Test strains of
S. pneumoniae and S. pyogenes were subjected to seed culture using brain heart
infusion agar (Becton Dickinson and Company, Tokyo, Japan) and 5%
defibrinated horse blood. Test strains of H. influenzae were subjected to seed
culture using sensitivity disk agar-N ‘Nissui’ (Nissui, Tokyo, Japan), 5%
defibrinated horse blood, 5 μg ml− 1 Hemin and 15 μg ml−1 nicotinamide
adenine dinucleotide. A 5 μl portion of cell suspension of the test strains having
about 106 CFU ml− 1 was inoculated into sensitivity disk agar supplemented
with 5% defibrinated horse blood, 5 μg ml− 1 Hemin and 15 μg ml−1 nicoti-
namide adenine dinucleotide, and incubated at 37 °C for 18–22 h. Then, the
MIC was measured.
8.50 (d, J = 2.5 Hz,
J = 1.5 Hz, 1 H).
1 H), 8.65 (dd, J = 2.5, 1.5 Hz, 1 H), 9.09 (d,
Methyl (7S)-6-N-((2′S, 4′R)-4′-(cyclopropylmethyl)-1′-N-
methylpiperidine-2′-carbonyl)-7-deoxy-7-(4-(pyrimidin-5-yl)
phenylthio)-α-thiolincosaminide (76)
Compound 47 (894.4 mg, 1.52 mmol), 36% aqueous formaldehyde (1.10 ml,
14.8 mmol), AcOH (0.85 ml, 14.8 mmol) and NaBH(OAc)3 (3.31 g,
14.8 mmol) in MeOH (44 ml) were treated at room temperature for 1 h
according to the similar procedure as described for the preparation of 59 to
afford 76 (916.3 mg, quant) as a colorless solid. [α]D22 +75.4° (c 0.96, MeOH);
ESI–MS m/z 603 (M+H)+ as C30H42N4O5S2; TOF–ESI–HR-MS (M+H)+ calcd
for C30H42N4O5S2: 603.2675, found: 603.2672; IR (KBr) cm− 1 1077, 1415,
1508, 1653, 2361, 3020 and 3690; 1H NMR (400 MHz, CD3OD) δ − 0.06 to
0.04 (m, 2 H), 0.37–0.46 (m, 2 H), 0.63–0.73 (m, 1 H), 1.12-–1.19 (m, 2 H),
1.25–1.38 (m, 2 H), 1.37 (d, J =6.8 Hz, 3 H), 1.44–1.58 (m, 1 H), 1.75–1.84
(m, 1 H), 1.92–2.02 (m, 1 H), 1.94 (s, 3 H), 2.18 (dt, J = 12.1, 2.3 Hz, 1 H),
2.30 (s, 3 H), 2.69 (dd, J = 11.6, 2.7 Hz, 1 H), 2.95-3.03 (m, 1 H), 3.59 (dd,
J = 10.2, 3.1 Hz, 1 H), 3.85 (br dd, J = 3.1, 0.7 Hz, 1 H), 3.95 (dq, J = 6.8,
2.7 Hz, 1 H), 4.11 (dd, J = 10.2, 5.6 Hz, 1 H), 4.43 (br dd, J = 9.9, 0.7 Hz, 1 H),
4.64 (dd, J = 9.9, 2.7 Hz, 1 H), 5.27 (d, J =5.6 Hz, 1 H), 7.52–7.58 (m, 2 H),
7.65–7.72 (m, 2 H), 9.06 (s, 2 H), 9.11 (s, 1 H); 13C NMR (100 MHz, CD3OD)
δ 5.1, 9.3, 13.9, 20.8, 30.8, 32.8, 37.3, 38.5, 42.6, 44.6, 44.8, 53.8, 56.8, 69.5,
70.2, 70.8, 70.9, 72.2, 90.3, 128.6, 131.9, 133.0, 135.2, 138.4, 155.9, 157.9
and 176.3.
