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

Article abstract of DOI:10.1038/ja.2015.119

We synthesized 7(S)-7-deoxy-7-arylthiolincomycin derivatives possessing a heterocyclic ring at the C-7 position via sulfur atom by either Mitsunobu reaction of 2,3,4-tris-O-(trimethylsiliyl)lincomycin or S N 2 reaction of 7-O-methanesulfonyl-2,3,4-tri-O-t

Full text of DOI:10.1038/ja.2015.119

The Journal of Antibiotics (2015), 1–13
2015 Japan Antibiotics Research Association All rights reserved 0021-8820/15
www.nature.com/ja
&
ORIGINAL ARTICLE
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
Yoshinari Wakiyama, Ko Kumura, Eijiro Umemura, Kazutaka Ueda, Satomi Masaki, Megumi Kumura,
Hideki Fushimi and Keiichi Ajito
We synthesized 7(S)-7-deoxy-7-arylthiolincomycin derivatives possessing a heterocyclic ring at the C-7 position via sulfur atom by either
Mitsunobu reaction of 2,3,4-tris-O-(trimethylsiliyl)lincomycin or SN2 reaction of 7-O-methanesulfonyl-2,3,4-tri-O-trimethylsiliyllincomycin.
As a result, 7(S)-7-deoxy-7-arylthiolincomycin derivatives 16, 21 and 27 exhibited antibacterial activities against respiratory
infection-related Gram-positive bacteria with erm gene, although clindamycin did not have any activities against those pathogens.
Furthermore, 7(S)-configuration of lincomycin derivatives was found to be necessary for enhancing antibacterial activities from the
comparison results of configurations of 16 (S-configuration) and 30 (R-configuration) at the 7-position.
The Journal of Antibiotics advance online publication, 16 December 2015; doi:10.1038/ja.2015.119
INTRODUCTION
Clarithromycin11 and azithromycin12 (Figure 1) are not effective
Macrolide antibiotics possess broad spectrum of antibacterial activity enough against resistant bacteria (S. pneumoniae and S. pyogenes) with
against Gram-positive bacteria (Streptococcus pneumoniae, Streptococcus erm gene and influenced by S. pneumoniae with mef gene. On the
pyogenes, etc.), Haemophilus influenzae, Moraxella catarrhalis, Myco- other hand, telithromycin (TEL),13 which was launched as the first
plasma pneumoniae and Neisseria gonorrhoeae and also have a safety ketolide antibiotic, is effective against resistant bacteria with erm and
profile as oral drugs. Therefore, macrolide antibiotics have been used mef genes. X-ray crystallographic6,14 and footprinting analysis15–17
as chemotherapeutic agents in clinical sites over many years. Resistant indicated that TEL would be capable to bind to not only domain V
bacteria, however, have markedly increased recently,1–3 and this (A2058Ec, A2059Ec) of 23S rRNA but also to domain II (A752). TEL,
phenomenon has caused serious problems in the treatment of bacterial however, has possibility to cause serious liver damage18,19 and loss of
respiratory infections.
consciousness,20,21 and it is scarcely used in Japan. No oral antibiotic,
Macrolide antibiotics inhibit bacterial protein synthesis. Macrolide which is effective against the resistant bacteria with erm and mef genes,
antibiotics have potent antibacterial activities through inhibiting with no problems in terms of safety or taste, has been launched so far.
elongation of an amino-acid sequence by binding to 23S ribosomal
Lincomycin (LCM)22–25 was isolated as a secondary metabolite
RNA.4–6 The mechanisms of action for bacteria to gain resistance are from the fermentation broth of Streptomyces lincolnensis. Clindamycin
manifold, but in general, these can be characterized as involving drug (CLDM)26 was synthesized by chemical modification of LCM (Figure 1)
efflux, alterations in the drug target site or drug inactivation. Resistant and exhibited improved antimicrobial activities and pharmacokinetics
mechanisms in macrolides have diversified recently. Notably, there are compared with LCM. But they are not effective against resistant
major bacterial strains in clinical site, with point mutation in the drug bacteria (S. pneumoniae and S. pyogenes) with erm gene (Table 1).
target site,7,8 with methylase produced by erm gene and with efflux
pump produced by mef gene.
Chemical modifications at the C-7 positions of LCM
(7-dehydrolincomycin (7-ketolincomycin),27 7-deoxylincomycin,28
The methylase of bacteria inhibits macrolide binding to 23S lincomycin-7-acylate29 and lincomycin-7-carbonate,29 7(R)-7-azido-7-
ribosomal RNA through either methylation or dimethylation at the deoxylincomycin,25 7(R)-7-amino-7-deoxylincomycin,25 7(R)-7-
N-6 position of the adenine residue (A2058Ec).7,9,10 On the other cyano-7-deoxylincomycin,25 7(R)-7-deoxy-7-thiolincomycin,30
hand, the efflux pump of bacteria is able to transport a variety of 7(S)-7-deoxy-7-thiolincomycin,30 7(S)-7-bromo-7-deoxylincomycin,26
compounds, thus conferring resistance to a broad range of antibiotics. 7(S)-7-deoxy-7-iodolincomycin,26 7(R)-7-chloro-7-deoxylincomycin,26
Pharmaceutical Research Center, Meiji Seika Pharma Co., Ltd, Kohoku-ku, Yokohama, Japan
Correspondence: Dr K Ajito, Pharmaceutical Research Center, Meiji Seika Pharma Co., Ltd, 760 Morooka-cho, Kohoku-ku, Yokohama 222–8567, Japan.
E-mail: keiichi.ajito@meiji.com
Received 4 August 2015; revised 15 September 2015; accepted 29 October 2015

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Me
N
O
Me
HO
Me
Me
OMe
Me
Me
Me
HO
Me
Me
O Me
OH
Me
O
R2
R1
O
OH
Me
OH
Me
NMe2
Me
NMe2
Me
N
HO
HN
HO
O
O
O
O
O
Me
H
Me
Me
HO
SMe
O
O
O
O
OMe
Me
OMe
Me
Me
Me
Me
HO
OH
OH
OH
O
O
Me
LCM: R1 = OH, R2 = H
CLDM: R1 = H, R2 = Cl
Clarithromycin (CAM)
Azithromycin (AZM)
Figure 1 Chemical structures of the representative macrolides, lincomycin (LCM) and clindamycin (CLDM).
Table 1 Antibacterial activities (MIC, μg ml− 1) of the representative macrolides, lincomycin (LCM) and clindamycin (CLDM)
Abbreviations: AZM, azithromycin; CAM, clarithromycin.
aAll strains except standard organisms were clinically isolated.
b(c): constitutive; (i): inducible.
Grey shading strains are target strains.
and 7-epilincomycin (7(S)-lincomycin),26 7-deoxy-7-methyllincomycin31 than LCM against Gram-positive or Gram-negative organisms, and
and so on) have been investigated so far. In these compounds, 7(S)-7- 7(R)-7-deoxy-7-imidazol-2-yl-thiolincomycin, which had been reported
bromo-7-deoxylincomycin and 7(S)-7-deoxy-7-iodolincomycin exhib- by Sztaricskai et al.,39 retained the same order of magnitude of
ited enhanced antibacterial activities in the same order of magnitude as antibacterial activities against tested organisms as those of LCM.
CLDM, and 7(R)-7-azido-7-deoxylincomycin had the same antibac- Antibacterial activities were affected by both configuration and
terial activities as LCM.
a structure of a substituent at the 7-position. 7(S)-7-deoxy-7-
In the case of possessing a chlorine atom at the 7-position, CLDM phenylthiolincomycin was reported by Bannister et al.38 but no
(7(S)-Cl) had stronger antibacterial activities than 7-epiclindamycin antibacterial activity of this compound was reported.
(7(R)-Cl). 7-Epilincomycin (7(S)-lincomycin) had one-half of the
Thus we were interested in derivatives with a heterocyclic ring
potency of the LCM possessing 7(R)-configuration (7(S)-OHo7(R)-OH). introduced via sulfur atom at the C-7 position with 7(S)-
7(R)-7-O-methyllincomycin, of which 7-hydrolyl group was pro- configuration. According to the above publications, LCM derivatives
tected, showed improved potency, whereas 7(S)-7-O-methyllincomy- exhibited much stronger in vitro activities compared with LCM, but
cin had stronger activities of 3.5 times the response of LCM against no LCM derivatives were effective against resistant bacteria with
Sarcina lutea (7(S)-OMe47(R)-OMe).32,33 Unfortunately, both larger erm gene.
alkoxy groups and substituted alkoxy groups resulted in weaker
LCM and CLDM inhibited bacterial protein synthesis similar to
antibacterial activities than those of LCM.
macrolide antibiotics. The structures of lincomycin derivatives are
On the other hand, both 7(S)-7-deoxy-7-thiolincomycin and different from those of macrolide antibiotics, but X-ray crystal-
7(R)-7-deoxy-7-thiolincomycin showed only 10% activity as lographic analysis indicated that their binding sites to rRNA are
compared with LCM. 7(S)-7-alkylthio-7-deoxylincomycin and closely located in a neighboring area.4,6 According to the report,4,6
7(S)-7-substituted alkylthio-7-deoxylincomycin34–38 were more active there were several major interactions by hydrogen bonding between
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Scheme 1 Synthesis of 7(S)-7-arylthio-7-deoxylincomycin derivatives. Conditions: a, TMSCl, HMDS, Py, r.t., 2 h; b, 80% AcOH, MeOH, r.t., 16 h; Method A:
c, PPh3, DEAD, the corresponding HS-Ar, THF or toluene, 0 °C to 50 °C, 16–18 h, d, 1–2 N HCl, MeOH, r.t., 30 min; Method B: c, PBu3, DEAD, the
corresponding Ar-S-S-Ar, THF, 0 °C to r.t., 19–25 h; d, 2 N HCl, r.t., 0.5–3 h; Method C: c, PPh3, DEAD, tert-butyl 5-mercapto-1,3,4-thiadiazol-2-
ylcarbamate or tert-butyl 5-mercapto-1,3,4-thiadiazol-2-yl(methyl)carbamate, THF, 0 °C to r.t., 17 h, d, TFA, r.t., 60 min; e, NaOMe, allyl iodide, MeOH, r.t.;
f, SnCl2·H2O, NaBH4, EtOH, r.t., 3 h; g, 6-aminobenzo[d]thiazole-2-thiol, K2CO3, DMF, 100 °C, 16 h; h, SnCl2·H2O, NaBH4, EtOH, r.t., 3 h; i, MsCl, TEA,
DMF, r.t., 20 min; j, PPh3, DEAD, tert-butyl 2-(5-mercapto-1,3,4-thiadiazol-2-ylamino)-2-oxoethylcarbamate, THF, 0 °C to r.t., 17 h, k, TFA, r.t., 0.5 h; l,
TMSCl, HMDS, Py, r.t., 2.5 h; m, 2-methoxyacetyl chloride, TEA, THF, 0 °C, 2 h; n, 1 N HCl, MeOH, r.t., 2 h; o, MsCl, TEA, CHCl3, r.t., 3 h; p, the
corresponding HS-Ar, K2CO3, DMF, 80 °C, 3–16 h, q, 1 N HCl, MeOH, r.t., 0.5–2 h.
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Table 2 Antibacterial activities (MIC, μg ml− 1) of 7-thio-substituted LCM derivatives
Abbreviations: CLDM, clindamycin; LCM, lincomycin.
aAll strains except standard organisms were clinically isolated.
b(c): constitutive; (i): inducible.
Grey shading strains are target strains.
the peptidyl transferase cavities (A2058Ec, A2059Ec and G2520Ec) and had the same antibacterial activity as LCM. Here we planned synthesis
hydroxyl groups at the sugar portion of CLDM. These data suggest of lincomycin analogs possessing a heterocyclic ring via sulfur atom
that it is difficult for us to improve antibacterial activity by chemical focusing on the 7(S)-configuration at the 7-position, in order to
modification at the sugar moiety. In fact, 2-deoxylincomycin40 generate unreported antibacterial activity against respiratory infection-
has been reported to show only 1% activity compared with related Gram-positive bacteria with erm gene.
LCM.
As we previously described, TEL has a risk of causing serious side RESULTS AND DISCUSSION
effects18–21 and it is rarely used in Japan. Furthermore, its production Design of LCM derivatives
cost seems to be relatively high owing to its complicated structure. On The results of X-ray crystallographic analysis4–6 have already been
the other hand, CLDM possessing a simple structure has similar reported in application of CLDM. According to three-dimensional
antibacterial activity against susceptible strains such as clarithromycin information around the 7-position of CLDM, we hypothesized that
and exhibits acceptable oral absorption in animals and humans. CLDM had enough three-dimensional space around the 7-position,
However, CLDM is not effective enough against resistant bacteria of and it might be able to enhance antibacterial activities by filling the
S. pneumoniae or S. pyogenes with erm gene. So a novel oral space with an appropriate substituent. So we designed 7(S)-LCM
lincomycin analog, which is effective against resistant bacteria with derivatives possessing a hydrophobic heterocyclic ring via sulfur atom
erm gene and/or mef gene and does not have any problems in safety, and practically synthesized 7(S)-7-arylthio-7-deoxylincomycin by
taste or pharmacokinetics, is strongly desired for treatment of Mitsunobu reaction.
respiratory infections in clinical sites.
