Synthesis, anti-HIV activity, and metabolic stability of new alkenyldiarylmethane HIV-1 non-nucleoside reverse transcriptase inhibitors

6140

J. Med. Chem. 2005, 48, 6140-6155

Synthesis, Anti-HIV Activity, and Metabolic Stability of New

Alkenyldiarylmethane HIV-1 Non-Nucleoside Reverse Transcriptase Inhibitors

Bo-Liang Deng,^†Tracy L. Hartman,^‡Robert W. Buckheit, Jr.,^‡Christophe Pannecouque,^§Erik De Clercq,^§

Phillip E. Fanwick,^|and Mark Cushman^†,*

Department of Medicinal Chemistry and Molecular Pharmacology and the Purdue Cancer Center, School of Pharmacy and

Pharmaceutical Sciences, Purdue University, West Lafayette, Indiana 47907, ImQuest BioSciences, 7340 Executive Way,

Suite R, Frederick, Maryland 21704, Rega Institute for Medical Research, Katholieke Universiteit Leuven, B-3000 Leuven,

Belgium, and Department of Chemistry, Purdue University, West Lafayette, Indiana 47907

Received May 11, 2005

Non-nucleoside inhibitors of HIV-1 reverse transcriptase (NNRTIs) are part of the combination

therapy currently used to treat HIV infection. Based on analogy with known HIV-1 NNRT

inhibitors, 18 novel alkenyldiarylmethanes (ADAMs) containing 5-chloro-2-methoxyphenyl,

3-cyanophenyl, or 3-fluoro-5-trifluoromethylphenyl groups were synthesized and evaluated as

HIV inhibitors. Their stabilities in rat plasma have also been investigated. Although introducing

5-chloro-2-methoxyphenyl or 3-fluoro-5-trifluoromethylphenyl groups into alkenyldiaryl-

methanes does not maintain the antiviral potency, the structural modification of alkenyl-

diarylmethanes with a 3-cyanophenyl substituent can be made without a large decrease in

activity. The oxazolidinonyl group was introduced into the alkenyldiarylmethane framework

and found to confer enhanced metabolic stability in rat plasma.

Introduction

improved characteristics influencing drug compliance

will be essential to the future management of HIV

infection.

Acquired immunodeficiency syndrome (AIDS) was

responsible for an estimated 3 million deaths in 2004,

with an estimated 39.4 million people living with HIV,

which includes the 4.9 million people who acquired HIV

in 2004.¹The reverse transcriptase (RT) of the human

immunodeficiency virus type 1 (HIV-1) plays an es-

sential and central role in the viral replication cycle by

conversion of the single-stranded RNA genome of HIV-1

into a double-stranded DNA chain that subsequently

is incorporated into the DNA of the infected host cell.

HIV-1 RT is a multifunctional heterodimer consisting

of a 66-kDa subunit and a 51-kDa subunit that, as a

proteolytic product of the p66 subunit, has the same

sequence as the corresponding region of p66 subunit but

adopts a different conformation.

As an essential viral enzyme, HIV-1 RT is one of the

major targets of the antiretroviral drug therapies that

are used in the treatment of AIDS. Non-nucleoside

inhibitors of HIV-1 reverse transcriptase (NNRTIs)

inhibit the enzyme by occupation of an induced allo-

steric binding site very close to the active site.^2,3

However, the emergence of resistant HIV viral strains

is a limitation for all therapeutic classes. The emerging

cross-resistance among the approved drugs (nevirapine,

delavirdine, and efavirenz) has particularly limited the

use of the NNRTI class. Therefore, the development of

new NNRTIs with more favorable side effect profiles and

The alkenyldiarylmethanes (ADAMs) are a unique

class of non-nucleoside reverse transcriptase in-

hibitors.^4-13A number of HIV-1 strains containing AZT

resistance mutations have shown increased sensitivity

to some of the ADAMs, indicating a possible therapeutic

role for the ADAMs in combination with AZT.⁶Certain

ADAMs have been found to inhibit the cytopathic effect

of HIV-1 in cell culture at low nanomolar concentrations.