In vitro antibacterial activity (sensitivity distribution against S.
pneumoniae of 60 strains)
The MIC for S. pneumoniae was determined by the twofold microdilution
broth method using cation-adjusted Mueller–Hinton broth (Difco Laboratories,
Detroit, MI, USA) supplemented with 2% lysed horse blood recommended by
the Clinical and Laboratory Standards Institute.61 The inoculum was prepared
by making a direct colony Suspension, equivalent to a 0.5 McFarland standard,
with isolated colonies selected from Mueller–Hinton agar（Difco Laboratories)
supplemented with 5% defibrinated sheep blood. Fifty microliters of the
adjusted inoculum was added to each well already containing 50 μl of
antimicrobial agent in the dilution series. The final test concentration of
bacteria was approximately 5 × 104 CFU per well. The MIC was determined as
the lowest concentration that prevented visible growth of bacteria after
incubation at 35 °C for 20 h.
Neutropenic rat lung infection model
Methyl (7S)-6-N-((2′S, 4′R)-4′-(cyclopropylmethyl)piperidine-2′-
carbonyl)-7-deoxy-7-(4-(1,2,3-thiadiazol-4-yl)phenylthio)-α-
thiolincosaminide (77)
The study and its protocol were complied with Guidelines on the Management of
Animal Experiments established by the Pharmaceutical Research Center, Meiji
Seika Pharma Co., Ltd and approved by the Animal Experiment Management
Committee of it. Rats used in this study are 6-week-old, specific-pathogen-free,
male Sprague-Dawley rats (SD-rats) (n=3) (Charles River Laboratories Japan,
Inc., Kanagawa, Japan) weighing 160–180 g. These rats were bred under
controlled conditions (temperature, 21–25 °C; humidity, 50–70%; lighting hours,
0700–1900 h), and feed (CRF-1; Oriental Yeast Co., Ltd, Tokyo, Japan) and
water were available ad libitum. The rats were allowed to acclimatize for 1 week
before the study. The rats were rendered neutropenic by intraperitoneal
administration of cyclophosphamide (Sigma-Aldrich) 4 days and the day before
infection (80 mg kg−1 of body weight). The rats were infected with S.
pneumoniae by the injection of 106 CFU into lung through trachea under
anesthesia with mixture of ketamine hydrochloride and xylazine hydrochloride
(5:1) by injection intramuscularly. The rats were treated by subcutaneous
administration of the test compound at 2 h after infection and were killed
24 h after infection by injection of excessive amounts of pentobarbital. The lung
was removed and homogenized. Each homogenate was diluted 10-fold serially
with physiological saline and an aliquot of each initial homogenate and dilution
series was smeared onto a plate of brain heart infusion agar with 5% horse blood.
After was incubation at 35 °C for 24 h, the number of colonies grown on the
plate was counted. The detection limit was set at o2.0 log10 CFU per lung; if no
colonies were detected in the initial homogenate, the value of 2.0 log10 CFU per
lung was adopted. The data were expressed as the mean s.d. log10 CFU
per lung.
Compound 65 (crude) and 2,2,2-trifluoroacetic acid (0.50 ml) were treated at
0 °C for 30 min according to the similar procedure as described for the
preparation of 44 to afford 77 (44.3 mg, 51% in 2 steps from 33) as a colorless
solid. [α]D +80.4° (c 0.36, MeOH); ESI–MS m/z 595 (M+H)+ as
27
C27H38N4O5S3; TOF–ESI–HR-MS (M+H)+ calcd for C27H38N4O5S3:
595.2083, found: 595.2073; 1H NMR (400 MHz, CD3OD) δ 0.01–0.09 (m, 2
H), 0.43–0.54 (m, 2 H), 0.66–0.78 (m, 1 H), 1.15–1.22 (m, 1 H), 1.25–1.45 (m,
3 H), 1.38 (d, J =6.9 Hz, 3 H), 1.77–1.91 (m, 1 H), 1.94 (s, 3 H), 1.96–2.04 (m,
1 H), 2.32–2.41 (m, 1 H), 3.02 (dt, J = 13.1, 3.1 Hz, 1 H), 3.37-3.45 (m, 1 H),
3.59 (dd, J = 10.2, 3.2 Hz, 1 H), 3.38 (dd, J =12.6, 3.1 Hz, 1 H), 3.89 (dd,
J = 3.2, 0.9 Hz, 1 H), 3.94 (dq, J = 6.9, 2.5 Hz, 1 H), 4.10 (dd, J = 10.2, 5.6 Hz, 1
H), 4.47 (dd, J = 9.9, 0.9 Hz, 1 H), 4.66 (dd, J = 9.9, 2.5 Hz, 1 H), 5.28 (d,
J = 5.6 Hz, 1 H), 7.49–7.56 (m, 2 H), 8.01–8.09 (m, 2 H), 9.22 (s, 1 H).