On the other hand, 7(S)-7-azido-7-deoxylincomycin, CLDM, 7(S)- Synthesis of 7(S)-7-arylthio-7-deoxylincomycin derivatives
7-bromo-7-deoxylincomycin and 7(S)-7-alkylthio-7-deoxylincomycin Synthesis of 7(S)-7-arylthio-7-deoxylincomycin derivatives is outlined
had the same or stronger antibacterial activity compared with LCM. in Scheme 1. We first prepared a key intermediate 141 derived from
According to the relationships between configuration and a substituent LCM in two steps in order to construct the same configuration at the
(7(S)-Cl47(R)-Cl and 7(S)-OMe47(R)-OMe), enhancement of 7-position as CLDM in final target molecules. Our synthesis began
activities in 7(S)-configuration might require a hydrophobic substi- with silylation of all OH groups of LCM, and the 7-O-TMS group was
tuent such as a chlorine atom or a methyl group, not as OH or SH selectively deprotected by AcOH to give the key intermediate (1) with
(7(S)-OHo7(R)-OH (LCM), 7(S)-SH≈7(R)-SHoLCM). Larger an excellent yield. LCM derivatives (2–5, 7–17 and 21–27), which
alkoxy groups and substituted alkoxy groups with 7(S)-configuration possess a heterocyclic ring at the C-7 position via sulfur atom, were
resulted in weaker antibacterial activities than those of LCM, while 7 synthesized from
1 with the corresponding thiol under the
(S)-7-alkylthio-7-deoxylincomycin was more active than LCM against Mitsunobu condition (Methods A and C).42,43 Compounds 638 and
Gram-positive organisms. As a result, a sulfur atom might be 18–20 possessing a phenyl thiol group were synthesized by Method B
preferable to an oxygen atom at the 7-position for enhancing in application of the corresponding disulfide. Furthermore,
antibacterial activities. 7(R)-7-deoxy-7-imidazol-2-yl-thiolincomycin compound 2838 was prepared by allylation of 5 under the NaOMe
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Table 3 Antibacterial activities (MIC, μg ml− 1) of LCM derivatives possessing a substituted benzothiazol-2-ylthio group at the 7-position
Abbreviation: LCM, lincomycin.
aAll strains except standard organisms were clinically isolated.
b(c): constitutive; (i): inducible.
Grey shading strains are target strains.
condition to investigate structure–activity relationship (SAR) of an sulfur atom, is shown in Table 2. Compound 2 was shown to be
allyl group. As a part of chemical modification of the benzothiazole slightly more potent against H. influenzae than CLDM. Compound 3
group, 29 was also prepared by reduction of the nitro group of 17 had weak activity against S. pyogenes with erm gene, although CLDM
using SnCl2·H2O-NaBH4. Next, 30 was synthesized by SN2 reaction did not have any activities against the pathogen. So we pursued further
of CLDM with the corresponding thiol under the basic optimization at the 7-position. As a result, derivatives possessing a
condition to confirm the effect on antibacterial activity by phenyl, thienyl or 1,3,4-thiadiazolyl group did not exhibit remarkable
configuration at the C-7 position. On the other hand, the nitrophenyl activity against S. pyogenes with erm gene.
Filling a space around the C-7 position might enhance antibacterial
activities against resistant S. pyogenes with erm gene. Thus we selected
3 as a fundamental bicycle framework for further optimization.
Additionally, 6 and 11 were selected as general examples of an isolated
6-membered ring and an isolated 5-membered ring, respectively. Next
we tried to enhance antibacterial activities by introducing a substitute
to the selected three frameworks.
derivatives (18–20), which were synthesized under the
Mitsunobu condition, were reduced to give the corresponding
aminophenyl derivatives (31–33). Because compound 33 was the
most potent compared with 31 or 32, 33 was converted to
compound 34. A Boc group and three trimethylsilyl (TMS) groups
of 35 prepared by the Mitsunobu condition were simultaneously
deprotected to give a desired compound 36. TMS protection of 21
gave 37, which was reacted with 2-methoxyacetyl chloride with
triethylamine, and then deprotected to provide a methoxyacethyl
derivative (38).
SAR analysis of LCM derivatives possessing a benzothiazol-2-ylthio
group at the 7-position
LCM derivatives having a benzothiazoyl or a thiazoropyridyl group at
the 7-position were synthesized and their antibacterial activities are
shown in Table 3. Notably, conversion of 3 to 12, 15 or 16 at the
7-position improved antibacterial activity against S. pneumoniae with
erm gene. Especially, antibacterial activity of 16 was significantly
enhanced. An amino group might have a role to enhance antibacterial
activity and may interact with a certain binding site on 23S rRNA.
Compound 29 possessing an amino group at the 5-position in the
benzothiazole ring generally exhibited improved antibacterial activity
On the other hand, Mitsunobu conditions still had problems, and
thus compounds 18, 20 and 40 were synthesized in only low yields. So
compounds 20, 40 and 41 were synthesized by SN2 reactions with the
corresponding thiol in good yields under the basic conditions in
application of a methanesulfonate 39 synthesized from 1. SAR of novel
LCM derivatives are shown in Tables 2–5.
SAR analysis of LCM derivatives possessing a heterocyclic ring at
the C-7 position via sulfur atom
Antibacterial activity of LCM derivatives, which possessed a hetero- against S. pneumoniae with erm gene compared with 3. On the other
cyclic ring, the benzene ring or an allyl group at the C-7 position via hand, we prepared 30 possessing the (R)-configuration at the
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Table 4 Antibacterial activities (MIC, μg ml− 1) of LCM derivatives possessing a substituted phenylthio group at the 7-position
Abbreviation: LCM, lincomycin.
aAll strains except standard organisms were clinically isolated.
b(c): constitutive; (i): inducible.
Grey shading strains are target strains.
7-position to confirm its potency. Based on comparison of antibacter- SAR analysis of LCM derivatives possessing a 1,3,4-thiadiazolylthio
group at the 7-position
ial activities of compound 30 to those of compound 16, we found that
(S)-configuration at the 7-position was important for potent anti-
bacterial activities.
Next we pursued chemical modification of LCM derivatives possessing
a substituted 1,3,4-thiadiazole at the C-7 position via sulfur atom and
their antibacterial activities are shown in Table 5. We could find
SAR analysis of LCM derivatives possessing a phenylthio group at several important functional moieties for improvement of activity so
the 7-position
far. Then we first introduced an amino group on the 1,3,4-thiadiazole
ring. Compound 21 exhibited improved activities against both
resistant bacteria with erm gene and H. influenzae compared with
11. We synthesized several compounds 22, 23, 36 and 38, which have
an additional group introduced to the amino group of 21. Compound
36 possessing a glycyl moiety as an aliphatic amine had weaker
antibacterial activities than 21. Conversion of the glycyl moiety to a
methoxyacetyl moiety (36→ 38) improved antibacterial activities.
Furthermore, derivatives 22 and 23 were synthesized and a difluor-
omethylthiophenyl analog (23) showed stronger activities against
S. pneumoniae with erm gene than 21. These results suggest that the
phenyl moiety of 23 is an important group and that it enhances
antibacterial activities against resistant bacteria with erm gene. We
synthesized 27 in order to confirm this hypothesis. As expected, 27
showed relatively stronger antibacterial activities against bacteria with
erm gene compared with 21. Finally, we were interested in conversion
of a NH-CO bonding to a CO-NH bonding (36 and 38→ 24–26).
Compound 26 also exhibited effective antibacterial activities against
bacteria with erm gene. These results suggest that filling a space around
the 7-position of LCM has an important role to enhance antibacterial
activities by hydrogen bonding, π-π stacking or CH–π interaction to
undefined binding site on 23S rRNA.
Next we consequently pursued modification of LCM derivatives
possessing a substituted phenyl group at the C-7 position via sulfur
atom and their antibacterial activities are shown in Table 4. The
enhanced antibacterial activities by introducing an amino (16) or a
nitro group (15) as shown in Table 3 encouraged us to further explore
SAR through introducing an amino or a nitro group at the o-, m- and
p-position on the phenyl ring. Unexpectedly, compounds 18–20 and
31–33 showed weaker antibacterial activities against resistant bacteria
with erm gene than 15 or 16. Among nitrophenyl and aminophenyl
derivatives in Table 4, the para-amino derivative (33) exhibited
relatively stronger activities against susceptible S. pneumoniae and
H. influenzae. Conversion of the amino group to a methoxycarbonyl
group (33 to 40) at the p-position on the phenyl ring improved
antibacterial activities against bacteria with erm gene. Based on SAR
analysis of compounds 18–20, 31–33, 40 and 41, para-substituted
analogs exhibited relatively stronger antibacterial activities against
resistant bacteria than o-substituted or m-substituted analogs. Further-
more, 34 possessing a methanesulfonyl group at the amino group of
33 exhibited the most potent antibacterial activity in the phenylthio
derivatives, except some strains belonging to S. pneumoniae with erm
gene. These results suggest that (i) it is important for a substituent to
keep a specific size, length and three-dimensional direction for
appropriate binding to rRNA, and (ii) there are several important
CONCLUSION
hydrogen bondings with some functional moieties, such as C = O, With a purpose of generating new effective templates against bacteria,
N = O, S = O or NH2.
we first prepared the key intermediate 141 derived from LCM with two
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Table 5 Antibacterial activities (MIC, μg ml− 1) of LCM derivatives possessing a substituted 1, 3, 4-thiadiazolylthio group at the 7-position
Abbreviations: LCM, lincomycin; ND, not detected.
aAll strains except standard strains were clinically isolated.
b(c): constitutive; (i): inducible.
Grey shading strains are target strains.
steps to synthesize LCM analogs possessing the same configuration at 2,3,4-Tris-O-(trimethylsilyl)lincomycin (1). To a solution of lincomycin (50 g,
123 mmol) in pyridine (200 ml) were added trimethylchlorosilane (90 ml, 704
mmol) and hexamethyldisilazane (65 ml, 310 mmol) and stirred at room
temperature (RT) for 2 h, and then it was concentrated under reduced pressure.
the 7-position as CLDM in final target molecules. Our LCM
derivatives were generally synthesized under Mitsunobu condition
with the corresponding thiol from the key intermediate (1).
The residue was diluted with water, then extracted with hexane, washed with
Compounds 16, 21 and 27 exhibited antibacterial activities against
water and concentrated under reduced pressure. To a solution of the resulting
respiratory infection-related Gram-positive bacteria with erm gene,
although CLDM did not have any activities against those pathogens.
residue in methanol (150 ml) was added 80% aqueous acetic acid (22.5 ml)
stirred at RT for 16 h. The mixture was diluted with saturated aqueous
Furthermore, we confirmed that 7(S)-configuration was necessary for
enhancing antibacterial activities on the basis of comparison results of
configurations of 16 and 30. This work suggests that LCM derivatives
may overcome resistant bacteria. SAR analysis, as indicated in this
paper, would be useful for further medicinal chemistry in application
of LCM derivatives. Our synthetic research in LCM derivatives is in
progress.
NaHCO3 (30 ml) and concentrated under reduced pressure. The residue was
diluted with water and hexane, then extracted with hexane, washed with water,
dried over MgSO4 and concentrated under reduced pressure. The title
compound was obtained as a colorless solid (69.5 g, 91%). ESI-MS (m/z)
623 (M+H)+ as C27H58N2O6SSi3; 1H NMR (400 MHz, chloroform-d) δ 0.14
(s, 18 H), 0.18 (s, 9 H), 0.85–0.93 (m, 3 H), 1.14 (d, J = 6.4 Hz, 3 H), 1.22–1.35
(m, 4 H), 1.79–1.90 (m, 1 H), 1.92–2.07 (m, 3 H), 2.09 (s, 3 H), 2.38 (s, 3 H),
3.00 (dd, J = 10.9, 3.9 Hz, 1 H), 3.07 (br d, J =1.6 Hz, 1 H), 3.12–3.21 (m, 1 H),
3.59 (dd, J =9.5, 2.5 Hz, 1 H), 3.80 (br d, J = 2.5 Hz, 1 H), 4.00 (d, J = 9.5 Hz,
1 H), 4.04–4.13 (m, 1 H), 4.15 (dd, J = 9.5, 5.6 Hz, 1 H), 4.27–4.33 (m, 1 H),
5.21 (d, J = 5.6 Hz, 1 H), 7.42 (d, J = 9.8 Hz, 1 H).
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 (MS) 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 thin layer chromatography was performed with silica gel (Merck,
Darmstadt, Germany: TLC plates Silica gel 60 F254). All organic extracts were
dried over anhydrous MgSO4, and the solvent was removed with a rotary
evaporator under reduced pressure.
