Design and synthesis of potent macrocyclic HIV-1 protease inhibitors involving P1-P2 ligands

Article abstract of DOI:10.1039/c4ob00738g

A series of potent macrocyclic HIV-1 protease inhibitors have been designed and synthesized. The compounds incorporated 16- to 19-membered macrocyclic rings between a nelfinavir-like P2 ligand and a tyrosine side chain containing a hydroxyethylamine sulfonamide isostere. All cyclic inhibitors are more potent than their corresponding acyclic counterparts. Saturated derivatives showed slight reduction of potency compared to the respective unsaturated derivatives. Compound 8a containing a 16-membered ring as the P1-P2 ligand showed the most potent enzyme inhibitory and antiviral activity. This journal is the Partner Organisations 2014.

Full text of DOI:10.1039/c4ob00738g

Organic &
Biomolecular Chemistry
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PAPER
Design and synthesis of potent macrocyclic HIV-1
protease inhibitors involving P1–P2 ligands†
Cite this: Org. Biomol. Chem., 2014,
12, 6842
Arun K. Ghosh,*a Gary E. Schiltz,a Linah N. Rusere,a Heather L. Osswald,a
D. Eric Walters,b Masayuki Amanoc and Hiroaki Mitsuyac,d
A series of potent macrocyclic HIV-1 protease inhibitors have been designed and synthesized. The com-
pounds incorporated 16- to 19-membered macrocyclic rings between a nelfinavir-like P2 ligand and a
tyrosine side chain containing a hydroxyethylamine sulfonamide isostere. All cyclic inhibitors are more
potent than their corresponding acyclic counterparts. Saturated derivatives showed slight reduction of
potency compared to the respective unsaturated derivatives. Compound 8a containing a 16-membered
ring as the P1–P2 ligand showed the most potent enzyme inhibitory and antiviral activity.
Received 7th April 2014,
Accepted 27th June 2014
DOI: 10.1039/c4ob00738g
www.rsc.org/obc
mutations lead to decreased van der Waals interactions and
increased the size of the subsite hydrophobic pocket.12,13 On
Introduction
HIV-1 protease inhibitors are a critical component of antiretro- the basis of this insight of enzyme flexibility in accommo-
viral therapy (ART) for the treatment of patients with HIV dating alternate packing, we designed flexible macrocycles
infection and AIDS.1,2 The use of ART has reduced both the between the P1′-side chain and a suitable P2′-ligand to fill in
mortality and morbidity rates among HIV-infected patients. the S2′ and S1′-subsites. As shown in Fig. 1, this effort led to a
However, the emergence of drug resistance has raised serious series of potent macrocyclic inhibitors, as represented by
concerns about the prospects of long-term treatment inhibitor 2, containing the P1–P2-ligands of darunavir.
options.3,4 In our continuing studies to combat drug resist-
In an alternate design approach, we have designed macro-
ance, our structure-based design strategies targeting the cyclic inhibitors as represented by inhibitor 3, where the
protein backbone have led to the discovery of a variety of novel macrocycles involve the P1–P2 ligands, incorporating 2,3-di-
HIV-1 protease inhibitors (PIs), including the FDA approved hydroxybenzoic acid derivatives as the P2-ligand, and aliphatic
HIV-1 protease inhibitor darunavir with broad-spectrum activity chains as the P1 ligand. Fairlie and co-workers also designed a
against multidrug-resistant HIV-1 variants.5–8
number of different macrocyclic HIV-1 protease inhibitors, as
In another approach to developing inhibitors with broad- represented in inhibitor 4.14 Based upon our previous results,
spectrum activity, we have been exploring the design of various we have now investigated macrocyclic inhibitors involving
macrocyclic HIV-1 protease inhibitors. Recently, we have P1–P2 ligands which incorporate 3-hydroxy-2-alkylbenzoic acid
reported the design of a series of potent PIs that incorporate derivatives as the P2-ligand and alkylated tyrosine side chains
flexible macrocycles involving P1′–P2′-ligands and P1–P2 as the P1 ligand. In particular, as shown in Fig. 2, inhibitors
ligands to effectively fill in the S1′–S2′ and S1–S2 subsites of are designed by taking advantage of the large hydrophobic
HIV-1 protease, respectively.9–11 The concept of this macro- pocket in the HIV-1 protease S1–S2 active site. These inhibitors
cyclic design evolved from the observation that certain incorporate the P2 ligand found in the FDA approved drug
nelfinavir 5 and the P1′–P2′ ligands found in TMC-126 (6).15,16
Various macrocyclic inhibitors can be synthesized conveniently
by ring-closing metathesis of the dienes 7 using Grubbs’
catalyst.
aDepartments of Chemistry and Medicinal Chemistry, Purdue University, West
Lafayette, IN 47907, USA. E-mail: akghosh@purdue.edu; Fax: +1 765 4961612;
Tel: +1 765 4945323
bDepartment of Pharmaceutical Sciences, Rosalind Franklin University of Medicine
and Science, North Chicago, IL 60064, USA
cKumamoto University School of Medicine, Department of Hematology and Infectious
Results and discussion
diseases, Kumamoto 860-8556, Japan
dExperimental Retrovirology Section, HIV and AIDS Malignancy Branch, National
In order to gain additional insight into the proposed inhibi-
Cancer Institute, Bethesda, Maryland 20892, USA
tors, a molecular model was obtained with one of the unsatu-
†Electronic supplementary information (ESI) available: Characterization of new
rated macrocycles overlaid with nelfinavir (Fig. 3).17 As can be
seen, the phenolic hydroxyl group of the macrocyclic inhibitor
compounds; copies of 1H NMR and 13C-NMR spectra are available. See DOI:
10.1039/c4ob00738g
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Fig. 1 Structures of Darunavir and macrocyclic HIV-1 protease inhibi-
tors 2–4.
Fig. 2 Design of macrocyclic inhibitor 8.
8a (16-membered macrocycle, n = 1) appears to be capable of
forming hydrogen bonds with the Asp30 backbone NH as well
as the side chain carbonyl residue in the S2 subsite. The benz-
amide carbonyl oxygen is positioned to form a hydrogen bond
with the tight-bound water molecule that can interact with one
of the sulfonamide oxygens. The 4-methoxy oxygen on the
P2′-sulfonamide ligand can also form hydrogen bonding inter-
actions with the Asp30′ backbone NH in the S2′-pocket. Fur-
thermore, it appears that as the ring size increases, the P2 and
P1 ligands would become distorted from their optimal position
and bind less tightly in the S2 pockets. Based upon this
model, it appears that inhibitors with 16–18 membered ring
sizes could optimally fit in the S2 hydrophobic pocket.
Synthesis of the desired tyrosine-derived hydroxyethylamine
sulfonamide isostere is shown in Scheme 1. The commercially
available butadiene monoxide 9 was reacted with p-benzyloxy-
phenylmagnesium bromide in the presence of a catalytic
Fig. 3 Model of inhibitor 8a (green, n = 1) overlaid with nelfinavir
(magenta) in the HIV-1 protease active site.
amount of cuprous cyanide to provide the corresponding ment with 2-acetoxyisobutyryl chloride in chloroform followed
allylic alcohol.18 Sharpless asymmetric epoxidation of the by reaction of the resulting chloroacetate with sodium
resulting alcohol using (−)-diethyl D-tartrate provided optically methoxide.22
active epoxide 10 in very good yield.19,20 Regioselective epoxide
Preparation of the elaborated sulfonamide intermediate
opening of 10 using TMSN3 and Ti(O-iPr)4 as described by was accomplished by opening epoxide 11 with isobutylamine
Sharpless and co-workers afforded the corresponding azido in 2-propanol at reflux.23 The resulting amine was reacted with
diol.21 The resulting diol was converted to epoxide 11 by treat- p-methoxyphenylsulfonyl chloride in the presence of aqueous
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Phosphorane 18 was prepared from maleic anhydride 17 using
reported procedures.24–26 Wittig reaction of phosphorane 18
with known27,28 aldehyde 19 provided dienoic acid 20 in good
yield (83%).29 Alkylation of 20 with LDA and 4-bromo-1-butene
in the presence of DMPU afforded the corresponding triene
derivative. This was exposed to trifluoroacetic anhydride
(TFAA) and triethylamine followed by NaBH4 in ethanol which
effected a 1,6-electrocyclization to afford benzoic acid ester
21.30 Saponification of ethyl ester 21 with KOH in methanol
provided the desired acid 22.
Synthesis of various acyclic and macrocyclic inhibitors is
shown in Scheme 3. Treatment of Boc-derivatives 13–16 with
trifluoroacetic acid in CH2Cl2 resulted in the deprotection of
the Boc group. The resulting amines were then coupled with
acid 22 to provide acyclic dienes 7a–d in good yields. Ring-
closing metathesis of the dienes 7a–d was carried out using
Grubbs’ first generation catalyst in CH2Cl2 at 23 °C for 4 h to
provide macrocycles 8a–d in excellent yields (78–89%).31,32 The
alkenes were formed as a mixture of trans/cis isomers. Trans/cis
Ratios of the unsaturated macrocycles were 1 : 1 for 8a
(16-membered ring); 3 : 1 for 8b (17-membered ring); 5 : 1 for
8c (18-membered ring); and essentially a single trans-isomer
for 8d (19-membered ring). The cis/trans isomers could not be
separated by silica gel chromatography. To obtain the corres-
ponding saturated macrocyclic inhibitors, we first attempted
hydrogenation of allyl ether 8a over 10% Pd/C in ethyl acetate
for 12 h. However, under these conditions, only the ring
Scheme 1 Reagents and conditions: (a) p-BnOPhMgBr, CuCN, THF,
−78 °C; 39%; (b) D(–)-DET, Ti(O-iPr)4, 4 A MS, TBHP, CH2Cl2, 79%;
(c) Ti(O-iPr)4, TMSN3, PhH, reflux, 55%; (d) AcOMe2CCOCl, CHCl3; (e)
NaOMe, THF, 71%, over 2 steps; (f) i-BuNH2, i-PrOH, reflux; (g) p-
MeOPhSO2Cl, aq. NaHCO3, CH2Cl2, 97% 2 steps; (h) H2, MeOH, Boc2O,
Pd/C, 75%; (i) acetone, K2CO3, alkenyl bromide, reflux, 94–96%.
NaHCO3 to provide azidosulfonamide 12 in excellent yield.