Methyl (7S)-6-N-((2′S, 4′R)-4′-(cyclopropylmethyl)-1′-N-
methylpiperidine-2′-carbonyl)-7-deoxy-7-(4-(1,2,3-thiadiazol-4-yl)
phenylthio)-α-thiolincosaminide (78)
Compound 77 (29.7 mg, 0.050 mmol), 36% aqueous formaldehyde (12 μl,
0.15 mmol), AcOH (17 μl, 0.30 mmol) and NaBH(OAc)3 (31.6 mg,
0.15 mmol) in MeOH (0.5 ml) were treated at room temperature for 30 min
according to the similar procedure as described for the preparation of 59 to
23
afford 78 (27.3 mg, 90%) as a colorless solid. [α]D +48.9° (c 0.28, MeOH);
ESI–MS m/z 609 (M+H)+ as C28H40N4O5S3; TOF–ESI–HR-MS (M+H)+ calcd
for C28H40N4O5S3: 609.2239, found: 609.2231; 1H NMR (400 MHz, CD3OD) δ
− 0.14 to 0.04 (m, 2 H), 0.30–0.40 (m, 2 H), 0.52–0.65 (m, 1 H), 1.00–1.18 (m,
2 H), 1.25–1.38 (m, 2 H), 1.30 (d, J = 7.0 Hz, 3 H), 1.50–1.67 (m, 1 H), 1.78–
DEDICATION
Dedicated to Professor K. C. Nicolaou and his outstanding contribu-
1.88 (m, 1 H), 1.86 (s, 3 H), 1.97–2.06 (m, 1 H), 2.49 (s, 3 H), 2.50–2.64 (m, 1 tions to complex natural product total synthesis and chemical biology.
The Journal of Antibiotics

Synthesis and SARs of novel lincomycin derivatives Part 5
Y Wakiyama et al
19
CONFLICT OF INTEREST
The authors declare no conflict of interest.
25 Bannister, B. Modifications of lincomycin involving the carbohydrate portion. Part III.
The 7-O-methyl and 6-de-(1-hydroxyethyl) analogues. J. Chem. Soc. Perkin Trans. I
1676–1682 (1973).
26 Bannister, B. Modifications of lincomycin involving the carbohydrate portion. Part IV.
(7S)-7-alkoxy-7-deoxy-analogues. J. Chem. Soc. Perkin Trans. I 1974, 360–369 (1974).
ACKNOWLEDGEMENTS
27 Bannister, B.
& Mydlow, P. K. The S-alkylation of sulphides by an activated
We thank Mr A. Tamura, Dr E. Shitara and Dr T. Yoshida for encouragement
and valuable discussion. We are grateful to Professor Emeritus Dr M. Konno
for supervision through our in-house drug discovery program in LCM field.
We also thank Dr T. Murata for ROESY analysis; Ms M. Ishii for direction in
intellectual properties; Mr T. Watanabe for computational chemistry; Ms T.
Miyara, Ms S. Miki and Ms K. Kaneda for analytical and synthetic chemistry;
Mr Y. Takayama and Ms K. Yamada for biological studies; and Ms M. Takagi
and Ms Y. Saito for English manuscript.
carbohydrate epimine under acidic catalysis: the formation of α-acetamido-sulphides.
Part 5. The introduction of functionality into the sulphide substituent. J. Chem. Res. (S)
1989, 90–91 (1989).
28 Bannister, B. The S-alkylation of sulphides by an activated carbohydrate epimine under
acidic catalysis: The formation of α-acetamido-sulphides. Part 4. Reaction with dithioa-
cetals and monothioacetals. J. Chem. Soc. Perkin. Trans. I 1980, 540–552 (1980).
29 Bannister, B. 7S)-7-deoxy-7-substituted-alkylthio-lincomycin. S-Alkylation of sulphides
by an activated epimine under acidic catalysis: formation of α-acetamido-sulphides.
Tetrahedron 40, 1633–1660 (1984).