For example, the oxazolidinone ADAM analogue 1

displays an EC₅₀of 0.02 µM for inhibition of the

cytopathic effect of HIV-1_RFin CEM-SS cells, and it

inhibits HIV-1 RT with poly(rC)‚oligo(dG) as the tem-

plate primer with an IC₅₀of 0.499 µM.⁹The dimethoxy-

phenyl compound 2 inhibits the cytopathic effect of HIV-

1_RFin CEM-SS cell culture with an EC₅₀of 0.21 µM,

and inhibits HIV-1 RT with an IC₅₀of 0.074 µM, which

is the most potent RT inhibitor in the ADAM series to

date.¹¹The main impetus for the present study stems

from the fact that the methyl ester moieties present in

the biologically active ADAMs are hydrolyzed to biologi-

cally inactive acids in blood plasma. A general effort has

therefore been initiated to find metabolically stable

replacements for the methyl ester moieties that would

still preserve the desired antiviral activity. We envis-

aged that compound 3, with the replacement of methyl

ester moiety of the ADAM 2 with a 2-oxoxazolidinyl

group, might retain the anti-HIV potency of the parent

compound. The isomeric compound 4 might also result

in the retention of anti-HIV activity. It might be

expected that the cyclic carbamate present in 3 and 4

would be more metabolically stable than the corre-

* To whom correspondence should be addressed. E-mail: cushman@

pharmacy.purdue.edu. Phone: 765-494-1465. Fax: 765-494-6790.

^†Medicinal Chemistry, Purdue.

^‡ImQuest BioSciences.

^§Katholieke Universiteit Leuven.

^|Chemistry, Purdue.

Published on Web 08/19/2005

Alkenyldiarylmethane HIV-1 NNRTIs

Journal of Medicinal Chemistry, 2005, Vol. 48, No. 19 6141

sponding ester of 2. Therefore, compounds 3 and 4 were

selected as targets for synthesis.

Recently, benzophenones 5 and 6 containing 5-chloro-

phenyl, 3-cyanophenyl, or 3-fluoro-5-trifluoromethyl-

phenyl groups were reported as NNRTIs of HIV-1.

These inhibitors displayed IC₅₀values of e2 nM against

wild-type HIV-1 and <10 nM against 16 mutants.¹⁴

Since these NNRTIs are structurally related to the

ADAMs, we were intrigued by the possibility that the

substituted phenyl rings of the ADAMs could be re-

placed by those of 5 and 6. More specifically, the analogy

that we had considered would view the halogenated

rings of 5 and 6 as equivalent to the two aromatic rings

of the ADAMs, while the remaining part would cor-

respond to the alkenyl side chain of the ADAMs.

Alkenyldiarylmethanes 7-22, with 5-chloro-2-methoxy-

phenyl, 3-cyanophenyl, or 3-fluoro-5-trifluoromethyl-

phenyl groups, were therefore designed and have been

synthesized via the Sonogashira and Stille cross-

coupling reactions. The isoxazole rings of compounds

19-22 were conceived as metabolically stable replace-

ments for the 4-methoxy-3-methoxycarbonyl substitu-

ents found in many of the active ADAMs. In this paper,

we report the synthesis of alkenyldiarylmethanes 3, 4,

and 7-22, their anti-HIV activities, and their metabolic

stabilities in rat blood plasma.

2-oxazolidinone to afford the alkylated intermediate 25.

The Sonogashira coupling of the terminal alkyne 25

with the aryl iodides 29 or 33 yielded the disubstituted

alkynes 30 or 34. The hydrostannation of 30 or 34 with

tri-n-butyltin hydride in the presence of Pd(PPh₃)₄

afforded the regiochemically and stereochemically de-

fined vinylstannanes 31 or 35, that underwent the Stille

cross-coupling with the aryl iodides 33 or 29 to afford

the desired target compounds 3 or 4.

3-Butynyl-1-tosylate (24) was previously synthesized

in 83% yield from 3-butyn-1-ol (23) with p-toluene-

sulfonyl chloride in the presence of pyridine according

to a literature procedure.¹⁵However, there are some

limitations for this reaction. First, since no solvent was

used for the reaction, it is difficult to stir the reaction

Chemistry

Alkenyldiarylmethanes 3 and 4 were prepared ac-

cording to the procedures shown in Scheme 1. Com-

mercially available 3-butyn-1-ol (23) was converted to

the corresponding tosylate 24, which reacted with

6142 Journal of Medicinal Chemistry, 2005, Vol. 48, No. 19

Deng et al.

Scheme 1^a

would allow the reaction to be scaled up. This was

accomplished by performing the reaction in aqueous

THF with sodium hydroxide as the base, which allowed

24 to be synthesized on a 27-g scale. This reaction occurs

rapidly at room temperature and the workup is very

easy.