Catalytic hydrogenation of 12 over Pd/C in the presence of
Boc2O provided the Boc-protected amine as well as the free
phenol in an efficient one-pot operation. The resulting phenol
derivative was alkylated with an appropriate alkenylbromide in
acetone in the presence of K2CO3 to furnish the requisite
olefins 13–16 in excellent yields.
Synthesis of 3-hydroxy-2-alkenylbenzoic acid, the corres-
ponding alkenyl metathesis substrate, is shown in Scheme 2.
Scheme 2 Reagents and conditions: (a) PPh3, acetone; (b) EtOH,
35%, over 2 steps; (c) PhCH3, hydroquinone, 83%; (d) LDA, THF, DMPU,
4-bromo-1-butene; (e) TFAA, Et3N; (f) NaBH4, EtOH, 48%, over 2 steps;
(g) KOH, MeOH, reflux, 89%.
Scheme 3 Reagents and conditions: (a) TFA, CH2Cl2; (b) acid 22, EDCI,
HOBt, Et3N, DMF, 60–78%, over 2 steps; (c) Grubbs’ 1st Gen. Cat. (20 mol%),
CH2Cl2, 23 °C, 78–89%; (d) H2, Pd/C, EtOAc.
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opened compound 23 was isolated as the main product. (compound 23) showed enhanced potency (Ki = 0.41 nM). In
The use of PtO2 as a catalyst also resulted in an allylic ring general, inhibitors with a longer chain showed reduction in
cleavage to afford the ring-opened product. A similar effect potency. Interestingly, conversion of acyclic inhibitors to their
had been reported by us in the context of the synthesis of corresponding cyclic derivatives after RCM resulted in signifi-
cycloamide based HIV-1 protease inhibitors.11
cant improvement in enzyme inhibitory activity. As shown in
To prevent cleavage of the allylic ether, we carried out the Table 2, acyclic inhibitor 7a (Ki = 5 nM and antiviral IC50
>
hydrogenation according to the procedure reported by Sajiki 1μM) upon RCM provided 16-membered macrocycles 8a (E/Z =
and Hirota.33 As shown in Scheme 4, hydrogenation of 8a in 1 : 1) which showed a Ki value of 0.2 nM. The mixture of
the presence of 5% Pd/C in 1% NH3 in methanol for 4 hours isomers also displayed an antiviral IC50 value of 0.21 μM
afforded the saturated macrocyclic inhibitor 24a in 40% iso- in MT-2 cells. Saturation of double bonds provided
a
lated yield. This condition also provided the ring opened com- saturated inhibitor 24a which showed comparable
a
pound 23 as the byproduct (27%). Catalytic hydrogenation of enzyme inhibitory activity. An acyclic inhibitor 7b (Ki = 7 nM)
unsaturated macrocycles 8b–8d however, proceeded smoothly following RCM afforded a cyclic inhibitor 8b (E/Z = 3 : 1) which
over 10% Pd/C in ethyl acetate to provide saturated derivatives also showed improvement of enzyme Ki over its acyclic deriva-
24b–d respectively in excellent yields (88–94%).
tives. The 17-membered macrocycles showed a comparable
The inhibitory potencies of acyclic and cyclic inhibitors antiviral activity to 16-membered inhibitors. The corres-
were measured by the assay protocol of Toth and Marshall.34 ponding saturated inhibitor 24b displayed reduction in inhibi-
The results are shown in Tables 1 and 2. A number of selected tory potency (Ki
= 2.3 nM). However, this compound
compounds that showed potent enzyme inhibitory Ki values maintained a similar antiviral activity as its unsaturated
were further evaluated in an antiviral assay. Antiviral activity mixtures.
was determined based on a previously published assay proto-
An acyclic inhibitor 7c upon cyclization provided a cyclic
col.35 As can be seen, acyclic inhibitors in Table 1 displayed inhibitor 8c (E/Z = 5 : 1) which displayed Ki of 10 nM and an
enzyme inhibitory potency ranging from 5 nM to 45 nM. An antiviral activity of 420 nM. Interestingly, the corresponding
acyclic ring opened product with a P1-tyrosine side chain saturated derivative 24c showed improvement in enzyme
inhibitory activity. The antiviral activity of inhibitor 24c was
reduced nearly by a factor of 2 over its unsaturated derivative.
An acyclic inhibitor 7d (Ki = 30 nM) was subjected to RCM and
provided a cyclic derivative 8d as a single E-isomer. This com-
pound showed improvement in enzyme Ki over its acyclic
derivative. Saturation of the double bond in 8d provided a
saturated derivative 24d which showed 5-fold reduction in
inhibitory activity.
To gain insight into specific ligand-binding site inter-
actions, an energy minimized model structure of inhibitor 24b
was created. The structure was modelled in the HIV-1 protease
active site based on our published X-ray crystal structure of
Scheme 4 Reagents and conditions: (a) for n = 1, H2, 5% Pd/C, 1% NH3
in MeOH, 40%; (b) for n = 2–4, H2, Pd/C, EtOAc, 88–94%.
inhibitor 1 and HIV-1 protease complex (Protein Data Bank
entry 1S6G) as a template.36 As can be seen in Fig. 4, the
3-hydroxy group of the P2-ligand appeared to be within proxi-
mity to form a hydrogen bond with Asp30 backbone NH as
well as with the side chain carboxylic acid. The P2-carbonyl
Table 1 Potency (Ki) of acyclic inhibitors
group appears to form effective hydrogen bonds with the tight-
bound structural water molecule through one of the P2′-sulfon-
amide oxygens. The macrocyclic carbon chain is nicely accom-
modated in the S1–S2 hydrophobic pockets. Interestingly,
saturation of the ring olefin in 8b resulted in a more flexible
carbon chain which may have resulted in unfavorable van der
Waals interactions in the S2-subsite. This may explain the
reduction of enzyme inhibitory activity for compound 24b. It
appears that the 16-membered saturated macrocycle in 24a
makes more favorable interactions in the S2-subsite of the pro-
tease active site than the corresponding 17-membered macro-
cycle in compound 24b. The OMe-group on the P2′-
sulfonamide of inhibitor 24b appears to maintain hydrogen
bonding interactions with Asp30′ backbone NH as well as with
the side chain carboxylic acid.
Compd
Ring size (after RCM)
n
Ki a (nM)
7a
7b
7c
7d
23
16
17
18
19
—
1
2
3
4
5
7
45
30
0.41
—
a Darunavir exhibited Ki = 16 pM.
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Table 2 Enzymatic inhibitory and antiviral activity of macrocyclic inhibitors
Entry Inhibitor
1
Ki (nM) IC50 a,b (μM) Entry Inhibitor
Ki (nM) IC50 a,b (μM)
0.2
0.21
5
6
7
10
0.42
0.80
nt
2
3
0.25
nt
4
0.5
0.28
4
4
2.3
0.31
8
20
nt
a Human T-lymphoid (MT-2) cells were exposed to 100 TCID50 values of HIV-1LAI and cultured in the presence of each PI, and IC50 values were
determined using the MTT assay. Darunavir exhibited Ki = 16 pM, IC50 = 0.003 μM. b nt = not tested.
design of macrocycles is based on the hypothesis that the
cyclic flexible chain would effectively pack the hydrophobic
pocket in the S1 to S2 subsites. We have synthesized acyclic
derivatives involving P1-tyrosine and P2-3-hydroxy-2-alkenylbenz-
amide derivatives. Ring-closing metathesis using Grubbs’ 1st
generation catalyst efficiently provided 16–19 membered macro-
cyclic rings containing both E/Z olefins as the P1–P2 ligands in
these inhibitors. Catalytic hydrogenation provided the corres-
ponding saturated derivatives. In general, all cyclic inhibitors
containing E/Z olefins showed improved enzyme inhibitory
potency compared to their acyclic counterparts. The saturated
derivatives are less potent than the corresponding unsaturated
Fig. 4 An energy-minimized model of 17-membered macrocyclic
derivatives. Compound 8a showed the best enzyme inhibitory
inhibitor 24b in the HIV-1 protease active site. Putative hydrogen bonds
and antiviral activity in this series. A model of the E-isomer of
are shown as dotted lines.
8b was created to obtain ligand-binding site interactions. As it
appears, the unsaturated macrocyclic ring is nicely accommo-
dated in the S1–S2 hydrophobic pocket. Saturation of the ring
olefin most likely resulted in unfavorable van der Waals inter-
Conclusions
In summary, a novel series of macrocyclic HIV-1 protease
inhibitors has been designed, synthesized and evaluated. The
action in the S2-subsite. This may explain the reduction of
enzyme inhibitory activity for the saturated compound 24b.
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One of the important features of these macrocyclic inhibitors 0.87 mmol) in dry DCM (1 mL) was added to the above
is that the inhibitors contain only two asymmetric centers and mixture and it was kept in a freezer at about −25 °C for 18 h.
can be synthesized efficiently using RCM reaction. Further To the reaction mixture H2O (3 mL) was added and stirred at 0 °C
design and optimization of these inhibitors are in progress.
for 30 minutes. A 10% aqueous NaOH solution was then added
and the mixture was warmed to room temperature for 1 h. The
product was extracted with DCM (3×), dried with Na2SO4, fil-
tered, and concentrated under reduced pressure. Purification
by flash column chromatography (30–40% EtOAc–hexanes)
afforded epoxy alcohol 10 (177 mg, 79%). [α]2D3 +12.5° (c 0.14
Experimental section
All reactions were carried out under an inert atmosphere,
either N2 or Ar, using magnetic stirring and oven-dried glass-
ware. All solvents were anhydrous and distilled prior to use.
Dichloromethane and triethylamine were distilled from
calcium hydride. Tetrahydrofuran, diethyl ether, and benzene
were distilled from sodium/benzophenone. All other solvents
were of HPLC grade or better. Flash column chromatography
was performed using EM Science 60–200 mesh silica gel. Thin-
layer chromatography was performed using 60 F-254 E. Merck
1
CHCl3); H-NMR (500 MHz, CDCl3) δ 7.45 (d, 2H, J = 7.0 Hz),
7.41, (t, 2H, J = 5.5 Hz), 7.34 (t, 1H, J = 7.5 Hz), 7.17 (td, 2H, J =
2.0, 8.5 Hz), 6.95 (td, 2H, J = 2.0, 8.5 Hz), 5.06 (s, 2H), 3.88 (dd,
1H, J = 2.5, 12.5 Hz), 3.60 (dd, 1H, J = 4.5, 12.5 Hz), 3.17 (dt,
1H, J = 2.5, 5.5 Hz), 2.98 (m, 1H), 2.86 (m, 2H); 13C-NMR
(125 MHz, CDCl3) δ 157.7, 137.1, 130.1, 129.3, 128.6, 128.0,
127.5, 115.0, 70.1, 61.6, 58.4, 56.2, 37.0.