30 Bannister, B. The Upjohn Company. Derivatives of lincomycin and its analogs and
process. US Patent US3915954 A (1973).
31 Bannister, B. The Upjohn Company. Derivatives of lincomycin and its analogs and
process. Canadian Patent CA-971956 A1 (1972).
32 Sztaricskai, F. et al. Semisynthetic modification of antibiotic lincomycin. J. Antibiot.
49, 941–943 (1996).
1
2
Reinert, R. R., van der Linden, M. & Al-Lahham, A. Molecular characterization of the
first telithromycin-resistant Streptococcus pneumoniae isolate in Germany. Antimicrob.
Agents Chemother. 49, 3520–3522 (2005).
Kim, S. H. et al. Changing trends in antimicrobial resistance and serotypes of
Streptococcus pneumoniae isolates in Asian countries: an Asian Network for Surveil-
lance of Resistant Pathogens (ANSORP) study. Antimicrob. Agents Chemother. 56,
1418–1426 (2012).
Ajito, K., Miura, T., Furuuchi, T. & Tamura, A. Sixteen-membered macrolides: chemical
modifications and future applications. Heterocycles 89, 281–352 (2014).
Morimoto, S., Takahashi, Y., Watanabe, Y. & Omura, S. Chemical modification of
erythromycins I. Synthesis and antibacterial activity of 6-O-methylerythromycins A. J.
Antibiot. 37, 187–189 (1984).
Slobodan, D. et al. Erythromycin series. Part 13. Synthesis and structure elucidation of
10-dihydro-10-deoxo-11-methyl-11-azaerythromycin A. J. Chem. Res. Synop. 40,
152–153 (1988).
Retsema, J. et al. Spectrum and mode of action of azithromycin (CP-62,993), a new
15-membered-ring macrolide with improved potency against Gram-Negative Organisms.
Antimicrob. Agents Chemother. 31, 1939–1947 (1987).
Denis, A. et al. Synthesis and antibacterial activity of HMR 3647 a new ketolide highly
potent against erythromycin-resistant and susceptible pathogens. Bioorg. Med. Chem.
Lett. 9, 3075–3080 (1999).
33 Umemura, E. et al. Lincomycin derivative and antibacterial agent containing the same
as active ingredient. Japanese Patent WO/2007/066805 A1 (14 June 2007).
34 Wakiyama, Y. et al. Lincomycin derivatives and antibacterial agents containing the same
as the active ingredient. Japanese Patent WO/2008/146917 A1 (4 December 2008).
35 Umemura, E. et al. Lincosamide derivative, and antibacterial agent comprising the
same as active ingredient, WO/2008/146919 A1 (4 December 2008).
36 Umemura, E. et al. Synthesis of novel lincomycin derivatives and their in vitro
antibacterial activities. J. Antibiot. 66, 195–198 (2013).
37 Wakiyama, Y. et al. Synthesis and structure–activity relationships of novel lincomycin
derivatives. Part 1. Newly generated antibacterial activities against Gram-positive
bacteria with erm gene by C-7 modification. J. Antibiot. 69, 368–380 (2016).
38 Wakiyama, Y. et al. Synthesis and structure–activity relationships of novel
lincomycin derivatives. Part 2. Synthesis of 7(S)-7-deoxy-7-(4-morpholinocarbonylphe-
nylthio)lincomycin and its 3-dimensional analysis with rRNA. J. Antibiot. 69,
428–439 (2016).
39 Kumura, K. et al. Synthesis and antibacterial activity of novel lincomycin derivatives. I.
Enhancement of antibacterial activities by introduction of substituted azetidines. J.
Antibiot. 69, 440–445 (2016).
40 Wakiyama, Y. et al. Synthesis and structure–activity relationships of novel lincomycin
derivatives Part 3: discovery of the 4-(pyrimidin-5-yl)phenyl group in synthesis of 7(S)-
thiolincomycin analogs. J. Antibiot. 70, 52–64 (2017).
41 Kumura, K. et al. Synthesis and antibacterial activity of novel lincomycin derivatives. II.
Exploring (7S)-7-(5-aryl-1,3,4-thiadiazol-2-yl-thio)-7-deoxylincomycin derivatives. J.
Antibiot. 70, 655–663 (2017).