7(S)-7-(Benzo[d]oxazol-2-ylthio)-7-deoxylincomycin (2). To
a solution of
compound 1 (240 mg, 0.39 mmol) in tetrahydrofuran (THF; 5 ml) at 0 °C
were added triphenylphosphine (150 mg, 0.57 mmol), diethylazodicarboxylate
(0.10 ml, 0.55 mmol) and benzo[d]oxazole-2-thiol (85 mg, 0.56 ml) and stirred
at 0 °C for 1 h. The mixture was stirred at RT for 16 h. The mixture was diluted
with 2 N HCl (1 ml)-MeOH (1 ml) and then stirred at RT for 30 min and
concentrated under reduced pressure. The resulting residue was dissolved by
water and washed with diethyl ether. The mixture was added to NaHCO3
(150 mg), then extracted with ethyl acetate, washed with water, dried over
MgSO4 and concentrated under reduced pressure. The resulting residue was
purified by preparative TLC (CHCl3/CH3OH/28% aq NH4OH= 20/1/0.1) to
26
obtain the title compound as a colorless solid (147.6 mg, 71%). [α]D +77.6°
(c 0.77, MeOH); ESI-MS (m/z) 540 (M+H)+ as C25H37N3O6S2; TOF-
ESI-HRMS (M+H)+ calcd for C25H37N3O6S2: 540.2202, found: 540.2204; 1H
NMR (400 MHz, methanol-d4) δ 0.85–0.97 (m, 3 H), 1.26–1.40 (m, 4 H), 1.61
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(d, J =6.8 Hz, 3 H), 1.77–1.85 (m, 1 H), 1.87 (s, 3 H), 1.97–2.09 (m, 2 H),
(d, J = 6.9 Hz, 3 H), 1.31–1.41 (m, 4 H), 1.80–1.90 (m, 1 H), 1.95–2.04
2.12–2.28 (m, 1 H), 2.35 (s, 3 H), 2.98 (dd, J = 10.5, 5.2 Hz, 1 H), 3.21 (m, 1 H), 2.00 (s, 3 H), 2.05–2.25 (m, 2 H), 2.39 (s, 3 H), 2.98 (dd, J =10.7,
(dd, J = 8.5, 6.2 Hz, 1 H), 3.56 (dd, J = 10.2, 3.2 Hz, 1 H), 3.83 (br d, J = 3.2 Hz,
1 H), 4.10 (dd, J = 10.2, 5.6 Hz, 1 H), 4.43 (br d, J = 9.8 Hz, 1 H), 4.45
(dq, J = 6.8, 3.2 Hz, 1 H), 4.64 (dd, J = 9.8, 3.2 Hz, 1 H), 5.24 (d, J = 5.6 Hz,
1 H), 7.27–7.36 (m, 2 H), 7.49–7.60 (m, 2 H).
4.6 Hz, 1 H), 3.24 (dd, J = 8.3, 5.9 Hz, 1 H), 3.58 (dd, J = 10.2, 3.3 Hz, 1 H),
3.74 (br d, J = 3.3 Hz, 1 H), 3.86 (qd, J = 6.9, 2.6 Hz, 1 H), 4.10 (dd, J = 10.2,
5.6 Hz, 1 H), 4.35 (dd, J = 9.7, 0.6 Hz, 1 H), 4.41 (dd, J = 9.7, 2.6 Hz, 1 H), 5.26
(d, J = 5.6 Hz, 1 H), 7.22–7.28 (m, 1 H), 7.29–7.36 (m, 2 H), 7.40–7.46
(m, 2 H).
7(S)-7-(Benzo[d]thiazol-2-ylthio)-7-deoxylincomycin
(3). Compound
1
(320 mg, 0.51 mmol) and benzo[d]thiazole-2-thiol (250 mg, 1.49 mmol) were
7(S)-7-Deoxy-7-(pyridin-4-ylthio)lincomycin (7). Compound 1 (100 mg, 0.16
mmol) and pyridine-4-thiol (27.6 mg, 0.25 mmol) were treated according to
the similar procedure as described for the preparation of 2 to afford 7 (99.8 mg,
treated according to the similar procedure as described for the preparation of 2
26
to afford 3 (225.5 mg, 79%) as a colorless solid. [α]D 74.1° (c 1.05, MeOH);
ESI-MS (m/z) 556 (M+H)+ as C25H37N3O5S3; TOF-ESI-HRMS (M+H)+ calcd
for C25H37N3O5S3: 556.1974, found: 556.1975; 1H NMR (400 MHz, methanol-
d4) δ 0.85–0.98 (m, 3 H), 1.24–1.40 (m, 4 H), 1.59 (d, J = 6.8 Hz, 3 H),
1.78–1.90 (m, 1 H), 1.83 (s, 3 H), 1.98–2.10 (m, 2 H), 2.12–2.27 (m, 1 H), 2.34
(s, 3 H), 3.01 (dd, J = 10.4, 5.3 Hz, 1 H), 3.19 (dd, J = 8.6, 6.1 Hz, 1 H), 3.58
(dd, J =10.3, 3.3 Hz, 1 H), 3.82 (br dd, J = 3.3, 0.6 Hz, 1 H), 4.11 (dd, J = 10.3,
5.6 Hz, 1 H), 4.43 (br dd, J = 9.7, 0.6 Hz, 1 H), 4.52 (dq, J =6.8, 3.1 Hz, 1 H),
4.62 (dd, J = 9.7, 3.1 Hz, 1 H), 5.25 (d, J = 5.6 Hz, 1 H), 7.35 (ddd, J = 8.1, 7.2,
1.2 Hz, 1 H), 7.45 (ddd, J = 8.1, 7.2, 1.2 Hz, 1 H), 7.81–7.89 (m, 2 H).
26
40%) as a colorless solid. [α]D +88.3° (c 0.94, MeOH); ESI-MS (m/z) 500
(M+H)+ as C23H37N3O5S2; TOF-ESI-HRMS (M+H)+ calcd for C23H37N3O5S2:
500.2253, found: 500.2259; 1H NMR (400 MHz, methanol-d4) δ 0.87–0.98
(m, 3 H), 1.28–1.40 (m, 4 H), 1.46 (d, J = 7.0 Hz, 3 H), 1.78 (s, 3 H), 1.79–1.89
(m, 1 H), 1.96–2.11 (m, 2 H), 2.13–2.25 (m, 1 H), 2.39 (s, 3 H), 2.98
(dd, J = 10.5, 4.9 Hz, 1 H), 3.24 (dd, J = 8.4, 5.9 Hz, 1 H), 3.57 (dd, J = 10.2,
3.2 Hz, 1 H), 3.80 (br dd, J = 3.2, 0.8 Hz, 1 H), 4.09 (dd, J = 10.2, 5.6 Hz, 1 H),
4.11 (dq, J = 7.0, 2.9 Hz, 1 H), 4.37 (br dd, J = 9.6, 0.8 Hz, 1 H), 4.59
(dd, J = 9.6, 2.9 Hz, 1 H), 5.23 (d, J =5.6 Hz, 1 H), 7.33–7.39 (m, 2 H),
8.29–8.35 (m, 2 H).
7(S)-7-(1H-Benzo[d]imidazol-2-ylthio)-7-deoxylincomycin (4). Compound 1
(240 mg, 0.39 mmol) and 1H-benzo[d]imidazole-2-thiol (87.9 mg, 0.59 mmol)
were treated according to the similar procedure as described for the preparation
7(S)-7-Deoxy-7-(pyrimidin-4-ylthio)lincomycin (8). Compound
1 (100 mg,
0.16 mmol) and pyrimidine-4-thiol (27.9 mg, 0.25 mmol) were treated
27
of 2 to afford 4 (157.7 mg, 76%) as a colorless solid. [α]D +91.9° (c 1.06,
according to the similar procedure as described for the preparation of 2 to
MeOH); ESI-MS (m/z) 539 (M+H)+ as C25H38N4O5S2; TOF-ESI-HRMS
(M+H)+ calcd for C25H38N4O5S2: 539.2362, found: 539.2361; 1H NMR
(400 MHz, methanol-d4) δ 0.87–0.97 (m, 3 H), 1.25–1.38 (m, 4 H), 1.47
(d, J =7.1 Hz, 3 H), 1.72–1.83 (m, 1 H), 1.90–2.05 (m, 2 H), 1.93 (s, 3 H),
2.14–2.28 (m, 1 H), 2.24 (s, 3 H), 3.01 (dd, J = 10.3, 5.4 Hz, 1 H), 3.13
(dd, J = 8.6, 6.2 Hz, 1 H), 3.60 (dd, J = 10.3, 3.4 Hz, 1 H), 3.84 (br d, J = 3.4 Hz,
1 H), 4.12 (dd, J = 10.3, 5.6 Hz, 1 H), 4.16 (dq, J = 7.1, 3.2 Hz, 1 H), 4.43–4.49
(m, 1 H), 4.51 (dd, J = 9.5, 3.2 Hz, 1 H), 5.24 (d, J = 5.6 Hz, 1 H), 7.19–7.26
(m, 2 H), 7.50 (br s, 2 H).
27
afford 8 (124 mg, 50%) as a colorless solid. [α]D +85.0° (c 1.53, MeOH);
ESI-MS (m/z) 501 (M+H)+ as C22H36N4O5S2; TOF-ESI-HRMS (M+H)+ calcd
for C22H36N4O5S2: 501.2205, found: 501.2208; 1H NMR (400 MHz, methanol-
d4) δ 0.87–0.98 (m, 3 H), 1.26–1.41 (m, 4 H), 1.48 (d, J = 6.7 Hz, 3 H), 1.79
(s, 3 H), 1.79–1.90 (m, 1 H), 1.97–2.12 (m, 2 H), 2.13–2.26 (m, 1 H), 2.37
(s, 3 H), 3.01 (dd, J = 10.5, 5.1 Hz, 1 H), 3.24 (dd, J = 8.4, 6.0 Hz, 1 H), 3.55
(dd, J = 10.2, 3.2 Hz, 1 H), 3.80 (br dd, J =3.2, 0.7 Hz, 1 H), 4.10 (dd, J =10.2,
5.6 Hz, 1 H), 4.34 (br dd, J = 9.5 Hz, 0.7, 1 H), 4.49–4.60(m, 2 H), 5.23
(d, J =5.6 Hz, 1 H), 7.40 (dd, J = 5.6, 1.5 Hz, 1 H), 8.36 (br dd, J = 5.6, 0.4 Hz,
1 H), 8.87 (br dd, J = 1.5, 0.4 Hz, 1 H).
7(S)-S-(7-Deoxylincomycin-7-yl)benzothioate (5). To a solution of compound
1 (500 mg, 0.8 mmol) in toluene (5 ml) at 0 °C were added triphenylphosphine
(316 mg, 1.20 mmol), diethylazodicarboxylate (0.22 ml, 1.20 mmol) and
benzothioic S-acid (172 mg, 1.24 mmol) and stirred at RT for 3 h. The mixture
was diluted with 2 N HCl (2 ml) and concentrated under reduced pressure.
The resulting residue was dissolved by water and washed with diethyl ether.
The mixture was added NaHCO3 (150 mg), then extracted with ethyl
acetate, washed with water, dried over MgSO4 and concentrated under
reduced pressure. The resulting residue was purified by preparative TLC
(CHCl3/CH3OH/28% aq NH4OH= 9/1/0.1) to obtain the title compound as a
colorless solid (100 mg, 24%). ESI-MS (m/z) 527 (M+H)+ as C25H38N2O6S2;
1H NMR (400 MHz, methanol-d4) δ 0.85–0.98 (m, 3 H), 1.23–1.39 (m, 4 H),
1.44 (d, J = 6.8 Hz, 3 H), 1.83–1.92 (m, 1 H), 1.88 (s, 3 H), 1.98–2.07 (m, 1 H),
2.07–2.15 (m,1 H), 2.15–2.28 (m, 1 H), 2.43 (s, 3 H), 3.07 (dd, J = 10.5, 5.1 Hz,
1 H), 3.27 (dd, J = 8.3, 5.8 Hz, 1 H), 3.55 (dd, J = 10.2, 3.3 Hz, 1 H), 3.78–3.85
(m, 1 H), 4.11 (dd, J = 10.2, 5.7 Hz, 1 H), 4.23–4.32 (m, 2 H), 4.58 (dd, J = 9.7,
3.2 Hz, 1 H), 5.25 (d, J = 5.7 Hz, 1 H), 7.42–7.55 (m, 2 H), 7.59–7.68 (m, 1 H),
7.91–8.00 (m, 2 H).
7(S)-7-Deoxyl-7-(thiophen-2-ylthio)lincomycin (9). Compound
0.39 mmol) and thiophene-2-thiol (100 mg, 0.86 mmol) were treated according
1 (240 mg,
to the similar procedure as described for the preparation of 2 to afford 9
26
(19.4 mg, 10%) as a colorless solid. [α]D +140.7° (c 0.47, MeOH); ESI-MS
(m/z) 505 (M+H)+ as C22H36N2O5S3; TOF-ESI-HRMS (M+H)+ calcd for
1
C22H36N2O5S3: 505.1865, found: 505.1863; H NMR (400 MHz, methanol-d4)
δ 0.89–0.98 (m, 3 H), 1.27 (d, J = 7.1 Hz, 3H), 1.30–1.41 (m, 4 H), 1.78–1.89
(m, 1 H), 1.92–2.00 (m, 1 H), 2.01–2.08 (m, 1 H), 2.08–2.19 (m, 1 H), 2.21
(s, 3 H), 2.33 (s, 3 H), 2.96 (dd, J = 10.7, 4.6 Hz, 1 H), 3.20 (dd, J = 8.1,
5.6 Hz, 1 H), 3.54–3.65 (m, 2 H), 3.73 (br d, J = 2.8 Hz, 1 H), 4.11 (dd, J =10.3,
5.6 Hz, 1 H), 4.34 (dd, J = 9.8, 2.9 Hz, 1 H), 4.37–4.43 (m, 1 H), 5.29 (d,
J = 5.6 Hz, 1 H), 7.06 (dd, J = 5.4, 3.5 Hz, 1H), 7.22 (dd, J = 3.5, 1.2 Hz, 1 H),
7.55 (dd, J = 5.4, 1.2 Hz, 1 H).