1
silica gel plates. H- and 13C-NMR were recorded using Bruker
(1S,2R)-2-[1-Azido-2-(4-benzyloxyphenyl)-ethyl]-oxirane (11)
AV-500, Avance DRX-500, Varian Mercury-Vx-300, and Gemini-
2300 spectrometers and Me4Si as an internal standard. Infra-
red spectra were recorded on an ATI Mattson Genesis Series
FT-IR. Optical rotations were recorded on a Perkin-Elmer 341
polarimeter. A Thermo Finnigan LCQ Classic mass spec was
used for MS analyses.
Dry benzene (5 mL), Ti(Oi-Pr)4 (160 μL), and TMSN3 (72 μL)
were refluxed for 5 hours. A solution of epoxy alcohol 10
(0.123 g, 0.455 mmol) in dry benzene (3 mL) was added and
the solution was refluxed for 30 minutes. After cooling to room
temperature, 5% H2SO4 (2 mL) was added and the solution
was stirred at room temperature for 1 hour. The layers were
separated and the aqueous portion was extracted with ethyl
acetate (3×). The organic solution was dried with Na2SO4, fil-
(2R,3R)-3-(4-benzyloxybenzyl-oxiran-2yl)-methanol (10)
To a suspension of magnesium turnings (101.6 mg, 4.2 mmol) tered, and concentrated under reduced pressure. Purification
in 25 mL THF was added a solution of 4-benzyloxybromo- by flash column chromatography (40–50% EtOAc–hexanes)
benzene (1.0 g, 3.8 mmol) in THF. The mixture was heated at gave
(2R,3S)-3-azido-4-(4-benzyloxyphenyl)-1,2-butanediol
65 °C for 30 min and the solution was cooled to room tempera- (78.9 mg, 55% yield). [α]2D3 +18.1° (c 0.19 CHCl3); 1H-NMR
ture. Grignard solution was added dropwise to a solution of (500 MHz, CDCl3) δ 7.44 (d, 2H, J = 7.0 Hz), 7.39 (t, 2H, J = 7.5
CuCN (26 mg, 0.30 mmol) and butadiene monoxide 9 Hz), 7.34 (t, 1H, J = 7.0 Hz), 7.19 (d, 2H, J = 8.5 Hz), 6.95 (td,
(220 mg, 3.1 mmol) in 80 mL of anhydrous THF at −78 °C. 2H, J = 2.0, 8.5 Hz), 5.05 (s, 2H), 3.80–3.67 (m, 4H), 3.26 (bs,
The reaction was stirred for 30 min at −78 °C, after which it 1H), 2.99 (dd, 1H, J = 3.0, 14.0 Hz), 2.77–2.73 (m, 2H);
was quenched with 15 mL of saturated NH4Cl followed by 13C-NMR (125 MHz, CDCl3) δ 157.8, 137.0, 130.4, 129.5, 128.6,
15 mL of NH4OH. The aqueous layer was extracted twice with 128.0, 127.6, 115.1, 73.1, 70.1, 65.7, 63.3, 36.2; HRMS m/z
ethyl acetate. The combined organic phases were dried over (M + Na)+ calcd for C17H19N3O3Na 336.1324, found 336.1317.
sodium sulfate and concentrated in vacuo. The residue was
(2R,3S)-3-Azido-4-(4-benzyloxyphenyl)-1,2-butanediol (84.4 mg,
purified by flash chromatography on silica gel with 15–20% 0.269 mmol) and chloroform (3 mL) were cooled to 0 °C. 1-Chloro-
ethyl acetate–hexanes to give trans-4-(4-benzyloxy)phenyl- carbonyl-1-methylethyl acetate (58.5 μL, 0.404 mmol) was added
2-buten-1-ol (308 mg, 1.21 mmol, 39% yield). 1H-NMR and the solution was stirred at room temperature for 20 hours.
(500 MHz, CDCl3) δ 7.44 (d, 2H, J = 7.0 Hz), 7.39 (dt, 2H, A saturated solution of NaHCO3(aq) was added and the mixture
J = 2.0, 7.0 Hz), 7.33 (tt, 1H, J = 2.5, 7.5 Hz), 7.11 (td, 2H, stirred for 15 minutes. The crude chloroacetate was extracted
J = 2.5, 9.0 Hz), 6.92 (td, 2H, J = 2.0, 8.5 Hz), 5.84 (dtt, 1H, with chloroform, dried with Na2SO4, filtered, and concentrated
J = 1.5, 6.5, 15.0 Hz), 5.69 (dtt, 1H, J = 1.5, 6.0, 15.5 Hz), 5.05 in vacuo. The residue was dissolved in dry THF (5 mL) and
(s, 2H), 4.12 (dd, 2H, J = 1.0, 55 Hz), 3.34 (d, 2H, J = 7.0 Hz), cooled to 0 °C. Solid NaOMe (24.7 mg) was added and the reac-
1.48 (s, 1H); 13C-NMR (125 MHz, CDCl3) δ 157.3, 137.2, tion mixture was stirred at room temperature for 2 hours. The
132.4, 132.0, 130.0, 129.6, 128.6, 128.0, 127.5, 114.9, 70.1, reaction was quenched with saturated NH4Cl(aq) and extracted
63.6, 37.8.
with ethyl acetate. Drying over Na2SO4, filtering, and concen-
Molecular sieves (500 mg) were flame dried in a flask and trating under reduced pressure afforded a residue which was
then allowed to cool to room temperature. Dry dichloro- purified by flash column chromatography (12% EtOAc–
methane (4 mL) and D-DET (11 mg, 0.05 mmol) were added hexanes) to afford pure azido epoxide 11 (56.5 mg, 71% yield).
1
and the suspension was cooled to −25 °C. To this, Ti(Oi-Pr)4 [α]2D3 +11.3° (c 0.34 CHCl3); H-NMR (500 MHz, CDCl3) δ 7.44
(20.7 μL, 0.07 mmol) and TBHP (0.35 mL, 1.92 mmol) were (d, 2H, J = 7.5 Hz), 7.40 (t, 2H, J = 8.0 Hz), 7.34 (t, 1H, J =
added and the mixture was stirred at −25 °C for 30 minutes. A 7.0 Hz), 7.17 (d, 2H, J = 11.0 Hz), 6.95 (td, 2H, J = 2.0, 11.5 Hz),
solution of trans-4-(4-benzyloxy)phenyl-2-buten-1-ol (211 mg, 5.06 (s, 2H), 3.56 (quintet, 1H, J = 4.0, 5.0 Hz), 3.07–3.05
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(m, 1H), 2.94 (dd, 1H, J = 4.5, 14.0 Hz), 2.84–2.82 (m, 1H), (dd, 2H, J = 2.0, 6.5 Hz), 7.15 (d, 2H, J = 8.5 Hz), 6.97 (dd, 2H, J
2.81–2.75 (m, 2H); 13C-NMR (125 MHz, CDCl3) δ 157.9, 137.0, = 2.0, 7.0 Hz), 6.85 (dd, 2H, J = 2.0, 6.5 Hz), 6.08–6.02 (m, 1H),
130.4, 128.9, 128.6, 128.0, 127.5, 115.0, 70.1, 63.8, 53.0, 45.2, 5.41 (dd, 1H, J = 1.5, 17.5 Hz), 5.28 (dd, 1H, J = 1.0, 10.5 Hz),
37.4.
4.62–4.61 (m, 1H), 4.51 (dt, 2H, J = 1.5, 5.5 Hz), 3.86 (s, 3H),
1.35 (s, 9H), 0.90 (d, 3H, J = 6.5 Hz), 0.86 (d, 3H, J = 6.5 Hz);
13C-NMR (125 MHz, CDCl3) δ 163.0, 157.3, 156.1, 133.4, 130.5,
129.9, 129.5, 117.6, 114.8, 114.6, 114.3, 79.7, 72.7, 68.8, 58.7,
(2R,3S)-N-[3-Azido-4-(4-benzyloxyphenyl)-2-hydroxy-butyl]-N-
isobutyl-4-methoxy-benzenesulfonamide (12)
To epoxide 11 (0.60 g, 2.03 mmol) in isopropanol (10 mL), 55.6, 54.7, 53.8, 34.5, 28.3, 27.2, 20.2, 19.9.
was added isobutylamine (2 mL) and the solution was refluxed
for 2 hours. The reaction was concentrated in vacuo and used
as it is in the next reaction. The residue was taken up in DCM
(10 mL), saturated aqueous NaHCO3 (2 mL) and 4-methoxy-
benzenesulfonyl chloride (0.50 g) were added and the reaction
was stirred for 18 hours at room temperature. The organic
layer was separated and the aqueous portion was extracted
with DCM. The combined organics were dried with Na2SO4, fil-
tered, and concentrated under reduced pressure. Flash column
chromatography (15–25% EtOAc–hexanes) afforded sulfon-
(1S,2R)-{1-(4-(3-Butenyloxy)-benzyl)-2-hydroxy-3-[isobutyl-(4-
methoxy-benzenesulfonyl)-amino]-propyl}-carbamic acid tert-
butyl ester (14)
(1S,2R)-{2-Hydroxy-1-(4-hydroxybenzyl)-3-[isobutyl-(4-methoxy-
benzenesulfonyl)-amino]-propyl}-carbamic acid tert-butyl ester
(36.4 mg, 0.07 mmol) was dissolved in acetone (5 mL). To this
was added K2CO3 (24 mg) and 4-bromo-1-butene (7 μL) and
the reaction was refluxed for 18 hours. After concentrating
under reduced pressure, the product was purified by flash
column chromatography (25% EtOAc–hexanes) to afford 14
1
amide 12 (1.06 g, 97% yield over 2 steps). H-NMR (500 MHz,
CDCl3) δ 7.75 (dd, 2H, J = 2.0, 9.0 Hz), 7.45–7.43 (m, 2H), 7.39
(t, 2H, J = 7.5 Hz), 7.34–7.33 (m, 1H), 7.19 (d, 2H, J = 9.0 Hz),
7.01 (dd, 2H, J = 2.0, 9.0 Hz), 6.94 (dd, 2H, J = 2.0, 8.5 Hz), 5.06
(s, 2H), 3.83 (s, 3H), 3.78–3.75 (m, 1H), 3.59–3.55 (m, 2H), 3.24
(dd, 1H, J = 9.5, 15.5 Hz), 3.09–3.02 (m, 3H), 2.80 (dd, 1H, J =
6.5, 13.5 Hz), 2.75 (dd, 1H, J = 9.0, 14.0 Hz), 1.71–1.69 (m, 1H),
0.94 (d, 3H, J = 6.5 Hz), 0.88 (d, 3H, J = 6.5 Hz); 13C-NMR
(125 MHz, CDCl3) δ 163.2, 157.8, 137.0, 130.4, 129.7, 129.5,
128.6, 128.0, 127.5, 115.1, 114.5, 71.8, 70.0, 66.7, 58.9, 55.7,
52.9, 36.0, 27.2, 20.2, 19.8; HRMS m/z (M + Na)+ calcd for
C28H34N4O5SNa 561.2148, found 561.2166.