It was previously reported that the reaction of 4-bromo-

1-butene with 2-oxoazolidinone using cesium carbonate

as the base in acetone gave 3-(but-3-enyl)-1,3-oxazolidin-

2-one in very good yield.⁹However, an attempted

synthesis of 3-(but-3-ynyl)-1,3-oxazolidin-2-one (25) from

3-butyn-1-bromide or 3-butyn-1-iodide and 2-oxazolidi-

none failed due to an elimination reaction. To minimize

the competitive elimination reaction, the halide leaving

group was changed to a tosylate, which favors nucleo-

philic substitution over elimination when a competition

between S_N2 and E2 processes is involved.¹⁶Since

2-oxoazolidinone has tautomers under certain condi-

tions, the alkylation may give rise to N-alkyl derivatives

or O-alkyl derivatives. Although it is known that alkyl-

ation of 2-oxoazolidinone with 4-bromo-1-butene results

in N-alkylation, it is still difficult to estimate the effect

of the reaction medium, the alkylator, and other factors

on the regiochemistry of the process. Phase-transfer

catalysis is widely used as a way to influence the

product ratio in alkylation of ambident anions.^17,18

Taking this into account, the reaction of 2-oxazolidinone

with 3-butyl-1-tosylate in the presence of tetrabutyl-

ammonium bromide and potassium carbonate was

examined in dichloromethane and water at reflux tem-

perature, but no product was formed. Eventually the

alkylation of 2-oxazolidinone with 3-butynyl-1-tosylate

(24) in the presence of tetrabutylammonium bromide

in toluene was carried out successfully to afford 3-but-

3-ynyl-1,3-oxazolidin-2-one (25) in 83% yield.

Methyl 5-iodo-3-methyl-2-methoxybenzoate (29) was

previously synthesized from methyl 2-hydroxy-5-iodo-

3-methylbenzoate (28) with dimethyl sulfate and potas-

sium carbonate in refluxing acetone.¹⁰Methyl 2-hydroxy-

5-iodo-3-methylbenzoate(28)waspreparedfrom3-methyl-

salicylic acid (26).¹⁰In the reported route, 3-methyl

salicylic acid (26) was converted into its methyl ester

27 using (trimethylsilyl)diazomethane in a mixture of

methanol and benzene. The product 27 was then iodi-

nated with sodium iodide in the presence of sodium

hypochlorite and sodium hydroxide. The overall yield

was very good. However, an excess of (trimethylsilyl)-

diazomethane had to be added to complete the trans-

formation of 26 to 27.

To avoid using the expensive reagent (trimethylsilyl)-

diazomethane, a new synthetic method has been devel-

oped to synthesize 29. 3-Methylsalicylic acid (26) was

converted into its methyl ester 27 using dimethyl sulfate

and potassium carbonate in the presence of tetrabutyl-

ammonium bromide in a mixture of dichloromethane

and water at room temperature. The methyl ester 27

was iodinated with sodium iodide in the presence of

sodium hypochlorite and sodium hydroxide to afford

methyl 2-hydroxy-5-iodo-3-methylbenzoate (28) in

98% overall yield. Methyl 5-iodo-3-methyl-2-methoxy-

benzoate (29) was synthesized in 91% yield from methyl

2-hydroxy-5-iodo-3-methylbenzoate (28) with dimethyl

sulfate in the presence of tetrabutylammonium bromide

and sodium hydroxide in a mixture of dichloromethane

^aReagents and conditions: (a) TsCl/pyridine, <20 °C; or KOH,

THF-H₂O, room temperature; (b) 2-oxazolidinone, K₂CO₃, Bu₄NBr,

toluene, reflux; (c) TMSCHN₂, MeOH, benzene, room temperature;

or dimethyl sulfate, K₂CO₃, Bu₄NBr, CH₂Cl₂-H₂O, room temper-

ature; (d) NaI, NaOH, NaOCl, 0-3 °C; (e) dimethyl sulfate, K₂CO₃,

acetone, reflux; or dimethyl sulfate, NaOH, Bu₄NBr, CH₂Cl₂-H₂O,

room temperature; (f) compound 25, PdCl₂(PPh₃)₂, Cu(I)I, Et₃N,

THF, room temperature; (g) Bu₃SnH, Pd(PPh₃)₄, THF, room

temperature; (h) compound 33, Pd₂(dba)₃, AsPh₃, CuI, NMP, 80

°C; (i) I₂, CH₂Cl₂, room temperature; (j) 3,4-dimethoxyphenyl-

boronic acid, Pd(OAc)₂, 2-(di-tert-butylphosphine)biphenyl, KF,

THF, 60 °C; (k) compound 29, Pd(PBu^t₃)₂, toluene, reflux.