7(S)-7-Deoxy-7-(thiazol-2-ylthio)lincomycin (10). Compound 1 (240 mg, 0.39
mmol) and thiazole-2-thiol (43.0 mg, 0.37 mmol) were treated according to the
similar procedure as described for the preparation of 2 to afford 10 (13.6 mg,
26
7%) as a colorless solid. [α]D +109.5° (c 0.67, MeOH); ESI-MS (m/z) 506
(M+H)+ as C21H35N3O5S3; TOF-ESI-HRMS (M+H)+ calcd for C21H35N3O5S3:
506.1817, found: 506.1802; 1H NMR (400 MHz, methanol-d4) δ 0.88–0.97
(m, 3 H), 1.27–1.40 (m, 4 H), 1.61 (d, J = 7.0 Hz, 3 H), 1.79–1.92 (m, 1H),
1.95–2.14 (m, 2H), 2.01 (s, 3H), 2.15–2.29 (m, 1 H), 2.35 (s, 3 H), 3.01
(dd, J = 10.4, 5.3 Hz, 1 H), 3.26 (dd, J = 8.6, 6.1 Hz, 1 H), 3.57 (dd, J = 10.3,
3.3 Hz, 1 H), 3.78 (br d, J = 3.3 Hz, 1 H), 4.10 (dd, J = 10.3, 5.6 Hz, 1 H),
4.13 (dq, J =7.0, 3.1 Hz, 1 H), 4.39 (br d, J = 9.8 Hz, 1 H), 4.51 (dd, J = 9.8,
3.1 Hz, 1 H), 5.25 (d, J = 5.6 Hz, 1 H), 7.54 (d, J = 3.5 Hz, 1 H), 7.73
(d, J = 3.5 Hz, 1 H).
7(S)-7-Deoxy-7-phenylthiolincomycin (6). To a solution of compound 1 (1.0 g,
1.6 mmol) in THF (15 ml) at 0 °C were added tributylphosphine (971 mg,
4.8 mmol), diethylazodicarboxylate (0.59 ml, 3.2 mmol) and 1,2-diphenyldisul-
fide (530 mg, 2.4 mmol) and stirred at RT for 24 h. The mixture was diluted
with 2 N HCl (1 ml) and stirred at RT for 30 min and then concentrated under
reduced pressure. The resulting residue was dissolved by water and washed with
diethyl ether. The mixture was added to NaHCO3 (150 mg), then extracted
with ethyl acetate, washed with water, dried over MgSO4 and concentrated
under reduced pressure. The resulting residue was purified by silica gel column
chromatography (CHCl3/CH3OH/28% aq NH4OH= 20/1/0.1→ 9/1/0.1) to
26
obtain the title compound as a colorless solid (724.0 mg, 91%). [α]D
7(S)-7-Deoxy-7-(1,3,4-thiadiazol-2-ylthio)lincomycin (11). Compound
1
+111.1° (c 0.63, MeOH); ESI-MS (m/z) 499 (M+H)+ as C24H38N2O5S2;
(240 mg, 0.39 mmol) and 1,3,4-thiadiazole-2-thiol (80.0 mg, 0.68 mmol) were
TOF-ESI-HRMS (M+H)+ calcd for C24H38N2O5S2: 499.2300, found:
treated according to the similar procedure as described for the preparation of 2
499.2304; 1H NMR (400 MHz, methanol-d4) δ 0.88–0.97 (m, 3 H), 1.29 to afford 11 (121.0 mg, 62%) as a colorless solid. [α]D +100.2° (c 2.03,
27
The Journal of Antibiotics

Novel lincomycin derivatives
Y Wakiyama et al
9
MeOH); ESI-MS (m/z) 507 (M+H)+ as C20H34N4O5S3; TOF-ESI-HRMS
mmol) were treated according to the similar procedure as described for the
(M+H)+ calcd for C20H34N4O5S3: 507.1770, found: 507.1773; 1H NMR preparation of 2 to afford 16 (386.7 mg, 67%) as a colorless solid. [α]D26 +89.0°
(c 1.11, MeOH); ESI-MS (m/z) 571 (M+H)+ as C25H38N4O5S3; TOF-
(400 MHz, methanol-d4) δ 0.87–0.98 (m, 3 H), 1.26–1.42 (m, 4 H), 1.53
(d, J = 6.8 Hz, 3 H), 1.80–1.90 (m, 1 H), 1.93 (s, 3 H), 1.97–2.12 (m, 2 H),
ESI-HRMS (M+H)+ calcd for C25H38N4O5S3: 571.2083, found: 571.2075; 1H
NMR (400 MHz, methanol-d4) δ 0.86–0.97 (m, 3 H), 1.26–1.38 (m, 4 H), 1.52
(d, J =7.0 Hz, 3 H), 1.75–1.89 (m, 1 H), 1.94 (s, 3 H), 1.95–2.11 (m, 2 H),
2.12–2.25 (m, 1 H), 2.32 (s, 3 H), 3.03 (dd, J =10.4, 5.3 Hz, 1 H),
3.17 (dd, J = 8.6, 6.2 Hz, 1 H), 3.58 (dd, J = 10.2, 3.2 Hz, 1 H), 3.81 (br dd,
J = 3.2, 0.7 Hz, 1 H), 4.10 (dd, J = 10.2, 5.5 Hz, 1 H), 4.27 (dq, J = 7.0, 3.1 Hz,
1 H), 4.43 (br dd, J = 9.8, 0.7 Hz, 1 H), 4.55 (dd, J = 9.8, 3.1 Hz, 1 H), 5.25
(d, J = 5.5 Hz, 1 H), 6.85 (dd, J =8.7, 2.3 Hz, 1 H), 7.08 (dd, J = 2.3, 0.25 Hz,
1 H), 7.59 (dd, J =8.7, 0.25 Hz, 1 H).
2.15–2.28 (m, 1 H), 2.38 (s, 3 H), 3.03 (dd, J = 10.5, 5.1 Hz, 1 H), 3.27
(dd, J = 8.4, 6.1 Hz, 1 H), 3.57 (dd, J = 10.2, 3.2 Hz, 1 H), 3.81 (br dd, J = 3.2,
0.8 Hz, 1 H), 4.11 (dd, J = 10.2, 5.6 Hz, 1 H), 4.37–4.46 (m, 2 H), 4.60
(dd, J = 9.8, 3.2 Hz, 1 H), 5.26 (d, J =5.6 Hz, 1 H), 9.37 (s, 1H).
7(S)-7-(5-Chlorobenzo[d]thiazol-2-ylthio)-7-deoxylincomycin (12). Compound
1 (160 mg, 0.26 mmol) and 5-chlorobenzo[d]thiazole-2-thiol (160 mg, 0.79
mmol) were treated according to the similar procedure as described for the
preparation of 2 to afford 12 (110.6 mg, 73%) as a colorless solid. [α]D26 +52.8°
(c 0.25, MeOH); ESI-MS (m/z) 590 (M+H)+ as C25H36ClN3O5S3; TOF-
ESI-HRMS (M+H)+ calcd for C25H36ClN3O5S3: 590.1584, found: 590.1581;
7(S)-7-Deoxy-7-(5-nitrobenzo[d]thiazol-2-ylthio)lincomycin (17). Compound
1 (320 mg, 0.51 mmol) and 5-nitrobenzo[d]thiazole-2-thiol (120 mg, 0.57
mmol) were treated according to the similar procedure as described for the
preparation of 2 to afford 17 (138.8 mg, 45%) as a colorless solid. [α]D26 +58.2°
(c 0.81, MeOH); ESI-MS (m/z) 601 (M+H)+ as C25H36N4O7S3; TOF-ESI-
HRMS (M+H)+ calcd for C25H36N4O7S3: 601.1824, found: 601.1826; 1H NMR
(400 MHz, methanol-d4) δ 0.88–0.97 (m, 3 H), 1.30–1.40 (m, 4 H), 1.62
(d, J =6.8 Hz, 3 H), 1.80–1.90 (m, 1 H), 1.85 (s, 3 H), 1.99–2.10 (m, 2 H),
2.16–2.30 (m, 1 H), 2.36 (s, 3 H), 3.01 (dd, J = 10.3, 5.3 Hz, 1 H), 3.25 (dd,
J = 8.7, 6.2 Hz, 1 H), 3.57 (dd, J = 10.3, 3.2 Hz, 1 H), 3.84 (br dd, J = 3.2,
0.8 Hz, 1 H), 4.11 (dd, J = 10.3, 5.7 Hz, 1 H), 4.42 (br dd, J = 9.6, 0.8 Hz, 1 H),
1H NMR (400 MHz, methanol-d4)
δ 0.87–0.96 (m, 3 H), 1.27–1.39
(m, 4 H), 1.59 (d, J = 7.0 Hz, 3 H), 1.78–1.88 (m, 1 H), 1.86 (s, 3 H),
1.97–2.08 (m, 2 H), 2.13–2.27 (m, 1 H), 2.32 (s, 3 H), 2.98 (dd, J = 10.5,
5.2 Hz, 1 H), 3.20 (dd, J =8.5, 6.2 Hz, 1 H), 3.56 (dd, J = 10.2, 3.2 Hz, 1 H),
3.82 (br dd, J = 3.2, 0.9 Hz, 1 H), 4.10 (dd, J =10.2, 5.6 Hz, 1 H), 4.41 (br dd,
J = 9.7, 0.9 Hz, 1 H), 4.53 (dq, J = 7.0, 3.3 Hz, 1 H), 4.61 (dd, J = 9.7, 3.3 Hz,
1 H), 5.24 (d, J = 5.6 Hz, 1 H), 7.35 (dd, J = 8.6, 2.1 Hz, 1 H), 7.81–7.87
(m, 2 H).
7(S)-7-Deoxyl-7-(thiazolo[5,4-c]pyridin-2-ylthio)lincomycin (13). Compound
1 (320 mg, 0.51 mmol) and thiazolo[5,4-c]pyridine-2-thiol (250 mg, 1.49
mmol) were treated according to the similar procedure as described for the
preparation of 2 to afford 13 (205.9 mg, 72%) as a colorless solid. [α]D26 +67.1°
(c 0.50, MeOH); ESI-MS (m/z) 505 (M+H)+ as C24H36N4O5S3; TOF-
ESI-HRMS (M+H)+ calcd for C24H36N4O5S3: 557.1926, found: 557.1924; 1H
NMR (400 MHz, methanol-d4) δ 0.87–0.98 (m, 3 H), 1.27–1.41 (m, 4 H), 1.62
(d, J = 6.7 Hz, 3 H), 1.82 (s, 3 H), 1.80–1.91 (m, 1 H), 1.98–2.13 (m, 2 H),
2.15–2.28 (m, 1 H), 2.38 (s, 3 H), 3.03 (dd, J = 10.4, 5.3 Hz, 1 H), 3.24
(dd, J = 8.6, 6.2 Hz, 1 H), 3.56 (dd, J = 10.3, 3.2 Hz, 1 H), 3.83 (br dd, J = 3.2,
0.73 Hz, 1 H), 4.11 (dd, J = 10.3, 5.6 Hz, 1 H), 4.43 (br dd, J = 9.5, 0.73 Hz,
1 H), 4.63–4.72 (m, 2 H), 5.24 (d, J = 5.6 Hz, 1 H), 7.82 (dd, J = 5.6, 0.9 Hz,
1 H), 8.51 (d, J = 5.6 Hz, 1 H), 9.06 (d, J = 0.9 Hz, 1 H).
4.61 (dd, J = 6.8, 3.3 Hz,
(d, J = 5.7 Hz, 1 H), 8.08 (d, J = 8.8, 1 H), 8.21 (dd, J = 8.8, 2.2, Hz, 1 H),
8.64 (br dd, J = 2.2, 0.24 Hz, 1 H).
1 H), 4.65 (dd, J = 9.6, 3.3 Hz, 1 H), 5.25
7(S)-7-Deoxy-7-(2-nitrophenylthio)lincomycin (18). Compound
1 (200 mg,
0.32 mmol) and 1,2-bis(2-nitrophenyl)disulfide (148.5 mg, 0.48 mmol) were
treated according to the similar procedure as described for the preparation of 6
to afford 18 (40.1 mg, 23%) as a colorless solid. [α]D27 +69.9° (c 0.91, MeOH);
ESI-MS (m/z) 544 (M+H)+ as C24H37N3O7S2; TOF-ESI-HRMS (M+H)+ calcd
for C24H37N3O7S2: 544.2151, found: 544.2157; 1H NMR (400 MHz,
methanol-d4) δ 0.86–0.99 (m, 3 H), 1.29–1.38 (m, 4 H), 1.38 (d, J = 6.8 Hz,
3 H), 1.79 (s, 3 H), 1.81–1.92 (m, 1 H), 1.98–2.14 (m, 2 H), 2.14–2.26 (m, 1
H), 2.42 (s, 3 H), 3.01 (dd, J = 10.6, 4.8 Hz, 1 H), 3.28 (dd, J = 8.7, 6.1 Hz, 1 H),
3.57 (dd, J = 10.3, 3.2 Hz, 1 H), 3.79 (br dd, J = 3.2, 0.8 Hz, 1 H), 4.06
(dq, J = 6.8, 2.7 Hz, 1 H), 4.08 (dd, J =10.3, 5.6 Hz, 1 H), 4.37 (br dd, J = 9.8,
0.8 Hz, 1 H), 4.57 (dd, J = 9.8, 2.7 Hz, 1 H), 5.21 (d, J = 5.6 Hz, 1 H), 7.38
(ddd, J = 8.3, 7.2, 1.2 Hz, 1 H), 7.64 (ddd, J =8.2, 7.2, 1.4 Hz, 1 H), 7.70
(br dd, J = 8.2, 1.2 Hz, 1 H), 8.05 (dd, J = 8.3, 1.4 Hz, 1 H).