42 Wakiyama, Y. et al. Synthesis and structure-activity relationships of novel
lincomycin derivatives Part 4. Synthesis of novel lincomycin analogs modified at the
6- and 7-positions and their potent antibacterial activities. J. Antibiot. 70,
888–906 (2017).
43 Kumura, K. et al. Synthesis and antibacterial activity of novel lincomycin derivatives. III.
Optimization of a phenyl thiadiazole moiety. J. Antibiot. (e-pub ahead of print 5 July
2017; doi:10.1038/ja.2017.59).
44 Argoudelis, A. D., Coats, J. H., Mason, D. J. & Sebek, O. K. Microbial transformation of
antibiotics. III. Conversion of clindamycin to 1′-demethylclindamycin and clindamycin
sulfoxide by Streptomyces species. J. Antibiot. 22, 309–314 (1969).
45 Magerlein, B. J., Birkenmeyer, R. D. & Kagan, F. Lincomycin. VI. 4′-alkyl analogs of
lincomycin. Relationship between structure and antibacterial activity. J. Med. Chem.
10, 355–359 (1967).
3
4
5
6
7
8
9
Clay, K. D. et al. Severe hepatotoxicity of telithromycin: three case reports and
literature review. Ann. Intern. Med. 144, 415–420 (2006).
Ross, D. B. The FDA and the case of Ketek. N. Engl. J. Med. 356, 1601–1604 (2007).
10 Gleason, P. P., Walters, C., Heaton, A. H. & Schafer, J. A. Telithromycin: the perils of
hasty adoption and persistence of off-label prescribing. J. Manag. Care Pharm. 13,
20–25 (2007).
11 Department of Health and Human Services. Telithromycin (marketed as Ketek)
information available at http://www.fda.gov/drugs/drugsafety/postmarketdrugsafetyinfor-
mationforpatientsandproviders/ucm107824.htm Accessed 26 April 2007.
12 Miura, T. et al. Novel azalides derived from sixteen-membered macrolides. I. Isolation of
the mobile dialdehyde and its one-pot macrocyclization with an amine. J. Antibiot. 60,
407–435 (2007).
13 Miura, T. et al. Novel azalides derived from 16-membered macrolides. III. Azalides
modified at the C-15 and 4” positions: improved antibacterial activities. Bioorg. Med.
Chem. 18, 2735–2747 (2010).
14 Mason, D. J., Dietz, A. & Deboer, C. Lincomycin, a new antibiotic I. Discovery and
biological properties. Antimicrob. Agents Chemother. 554–559 (1962).
15 Magerlein, B. J. & Lincomycin, X. The chemical synthesis of lincomycin. Tetrahedron
Lett. 1, 33–36 (1970).
46 Magerlein, B. J. Lincomycin. 14. An improved synthesis and resolution of the
antimalarial agent, 1′-demethyl-4′-depropyl-4′ (R)- and -(S)-pentylclindamycin hydro-
chloride (U-24,729A). J. Med. Chem. 15, 1255–1259 (1972).
47 Magerlein, B. J. & Lincomycin. VII. 4′-depropyl-4′-ethoxylincomycins. J. Med. Chem.
10, 1161–1163 (1967).
16 Howarth, G. B., Szarek, W. A. & Jones, J. K.N. The synthesis of lincomycin. J. Chem.
Soc. (c) 16, 2218–2224 (1970).
17 Perlman, D. Structure-Activity Relationships Among the Semisynthetic Antibiotics.
Academic Press: New York, San Francisco, London, A Subsidiary of Harcourt Brace
Jovanovich Publishers, 1977, pp 600–651.
48 Lewis, J. G. et al. Novel lincomycin derivatives possessing antimicrobial activity. WO/
2006/055070 A2 (26 May 2006).
49 Birkenmeyer, R. D., Kroll, S. J., Lewis, C., Stern, K. F. & Zurenko, G. E. Synthesis and
antimicrobial activity of clindamycin analogues: pirlimycin, a potent antibacterial agent.
J. Med. Chem. 27, 216–223 (1984).
50 O’Dowd, H. et al. Novel antibacterial azetidine lincosamides. Bioorg. Med. Chem. 18,
2645–2648 (2008).
18 Birkenmeyer, R. D. & Kagan, F. Lincomycin. XI. Synthesis and structure of clindamycin.
A potent antibacterial agent. J. Med. Chem. 13, 616–619 (1970).