1
(37 mg, 96% yield). H-NMR (500 MHz, CDCl3) δ 7.69 (dd, 2H,
J = 2.0, 9.0 Hz), 7.14 (d, 2H, J = 8.5 Hz), 6.96 (dd, 2H, J = 2.0,
9.0 Hz), 6.83 (d, 2H, J = 9.0 Hz), 5.94–5.86 (m, 1H), 5.16 (ddd,
1H, J = 1.5, 2.0, 17.0 Hz), 5.10 (ddd, 1H, J = 1.0, 1.5, 10.0 Hz),
4.64 (d, 1H, J = 8.0 Hz), 3.98 (t, 2H, J = 7.0 Hz), 3.94–3.92 (m,
1H), 3.86 (s, 3H), 3.78–3.75 (m, 1H), 3.71–3.68 (m, 1H),
3.10–2.77 (m, 6H), 2.55–2.51 (m, 2H), 1.84–1.79 (m, 1H), 1.35
(s, 9H), 0.89 (d, 3H, J = 6.5 Hz), 0.85 (d, 3H, J = 6.5 Hz);
13C-NMR (125 MHz, CDCl3) δ 163.0, 157.6, 156.1, 134.5, 130.5,
130.0, 129.8, 129.5, 117.0, 114.6, 114.3, 79.6, 72.7, 67.2, 58.6,
55.6, 54.7, 53.8, 34.5, 29.3, 28.3, 27.2, 20.2, 19.9.
(1S,2R)-{1-(4-Allyloxy-benzyl)-2-hydroxy-3-[isobutyl-(4-methoxy-
benzenesulfonyl)-amino]-propyl}-carbamic acid tert-butyl
ester (13)
(1S,2R)-2-Hydroxy-3-[isobutyl-(4-methoxy-benzenesulfonyl)-
amino]-1-(4-(4-pentenyloxy)-benzyl)-propyl]-carbamic acid tert-
butyl ester (15)
Azide 12 (55.1 mg, 0.10 mmol) was dissolved in methanol
(5 mL) and Boc2O (27 mg) and 10% Pd/C (10 mg) were added
and the reaction mixture was stirred under an H2 atmosphere
for 18 hours. The mixture was filtered through Celite and con- (1S,2R)-{2-Hydroxy-1-(4-hydroxybenzyl)-3-[isobutyl-(4-methoxy-
centrated under reduced pressure. Flash column chromato- benzenesulfonyl)-amino]-propyl}-carbamic acid tert-butyl ester
graphy (30% EtOAc–hexanes) afforded (1S,2R)-{2-hydroxy-1-(4- (54.8 mg, 0.105 mmol), K2CO3 (43.5 mg), and 5-bromo-1-
hydroxybenzyl)-3-[isobutyl-(4-methoxy-benzenesulfonyl)-
pentene (62 μL) were added to acetone (3 mL). The mixture
amino]-propyl}-carbamic acid tert-butyl ester (40 mg, 75% was refluxed for 18 hours, and then concentrated under
yield). 1H-NMR (500 MHz, CDCl3) δ 7.68 (d, 2H, J = 8.5 Hz), reduced pressure. Flash column chromatography (30% EtOAc–
7.06 (m, 2H), 6.96 (d, 2H, J = 9.0 Hz), 6.73–6.71 (m, 2H), hexanes) afforded olefin 15 (59.6 mg, 94% yield). 1H-NMR
6.35–6.25 (bs, 1H), 4.78 (d, 1H, J = 8.0 Hz), 4.01–3.99 (m, 1H), (500 MHz, CDCl3) δ 7.69 (d, 2H, J = 8.0 Hz), 7.14 (d, 2H, J = 8.5
3.84 (s, 3H), 3.81–3.79 (m, 1H), 3.71–3.69 (m, 1H), 3.10–2.77 Hz), 6.96 (dd, 2H, J = 2.0, 7.0 Hz), 6.82 (d, 2H, J = 8.5 Hz),
(m, 6H), 1.86–1.81 (m, 1H), 0.89–0.85 (m, 6H); 13C-NMR 5.89–5.80 (m, 1H), 5.05 (ddd, 1H, J = 1.5, 2.0, 17.0 Hz), 4.99
(125 MHz, CDCl3) δ 163.0, 156.3, 154.7, 130.6, 129.8, 129.5, (dd, 1H, J = 1.5, 10.0 Hz), 4.65 (d, 1H, J = 8.0 Hz), 3.94 (t, 2H, J
129.3, 115.4, 114.4, 80.0, 72.8, 58.6, 55.6, 54.9, 53.6, 34.6, 28.3, = 6.5 Hz), 3.86 (s, 3H), 3.77 (m, 1H), 3.70 (m, 1H), 3.07–3.03
27.2, 20.1, 19.9.
(m, 2H), 2.95–2.86 (m, 3H), 2.81–2.77 (m, 1H), 2.23 (q, 2H, J =
The above phenol derivative (13 mg, 0.02 mmol) was dis- 7.0 Hz), 1.90–1.82 (m, 3H), 1.35 (s, 9H), 0.90–0.86 (m, 6H);
solved in acetone (2 mL), K2CO3 (5.2 mg) and allyl bromide 13C-NMR (125 MHz, CDCl3) δ 163.0, 157.7, 156.1, 137.9, 130.5,
(22 μL) were added, and the reaction was refluxed for 16 hours, 130.0, 129.6, 129.5, 115.2, 114.5, 114.3, 79.6, 72.7, 67.2, 58.6,
and then concentrated under reduced pressure. Flash column 55.6, 54.7, 53.7, 34.5, 30.1, 28.5, 28.3, 27.2, 20.2, 19.9; HRMS
chromatography (25% EtOAc–hexanes) afforded allylic ether 13 m/z (M + Na)+ calcd for C31H46N2O7SNa 613.2923, found
(13.4 mg, 96% yield). 1H-NMR (500 MHz, CDCl3) δ 7.69 613.2906.
6848 | Org. Biomol. Chem., 2014, 12, 6842–6854
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(1S,2R)-{1-(4-(5-Hexenyloxy)-benzyl)-2-hydroxy-3-[isobutyl-(4-
methoxy-benzenesulfonyl)-amino]-propyl}-carbamic acid tert-
butyl ester (16)
centrated under reduced pressure. Short-path distillation
afforded 3-trimethylsilanyl-1-hydroxy-2-propyne (39.9 g, 87%
1
yield). H-NMR (500 MHz, CDCl3) δ 4.27 (s, 2H), 1.61 (s, 1H),
0.18 (s, 9H); 13C-NMR (125 MHz, CDCl3) δ 130.8, 90.8,
51.7, −0.2.
(1S,2R)-{2-Hydroxy-1-(4-hydroxybenzyl)-3-[isobutyl-(4-methoxy-
benzenesulfonyl)-amino]-propyl}-carbamic acid tert-butyl ester
(51.5 mg, 0.0985 mmol), K2CO3 (41 mg), and 6-bromo-1-
hexene (66 μL) were added to acetone (3 mL). The mixture was
refluxed for 16 hours, and then concentrated under reduced
pressure. Flash column chromatography (25% EtOAc–hexanes)
afforded olefin 16 (58.5 mg, 96% yield). 1H-NMR (500 MHz,
CDCl3) δ 7.69 (ddt, 2H, J = 3.0, 8.5 Hz), 7.14 (d, 2H, J = 8.5 Hz),
6.96 (ddt, 2H, J = 2.5, 9.0 Hz), 6.82 (d, 2H, J = 8.5 Hz),
5.86–5.78 (m, 1H), 5.04 (ddd, 1H, J = 1.5, 2.0, 17.0 Hz), 4.96
(ddd, 1H, J = 1.0, 2.0, 10.5 Hz), 4.65 (d, 1H, J = 8.5 Hz), 3.93 (t,
2H, J = 6.5 Hz), 3.86 (s, 3H), 3.77 (m, 1H), 3.70 (m, 1H),
3.07–3.02 (m, 2H), 2.93–2.86 (m, 3H), 2.81–2.78 (m, 1H), 2.12
(q, 2H, J = 7.0 Hz), 1.85–1.76 (m, 3H), 1.59–1.53 (m, 2H), 1.35
(s, 9H), 0.89 (d, 3H, J = 6.5 Hz), 0.86 (d, 3H, J = 6.5 Hz);
13C-NMR (125 MHz, CDCl3) δ 163.0, 157.8, 156.1, 138.6, 130.5,
130.0, 129.6, 129.5, 114.8, 114.5, 114.3, 79.6, 72.7, 67.8, 58.6,
55.6, 54.7, 53.7, 34.5, 33.5, 28.8, 28.3, 27.2, 25.3, 20.2, 19.9;
HRMS m/z (M + Na)+ calcd for C32H48N2O7S 627.3080, found
627.3087.
Dry diethyl ether (10 mL) and red-Al (6.2 mL, 21.8 mmol,
3.5 M in toluene) were cooled to 0 °C. 3-Trimethylsilanyl-1-
hydroxy-2-propyne (1.86 g, 14.5 mmol) in dry ether (15 mL)
was added dropwise and the solution was stirred at room
temperature for 2 hours. The reaction was cooled to 0 °C and
3.6 M H2SO4 (15 mL) was added. After extraction with diethyl
ether (3×), drying with Na2SO4, filtering, and concentrating
under reduced pressure, the residue was purified by flash
column chromatography (2–15% EtOAc–hexanes) to give 3-tri-
methylsilanyl-1-hydroxy-2-propene (1.19 g, 63% yield).