7(S)-7-(6-Cyanobenzo[d]thiazol-2-ylthio)-7-deoxylincomycin (14). Compound
1 (160 mg, 0.26 mmol) and 6-cyanobenzo[d]thiazole-2-thiol (55 mg, 0.29
mmol) were treated according to the similar procedure as described for the
preparation of 2 to afford 14 (98.4 mg, 66%) as a colorless solid. [α]D26 +73.0°
(c 1.10, MeOH); ESI-MS (m/z) 581 (M+H)+ as C26H36N4O5S3; TOF-
ESI-HRMS (M+H)+ calcd for C26H36N4O5S3: 581.1926, found: 581.1926; 1H
NMR (400 MHz, methanol-d4) δ 0.87–0.97 (m, 3 H), 1.25–1.41 (m, 4 H), 1.61
(d, J = 6.6 Hz, 3 H), 1.78–1.89 (m, 1 H), 1.82 (s, 3 H), 1.98–2.09 (m, 2 H),
2.14–2.26 (m, 1 H), 2.35 (s, 3 H), 2.98 (dd, J = 10.4, 5.1 Hz, 1 H), 3.21
(dd, J = 8.5, 6.2 Hz, 1 H), 3.56 (dd, J = 10.2, 3.2 Hz, 1 H), 3.82 (br dd, J = 3.2,
0.8 Hz, 1 H), 4.10 (dd, J = 10.2, 5.7 Hz, 1 H), 4.42 (br dd, J = 9.5, 0.8 Hz, 1 H),
4.60–4.70 (m, 2 H), 5.24 (d, J =5.7 Hz, 1 H), 7.76 (dd, J = 8.5, 1.7 Hz, 1 H),
7.94 (br dd, J = 8.5, 0.6 Hz, 1 H), 8.32 (br dd, J = 1.7, 0.6 Hz, 1 H).
7(S)-7-Deoxy-7-(3-nitrophenylthio)lincomycin (19). Compound 1 (1.0 g, 1.6
mmol) and 1,2-bis(3-nitrophenyl)disulfide (742 mg, 2.4 mmol) were treated
according to the similar procedure as described for the preparation of 6 to
29
afford 19 (366.5 mg, 42%) as a colorless solid. [α]D +75.2° (c 0.48, MeOH);
ESI-MS (m/z) 544 (M+H)+ as C24H37N3O7S2; TOF-ESI-HRMS (M+H)+ calcd
for C24H37N3O7S2: 544.2151, found: 544.2148; 1H NMR (400 MHz, methanol-
d4) δ 0.89–0.97 (m, 3 H), 1.30–1.37 (m, 4 H), 1.38 (d, J = 6.8 Hz, 3 H),
1.80–1.91 (m, 1 H), 1.93 (s, 3 H), 1.97–2.12 (m, 2 H), 2.13–2.24 (m, 1 H), 2.40
(s, 3 H), 2.99 (dd, J = 10.6, 4.8 Hz, 1 H), 3.24 (dd, J = 8.3, 5.9 Hz, 1 H), 3.58
(dd, J = 10.2, 3.3 Hz, 1 H), 3.79 (br dd, J = 3.3, 0.8 Hz, 1 H), 3.99 (dq, J = 6.8,
2.8 Hz, 1 H), 4.10 (dd, J = 10.2, 5.6 Hz, 1 H), 4.36 (br dd, J = 9.5, 0.8 Hz, 1 H),
7(S)-7-Deoxy-7-(6-nitrobenzo[d]thiazol-2-ylthio)lincomycin (15). Compound
1 (240 mg, 0.39 mmol) and 6-nitrobenzo[d]thiazole-2-thiol (180 mg, 0.85
mmol) were treated in toluene (5 ml) according to the similar procedure as
described for the preparation of 2 to afford 15 (152.7 mg, 66%) as a colorless
4.52 (dd, J = 9.5, 2.8 Hz,
(m, 1 H), 7.81 (ddd, J = 7.9, 1.8, 0.9 Hz, 1 H), 8.09 (br ddd, J = 8.2, 2.2,
0.9 Hz, 1 H), 8.21–8.23 (m, 1 H).
1 H), 5.25 (d, J = 5.6 Hz, 1 H), 7.55–7.61
solid. [α]D +67.6° (c 0.60, MeOH); ESI-MS (m/z) 601 (M+H)+ as
29
C25H36N4O7S3; TOF-ESI-HRMS (M+H)+ calcd for C25H36N4O7S3: 601.1824,
found: 601.1827; 1H NMR (400 MHz, methanol-d4) δ 0.87–0.98 (m, 3 H),
1.28–1.40 (m, 4 H), 1.62 (d, J = 6.7 Hz, 3 H), 1.77–1.89 (m, 1 H), 1.83 (s, 3 H),
1.98–2.09 (m, 2 H), 2.14–2.27 (m, 1 H), 2.36 (s, 3 H), 2.99 (dd, J = 10.5,
5.1 Hz, 1 H), 3.22 (dd, J =8.5, 6.2 Hz, 1 H), 3.56 (dd, J = 10.1, 3.2 Hz, 1 H),
3.83 (br dd, J = 3.2, 0.8 Hz, 1 H), 4.10 (dd, J =10.1, 5.6 Hz, 1 H), 4.43 (br dd,
J = 9.5, 0.8 Hz, 1 H), 4.62–4.71 (m, 2 H), 5.24 (d, J = 5.6 Hz, 1 H),
7.95 (d, J =9.0, 1 H), 8.32 (dd, J = 9.0, 2.3, Hz, 1 H), 8.85 (d, J = 2.3 Hz, 1 H).
7(S)-7-Deoxy-7-(4-nitrophenylthio)lincomycin (20). Compound
1 (200 mg,
0.32 mmol) and 1,2-bis(4-nitrophenyl)disulfide (148.5 mg, 0.48 mmol) were
treated according to the similar procedure as described for the preparation of
6 to afford 20 (29.7 mg, 17%) as a colorless solid. [α]D26 +67.1° (c 0.29, MeOH);
ESI-MS (m/z) 544 (M+H)+ as C24H37N3O7S2; TOF-ESI-HRMS (M+H)+ calcd
1
for C24H37N3O7S2: 544.2151, found: 544.2151; H NMR (400 MHz, methanol-
d4) δ 0.87–0.98 (m, 3 H), 1.30–1.39 (m, 4 H), 1.44 (d, J=6.8 Hz, 3 H), 1.79–1.90
(m, 1 H), 1.81 (s, 3 H), 1.97–2.12 (m, 2 H), 2.13–2.26 (m, 1 H), 2.40 (s, 3 H),
7(S)-7-(6-Aminobenzo[d]thiazol-2-ylthio)-7-deoxylincomycin (16). Compound 3.00 (dd, J=10.6, 5.0 Hz, 1 H), 3.25 (dd, J=8.4, 6.1 Hz, 1 H), 3.57 (dd, J =10.2,
1 (630 mg, 1.01 mmol) and 6-aminobenzo[d]thiazole-2-thiol (300 mg, 1.65 3.2 Hz, 1 H), 3.80 (br dd, J =3.2, 0.8 Hz, 1 H), 4.09 (dd, J =10.2, 5.6 Hz, 1 H),
The Journal of Antibiotics

Novel lincomycin derivatives
Y Wakiyama et al
10
4.03–4.16 (m, 1 H), 4.37 (br dd, J=9.7, 0.8 Hz, 1 H), 4.58 (dd, J=9.7, 2.9 Hz,
1 H), 5.24 (d, J =5.6 Hz, 1 H), 7.51–7.57 (m, 2 H), 8.13–8.19 (m, 2 H).
procedure as described for the preparation of 2 to afford 24 (67.8 mg, 32%) as a
26
colorless solid. [α]D +83.6° (c 0.69, MeOH); ESI-MS (m/z) 550 (M+H)+ as
C21H35N5O6S3; TOF-ESI-HRMS (M+H)+ calcd for C21H35N5O6S3: 550.1828,
found: 550.1829; 1H NMR (400 MHz, methanol-d4) δ 0.86–0.97 (m, 3 H),
1.30–1.41 (m, 4 H), 1.57 (d, J = 7.0 Hz, 3 H), 1.78–1.89 (m, 1 H), 1.94 (s, 3 H),
1.97–2.09 (m, 2 H), 2.13–2.26 (m, 1 H), 2.37 (s, 3 H), 2.99 (dd, J = 10.5,
5.1 Hz, 1 H), 3.24 (dd, J = 8.5, 6.2 Hz, 1 H), 3.56 (dd, J = 10.3, 3.2 Hz, 1 H),
3.81 (br dd, J =3.2, 0.8 Hz, 1 H), 4.10 (dd, J =10.3, 5.6 Hz, 1 H), 4.40 (br dd,
J = 9.7, 0.8 Hz, 1 H), 4.49 (dq, J = 7.0, 3.1 Hz, 1 H), 4.61 (dd, J = 9.7, 3.1 Hz,
1 H), 5.25 (d, J = 5.6 Hz, 1 H). For the qualified analytical purpose, the above
colorless solid was further purified by reverse-phase column chromatography
7(S)-7-(5-Amino-1,3,4-thiadiazol-2-ylthio)-7-deoxylincomycin (21). To a solu-
tion of compound 1 (240 mg, 0.39 mmol) in THF (5 ml) at 0 °C were added
triphenylphosphine (150 mg, 0.57 mmol), diethylazodicarboxylate (0.1 ml, 0.55
mmol) and t-butyl (5-mercapto-1,3,4-thiadiazol-2-yl)carbamate (130 mg, 0.56
mmol) and stirred at RT for 17 h. The mixture was concentrated under reduced
pressure and diluted with saturated aqueous NaHCO3 (10 ml), extracted with
ethyl acetate, washed with water, dried over MgSO4 and concentrated under
reduced pressure. The resulting residue was purified by silica gel column
chromatography (hexane/ethyl acetate) to obtain 7(S)-7-(5-amino-1,3,4-thia-
diazol-2-ylthio)-7-deoxy-2,3,4-tris-O-(trimethylsilyl)lincomycin as a colorless
solid (271.3 mg, 84%). 7(S)-7-(5-Amino-1,3,4-thiadiazol-2-ylthio)-7-deoxy-
2,3,4-tris-O-(trimethylsilyl)lincomycin (271.3 mg, 0.32 mmol) in 90% aqueous
(YMC triart C18, 20× 250 mm, RT, 18.9 ml min− 1
, 50 mM AcONH4/
CH3CN = 50/50) to obtain the highly purified title compound as
a
colorless solid.
trifluoroacetic acid (5 ml) was kept at RT for 1 h. The mixture was concentrated 7(S)-7-Deoxy-7-(5-methylcarbamoyl-1,3,4-thiadiazol-2-ylthio)lincomycin (25).
under reduced pressure and diluted with saturated aqueous NaHCO3 (10 ml) Compound 1 (240 mg, 0.39 mmol) and 5-mercapto-N-methyl-1,3,4-thiadia-
and then extracted with ethyl acetate, washed with water, dried over MgSO4 zole-2-carboxamide (100 mg, 0.57 mmol) were treated according to the similar
and concentrated under reduced pressure. The resulting residue was purified by procedure as described for the preparation of 2 to afford 25 (26.1 mg, 12%) as a
26
preparative TLC (CHCl3/CH3OH/28% aq NH4OH= 5/1/0.1) to obtain the title
colorless solid. [α]D
+81.8° (c 1.29, MeOH); ESI-MS (m/z) 564
compound as a colorless solid (111.4 mg, 66%). [α]D +139.8° (c 0.28, (M+H)+ as C22H37N5O6S3; TOF-ESI-HRMS (M+H)+ calcd for C22H37N5O6S3:
26
MeOH); ESI-MS (m/z) 520 (M+H)+ as C20H35N5O5S3; TOF-ESI-HRMS 564.1984, found: 564.1977; 1H NMR (400 MHz, methanol-d4) δ 0.85–0.98
(M+H)+ calcd for C20H35N5O5S3: 522.1879, found: 522.1877; 1H NMR
(m, 3 H), 1.26–1.42 (m, 4 H), 1.56 (d, J = 6.8 Hz, 3 H), 1.78–1.89 (m, 1 H),
(400 MHz, methanol-d4) δ 0.87–0.97 (m, 3 H), 1.27–1.38 (m, 4 H), 1.41 1.94 (s, 3 H), 1.97–2.12 (m, 2 H), 2.13–2.27 (m, 1 H), 2.38 (s, 3 H), 2.94
(d, J =7.0 Hz, 3 H), 1.76–1.90 (m, 1 H), 1.92–2.07 (m, 2 H), 2.11 (s, 3 H), (s, 3 H), 3.00 (dd, J = 10.5, 5.1 Hz, 1 H), 3.25 (dd, J = 8.6, 6.1 Hz, 1 H), 3.56
2.14–2.26 (m, 1 H), 2.33 (s, 3 H), 2.97 (dd, J = 10.5, 4.9 Hz, 1 H), 3.26 (dd, J =10.2, 3.2 Hz, 1 H), 3.79–3.84 (m, 1 H), 4.10 (dd, J = 10.2, 5.6 Hz, 1 H),
(dd, J = 8.6, 6.2 Hz, 1 H), 3.57 (dd, J = 10.3, 3.2 Hz, 1 H), 3.74–3.78 (m, 1 H), 4.40 (br d, J = 9.8 Hz, 1 H), 4.48 (dq, J = 6.8, 3.1 Hz, 1 H), 4.62 (dd, J = 9.8,
3.94 (dq, J = 7.0, 2.9 Hz, 1 H), 4.10 (dd, J = 10.3, 5.6 Hz, 1 H), 4.39 (br dd, 3.1 Hz, 1 H), 5.25 (d, J = 5.6 Hz, 1 H). For the qualified analytical purpose,
J = 9.8, 0.5 Hz, 1 H), 4.45 (dd, J = 9.8, 2.9 Hz, 1 H), 5.26 (d, J = 5.6 Hz, 1 H). the above colorless solid was further purified by reverse-phase
For the qualified analytical purpose, the above colorless solid was further column chromatography (YMC triart C18, 20× 250 mm, RT, 11.3 ml min− 1
purified by reverse-phase column chromatography (YMC triart C18, 0.1% aq. TFA/CH3CN = 60/40) to obtain the highly purified title compound as
20× 250 mm, RT, 18.9 ml min− 1
50 mM AcONH4/CH3CN= 70/30) and a colorless solid.