mixture, which sometimes leads to low yield. Second,

it is time-consuming to remove the pyridine after the

reaction. Therefore, it would be advantageous to have

an alternative method to synthesize compound 24 that

Alkenyldiarylmethane HIV-1 NNRTIs

Journal of Medicinal Chemistry, 2005, Vol. 48, No. 19 6143

Scheme 2^a

and water at room temperature. The new method using

phase transfer catalysis is superior to the established

method. First of all, the very expensive reagent (tri-

methylsilyl)diazomethane and anhydrous solvents,

methanol and benzene, are avoided. Second, these

reactions occur rapidly at room temperature, and the

workup is very easy. Therefore, these reactions can be

scaled up easily.

The Sonogashira reaction of compound 25 with iodo

compounds 29 or 33 afforded alkynes 30 or 34 in a good

yield. In our initial attempts, the hydrostannation of the

alkynes 30 or 34 in the presence of Pd(PPh₃)₄to afford

the regio- and stereodefined vinylstannane 31 or 35

proceeded with low conversions. The process of Pd-

catalyzed addition of trialkyl-stannanes to triple bonds

is generally best for terminal alkynes, and yields and

selectivity suffer with sterically hindered internal

alkynes. A general problem is that the activated Pd-H

intermediate Bu₃Sn-Pd-H can proceed down an alter-

nate path by irreversible generation of H₂, dimerization

of the stannane, and precipitation of the Pd as pal-

ladium black. Attempts were made to optimize this

reaction by using Pd(PPh₃)₂Cl₂as the catalyst and

employing slow addition of the Bu₃SnH. The results

were still disappointing. This undesired side reaction

could be minimized by maintaining a low concentration

of tin hydride, which is more readily achieved by

dropwise addition as mentioned in the literature.¹⁹The

concentration of catalyst and the temperature might

also be manipulated to minimize the side reactions.

Therefore, the hydrostannations were preformed with

low concentrations of the alkynes 30 or 34 by a very

slow dropwise addition of tributyltin hydride with low

load of catalyst at 0 °C to afford the regio- and stereo-

defined vinylstannanes 31 or 35 in excellent yields. Two

side products 36 and 37 were also isolated as minor

products.

^aReagents and conditions: (a) Pd(PBu^t₃)₂, toluene, reflux.

the basis of these initial results, improving the rate of

the transmetalation step of the Stille coupling became

crucial in the successful execution of this reaction. It

has been shown that under certain conditions, copper

iodide reacts with organostannanes to produce transient

organocopper intermediates that are presumably more

reactive than organostannanes toward transmetalation

to palladium.²⁴However, the reaction of vinylstannane

31 with aryl iodide 33 in the presence of CuI with CsF

and AsPh₃in THF at reflux temperature only led to the

recovery of starting materials. Compound 3 was finally

synthesized in about 43% yield in the highly polar

solvent 1-methyl-2-pyrrolidinone (NMP) at 80 °C. The

Suzuki coupling^22,25of the vinyl iodide 32 with 3,4-

dimethoxyphenylboronic acid in the presence of pal-

ladium acetate and 2-(di-tert-butylphosphine)biphenyl

also afforded compound 3 in 62% optimized yield.

However, the synthesis of compound 4 using a similar

method did not work very well. Compound 4 was finally

synthesized in 77% yield from the vinylstannane 35

with aryl iodide 29 in the presence of Pd(PBu^t₃)₂with

CsF in toluene at reflux temperature. These conditions

are very general and practical and have been employed

to synthesize all of ADAMs as shown in the following

schemes.

The stereoselective syntheses of alkenyldiarylmethanes

7, 8, and 9 with trifluoromethyl compounds 38 or 39

are outlined in Scheme 2. The synthesis relies on the

Stille coupling of 1-bromo-3-fluoro-5-trifluoromethyl-

benzene (38) or 2-bromo-4-fluoro-1-trifluoromethyl-

benzene (39) with the tributyltin derivatives 31 or 35

in the presence of Pd(PBu^t₃)₂with CsF in toluene at

reflux temperature.