To 3-trimethylsilanyl-1-hydroxy-2-propene (0.11 g, 0.84 mmol)
and dry DCM (5 mL) was added MnO2 (0.51 g, 5.87 mmol)
and the reaction mixture was stirred for 30 minutes at room
temperature and 3 hours at reflux. After cooling to room
temperature, 2 additional equivalents of MnO2 were added
and the mixture was stirred at room temperature for 16 hours.
Silica gel was added, and the mixture was filtered through a
silica gel plug after washing with DCM, and concentrated
under reduced pressure to provide conjugated aldehyde 19
(102 mg, 95%). 1H-NMR (300 MHz, CDCl3) δ 9.49 (d, 1H J =
7.5 Hz), 7.19 (d, 1H, J = 18.9 Hz), 6.50 (dd, 1H, J = 7.5, 20.7 Hz),
0.17 (s, 9H); 13C-NMR (75 MHz, CDCl3) δ 194.7, 158.7,
144.0, −2.0.
2-(Triphenylphosphoranylidene)-succinic acid 1-ethyl ester (18)
To a solution of acetone (100 mL) and PPh3 (28.8 g, 0.11 mol)
was added a solution of maleic anhydride (17, 10.8 g,
0.11 mol) in acetone (100 mL). After stirring at room tempera-
ture for 1 hour, the suspension was cooled to 0 °C. The (3E,5E)-3-Ethoxycarbonyl-6-trimethylsilyl-hexadienoic acid (20)
product was isolated by filtering through a sintered glass
funnel and washing with cold acetone. The product was then
dried under vacuum. To the resulting solid, EtOH (200 mL)
To a solution of aldehyde 19 (1.2 g, 7.8 mmol) in toluene
(50 mL) was added Wittig reagent 18 (3.8 g, 9.4 mmol) and
hydroquinone (8.6 mg) and the reaction was stirred for 2 days
was added and the solution was stirred for 2 days after which
at room temperature. After concentrating the reaction mixture
the mixture was concentrated under reduced pressure. The
under reduced pressure, flash column chromatography
carboxylic acid was recrystallized from 1 : 1 EtOAc–hexanes to
(0–20% EtOAc–hexanes) afforded diene 20 (1.98 g, 83% yield).
afford 18 (15.8 g, 35% over 2 steps) as a tan solid. 1H-NMR
FT-IR (film) 1711, 1628, 1414, 1373, 1285, 1249, 1206, 1076,
(500 MHz, CDCl3) δ 7.63–7.59 (m, 9H), 7.51–7.47 (m, 6H), 3.80
(q, 2H, J = 7.0 Hz), 2.83 (d, 2H, J = 14.5 Hz), 0.75 (t, 3H, J =
7.0 Hz); 13C-NMR (125 MHz, CDCl3) δ 172.8, 172.7, 170.3,
133.8, 133.7, 133.7, 129.5, 129.4, 122.6, 121.8, 61.1, 39.6, 39.0,
35.2, 13.8.
1
990, 858, 841 cm−1; H-NMR (500 MHz, CDCl3) δ 7.30 (d, 1H,
J = 11.0 Hz), 6.72 (ddd, 1H, J = 1.0, 10.0, 18.0 Hz), 6.45 (d, 1H,
J = 18.0 Hz), 4.23 (q, 2H, 7.0 Hz), 3.52 (s, 2H), 1.29 (dt, 3H, J =
1.0, 7.0 Hz), 0.12 (d, 9H, 1.0 Hz); 13C-NMR (125 MHz, CDCl3)
δ 176.8, 167.5, 147.2, 143.0, 137.3, 123.5, 61.2, 32.5, 14.2, −1.6.
3-Trimethylsilanyl-propenal (19)
Ethyl-2-(3-butenyl)-3-hydroxybenzoate (21)
Magnesium turnings (24.35 g, 1.00 mol) were added to dry Diisopropylamine (2.41 mL, 17.19 mmol) and dry THF (50 mL)
THF (500 mL). Ethyl bromide (75 mL, 1.00 mmol) was slowly were cooled to 0 °C. To this, n-BuLi (11.5 mL, 18.4 mmol, 1.6
added dropwise by an addition funnel over 1.5 hours. The M in hexane) was added and the solution was stirred for
mixture was heated at 50 °C for 1 hour, and then cooled to 30 minutes at 0 °C. After adding DMPU (3.86 mL), acid 20
0 °C. Propargyl alcohol (20.8 mL, 0.36 mol) in dry THF (21 mL) (2.05 g) in dry THF (10 mL) was added and the reaction
was then added over 1 hour, and the mixture was stirred at mixture was stirred at 0 °C for 1 hour. After cooling the
room temperature overnight. The mixture was cooled to 0 °C mixture to −78 °C, 4-bromo-1-butene (0.89 mL, 8.8 mmol) was
and TMSCl (127 mL, 1.91 mol) was slowly added, followed added and the reaction mixture was stirred for 1 hour, fol-
by refluxing for 2 hours. After cooling to room temperature, lowed by 2 hours at 0 °C. The reaction was quenched with
1.4 M H2SO4 (400 mL) was slowly added and the reaction was 5% HCl(aq), extracted with diethyl ether, dried with Na2SO4, fil-
stirred for 10 minutes. The reaction was extracted with diethyl tered, and concentrated under reduced pressure. Filtration
ether, washed with water, brine, dried with Na2SO4, and con- through a 10 g silica gel column eluting with 15% EtOAc–
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hexanes (100 mL) afforded the crude tris-olefin, which was used 6.28 (bs, 1H), 6.10–6.08 (m, 2H), 5.74–5.72 (m, 1H), 5.40 (dd,
as is in the next step. Dry THF (10 mL) was added to the crude 1H, J = 1.5, 17.0 Hz), 5.28 (dd, 1H, J = 1.5, 10.5 Hz), 4.93 (dd,
olefin (0.42 g, 1.35 mmol), followed by TFAA (0.38 mL) and 1H, J = 1.5, 17.0 Hz), 4.88 (d, 1H, J = 10.0 Hz), 4.50 (d, 2H),
TEA (0.57 mL). The reaction mixture was stirred at room temp- 450–4.49 (m, 2H), 4.13–4.11 (m, 1H), 3.86 (s, 3H), 3.15–3.13
erature for
2 hours. The reaction was quenched with (m, 1H), 3.09–3.04 (m, 2H), 2.96–2.92 (m, 2H), 2.84–2.82 (m,
5% HCl(aq) and extracted with diethyl ether. After drying with 1H), 2.55–2.49 (m, 2H), 2.19–2.18 (m, 2H), 2.05–2.03 (m, 1H),
Na2SO4, filtration, and concentrating under reduced pressure, 0.92 (d, 3H, J = 6.5 Hz), 0.87 (d, 3H, J = 6.5 Hz); 13C-NMR
the residue was taken up in absolute ethanol (10 mL). The (125 MHz, CDCl3) δ 170.6, 163.1, 157.4, 154.5, 138.4, 137.6,
reaction was cooled to 0 °C and NaBH4 (0.11 g, 2.71 mmol) 133.3, 130.3, 129.8, 129.7, 129.4, 126.9, 126.4, 118.7, 117.7,
was added. The mixture was stirred at room temperature for 117.1, 114.9, 114.9, 114.4, 73.1, 68.8, 58.9, 55.7, 54.3, 53.6,
2 hours, after which it was quenched with 5% HCl(aq)
.
33.9, 27.4, 26.5, 20.2, 19.9.
The crude product was extracted with diethyl ether, dried with
Na2SO4, filtered, and concentrated in vacuo. Flash column
chromatography (10% EtOAc–hexanes) afforded aromatic ester
21 (0.85 g, 48% yield, 2 steps). 1H-NMR (500 MHz, CDCl3)
(1S,2R)-2-(3-Butenyl)-N-{1-(4-(3-butenyloxy)-benzyl)-2-hydroxy-
3-[isobutyl-(4-methoxy-benzenesulfonyl)-amino]-propyl}-3-
hydroxy-benzamide (7b)
δ 7.40 (d, 1H, J = 1.0, 8.0 Hz), 7.11 (t, 1H, J = 8.0 Hz), 6.93 (dd, Boc-protected amine 14 (0.15 g) and 30% TFA–DCM (2 mL)
1H, J = 1.0, 8.0 Hz), 5.98–5.90 (m, 1H), 5.31 (bs, 1H), 5.09 (ddd, were stirred at room temperature for 2 hours, and then concen-
1H, J = 1.5, 3.5, 17.5 Hz), 4.99 (dd, 1H, J = 1.0, 10.0 Hz), 4.36 trated under vacuum. The residue was taken up in DMF (2 mL)
(q, 2H, J = 7.5 Hz), 3.01 (dd, 2H, J = 7.5, 9.5 Hz), 2.39–2.35 (m, and acid 22 (48.8 mg), EDCI (53.5 mg), HOBt (37.7 mg), and
2H), 1.39 (t, 3H, J = 7.0 Hz); 13C-NMR (125 MHz, CDCl3) TEA (53 μL) were added. The solution was stirred at room
δ 168.2, 154.2, 138.5, 132.2, 129.2, 126.6, 122.7, 118.7, 115.0, temperature for 16 hours. Brine was added and the reaction
61.1, 34.0, 26.5, 14.3.