,
,
precipitated (MeOH/ethyl acetate) to obtain the highly purified title compound
as a colorless solid.
7(S)-7-Deoxy-7-(5-(2-(pyrrolidin-1-yl)ethylcarbamoyl)-1,3,4-thiadiazol-2-ylthio)
lincomycin (26). Compound 1 (240 mg, 0.39 mmol) and 5-(2-(pyrrolidin-1-
yl)ethylcarbamoyl)-1,3,4-thiadiazole-2-thiol (130 mg, 0.50 mmol) were treated
7(S)-7-Deoxy-7-(5-methylamino-1,3,4-thiadiazol-2-ylthio)lincomycin (22).
Compound 1 (240 mg, 0.39 mmol) and t-butyl (5-mercapto-1,3,4-thiadiazol- according to the similar procedure as described for the preparation of 2 to
27
2-yl)(methyl)carbamate (100 mg, 0.40 mmol) were treated according to the afford 26 (69.8 mg, 28%) as a colorless solid. [α]D +78.0° (c 0.54, MeOH);
similar procedure as described for the preparation of 21 to afford 22 (147.1 mg,
ESI-MS (m/z) 647 (M+H)+ as C27H46N6O6S3; TOF-ESI-HRMS (M+H)+ calcd
71% (two steps)) as a colorless solid. [α]D +118.4° (c 0.27, MeOH); ESI-MS for C27H46N6O6S3: 647.2719, found: 647.2716; 1H NMR (400 MHz, methanol-
26
(m/z) 534 (M+H)+ as C21H37N5O5S3; TOF-ESI-HRMS (M+H)+ calcd for d4) δ 0.87–0.97 (m, 3 H), 1.28–1.39 (m, 4 H), 1.56 (d, J = 7.0 Hz, 3 H),
C21H37N5O5S3: 536.2035, found: 536.2039; H NMR (400 MHz, methanol-d4) 1.77–1.90 (m, 5 H), 1.94 (s, 3 H), 1.97–2.12 (m, 2 H), 2.13–2.26 (m, 1 H),
1
δ 0.87–0.98 (m, 3 H), 1.27–1.38 (m, 4 H), 1.41 (d, J = 7.0 Hz, 3 H), 1.77–1.88 2.37 (s, 3 H), 2.57–2.67 (m, 4 H), 2.73 (t, J = 6.7 Hz, 2 H), 2.98 (dd, J =10.5,
(m, 1 H), 1.93–2.01 (m, 1 H), 2.04 (dd, J =10.1, 8.7 Hz, 1 H), 2.12 (s, 3 H),
5.1 Hz, 1 H), 3.24 (dd, J = 8.5, 6.2 Hz, 1 H), 3.51–3.60 (m, 3 H), 3.81 (br dd,
2.14–2.26 (m, 1 H), 2.33 (s, 3H), 2.93–3.01 (m, 1 H), 2.97 (s, 3 H), 3.25 J = 3.2, 0.8 Hz, 1 H), 4.10 (dd, J = 10.2, 5.6 Hz, 1 H), 4.40 (br dd, J = 9.7,
(dd, J = 8.4, 6.2 Hz, 1 H), 3.57 (dd, J = 10.3, 3.2 Hz, 1 H), 3.78 (br dd, J = 3.2,
0.7 Hz, 1 H), 3.94 (dq, J = 7.0, 2.9 Hz, 1 H), 4.10 (dd, J = 10.3, 5.6 Hz, 1 H),
4.38 (br dd, J = 9.8, 0.7 Hz, 1 H), 4.46 (dd, J = 9.8, 2.9 Hz, 1 H), 5.26
(d, J = 5.6 Hz, 1 H).
0.8 Hz, 1 H), 4.48 (dq, J = 7.0, 3.1 Hz, 1 H), 4.62 (dd, J = 9.7, 3.1 Hz, 1 H), 5.25
(d, J = 5.6 Hz, 1 H).
7(S)-7-Deoxy-7-(5-phenyl-1,3,4-thiadiazol-2-ylthio)lincomycin
pound (240 mg, 0.39 mmol) and 5-phenyl-1,3,4-thiadiazole-2-thiol
(100 mg, 0.51 mmol) in toluene (5 ml) were treated according to the similar
(27). Com-
1
7(S)-7-Deoxy-7-(5-(4-(difluoromethylthio)phenylamino)-1,3,4-thiadiazol-2-
ylthio)lincomycin (23). Compound 1 (240 mg, 0.39 mmol) and 5-(4-(difluor- procedure as described for the preparation of 2 to afford 27 (46.5 mg, 21%) as a
27
omethylthio)phenylamino)-1,3,4-thiadiazole-2-thiol (120 mg, 0.41 mmol) were colorless solid. [α]D +157.2° (c 1.47, CHCl3); ESI-MS (m/z) 583 (M+H)+ as
treated according to the similar procedure as described for the preparation of 2
to afford 23 (99.5 mg, 38%) as a colorless solid. [α]D24 +96.7° (c 0.78, MeOH);
ESI-MS (m/z) 680 (M+H)+ as C27H39F2N5O5S4; TOF-ESI-HRMS (M+H)+
calcd for C27H39F2N5O5S4: 680.1880, found: 680.1876; 1H NMR (400 MHz,
methanol-d4) δ 0.85–0.95 (m, 3 H), 1.26–1.39 (m, 4 H), 1.46 (d, J = 7.0 Hz,
C26H38N4O5S3; TOF-ESI-HRMS (M+H)+ calcd for C26H38N4O5S3: 583.2083,
found: 583.2086; 1H NMR (400 MHz, methanol-d4) δ 0.86–0.97 (m, 3 H),
1.26–1.38 (m, 4 H), 1.57 (d, J =7.0 Hz, 3 H), 1.79–1.91 (m, 1 H), 1.96–2.11
(m, 2 H), 2.03 (s, 3 H), 2.15–2.28 (m, 1 H), 2.38 (s, 3 H), 3.03 (dd, J =10.5,
5.1 Hz, 1 H), 3.27 (dd, J = 8.5, 6.1 Hz, 1 H), 3.58 (dd, J = 10.3, 3.2 Hz, 1 H),
3 H), 1.78–1.88 (m, 1 H), 1.93–2.06 (m, 2 H), 2.12 (s, 3 H), 2.14–2.28 (m, 3.83 (br dd, J = 3.2, 0.7 Hz, 1 H), 4.12 (dd, J = 10.3, 5.6 Hz, 1 H), 4.36–4.46
1 H), 2.33 (s, 3 H), 2.95–3.02 (m, 1 H), 3.26 (dd, J = 8.4, 6.2 Hz, 1 H), 3.59 (m, 2 H), 4.60 (dd, J = 9.7, 3.2 Hz, 1 H), 5.27 (d, J =5.6 Hz, 1 H), 7.49–7.58
(dd, J = 10.3, 3.3 Hz, 1 H), 3.79 (br d, J = 3.3 Hz, 1 H), 4.02–4.10 (m, 1 H), 4.12 (m, 3 H), 7.89–7.95 (m, 2 H).
(dd, J = 10.3, 5.6 Hz, 1 H), 4.41 (br d, J = 9.8 Hz, 1 H), 4.49 (dd, J = 9.8, 3.6 Hz,
1 H), 5.28 (d, J = 5.6 Hz, 1 H), 7.00 (t, J = 56.8 Hz, 1 H), 7.52–7.58 (m, 2 H),
7.64–7.70 (m, 2 H).
7(S)-7-Allylthio-7-deoxylincomycin (28). To
(83.2 mg, 0.16 mmol) in methanol (1 ml) were added allyl iodide (26.5 mg,
0.16 mmol) and 28% sodium methoxide in mehtanol (0.56 ml) and stirred at
a solution of compound 5
7(S)-7-(5-Carbamoyl-1,3,4-thiadiazol-2-ylthio)-7-deoxylincomycin (24). Com- RT for 14 h. The mixture was diluted with 1 N HCl (1 ml) and concentrated
pound 1 (240 mg, 0.39 mmol), and 5-mercapto-1,3,4-thiadiazole-2-carboxa- under reduced pressure. The resulting residue was dissolved by water and
mide (95 mg, 0.59 mmol) were treated at 50 °C according to the similar washed with diethyl ether. The mixture was added to NaHCO3 (150 mg)
The Journal of Antibiotics

Novel lincomycin derivatives
Y Wakiyama et al
11
and then extracted with ethyl acetate, washed with water, dried over MgSO4 (m, 3 H), 1.17 (d, J = 7.1 Hz, 3 H), 1.28–1.40 (m, 4 H), 1.75–1.85 (m, 1 H),
and concentrated under reduced pressure. The resulting residue was purified by 1.89–1.98 (m, 1 H), 2.04–2.12 (m, 1 H), 2.14–2.23 (m, 1 H), 2.19 (s, 3 H), 2.32
(s, 3 H), 3.01 (dd, J = 10.6, 5.0 Hz, 1 H), 3.25 (dd, J = 8.3, 5.9 Hz, 1 H), 3.58
(dd, J = 10.2, 3.2 Hz, 1 H), 3.67 (dq, J = 7.1, 2.8 Hz, 1 H), 3.74 (br dd, J = 3.2,
0.5 Hz, 1 H), 4.11 (dd, J = 10.2, 5.6 Hz, 1 H), 4.31 (dd, J = 9.8, 2.8 Hz, 1 H),
4.38 (br dd, J = 9.8, 0.5 Hz, 1 H), 5.27 (d, J = 5.6 Hz, 1 H), 6.61–6.67 (m, 1 H),
6.81 (dd, J =8.1, 1.1 Hz, 1 H), 7.13 (ddd, J = 8.8, 7.2, 1.5 Hz, 1 H), 7.34
(dd, J = 7.7, 1.5 Hz, 1 H).
preparative TLC (CHCl3/CH3OH/28% aq NH4OH= 20/1/0.1) to obtain the
title compound as a colorless solid (22.0 mg, 30%). [α]D +115.3° (c 0.34,
25
MeOH); ESI-MS (m/z) 463 (M+H)+ as C21H38N2O5S2; TOF-ESI-HRMS
(M+H)+ calcd for C21H38N2O5S2: 463.2300, found: 463.2295; 1H NMR
(400 MHz, methanol-d4) δ 0.89–0.96 (m, 3 H), 1.27–1.40 (m, 4 H), 1.31
(d, J = 7.0 Hz, 3 H), 1.82–1.92 (m, 1 H), 2.00 (ddd, J = 12.5, 7.6, 4.7 Hz, 1 H),
2.08–2.27 (m, 2 H), 2.19 (s, 3 H), 2.44 (s, 3 H), 3.05 (dd, J = 10.5, 4.4 Hz, 1 H),
3.23–3.39 (m, 4 H), 3.56 (dd, J = 10.2, 3.3 Hz, 1 H), 3.67–3.74 (m, 1 H), 4.09
(dd, J =10.2, 5.6 Hz, 1 H), 4.21 (br d, J = 9.8 Hz,1 H), 4.27 (dd, J = 9.8,
2.4 Hz, 1 H), 5.04–5.11 (m, 1 H), 5.19 (dq, J = 17.0, 1.4 Hz, 1 H), 5.25
(d, J =5.6 Hz, 1 H), 5.85 (ddt, J = 17.0, 10.7, 1.0 Hz, 1 H).