Employing the same strategies used to synthesize

alkenyldiarylmethanes (ADAMs) having nonidentical

aromatic substituents, we synthesized vinylstannanes

43, 44, 51, and 52. As outlined in Scheme 3, the

methylation of the phenol group of 45 using dimethyl

sulfate in the presence of sodium hydroxide and tetra-

butylammonium bromide as a phase-transfer catalyst

in a mixture of dichloromethane and water at room

temperature gave 2-bromo-4-chloro-1-methoxybenzene

(47) in very good yield. Methyl 5-bromo-2-methoxy-3-

methylbenzoate (48) was synthesized by O-alkylation

of 5-bromo-3-methylsalicylic acid (46) with dimethyl

sulfate in acetone at reflux temperature, utilizing potas-

The palladium-catalyzed cross-coupling reaction be-

tween aryl or vinyl halides and triflates with organo-

stannanes, well-known as the Stille coupling,²⁰has been

developed in the recent decades into an extremely

popular synthetic tool for the construction of carbon-

carbon bonds.^21,22The three-step catalytic cycle includ-

ing oxidative addition, transmetalation, and reductive

elimination has been proposed for the Stille reaction.²³

It is known that the transmetalation is very often the

rate-determining step of the Stille reaction. Unfortu-

nately, use of the Stille coupling of aryl iodide and

vinylstannane to reach the final products 3 and 4 was

unsuccessful by using different catalysts [Pd₂(dba)₃, or

Pd(PPh₃)₄], solvents (toluene, dioxane, THF), additives

(CsF, PBu^t₃or PPh₃), and temperatures (room temper-

ature or reflux temperature). The aryl iodide decom-

posed, and the vinylstannane was partly recovered. On

6144 Journal of Medicinal Chemistry, 2005, Vol. 48, No. 19

Deng et al.

Scheme 3^a

Scheme 4^a

^aReagents and conditions: (a) methyl 5-hexynoate, PdCl₂(PPh₃)₂,

Cu(I)I, Et₃N, THF; (b) Bu₃SnH, Pd(PPh₃)₄, THF, room tempera-

ture; (c) for 45: dimethyl sulfate, NaOH, Bu₄NBr, CH₂Cl₂-H₂O,

room temperature; for 46: dimethyl sulfate, potassium carbonate,

acetone, reflux.

sium carbonate as the base. The Sonogashira coupling

of methyl 5-hexynoate with substituted aromatic bro-

mides 38, 40, 47, and 48, followed by hydrostannation

with tributyltin hydride, yielded vinyl stannanes 43, 44,

51, and 52 in very good yield.

^aReagents and conditions: (a) dimethyl sulfate, NaOH, TBAB,

CH₂Cl₂-H₂O, room temperature; (b) SO₂Cl₂, 50 °C; (c) Pd(PBu^t₃)₂,

toluene, reflux.

As outlined in Scheme 4, methylation of both the

phenol and carboxylic acid groups of 53 using dimethyl

sulfate in the presence of sodium hydroxide and tetra-

butylammonium bromide as the phase-transfer catalyst

in a mixture of dichloromethane and water at room

temperature gave methyl 5-iodo-2-methoxybenzoate 54.

However, chlorination of the aromatic ring at the C3

position of compound 54 with SO₂Cl₂in dichloromethane

did not give reproducible results.¹⁰Therefore, the reac-

tion was carried out without solvent at 50 °C to afford

the ester 55 in very good yield. The Stille approach was

also employed for the synthesis of ADAMs having

nonidentical aromatic rings as shown in Scheme 4. The

Stille coupling of vinyl stannanes 43, 44, 51, and 52 with

different halo aromatic derivatives in the presence of

Pd(PBu^t₃)₂with CsF in toluene at reflux temperature

afforded alkenyldiarylmethanes 10-18.

A methoxylated isoxazole replacement for the ester

group and the neighboring methoxyl group on the

Alkenyldiarylmethane HIV-1 NNRTIs

Journal of Medicinal Chemistry, 2005, Vol. 48, No. 19 6145

Scheme 5^a

Scheme 6^a

^aReagents and conditions: (a), N₂HOH.HCl, KOH, MeOH; (b),

carbonyldiimidazole, THF, reflux; (c), K₂CO₃, DMSO, CH₃I.