19 Shan, P. J., Vakil, N.
& Kabakov, A. Role of intravenous immune globulin in
streptococcal toxic shock syndrome and Clostridium difficile infection. Am. J. Health
Syst. Pharm. 72, 1013–1019 (2015).
51 O’Dowd, H. et al. Novel antibacterial azetidine lincosamides. 44 the Interscience
Conference on Antimicrobial Agents and Chemotherapy. Poster F-2037; Washington,
DC, USA, 2004.
20 Hoeksema, H. Octoses from antibiotics. The Upjohn Company, Kalamazoo, Mich.,Abstr.
Pap. Division of Carbohydrate Chemistry, 149th Meet, American Chemical Society. Am.
Chem Soc. Detroit, Mich p 9C (1965).
52 Lewis, J. G. et al. Novel antimicrobial 7-methyl lincosamides: Pipecolamide analogs.
43rd Interscience Conference on Antimicrobial Agents and Chemotherapy. Poster
F-1389; Washington, DC, USA, 2004.
53 Chen, T. et al. Novel 4′-cycloalkyl pipecolamide lincosamide analogs. 44 th Inter-
science Conference on Antimicrobial Agents and Chemotherapy. Poster F-2036;
Washington, DC, USA, 2004.
21 Magerlein, B. J., Birkenmeyer, R. D. & Kagan, F. Chemical modification of lincomycin.
Antimicrob. Agents Chemother. 727–736 (1966).
22 Sinkula, A. A., Morozowich, W., Lewis, C. & Mackellar, F. A. Synthesis and bioactivity of
lincomycin-7-monoesters. J. Pharm. Sci. 58, 1389–1392 (1969).
23 Magerlein, B. J.
& Kagan, F. Lincomycin. IX. 7-Thiol and thioamido analogs of
lincomycin. J. Med. Chem. 12, 974–977 (1969).
54 Lopez, S. L. et al. Characterization of the spectrum of in vitro activity of VIC-105555, a
new lincosamide. 44 th Interscience Conference on Antimicrobial Agents and
Chemotherapy. Poster F-2038; Washington, DC, USA, 2004.
24 Lewis, J. G. et al. Novel Antimicrobial 7-methyl Lincosamides: Prolamide Analogs. 43rd
Interscience Conference on Antimicrobial Agents and Chemotherapy Poster F-1388;
Washington, DC, USA.
The Journal of Antibiotics

Synthesis and SARs of novel lincomycin derivatives Part 5
Y Wakiyama et al
20
55 Shuman, R. T., Ornstein, P. L., Paschal, J. W. & Gesellchen, P. D. An improved
synthesis of homoproline and derivatives. J. Org. Chem. 55, 738–741 (1990).
56 Schroeder, W., Bannister, B. & Hoeksema, H. Lincomycin. III. The structure and
stereochemistry of the carbohydrate moiety. J. Am. Chem. Soc. 89,
2448–2453 (1967).
57 Houtman, R. L. & Mich, P. The Upjohn Company. Trimethylsilyl ethers of lincomycin
and its compounds. US Patent US3418414 (1966).
58 Itoh, T. & Mase, T. A general palladium-catalyzed coupling of aryl bromides/triflates
and thiols. Org. Lett 6, 4587–4590 (2004).
59 Magerlein, B. J. & Kagan, F. Lincomycin. 8. 4′-Alkyl-1′-demethyl-4′-depropylclinda-
mycins, potent antibacterial and antimalarial agents. J. Med. Chem. 12, 780 (1969).
60 Farrell, D. J., Morrissey, I., Bakker, S. & Felmingham, D. Molecular characterization of
macrolide resistance mechanisms among Streptococcus pneumoniae and Streptococ-
cus pyogenes isolated from the PROTEKT 1999-2000 study. J. Antimicrob. Chemother.
50(suppl_2), 39–47 (2002).
61 Clinical and Laboratory Standards Institute. Performance Standards for Antimicrobial
Susceptibility Testing; Sixteenth Informational Supplement. CLSI Document M100-
S16, Clinical and Laboratory Standards Institute, Wayne, PA, (2006).
Supplementary Information accompanies the paper on The Journal of Antibiotics website (http://www.nature.com/ja)
The Journal of Antibiotics