7(S)-7-(3-Aminophenylthio)-7-deoxylincomycin
(32). Compound
19
(238.2 mg, 0.44 mmol), SnCl2·H2O (494.4 mg, 2.19 mmol) and NaBH4
(82.9 mg, 2.19 mmol) were treated according to the similar procedure as
described for the preparation of 31 to afford 32 (36.0 mg, 16%) as a colorless
29
solid. [α]D +91.0° (c 0.60, MeOH); ESI-MS (m/z) 514 (M+H)+ as
C24H39N3O5S2; TOF-ESI-HRMS (M+H)+ calcd for C24H39N3O5S2: 514.2409,
found: 514.2408; 1H NMR (400 MHz, methanol-d4) δ 0.89–0.98 (m, 3 H), 1.31
(d, J = 7.0 Hz, 3 H), 1.30–1.40 (m, 4 H), 1.79–1.92 (m, 1 H), 1.93–2.10
(m, 2 H), 2.02 (s, 3 H), 2.11–2.23 (m, 1 H), 2.38 (s, 3 H), 2.97 (dd, J = 10.7,
4.6 Hz, 1 H), 3.25 (dd, J = 8.1, 5.6 Hz, 1 H), 3.59 (dd, J = 10.2, 3.3 Hz, 1 H),
3.72 (br d, J = 3.3 Hz, 1 H), 3.75–3.83 (m, 1 H), 4.10 (dd, J =10.2, 5.5 Hz, 1 H),
4.33–4.40 (m, 2 H), 5.26 (d, J = 5.5 Hz, 1 H), 6.59 (ddd, J =8.0, 2.2, 0.9 Hz,
1 H), 6.71 (ddd, J =7.7, 1.7, 0.9 Hz, 1 H), 6.78–6.82 (m, 1 H), 6.99–7.06 (m, 1 H).
7(S)-7-(5-Aminobenzo[d]thiazol-2-ylthio)-7-deoxylincomycin (29). To a solu-
tion of compound 17 (75.0 mg, 0.12 mmol) in ethanol (3.0 ml) were added
SnCl2·H2O (140 mg, 0.62 mmol) and NaBH4 (6.5 mg, 0.17 mmol) and stirred
at RT for 3 h. The mixture was concentrated under reduced pressure. The
resulting residue was dissolved by ethyl acetate, washed with water, dried over
MgSO4 and concentrated under reduced pressure. The resulting residue was
purified by preparative TLC (CHCl3/CH3OH/28% aq NH4OH= 20/1/0.1) to
25
obtain the title compound as a colorless solid (34.2 mg, 48%). [α]D +59.4°
(c 0.58, MeOH); ESI-MS (m/z) 571 (M+H)+ as C25H38N4O5S3; TOF-
ESI-HRMS (M+H)+ calcd for C25H38N4O5S3: 571.2083, found: 571.2090; 1H
NMR (400 MHz, methanol-d4) δ 0.87–0.96 (m, 3 H), 1.25–1.39 (m, 4 H), 1.55
(d, J = 7.0 Hz, 3 H), 1.76–1.86 (m, 1 H), 1.88 (s, 3 H), 1.96–2.08 (m, 2 H),
2.12–2.24 (m, 1 H), 2.32 (s, 3 H), 2.99 (dd, J = 10.5, 5.2 Hz, 1 H), 3.18
(dd, J = 8.5, 6.2 Hz, 1 H), 3.57 (dd, J =10.1, 3.2 Hz, 1H), 3.81 (br dd,
J = 3.2, 0.7 Hz, 1 H), 4.10 (dd, J = 10.1, 5.6 Hz, 1 H), 4.39 (dq, J = 7.0,
3.1 Hz, 1 H), 4.42 (br dd, J = 9.7, 0.7 Hz, 1 H), 4.58 (dd, J = 9.7, 3.1 Hz, 1 H),
5.24 (d, J = 5.6 Hz, 1 H), 6.81 (dd, J = 8.6, 2.2 Hz, 1H), 7.16–7.18 (m, 1 H), 7.52
(dd, J = 8.6, 0.2 Hz, 1 H).
7(S)-7-(4-Aminophenylthio)-7-deoxylincomycin (33). Compound 20 (29.3 mg,
0.054 mmol), SnCl2·H2O (60.8 mg, 0.27 mmol) and NaBH4 (10.0 mg, 0.26
mmol) were treated according to the similar procedure as described for the
preparation of 31 to afford 33 (9.7 mg, 35%) as a colorless solid. [α]D28 +142.0°
(c 0.51, MeOH); ESI-MS (m/z) 514 (M+H)+ as C24H39N3O5S2; TOF-ESI-
HRMS (M+H)+ calcd for C24H39N3O5S2: 514.2409, found: 514.2411; 1H NMR
(400 MHz, methanol-d4) δ 0.89–0.98 (m, 3 H), 1.20 (d, J = 7.1 Hz, 3 H),
1.30–1.41 (m, 4 H), 1.80–1.90 (m, 1 H), 1.92–2.00 (m, 1 H), 2.04–2.21
(m, 2 H), 2.17 (s, 3 H), 2.34 (s, 3 H), 2.98 (dd, J =10.6, 4.6 Hz, 1 H), 3.24
(dd, J = 8.2, 5.6 Hz, 1 H), 3.53 (dq, J = 7.1, 2.8 Hz, 1 H), 3.60 (dd, J = 10.3,
3.3 Hz, 1 H), 3.68–3.72 (m, 1 H), 4.10 (dd, J = 10.3, 5.6 Hz, 1 H), 4.25
(dd, J = 9.9, 2.8 Hz, 1 H), 4.38 (br d, J = 9.9 Hz, 1 H), 5.27 (d, J = 5.6 Hz, 1 H),
6.62–6.68 (m, 2 H), 7.20–7.26 (m, 2 H).
7(R)-7-(6-Aminobenzo[d]thiazol-2-ylthio)-7-deoxylincomycin (30). To a solu-
tion of clindamycin hydrochloride (460 mg, 1.0 mmol) in DMF (5 ml) were
added K2CO3 (152 mg, 1.1 mmol) and 6-aminobenzo[d]thiazole-2-thiol
(200 mg, 1.1 mmol) and stirred at 100 °C for 16 h. Then it was concentrated
under reduced pressure. The residue was diluted with water and then extracted
with ethyl acetate, washed with water, dried over MgSO4 and concentrated
under reduced pressure. The resulting residue was purified by preparative TLC
(CHCl3/CH3OH/28% aq NH4OH= 20/1/0.1) to obtain the title compound as a
colorless solid (233.3 mg, 41%). [α]D27 +129.5° (c 0.45, MeOH); ESI-MS (m/z)
571 (M+H)+ as C25H38N4O5S3; TOF-ESI-HRMS (M+H)+ calcd for
C25H38N4O5S3: 571.2083, found: 571.2079; 1H NMR (400 MHz, methanol-
d4) δ 0.87–0.96 (m, 3 H), 1.27–1.39 (m, 4 H), 1.50 (d, J =7.1 Hz, 3 H),
1.75–1.87 (m, 1 H), 1.95–2.01 (m, 1 H), 2.05 (dd, J = 10.2, 8.9 Hz, 1 H), 2.17
(s, 3 H), 2.13–2.26 (m, 1 H), 2.39 (s, 3 H), 2.98 (dd, J = 10.4, 5.0 Hz, 1 H), 3.21
(dd, J = 8.5, 6.2 Hz, 1 H), 3.54 (dd, J = 10.2, 3.3 Hz, 1 H), 3.80–3.84 (m, 1 H),
4.11 (dd, J = 10.2, 5.6 Hz, 1 H), 4.28 (br dd, J = 9.2, 0.6 Hz, 1 H), 4.30
(dq, J = 7.1, 3.9 Hz, 1 H), 4.65 (dd, J = 9.2, 3.9 Hz, 1 H), 5.29 (d, J = 5.6 Hz,
1 H), 6.84 (dd, J = 8.7, 2.3 Hz, 1 H), 7.08 (dd, J = 2.3, 0.4 Hz, 1 H), 7.57
(dd, J = 8.7, 0.4 Hz, 1 H). For the qualified analytical purpose, the above
colorless solid was further purified by reverse-phase column chromatography
7(S)-7-(4-Methanesulfonamidophenylthio)-7-deoxylincomycin (34). To a solu-
tion of compound 33 (83.8 mg, 0.16 mmol) in DMF (1 ml) were added
triethylamine (0.027 ml, 0.2 mmol) and methanesulfonyl chloride (0.015 ml,
0.2 mmol) and stirred at RT for 20 min. To the mixture was added saturated
aqueous NaHCO3 (10 ml) and then extracted with ethyl acetate, dried over
MgSO4 and concentrated under reduced pressure. The resulting residue was
purified by preparative TLC (CHCl3/CH3OH/28% aq NH4OH= 9/2/0.2) to
26
obtain the title compound as a colorless solid (28.0 mg, 29%). [α]D +94.2°
(c 1.01, MeOH); ESI-MS (m/z) 592 (M+H)+ as C25H41N3O7S3; TOF-ESI-
HRMS (M+H)+ calcd for C25H41N3O7S3: 592.2185, found: 592.2180; 1H NMR
(400 MHz, methanol-d4) δ 0.89–0.98 (m, 3 H), 1.28 (d, J = 7.0 Hz, 3 H),
1.31–1.41 (m, 4 H), 1.78–1.92 (m, 1 H), 1.99 (ddd, J = 12.9, 7.9, 5.0 Hz, 1 H),
2.04 (s, 3 H), 2.05–2.11 (m, 1 H), 2.11–2.23 (m, 1 H), 2.38 (s, 3 H), 2.94–3.03
(m, 1 H), 2.97 (s, 3 H), 3.25 (dd, J = 8.1, 5.6 Hz, 1 H), 3.58 (dd, J = 10.2,
3.2 Hz, 1 H), 3.74 (br d, J = 3.2 Hz, 1 H), 3.78 (dq, J = 7.0, 2.5 Hz, 1 H), 4.10
(dd, J = 10.2, 5.6 Hz, 1 H), 4.31–4.36 (m, 1 H), 4.38 (dd, J = 9.7, 2.5 Hz, 1 H),
5.26 (d, J = 5.6 Hz, 1 H), 7.18–7.25 (m, 2 H), 7.40–7.48 (m, 2 H).
(YMC triart C18, 20× 250 mm, RT, 18.9 ml min− 1
, 50 mM AcONH4/
7(S)-7-(5-(2-Aminoacetamido)-1,3,4-thiadiazol-2-ylthio)-7-deoxylincomycin
(36). To a solution of compound 1 (240 mg, 0.39 mmol) in THF (5 ml) at 0 °
C were added triphenylphosphine (150 mg, 0.57 mmol), diethylazodicarbox-
ylate (0.1 ml, 0.55 mmol) and t-butyl (2-((5-mercapto-1,3,4-thiadiazol-2-yl)
amino)-2-oxoethyl)carbamate (150 mg, 0.52 mmol) and stirred RT for 17 h.
The mixture was concentrated under reduced pressure, and the resulting
residue (compound 35) in 90% aqueous trifluoroacetic acid (5 ml) was stirred
at RT for 30 min. The mixture was concentrated under reduced pressure. The
resulting residue was purified by preparative reverse-phase column chromato-
graphy (YMC triart C18, 20 × 250 mm2, RT, 18.9 ml min− 1, 0.1% aq TFA/
CH3CN=85/15). This trifluoroacetate was desalted by preparative reverse-
CH3CN = 35/65) to obtain the highly purified title compound as
colorless solid.
a
7(S)-7-(2-Aminophenylthio)-7-deoxylincomycin (31). To a solution of com-
pound 18 (39.6 mg, 0.07 mmol) in ethanol (2 ml) were added SnCl2·H2O
(82.1 mg, 0.36 mmol) and NaBH4 (13.7 mg, 5.0 mmol) and stirred at RT for
3 h. To the mixture was added aq NaHCO3 and then extracted with ethyl
acetate, washed with water, dried over MgSO4 and concentrated under reduced
pressure. The resulting residue was purified by preparative TLC (CHCl3/
CH3OH/28% aq NH4OH= 9/1/0.1) to obtain the title compound as a colorless
solid (10.9 mg, 29%). [α]D28 +74.5° (c 0.33, MeOH); ESI-MS (m/z) 514 (M+H)
+
as C24H39N3O5S2; TOF-ESI-HRMS (M+H)+ calcd for C24H39N3O5S2: phase column chromatography (YMC triart C18, 20× 250 mm2, RT, 18.9
514.2409, found: 514.2412; 1H NMR (400 MHz, methanol-d4) δ 0.89–0.97 ml min− 1, H2O/MeOH= 100/0 (15 min)→ 0/100 (15–40 min)) to obtain the
The Journal of Antibiotics

Novel lincomycin derivatives
Y Wakiyama et al
12
25
highly purified title compound as a colorless solid (54.0 mg, 24%). [α]D
(dd, J = 9.5, 2.4 Hz, 1 H), 3.75 (br d, J = 2.4 Hz, 1 H), 3.90 (d, J =9.7 Hz, 1 H),
+100.4° (c 0.29, MeOH); ESI-MS (m/z) 578 (M+H)+ as C22H38N6O6S3; TOF- 4.15 (dd, J = 9.5, 5.6 Hz, 1 H), 4.70–4.78 (m, 1 H), 5.09–5.15 (m, 1 H), 5.16
ESI-HRMS (M+H)+ calcd for C22H38N6O6S3: 579.2093, found: 579.2095; 1H
NMR (400 MHz, methanol-d4) δ 0.86–0.97 (m, 3 H), 1.29–1.39 (m, 4 H), 1.42
(d, J =7.0 Hz, 3 H), 1.77–1.87 (m, 1 H), 1.93–2.09 (m, 2 H), 2.06 (s, 3 H),
2.13–2.25 (m, 1 H), 2.32 (s, 3 H), 2.98 (dd, J = 10.5, 5.0 Hz, 1 H), 3.26
(dd, J = 8.5, 6.2 Hz, 1 H), 3.57 (dd, J = 10.2, 3.2 Hz, 1 H), 3.54–3.62 (m, 2 H),
3.78 (br dd, J = 3.2, 0.5 Hz, 1 H), 4.08 (dq, J = 7.0, 2.8 Hz, 1 H), 4.10
(dd, J = 10.2, 5.6 Hz, 1 H), 4.40 (br dd, J = 9.8, 0.5 Hz, 1 H), 4.47 (dd, J = 9.8,
2.8 Hz, 1 H), 5.26 (d, J =5.6 Hz, 1 H).
(d, J = 5.6 Hz, 1 H), 7.61 (d, J = 10.7 Hz, 1 H).