aromatic ring in compounds 12 and 16 was proposed in

ADAMs 19 and 20. In these compounds, the nitrogen

of the isoxazole mimics the carbonyl oxygen of the ester,

and the methoxy group on the isoxazole mimics the

methoxy group on the methyl ester. This type of methyl

ester replacement was previously developed to substi-

tute for the methyl ester present in norarecoline.²⁶

These compounds are obviously conformationally con-

strained ester mimics that may provide information

about the biologically active conformation of the corre-

sponding methyl ester in the ADAMs. As outlined in

Scheme 5, 2,N-dihydroxy-5-iodo-3-methylbenzamide (56)

was prepared from methyl 2-hydroxy-5-iodo-3-methyl-

benzoate (28) and hydroxylamine hydrochloride in very

good yield. 5-Iodo-7-methylbenzo[d]isoxazol-3-one (57)

was synthesized from 2,N-dihydroxy-5-iodo-3-methyl-

benzamide (56) and carbonyldiimidazole in almost

quantitative yield.²⁷Methylation of 5-iodo-7-methyl-

benzo[d]isoxazol-3-one (57) with iodomethane afforded

5-iodo-2,7-dimethyl-benzo[d]isoxazol-3-one (58) and 5-

iodo-3-methoxy-7-methylbenzo[d]isoxazole (59). The

structure of 5-iodo-2,7-dimethyl-benzo[d]isoxazol-3-one

(58) was confirmed by X-ray crystallography.

^aReagents and conditions: (a) Pd(PBu^t₃)₂, toluene, reflux.

with IC₅₀values ranging from 0.75 to 97.8 µM. Four

ADAMs also prevented the cytopathic effect of HIV-1_RF

with EC₅₀values ranging from 7.0 to 8.3 µM. Sixteen

ADAMs were tested for inhibition of cytopathic effects

of both HIV-1_IIIBand HIV-2_RODin MT-4 cells, and the

resulting EC₅₀values are also listed in Table 1, along

with their cytotoxicities (CC₅₀values) in uninfected

MT-4 cells. Five compounds displayed EC₅₀versus HIV-

1_IIIBbetween 2.54 and 12.8 µM. In addition, the meta-

bolic stabilities of the ADAMs were investigated in rat

plasma, and the resulting half-lives of the compounds

are also summarized in Table 1.

The Stille approach was employed for the synthesis

of ADAMs 19-22 having isoxazole as shown in Scheme

6. The Stille coupling of vinyl stannanes 43, 44, and 51

with different halo aromatic derivatives in the presence

of Pd(PBu^t₃)₂with CsF in toluene at reflux temperature

afforded alkenyldiarylmethanes 19-22. Compound 22

was recrystallized from a mixture of ethyl acetate and

hexanes to yield colorless needles. The structure of

compound 22 was confirmed by X-ray crystallography.

Since the Stille coupling leads to the retention of the

stereochemical integrity of the coupling partners, the

E stereochemistry of the alkene 43 confirmed the

regioselective cis addition during the hydrostannation

reaction of the alkyne 41.

On the basis of the data in the Table 1, ADAM 3 that

replaces a methyl ester moiety of ADAM 2 with a

2-oxazolidinonyl group still retained the enzyme inhibi-

tory potency of the parent compound. However, it was

generally cytotoxic and lost the ability to inhibit the

cytopathic effect of the virus in cells at noncytotoxic

concentrations. Compound 4, with exchanged aromatic

rings relative to compound 3, lost both enzyme inhibi-

tory and antiviral activities. Introducing 5-chloro-2-

methoxyphenylor3-fluoro-5-trifluoromethylphenylgroups

into alkenyldiarylmethanes does not retain the antiviral

potency, except in the case of ADAMs 15 and 18. The

alkenyldiarylmethanes 16-18 with a 3-cyanophenyl

group displayed both enzyme inhibitory and antiviral

activities.

The stabilities of ADAMs 3, 4, 7-11, and 14-22 in

rat plasma were investigated. The ADAMs displayed a

range of metabolic stabilities in rat plasma, with half-

lives ranging from 0.4 to 9.4 min, except compounds 8

and 9. Compounds 8 and 9, which lack any methyl ester

moieties, had not been hydrolyzed at 37 °C after 3 days.

This demonstrates that the oxazolidinonyl group is

stable in rat plasma and that the metabolic instabilities

of the ADAMs are likely to be due to the presence of

methyl esters.

Biological Results and Discussion

The 18 new ADAMs synthesized in this study were

evaluated for prevention of the cytopathic effect of HIV-

1_RFin CEM-SS cells and for cytotoxicity in uninfected

CEM-SS cells. The biological data are listed in Table 1.