mixture was extracted with EtOAc, dried over Na2SO4, filtered,
and concentrated under reduced pressure. Flash column
2-(3-Butenyl)-3-hydroxybenzoic acid (22)
chromatography (30–50% EtOAc–hexanes) afforded diene 7b
1
Ester 21 (23.7 mg, 0.11 mmol) was taken up in MeOH (3 mL) (0.1295 g, 78% yield over 2 steps). H-NMR (500 MHz, CDCl3)
and 2 N KOH(aq) (3 mL) was added. The reaction was refluxed δ 7.66 (d, 2H, J = 9.0 Hz), 7.17 (d, 2H, J = 8.5 Hz), 6.94 (d, 2H,
for 36 hours. The MeOH was removed under reduced pressure J = 9.0 Hz), 6.88 (t, 1H, J = 7.5 Hz), 6.82 (d, 2H, J = 8.5 Hz), 6.75
and the aqueous mixture was acidified to pH = 2 with 6 N (d, 1H, 7.5 Hz), 6.50 (d, 1H, J = 7.5 Hz), 6.19 (d, 1H, J = 8.5 Hz),
HCl(aq). Crude acid was extracted with EtOAc, dried with 5.93–5.84 (m, 1H), 5.75–5.67 (m, 1H), 5.15 (ddd, 1H, J = 1.5,
Na2SO4, filtered, and concentrated under reduced pressure. 2.0, 15.5 Hz), 5.09 (dd, 1H, J = 1.5 Hz, 10.5), 4.89 (dd, 1H, J =
Flash column chromatography (20–50% EtOAc–hexanes) 1.5, 17.5 Hz), 4.83 (d, 1H, J = 10.0 Hz), 4.33–4.28 (m, 1H),
afforded pure acid 22 (18.5 mg, 89% yield). 1H-NMR (500 MHz, 3.99–3.95 (m, 3H), 3.83 (s, 3H), 3.18–3.04 (m, 3H), 2.98–2.85
CDCl3) δ 7.61 (d, 1H, J = 8.0 Hz), 7.17 (t, 1H, J = 8.0 Hz), 7.01 (m, 3H), 2.61–2.46 (m, 4H), 2.17 (q, 2H, J = 7.0, 7.5 Hz),
(d, 1H, J = 8.0 Hz), 5.96 (m, 1H), 5.09 (dd, 1H, J = 1.5, 17.0 Hz), 1.91–1.83 (m, 1H), 0.90 (d, 3H, J = 6.5 Hz), 0.86 (d, 3H, J = 6.5
5.01 (dd, 1H, J = 1.0, 10.0 Hz), 3.12 (t, 2H, J = 7.5 Hz), 2.39 (dd, Hz); 13C-NMR (125 MHz, CDCl3) δ 170.9, 163.1, 162.9, 157.7,
2H, J = 7.5, 15.5 Hz); 13C-NMR (125 MHz, CDCl3) δ 173.1, 155.0, 138.6, 137.4, 134.5, 130.3, 129.7, 129.7, 129.4, 126.8,
154.2, 138.5, 130.6, 130.2, 126.7, 124.0, 119.9, 115.2, 34.0, 26.4. 126.5, 118.2, 117.1, 114.8, 114.6, 114.4, 73.0, 67.2, 58.8, 55.7,
HRMS m/z (M − H)+ calcd for C11H12O3 191.0708, found 54.3, 53.6, 33.9, 33.7, 31.7, 27.3, 26.5, 20.2, 19.9; HRMS m/z
191.0706.
(M + H)+ calcd for C36H47N2O7S 651.3104, found 651.3098.
(1S,2R)-N-{1-(4-Allyloxy-benzyl)-2-hydroxy-3-[isobutyl-(4-
methoxy-benzenesulfonyl)-amino]-propyl}-2-(3-butenyl)-3-
hydroxy-benzamide (7a)
(1S,2R)-2-(3-Butenyl)-3-hydroxy-N-[2-hydroxy-3-[isobutyl-(4-
methoxy-benzenesulfonyl)-amino]-1-(4-(4-pentenyloxy)-benzyl)-
propyl]-benzamide (7c)
Boc-amine 13 (8.1 mg, 0.014 mmol) was dissolved in DCM Boc-amine 15 (40.4 mg, 0.0668 mmol) and 30% TFA–DCM
(1 mL) and stirred with 30% TFA–DCM (2 mL) for 2 hours at (4 mL) were stirred for 3 hours at room temperature, then con-
room temperature. After concentration under reduced centrated in vacuo. The residue was taken up in DMF (2 mL)
pressure, the residue was taken up in DMF (2 mL). To the solu- and acid 22 (12.8 mg), HOBt (9.0 mg), EDCI (12.8 mg), and
tion HOBt (2.1 mg), EDCI (3 mg), acid 22 (3 mg), and TEA TEA were stirred for 18 hours at room temperature. Brine was
(3 μL) were added. The reaction was stirred for 18 hours, and added and the product was extracted with ethyl acetate. After
then brine was added. The crude product was extracted with drying with Na2SO4, filtering, and concentrating under
ethyl acetate, dried with Na2SO4, filtered, and concentrated. reduced pressure, the product was purified by flash column
Flash column chromatography (30–40% EtOAc–hexanes) chromatography (30% EtOAc–hexanes) to afford diene 7c
1
afforded diene 7a (6.4 mg, 70% yield over 2 steps). 1H-NMR (26.6 mg, 60% over 2 steps). H-NMR (500 MHz, CDCl3) δ 7.69
(500 MHz, CDCl3) δ 7.68 (dd, 2H, J = 2.0, 7.0 Hz), 7.19 (d, 2H, (d, 2H, J = 8.0 Hz), 7.19 (d, 2H, J = 8.5 Hz), 6.98–6.95 (m, 3H),
J = 9.0 Hz), 6.98–6.95 (m, 2H), 6.92 (d, 1H, J = 8.0 Hz), 6.85 (d, 6.83 (d, 2H, J = 8.5 Hz), 6.77 (dd, 1H, J = 1.0, 8.0 Hz), 6.57 (dd,
2H, J = 8.5 Hz), 6.75 (d, 1H, J = 8.0 Hz), 6.54 (d, 1H, J = 7.5 Hz), 1H, J = 1.0, 7.5 Hz), 6.02 (d, 1H, 8.5 Hz), 5.89–5.80 (m, 1H),
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5.78–5.72 (m, 1H), 5.65 (bs, 1H), 5.06 (ddd, 1H, J = 1.5, 2.0, (m, 2H), 4.55–4.51 (m, 2H), 4.44–4.35 (m, 4H), 3.97–3.95 (m,
17.0 Hz), 5.00 (dd, 1H, J = 1.5, 10.0 Hz), 4.95 (dd, 1H, J = 1.5, 2H), 2.91–2.85 (m, 2H), 2.69–2.57 (m, 4H), 1.94–1.90 (m, 2H),
17.0 Hz), 4.90 (d, 1H), 4.33–4.29 (m, 1H), 4.24 (bs, 1H), 0.98 (dd, 3H, J = 2.5, 6.5 Hz), 0.92 (d, 3H, J = 6.5 Hz); 13C-NMR
3.99–3.96 (m, 1H), 3.94 (t, 2H, J = 6.5 Hz), 3.87 (s, 3H), 3.15 (d, (125 MHz, CDCl3) δ 170.0, 169.7, 163.2, 157. 2, 155.8, 154.6,
1H, J = 8.5 Hz), 3.10–3.04 (m, 2H), 2.99–2.90 (m, 2H), 2.85–2.81 139.8, 138.8, 137.5, 137.1, 133.0, 131.8, 131.2, 130.4, 129.6,
(m, 1H), 2.62–2.51 (m, 2H), 2.26–2.20 (m, 4H), 1.91–1.85 (m, 129.5, 128.7, 127.1, 126.9, 126.8, 125.2, 124.8, 124.3, 122.8,
3H), 1.68–1.61 (m, 1H), 0.93 (d, 3H, J = 6.5 Hz), 0.88 (d, 3H, J = 122.3, 122.2, 122.1, 119.2, 118.9, 117.2, 116.5, 114.5, 73.8, 72.1,
6.5 Hz); 13C-NMR (125 MHz, CDCl3) δ 170.5, 163.1, 157.9, 70.0, 59.2, 55.7, 54.2, 54.0, 53.8, 34.8, 30.3, 29.7, 29.3, 27.4,
154.3, 138.4, 137.8, 137.7, 130.3, 129.8, 129.4, 127.0, 126.3, 27.4, 26.6, 25.1, 20.2, 19.9; HRMS m/z (M − H)+ calcd
118.9, 117.1, 115.2, 115.0, 114.7, 114.4, 73.0, 67.2, 59.0, 55.7, C33H39N2O7S 607.2478, found 607.2479.
54.3, 53.7, 34.0, 30.1, 28.5, 27.4, 26.5, 20.2, 19.9; HRMS m/z
(2′R,3″S)-N-[2′-Hydroxy-2-(10-hydroxy-5-oxo-18-oxa-4-aza-
tricyclo[17.2.2.06,11]tricosa-1(22),6,8,10,14,19(23),20-heptaen-
(M + Na)+ calc’d for C37H48N2O7SNa 687.3080, found 637.3086.
(1S,2R)-2-(3-Butenyl)-N-{1-(4-(5-hexenyloxy)-benzyl)-2-hydroxy-
3-[isobutyl-(4-methoxy-benzenesulfonyl)-amino]-propyl}-3-
hydroxy-benzamide (7d)
3″-yl)-ethyl]-N-isobutyl-4-methoxy-benzene sulfonamide (8b)
Diene 7b (7.5 mg) was dissolved in dry DCM (3 mL) and
Grubbs’ first generation catalyst (0.9 mg) was added. The reac-
Boc-amine 16 (37.8 mg, 0.061 mmol) and 30% TFA–DCM tion was stirred for 4 hours at room temperature, and then
(5 mL) were stirred at room temperature for 6 hours, and then concentrated. Flash column chromatography (30–50% EtOAc–
concentrated under reduced pressure. The residue was taken hexanes) gave olefin 8b (5.6 mg, 78% yield) as an inseparable
up in DMF (2 mL) and acid 22 (11.7 mg), EDCI (11.7 mg), 3 : 1 (by 1H-NMR analysis) mixture of isomers. 1H-NMR
HOBt (8.3 mg), and TEA (12.8 μL) were added and the reaction (500 MHz, CDCl3) δ 7.73 (d, 2H, J = 9.0 Hz), 6.99–6.96 (m, 3H),
mixture was stirred at room temperature for 18 hours. Brine 6.89–6.85 (m, 3H), 6.71–6.70 (m, 1H), 6.64 (d, 1H, J = 7.5 Hz),
was added to the solution, and the product was extracted with 6.59 (d, 1H, J = 8.5 Hz), 6.14–6.12 (m, 1H), 5.33–5.28 (m, 1H),
ethyl acetate. After drying with Na2SO4, filtering, and concen- 5.15–5.09 (m, 1H), 4.47–4.41 (m, 1H), 4.36–4.32 (m, 1H),
trating under reduced pressure, the product was purified by 4.20–4.17 (m, 1H), 3.98–3.95 (m, 1H), 3.85 (s, 3H), 3.31 (m,
flash column chromatography (25% EtOAc–hexanes) to afford 1H), 3.18–3.15 (m, 1H), 3.08–3.01 (m, 2H), 2.92–2.88 (m, 1H),
1
diene 7d (25.7 mg, 62% yield for 2 steps). H-NMR (500 MHz, 2.53–2.45 (m, 1H), 2.42–2.40 (m, 1H), 2.30–2.26 (m, 2H),
CDCl3) δ 7.69 (d, 2H, J = 9.0 Hz), 7.19 (d, 2H, J = 8.5 Hz), 1.93–1.89 (m, 2H), 1.76–1.73 (m, 1H), 1.38–1.33 (m, 1H), 0.95
6.99–6.95 (m, 3H), 6.83 (d, 2H, J = 8.5 Hz), 6.77 (dd, 1H, J = 1.0, (s, 3H), 0.91 (s, 3H); 13C-NMR (125 MHz, CDCl3) δ 170.5, 163.2,
8.0 Hz), 5.77 (dd, 1H, J = 1.0, 7.5 Hz), 6.04 (d, 1H, J = 9.0 Hz), 158.6, 154.5, 138.7, 133.1, 129.6, 129.5, 126.7, 126.3, 125.5,
5.87–5.71 (m, 3H), 5.05 (ddd, 1H, J = 1.5, 2.0, 17.0 Hz), 118.1, 116.3, 114.5, 73.6, 66.6, 58.9, 55.7, 53.9, 53.8, 35.8, 34.5,
4.98–4.93 (m, 2H), 4.99 (d, 1H, J = 10.0 Hz), 4.33–4.29 (m, 1H), 34.5, 32.2, 27.3, 20.2, 19.9; HRMS m/z (M + Na)+ calcd for
4.26–4.25 (bs, 1H), 3.99–3.96 (m, 1H), 3.93 (t, 2H, J = 6.5 Hz), C34H42N2O7SNa 645.2610, found 645.2622.