7(S)-7-Deoxy-7-(4-methoxycarbonylphenylthio)lincomycin (40). To a solution
of compound 39 (100 mg, 0.14 mmol) in DMF (1.0 ml) were added K2CO3
(59.8 mg, 0.43 mmol) and methyl 4-mercaptobenzoate (48.9 mg, 0.29 mmol)
and stirred at 80 °C for 3 h. The mixture was cooled down to RT, diluted with
1 N HCl (2 ml)–MeOH (1 ml), stirred at RT for 2 h and concentrated under
reduced pressure. The resulting residue was dissolved by water, washed with
diethyl ether. To the mixture was added NaHCO3 (150 mg) and then extracted
with ethyl acetate, washed with water, dried over MgSO4 and concentrated
under reduced pressure. The resulting residue was purified by preparative TLC
(CHCl3/CH3OH/28% aq NH4OH= 5/1/0.1) to obtain the title compound as a
7(S)-7-(5-Amino-1,3,4-thiadiazol-2-ylthio)-7-deoxy-2,3,4-tris-O-(trimethylsilyl)
lincomycin (37). To a solution of compound 21 (403 mg, 0.77 mmol) in
pyridine (8 ml) were added trimethylchlorosilane (0.61 ml, 4.8 mmol) and
hexamethyldisilazane (1.05 ml, 5.0 mmol) and stirred at RT for 2.5 h, and then
it was concentrated under reduced pressure. The residue was diluted with
saturated aqueous NH4Cl and extracted with ethyl acetate, washed with brine,
dried over MgSO4 and concentrated under reduced pressure. The resulting
residue was purified by silica gel column chromatography (hexane/ethyl
acetate= 1/1) to obtain the title compound as a colorless solid (467 mg,
82%). ESI-MS (m/z) 738 (M+H)+ as C29H59N5O5S3Si3; 1H NMR (400 MHz,
chloroform-d) δ 0.13 (s, 18H), 0.17 (s, 9 H), 0.79–0.97 (m, 3 H), 1.15–1.37
(m, 4 H), 1.42 (d, J = 6.9 Hz, 3 H), 1.71–1.90 (m, 2 H), 1.91–2.06 (m, 2 H),
2.08 (s, 3 H), 2.40 (s, 3 H), 2.99 (dd, J = 10.7, 3.6 Hz, 1 H), 3.12–3.23 (m, 1 H),
3.61 (dd, J = 9.6, 2.5 Hz, 1 H), 3.74 (br d, J = 2.2 Hz, 1 H), 4.04–4.24 (m, 3 H),
24
colorless solid (58.0 mg, 73%). [α]D +84.6° (c 0.97, MeOH); ESI-MS (m/z)
557 (M+H)+ as C26H40N2O7S2; TOF-ESI-HRMS (M+H)+ calcd for
C26H40N2O7S2: 557.2355, found: 557.2359; 1H NMR (400 MHz, methanol-
d4) δ 0.88–0.96 (m, 3 H), 1.29–1.37 (m, 4 H), 1.40 (d, J = 6.8 Hz, 3 H),
1.79–1.91 (m, 1 H), 1.84 (s, 3 H), 1.96–2.05 (m, 1 H), 2.05–2.12 (m, 1 H),
2.12–2.25 (m, 1 H), 2.40 (s, 3 H), 3.00 (dd, J = 10.6, 4.8 Hz, 1 H), 3.24
(dd, J = 8.2, 5.7 Hz, 1 H), 3.58 (dd, J = 10.2, 3.2 Hz, 1 H), 3.78 (br dd, J = 3.2,
0.7 Hz,1 H), 3.89 (s, 3 H), 4.03 (dq, J = 6.8, 2.8 Hz,1 H), 4.10 (dd, J = 10.2,
5.6 Hz, 1 H), 4.37 (br dd, J = 9.7, 0.7 Hz, 1 H), 4.52 (dd, J = 9.7, 2.8 Hz, 1 H),
5.24 (d, J = 5.6 Hz, 1 H), 7.42–7.49 (m, 2 H), 7.90–7.97 (m, 2 H).
7(S)-7-Deoxy-7-(3-methoxycarbonylphenylthio)lincomycin (41). Compound 39
(200 mg, 0.29 mmol) and methyl 3-mercaptobenzoate (95.9 mg, 0.57 mmol)
were treated according to the similar procedure as described for the preparation
4.60–4.70 (m,
1 H), 5.23 (d, J = 5.5 Hz, 1 H), 5.50 (s, 2 H), 7.59
(d, J = 10.7 Hz, 1 H).
29
7(S)-7-Deoxy-7-(5-(2-methoxyacetamido)-1,3,4-thiadiazol-2-ylthio)lincomycin
(38). To a solution of compound 37 (104 mg, 0.14 mmol) in THF (3 ml)
were added triethylamine (0.06 ml, 0.43 mmol) and 2-methoxyacetyl chloride
(0.02 ml, 0.22 mmol) and stirred at 0 °C for 2 h. The mixture was diluted with
saturated aqueous NH4Cl and extracted with ethyl acetate, washed with brine,
dried over MgSO4 and concentrated under reduced pressure. The resulting
residue was purified by preparative TLC (CHCl3/CH3OH=19/1) to obtain 7
(S)-7-deoxy-7-(5-(2-methoxyacetamido)-1,3,4-thiadiazol-2-ylthio)-2,3,4-tris-
O-(trimethylsilyl)lincomycin as a colorless solid (109.8 mg, 96%). 7(S)-7-
Deoxy-7-(5-(2-methoxyacetamido)-1,3,4-thiadiazol-2-ylthio)-2,3,4-tris-O-(tri-
methylsilyl)lincomycin (109.8 mg, 0.14 mmol) in 1 N HCl (1 ml)–MeOH
(1 ml) was stirred at RT for 2 h. The mixture was concentrated under reduced
pressure. The resulting residue was dissolved by water and washed with diethyl
ether. The mixture was added NaHCO3 (150 mg) and then extracted with ethyl
acetate, dried over MgSO4 and concentrated under reduced pressure. The
resulting residue was purified by preparative TLC (CHCl3/CH3OH/28% aq
NH4OH= 5/1/0.1) to obtain the title compound as a colorless solid (37.8 mg,
of 40 to afford 41 (101.6 mg, 64%) as a colorless solid. [α]D +93.6° (c 2.37,
MeOH); ESI-MS (m/z) 557 (M+H)+ as C25H37N3O6S2; TOF-ESI-HRMS
(M+H)+ calcd for C25H37N3O6S2: 557.2355, found: 557.2355; 1H NMR
(400 MHz, methanol-d4) δ 0.88–0.97 (m, 3 H), 1.29–1.40 (m, 4 H), 1.33
(d, J = 7.0 Hz, 3 H), 1.78–1.91 (m, 1 H), 1.95–2.04 (m, 1 H), 1.97 (s, 3 H),
2.04–2.11 (m, 1 H), 2.11–2.23 (m, 1 H), 2.39 (s, 3 H), 2.99 (dd, J = 10.7,
4.7 Hz, 1 H), 3.23 (dd, J = 8.2, 5.7 Hz, 1 H), 3.58 (dd, J = 10.2, 3.3 Hz, 1 H),
3.74–3.79 (m, 1 H), 3.87–3.96 (m, 1 H), 3.91 (s, 3 H), 4.11 (dd, J = 10.2,
5.6 Hz, 1 H), 4.36 (br dd, J = 9.7, 0.6 Hz, 1 H), 4.48 (dd, J = 9.7, 2.8 Hz, 1 H),
5.27 (d, J = 5.6 Hz, 1 H), 7.42–7.49 (m, 1 H), 7.67 (ddd, J = 7.8, 1.8, 1.1 Hz,
1 H), 7.87–7.92 (m, 1 H), 8.02–8.06 (m, 1 H).
In vitro antibacterial activity
MIC, μg ml− 1 was determined by the agar dilution method, which was
described in Clinical and Laboratory Standards Institute (M7-A5 in 2000).
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’ (SDA; Nissui,
Tokyo, Japan), 5% defibrinated horse blood, 5 μg ml− 1 Hemin and 15 μg ml− 1
NAD. A 5-μl portion of cell suspension of the test strains having about 106 CFU
per ml was inoculated into SDA supplemented with 5% defibrinated horse
blood, 5 μg ml− 1 Hemin and 15 μg ml− 1 NAD and incubated at 37 °C for
18–22 h. Then MIC was measured.
47%). [α]D +98.3° (c 0.65, MeOH); ESI-MS (m/z) 594 (M+H)+ as
26
C23H39N5O7S3; TOF-ESI-HRMS (M+H)+ calcd for C23H39N5O7S3: 594.2090,
found: 594.2095; 1H NMR (400 MHz, methanol-d4) δ 0.88–0.97 (m, 3 H),
1.30–1.41 (m, 4 H), 1.46 (d, J = 7.0 Hz, 3 H), 1.82–1.92 (m, 1 H), 1.97–2.08
(m, 1 H), 2.04 (s, 3 H), 2.08–2.15 (m, 1 H), 2.15–2.27 (m, 1 H), 2.39 (s, 3 H),
3.08 (dd, J = 10.4, 5.0 Hz, 1 H), 3.25–3.34 (m, 1 H), 3.48 (s, 3 H), 3.57
(dd, J = 10.3, 3.2 Hz, 1 H), 3.77–3.81 (m, 1 H), 4.10 (dd, J = 10.3, 5.6 Hz, 1 H),
4.16–4.24 (m, 1 H), 4.21 (s, 2 H), 4.39 (br dd, J = 9.8, 0.6 Hz, 1 H), 4.53
(dd, J = 9.8, 3.1 Hz, 1 H), 5.26 (d, J = 5.6 Hz, 1 H).
CONFLICT OF INTEREST
The authors declare no conflict of interest.
7-O-Methanesulfonyl-2,3,4-tris-O-(trimethylsilyl)lincomycin (39). To a solution
of compound
1 (5.0 g, 8.0 mmol) in chloroform (25 ml) were added
ACKNOWLEDGEMENTS
We thank Mr A Tamura, Dr E Shitara, Dr T Okutomi, Dr T Yoshida, and
Mr M Yamamoto for encouragement and valuable discussion. We are grateful
triethylamine (2.79 ml, 20.1 mmol) and methanesulfonyl chloride (1.24 ml,
16.1 mmol) and stirred at RT for 3 h. The mixture was dissolved by chloroform
(60 ml), washed with saturated aqueous NaHCO3 (50 ml), dried over MgSO4
and concentrated under reduced pressure. The resulting residue was purified by to Professor Emeritus Dr M Konno for supervision through our in-house
silica gel column chromatography (hexane/ethyl acetate= 3/1) to obtain the
title compound as a colorless solid (5.50 g, 98%). ESI-MS (m/z) 701 (M+H)+ as
C28H60N2O8S2Si3; 1H NMR (400 MHz, chloroform-d) δ 0.13 (s, 9 H), 0.14 (s, 9
drug discovery program in lincomycin field. We also thank Ms M Ishii for
direction in intellectual properties; Mr T Watanabe for contribution toward
computational chemistry; Ms S Miki, Ms T Miyara and Ms K Kaneda for
H), 0.17 (s, 9 H), 0.89 (br t, J = 6.9 Hz, 3 H), 1.21–1.36 (m, 4 H), 1.40 analytical and synthetic chemistry; Mr Y Takayama, Ms Y Inoue, Mr T
(d, J = 6.6 Hz, 3 H), 1.79–1.89 (m, 1 H), 1.92–2.09 (m, 3 H), 2.11 (s, 3 H), 2.40 Matsuhira and Ms K Yamada for biological studies; and Ms M Takagi for
(s, 3 H), 2.99 (dd, J = 10.7, 3.7 Hz, 1 H), 3.09 (s, 3 H), 3.14–3.21 (m, 1 H), 3.52 English manuscript.
The Journal of Antibiotics

Novel lincomycin derivatives
Y Wakiyama et al
13
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The Journal of Antibiotics