The ADAMs were also tested for their ability to inhibit

HIV-1 RT, and the resulting IC₅₀values are also

included in Table 1. Ten analogues were found to inhibit

HIV-1_RTwith poly(rC)‚oligo(dG) as the template primer

6146 Journal of Medicinal Chemistry, 2005, Vol. 48, No. 19

Deng et al.

Table 1. Anti-HIV Activities, Cytotoxicities, and Metabolic Stabilities of ADAM Analogues

EC₅₀(µM)^b

CC₅₀(µM)^c

compd

IC₅₀(µM)^a

HIV-1_RF

HIV-1_IIIB

HIV-2_ROD

CEM-SS cells

MT-4 cells

rat plasma t_1/2(min ( SD)

1

0.499

0.074

1.0

0.02

NT^d

1.95

1.14

0.49

4.79

15.0

14.5

26.7

9.3

15.5

>5.0

16.1

8.3

12.0

23.3

20.2

16.3

2.1

NT^d

1.05

82.5

24.7

18.5

NT^d

5.41

13.8

5.70

NT^d

18.8

113

NT^d

2

0.21

NT^d

3

>100

8.30

>1.05

>33.8

9.60

>1.05

>35.4

>22.6

>13.4

NT^d

>5.41

>13.8

>5.89

NT^d

5.76 ( 0.68

0.79 ( 0.10

9.39 ( 0.73

NH^e

4

>100

15.7

97.8

>100

55.3

0.84

0.75

7.58

0.9

7

8

>100

>5.0

>100

7.30

>100

7.1

7.0

>100

>18.5

9

NT^d

NH^e

10

11

12

13

14

15

16

17

18

19

20

21

22

>5.41

>13.8

>5.51

NT^d

0.77 ( 0.08

0.98 ( 0.02

NT^d

>18.8

2.54

>14.5

10.6

0.47 ( 0.02

4.35 ( 0.41

0.71 ( 0.01

0.44 ( 0.05

0.42 ( 0.02

4.26 ( 0.01

1.46 ( 0.08

0.48 ( 0.06

0.87 ( 0.12

12.8

>169

>223

>67.6

>5.60

>5.63

>28.8

>43.2

153

8.55

213

9.11

g45.2

5.76

4.69

>28.8

39.8

>5.76

>2.05

>28.8

>35.7

5.7

8.2

>100

0.8

13.0

16.8

^aInhibitory activity vs HIV-1 reverse transcriptase with poly(rC)‚oligo(dG) as the template primer. ^bEC₅₀is the 50% inhibitory

concentration for inhibition of cytopathicity of HIV-1_RF, HIV-1_IIIBor HIV-2_ROD.

^cThe CC₅₀is the 50% cytotoxic concentration for mock-

infected CEM-SS cells or MT-4 cells. ^dNot tested. ^eNot hydrolyzed. All data are derived from triplicate tests with the variation of the

mean averaging 10%.

Conclusions

inhibitory activity is concerned. It is likely that the

ADAMs bind to the enzyme differently than NNRTIs 5

and 6. On the other hand, the concept did eventually

result in the active cyanophenyl ADAMs 16-18. In

addition, the ADAM 19, having meta F and CF₃groups,

is a submicromolar RT inhibitor, although it proved to

be too cytotoxic to be of value as an anti-HIV agent. In

the case of ADAM 15, which is an isomer of 12, anti-

HIV activity was observed, although the weak activity

of 15 vs RT and the activity of the compound vs HIV-

The main conclusions and significant accomplish-

ments resulting from the present study may be sum-

marized in the following points: (1) The structural

modifications introduced in the present series of ADAMs

document the fact that a 3-cyanophenyl can be incor-

porated into the ADAM system with retention of anti-

HIV activity. In addition, the hydrolysis data in rat

plasma indicate that the oxazolidinonyl group is stable

in the ADAMs.These studies will facilitate the future

development of novel metabolically stable ADAMs with

enhanced bioavailabilities and improved therapeutic

potentials for the treatment of AIDS. (2) An efficient

route was devised to prepare intermediate 29 on large

scale, and general methods were developed to synthesize

ADAMs using metal-catalyzed reactions (Sonogashira

reaction, hydrostannation, Stille coupling, and Suzuki

coupling). In particular, the protocol used for hydro-

stannation of sterically hindered internal alkynes is an

improvement over the literature procedures. The gen-

eral flexibility of the route opens up the opportunity to

synthesize the other alkenyldiarylmethanes (ADAMs)