3.86 (s, 3H), 3.19–3.13 (m, 1H), 3.09–3.03 (m, 2H), 3.00–2.90
(2′R,3″S)-N-[2′-Hydroxy-2-(10-hydroxy-5-oxo-19-oxa-4-aza-tri-
(m, 2H), 2.84–2.80 (m, 1H), 2.63–2.49 (m, 2H), 2.22–2.18 (m,
cyclo[18.2.2.06,11]tetracosa-1(23),6,8,10,14,20(24),21-heptaen-
3″-yl)-ethyl]-N-isobutyl-4-methoxy-benzenesulfonamide (8c)
2H), 1.60–1.53 (m, 2H), 0.93 (d, 3H, J = 6.5 Hz), 0.88 (d, 3H, J =
2H), 2.12 (q, 2H, J = 7.0 Hz), 1.91–1.85 (m, 1H), 1.82–1.76 (m,
6.5 Hz); 13C-NMR (125 MHz, CDCl3) δ 170.5, 1631, 157.9, To a solution of diene 7c (12.4 mg, 0.0187 mmol) and dry
154.3, 138.5, 138.4, 137.7, 130.3, 129.8, 129.4, 127.0, 126.4, DCM (5 mL) was added Grubbs’ first generation catalyst
118.9, 117.1, 115.0, 114.9, 114.8, 114.7, 114.4, 73.0, 67.8, 59.0, (1.2 mg) and the reaction was stirred for 4 hours, and then
55.7, 54.3, 53.7, 34.0, 33.5, 29.7, 28.8, 27.4, 26.5, 25.4, 20.2, concentrated under reduced pressure. Flash column chromato-
19.9; HRMS m/z (M + Na)+ calc’d for C38H50N2O7SNa 701.3236, graphy (30–40% EtOAc–hexanes) afforded olefin 8c (10.5 mg,
1
found 701.3217.
85% yield) as a 5 : 1 (by H-NMR analysis) mixture of insepar-
able isomers. 1H-NMR (500 MHz, CDCl3) δ 7.76 (dd, 2H, J =
2.0, 7.0 Hz), 7.08 (d, 2H, J = 8.5 Hz), 7.02–6.99 (m, 3H), 6.81 (d,
2H, J = 8.5 Hz), 6.75–6.07 (m, 2H), 5.86 (d, 1H, J = 9.5 Hz), 5.32
(bs, 1H), 5.26–5.20 (m, 1H), 5.12–5.06 (m, 1H), 4.35–4.29 (m,
(2′R,3″S)-N-[2′-Hydroxy-2-(10-hydroxy-5-oxo-17-oxa-4-aza-
tricyclo[16.2.2.06,11]docosa-1(21),6,8,10,14,18(22),19-heptaen-
3″-yl)-ethyl]-N-isobutyl-4-methoxy-benzenesulfonamide (8a)
Diene 7a (12 mg, 0.02 mmol) was dissolved in dry DCM 1H), 4.14–4.11 (m, 1H), 3.98–3.92 (m, 2H), 3.87 (s, 3H),
(5 mL). Grubbs’ first generation catalyst (2 mg) was added and 3.82–3.77 (bs, 1H), 3.30 (dd, 1H, J = 9.0, 15.0 Hz), 3.14 (dd, 2H,
the reaction mixture was stirred for 4 h. The solution was con- J = 2.5, 15.0 Hz), 3.07 (dd, 1H, J = 3.5, 13.0 Hz), 2.90 (dd, 1H,
centrated and purified by flash column chromatography (35% J = 6.5, 13.5 Hz), 2.52–2.47 (m, 1H), 2.36–2.28 (m, 1H),
EtOAc–hexanes) to afford olefin 8a (9.6 mg, 83% yield) as an 2.19–2.11 (m, 2H), 2.07–2.00 (m, 1H), 1.97–1.91 (m, 1H),
inseparable 1 : 1 mixture of cis/trans isomers and a mixture of 1.75–1.55 (m, 3H), 1.41–1.35 (m, 1H), 0.99 (d, 3H, J = 6.5 Hz),
diastereomers. 1H-NMR (500 MHz, CDCl3) δ 7.76–7.73 (m, 4H), 0.94 (d, 3H, J = 6.5 Hz); 13C-NMR (125 MHz, CDCl3) δ 169.9,
7.02–6.87 (m, 12 H) 6.76–6.69 (m, 4 H), 5.86 (dd, 2H, J = 9.5, 163.2, 158.9, 154.3, 138.5, 134.0, 130.1, 129.6, 127.3, 126.9,
21.5 Hz), 5.56–5.54 (m, 2H), 5.41–5.36 (m, 2H), 5.30–5.25 125.9, 118.4, 116.5, 115.4, 114.5, 73.6, 66.6, 59.2, 55.7, 54.7,
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54.0, 35.1, 32.0, 29.7, 29.4, 28.3, 27.7, 27.4, 20.2, 19.9; 2 Hz), 3.28–3.22 (m, 2H), 3.12–3.04 (m, 3H), 2.86 (dd, 1H, J =
HRMS m/z (M + Na)+ calcd for C35H44N2O7SNa 659.2767, 6.5, 13.5 Hz), 2.59–2.53 (m, 2H), 2.24 (td, 1H, J = 4.0, 12.8 Hz),
found 659.2766.
2.01–1.96 (m, 1H), 1.94–1.90 (m, 1H), 1.27–1.245 (m, 3H), 0.99
(d, 3H, J = 6.5 Hz), 0.93 (d, 3H, J = 7.0 Hz). 13C NMR (125 MHz,
CDCl3): δ 169.4, 163.1, 159.5, 154.8, 137.0, 130.8, 130.5, 129.5,
129.1, 127.8, 126.6, 119.7, 119.2, 117.3, 117.1, 114.5, 73.8, 69.5,
59.2, 55.6, 54.1, 53.8, 34.8, 30.8, 27.9, 27.4, 26.9, 26.0, 20.2,
(2′R,3″S)-N-[2′-Hydroxy-2-(10-hydroxy-5-oxo-20-oxa-4-aza-tri-
cyclo[19.2.2.06,11]pentacosa-1(24),6,8,10,14,21(25),22-heptaen-
3″-yl)-ethyl]-N-isobutyl-4-methoxy-benzenesulfonamide (8d)
To diene 7d (12.8 mg, 0.019 mmol) and dry DCM (4 mL) was 19.9. LRMS-ESI m/z: 633.5 (M + Na)+; HRMS m/z (M + Na)+
added Grubbs’ first generation catalyst (1.2 mg). The solution calc’d for C33H42N2O7SNa 633.2610, found 633.2631.
was stirred for 4 hours at room temperature, and then concen-
trated under reduced pressure. Flash column chromatography
(25–40% EtOAc–hexanes) afforded olefin 8d (10.7 mg, 87%
yield) as a single (by 1H-NMR analysis) isomer. 1H-NMR
(500 MHz, CDCl3) δ 7.76 (dd, 2H, J = 2.0, 7.0 Hz), 7.10 (d, 2H,
J = 8.5), 7.04–6.98 (m, 3H), 6.82–6.76 (m, 4H), 5.94 (d, 1H, J =
10.0 Hz), 5.30–5.22 (m, 3H), 4.36–4.33 (m, 1H), 4.15–4.06 (m,
2H), 3.98–3.95 (m, 1H), 3.87 (s, 3H), 3.82–3.80 (bs, 1H), 3.31
(dd, 1H, J = 9.0, 15.5 Hz), 3.20–3.04 (m, 3H), 2.89 (dd, 1H, J =
6.5, 13.5 Hz), 2.53 (t, 1H, J = 13.0 Hz), 2.38 (dt, 1H, J = 3.5,
11.5 Hz), 2.09–2.05 (m, 2H), 1.95–1.77 (m, 6H); 13C-NMR
(125 MHz, CDCl3) δ 169.9, 163.2, 156.9, 154.1, 138.3, 130.7,
130.0, 129.9, 129.6, 129.5, 126.9, 126.4, 118.7, 116.7, 115.2,
114.5, 73.7, 67.1, 59.2, 55.7, 54.3, 54.1, 34.9, 32.7, 30.9, 27.9,
27.4, 26.5, 24.0, 20.2, 19.9; HRMS m/z (M + H)+ calcd for
C34H46N2O7SNa 673.2923, found 673.2921.
Saturated inhibitor 24b
Olefin 8b (3.5 mg), EtOAc (2 mL), and 10% Pd/C (0.5 mg) were
stirred under a hydrogen atmosphere for 2 hours. The reaction
mixture was filtered through Celite and concentrated. Flash
column chromatography (30% EtOAc–hexanes) afforded satu-
1
rated macrocycle 24b (3.3 mg, 94% yield). H-NMR (500 MHz,
CDCl3) δ 7.75 (td, 2H, J = 3.0, 9.0), 7.13–7.05 (m, 1H), 6.98 (td,
2H, J = 2.0, 9.0 Hz), 6.92 (t, 1H, J = 7.5 Hz), 6.88 (d, 2H, J = 6.0
Hz), 6.71 (d, 2H, J = 9.0 Hz), 6.10 (bs, 1H), 6.04 (d, 1H, J = 9.5
Hz), 4.40–4.37 (m, 1H), 4.33–4.29 (m, 1H), 4.22 (td, 1H, J = 4.0,
12.0 Hz), 4.00–3.96 (m, 1H), 3.85 (s, 3H), 3.30 (dd, 1H, J = 9.0,
15.0 Hz), 3.16–3.11 (m, 2H), 3.05 (dd, 1H, J = 8.5, 13.0 Hz), 2.89
(dd, 1H, J = 6.5, 13.5 Hz), 2.57–2.51 (m, 1H), 2.38 (dt, 1H, J =
4.0, 13.0 Hz), 1.94–1.90 (m, 1H), 1.80–1.72 (m, 2H), 1.49–1.40
(m, 2H), 1.30–1.22 (m, 2H), 1.20–1.12 (m, 3H), 0.97 (d, 3H, J =
6.5 Hz), 0.92 (d, 3H, J = 6.5 Hz); 13C-NMR (125 MHz, CDCl3)
δ 170.1, 163.2, 158.0, 154.6, 137.7, 130.3, 130.2, 129.6, 129.5,
127.7, 126.5, 118.6, 117.2, 116.8, 114.5, 73.7, 68.2, 59.1, 55.7,
54.1, 53.9, 34.6, 29.1, 28.1, 27.4, 26.8, 24.0, 20.2, 19.9; HRMS
m/z (M + Na)+ calcd for C34H44N2O7SNa 647.2767, found
647.2761.
Inhibitor 23 and saturated inhibitor 24a
To a stirred solution of olefin 8a (9 mg, 0.02 mmol) in 5 mL of
1% NH3 in MeOH solution, 5% Pd/C (1 mg) was added, and
the resulting suspension was stirred at 23 °C under a hydrogen
filled balloon for 4 h. The mixture was filtered through Celite
and concentrated. Silica gel chromatography (40% EtOAc–
hexanes) afforded the ring-opened acyclic product 23 (2.5 mg,
27% yield) and saturated macrocycle 24a (3.6 mg, 40% yield).
Saturated inhibitor 24c
Olefin 8c (4.0 mg, 0.0063 mmol) was dissolved in ethyl acetate
(5 mL) and 10% Pd/C (1 mg) was added. The mixture was
Compound 23
1H NMR (500 MHz, CDCl3): δ 7.70 (d, 2H, J = 9 Hz), 7.14 (d, stirred under a hydrogen atmosphere for 4 hours and then fil-
2H, J = 8.5 Hz), 6.99–6.96 (m, 3H), 6.78–6.75 (m, 3H), 6.56 (d, tered through Celite. After concentration under reduced
1H, J = 7.5 Hz), 5.99 (d, 1H, J = 8.5 Hz), 5.21 (bs, 1H), 5.09 (bs, pressure, the product was purified by flash column chromato-
1H), 4.32–4.29 (m, 1H), 4.20 (m, 1H), 3.97–3.96 (m, 1H), 3.87 graphy (30% EtOAc–hexanes) to afford the macrocycle 24c
(s, 3H), 3.15–3.02 (m, 3H), 2.98–2.82 (m, 3H), 2.56–2.47 (m, (3.5 mg, 88% yield). 1H-NMR (500 MHz, CDCl3) δ 7.76 (ddd,
2H), 1.91–1.88 (m, 1H), 1.49–1.43 (m, 2H), 1.27–1.24 (m, 3H), 2H, J = 2.0, 3.0, 9.0 Hz), 7.09–7.04 (m, 3H), 6.99 (ddd, 2H, J =
0.93 (d, 3H, J = 7.0 Hz), 0.89 (d, 3H, J = 6.5 Hz), 0.85 (t, 3H, J = 2.0, 3.0, 9.0 Hz), 6.87 (dd, 1H, J = 1.0, 7.5 Hz), 6.82 (d, 2H, J =
6.5 Hz). 13C NMR (125 MHz, CDCl3): δ 170.5, 163.1, 154.5, 8.5 Hz), 6.80 (dd, 1H, J = 1.0, 8.0 Hz), 5.90 (d, 1H, J = 9.0 Hz),
154.1, 137.6, 130.5, 129.8, 129.6, 129.4, 127.2, 126.8, 119.0, 4.91 (bs, 1H), 4.37 (dt, 1H, J = 4.0, 12.0 Hz), 4.28–4.23 (m, 1H),
117.0, 115.5, 114.4, 72.9, 58.9, 55.6, 54.3, 53.7, 34.0, 32.1, 29.9, 4.17–4.13 (m, 1H), 3.98–3.95 (m, 1H), 3.86 (s, 3H), 3.30 (dd,
29.7, 27.4, 26.9, 22.5, 20.1, 19.9, 14.0. LRMS-ESI (m/z): 635.6 1H, J = 9.0, 15.5 Hz), 3.17–3.13 (m, 2H), 3.06 (dd, 1H, J = 8.6,
(M + Na)+; HRMS m/z (M + H)+ calcd for C33H44N2O7SH 13.0 Hz), 2.87 (dd, 1H, J = 6.5, 13.5 Hz), 2.71–2.65 (m, 1H), 2.60
613.2947, found 613.2955.
(dd, 1H, J = 12.0, 14.5 Hz), 2.03–1.97 (m, 1H), 1.96–1.90 (m,
2H), 1.62–1.55 (m, 3H), 1.45–1.42 (m, 2H), 1.39–1.34 (m, 1H),
1.05–1.01 (m, 3H), 0.98 (d, 3H, J = 6.5 Hz), 0.92 (d, 3H, J = 6.5
Saturated macrocycle 24a
1H NMR (500 MHz, CDCl3): δ 7.76 (d, 2H, J = 9.0 Hz), 7.23 (d, Hz); 13C-NMR (125 MHz, CDCl3) δ 170.1, 163.1, 156.9, 154.3,
1H, J = 9.5 Hz), 7.045–7.015 (m, 2H), 6.99 (d, 2H, J = 9 Hz), 6.91 137.3, 130.1, 129.7, 129.7, 129.5, 127.5, 126.7, 119.2, 117.1,
(d, 1H, J = 8 Hz), 6.82 (d, 2H, J = 9.5 Hz), 6.77 (d, 1H, J = 8 Hz), 115.8, 114.5, 73.6, 68.0, 59.2, 55.7, 55.0, 54.0, 34.9, 29.7, 29.4,
5.80 (d, 1H, J = 9.5 Hz), 4.89 (s, 1H), 4.30–4.26 (m, 2H), 28.9, 27.6, 27.4, 26.7, 26.1, 25.4, 20.2, 19.9; HRMS m/z
4.15–4.11 (m, 1H), 3.95 (m, 1H), 3.86 (s, 3H), 3.72 (d, 1H, J = (M + Na)+ calcd for C35H46N2O7SNa 661.2923, found 661.2921.
6852 | Org. Biomol. Chem., 2014, 12, 6842–6854
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Saturated inhibitor 24d
6 A. K. Ghosh, B. D. Chapsal, I. T. Weber and H. Mitsuya,
Acc. Chem. Res., 2008, 41, 78–86.
Olefin 8d (4.5 mg, 0.0069 mmol) was dissolved in EtOAc
(3 mL) and 10% Pd/C (0.5 mg) was added. The mixture was
stirred under a H2 atmosphere for 4 hours, then filtered
through Celite and concentrated under reduced pressure.
Flash column chromatography (40% EtOAc–hexanes) afforded
a saturated macrocycle 24d (4.0 mg, 89% yield). 1H-NMR
(500 MHz, CDCl3) δ 7.75 (ddd, 2H, J = 2.0, 2.5, 9.0 Hz), 7.12 (d,
2H, J = 8.5 Hz), 7.03 (t, 1H, J = 8.0 Hz), 7.00 (ddd, 2H, J = 3.0,
4.0, 9.0 Hz), 6.82 (d, 2H, J = 9.0 Hz), 6.80–6.76 (m, 2H), 5.94 (d,
1H, J = 9.5 Hz), 5.05 (bs, 1H), 4.40–4.34 (m, 1H), 4.18–4.12 (m,
2H), 3.99–3.95 (m, 1H), 3.87 (s, 3H), 3.31 (dd, 1H, J = 9.0, 15.0
Hz), 3.15–3.11 (m, 2H), 3.07 (dd, 1H, J = 9.0, 13.5 Hz), 2.88 (dd,
1H, J = 6.5, 13.5 Hz), 2.59 (dd, 1H, J = 12.0, 14.5 Hz), 2.50 (dt,
1H, J = 3.5, 12.5 Hz), 1.96–1.90 (m, 1H), 1.90–1.82 (m, 1H),
1.75–1.71 (m, 1H), 1.65–1.54 (m, 4H), 1.50–1.44 (m, 1H),
1.36–1.33 (m, 2H), 1.10–1.03 (m, 4H), 0.99 (d, 3H, J = 6.5 Hz),
0.93 (d, 3H, J = 6.5 Hz); 13C-NMR (125 MHz, CDCl3) δ 170.1,
163.2, 156.8, 154.1, 138.0, 129.9, 129.6, 129.6, 129.5, 127.1,
126.7, 119.0, 116.8, 115.1, 114.5, 73.7, 67.0, 59.2, 55.7, 54.2,
54.0, 34.7, 30.0, 29.7, 28.3, 27.4, 27.1, 27.0, 26.8, 26.2, 23.0,
20.2, 19.9; HRMS m/z (M + Na)+ calcd for C36H48N2O7SNa
675.3080, found 675.3086.
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Acknowledgements
Financial support for this work was provided by the National
Institute of Health (GM 53386). This work was also supported
by the Intramural Research Program of the Center for Cancer
Research, National Cancer Institute, National Institutes of
Health and in part by a Grant-in-aid for Scientific Research
(Priority Areas) from the Ministry of Education, Culture,
Sports, Science, and Technology of Japan (Monbu Kagakusho),
a Grant for Promotion of AIDS Research from the Ministry of
Health, Welfare, and Labor of Japan (Kosei Rohdosho: H15-
AIDS-001), and the Grant to the Cooperative Research Project
on Clinical and Epidemiological Studies of Emerging and Re-
emerging Infectious Diseases (Renkei Jigyo: No. 78, Kumamoto
University) of Monbu-Kagakusho. We would like to thank
Dr Kalapala Venkateswara Rao (Purdue University) for helpful
discussions.
18 A. K. Ghosh, W. J. Thompson, M. K. Holloway, S. P. McKee,
T. T. Duong, H. Y. Lee, P. M. Munson, A. M. Smith,
J. M. Wai and P. L. Darke, J. Med. Chem., 1993, 36, 2300–
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