having nonidentical aromatic substituents with opti-

mized biological activities. (3) This investigation dem-

onstrates the use of phase-transfer-catalyzed reactions

to synthesize several intermediates, such as 25, 27, 29,

47, and 54, in good yields. This offers several advan-

tages, such as operational simplicity, mild reaction

conditions in aqueous media, environmental benefits,

and suitability for large-scale reactions. (4) The struc-

tures of a representative ADAM compound 22, as well

as the intermediate 58, were determined by X-ray

crystallography. The crystal structure of 58 establishes

the outcome of the alkylation reaction used to prepare

both 58 and 59, while the structure of 22 confirms the

expected regiochemistry and stereochemistry of hy-

drostannation. (5) The inactivity of ADAM 12 indicates

that its hypothetical structural analogy to the very

potent NNRTI 5¹⁴is weak, at least as far as its enzyme

2_RODwould argue that the antiviral activity of compound

15 is not due to inhibition of RT. (6) A reduction in the

total number of ester groups in the molecule does not

necessarily result in a more metabolically stable ADAM,

even in compounds with similar structures. An example

of this is provided by comparison of the half-lives of 14

(t_1/20.47 min), 18 (t_1/20.42 min), and 21 (t_1/20.48 min).

It appears that the terminal ester on the alkenyl side

chain is a more important contributor to metabolic

instability than the ester on the aromatic ring. (7) The

structures of the lactim ether 19 and the amide 22 are

very similar, but differences in their enzyme inhibitory

activities are striking. ADAM 19 displays an IC₅₀of 0.9

µM vs HIV-1 RT, while 22 is inactive. Also, compound

19 is more stable in plasma (t_1/24.26 min) than 22 (t_1/2

0.87 min) even though the structural change is rela-

tively remote from the labile ester. (8) The stereochem-

ical orientation of the oxazolidinonyl side chain in

ADAMs 3 and 4 has a significant effect on the hydrolysis

rate of the methyl ester. Whereas the ester 3 has a half-

life of 5.76 min in rat blood plasma, the half-life of its

isomer 4 is 0.79 min. It appears that the oxazolidinonyl

side chain that is cis to the methyl ester in compound 3

may retard its hydrolysis due to a steric effect. (9) The

long-range objective of designing and synthesizing a

metabolically stable ADAM analogue that retains sig-

nificant antiviral activity or has enhanced antiviral

activity was not realized in the present series of

compounds.

Alkenyldiarylmethane HIV-1 NNRTIs

Journal of Medicinal Chemistry, 2005, Vol. 48, No. 19 6147

heated 80 °C for another 16 h. The residue was purified by

column chromatography on silica gel (40 g) using ethyl acetate

in hexanes (0-50%) to afford the product 4 (227 mg) as an oil

in 77% yield. IR (KBr) 2932, 1751, 1579, 1580, 1513, 1481,

Experimental Section

NMR spectra were obtained at 300 MHz (¹H) and 75 MHz

(¹³C) in CDCl₃using CHCl₃as internal standard. Flash

chromatography was performed with 230-400 mesh silica gel.

TLC was carried out using Baker-flex silica gel IB2-F plates

of 2.5 mm thickness. Melting points are uncorrected. Unless

otherwise stated, chemicals and solvents were of reagent grade

and used as obtained from commercial sources without further

purification. Tetrahydrofuran (THF) was freshly distilled from

sodium/benzophenone ketyl radical prior to use. Dichloro-

methane was freshly distilled from calcium hydride prior to

use. Lyophilized rat plasma (lot 052K7609) was obtained from

Sigma Chemical Co., St. Louis, MO. All yields given refer to

isolated yields.

1437, 1320, 1257, 1138, 1027, 804, 762 cm^-^{1 1}H NMR (300

;

MHz, CDCl₃) δ 7.43 (d, J ) 2.4 Hz, 1 H), 7.17 (d, J ) 2.1 Hz,

1 H), 6.87 (d, J ) 8.4 Hz, 1 H), 6.71 (dd, J ) 2.1 Hz, J ) 8.1

Hz, 1 H), 6.61 (d, J ) 1.8 Hz), 5.92 (t, J ) 7.5 Hz, 1 H), 4.22

(t, J ) 8.1 Hz, 2 H), 3.90 (s, 3 H), 3.86 (s, 3 H), 3.82 (s, 3 H),

3.79 (s, 3 H), 3.36 (t, J ) 6.9 Hz, 2 H), 3.32 (t, J ) 7.2 Hz, 2

H), 2.40 (m, 2 H), 2.24 (s, 3 H); ¹³C NMR (75 MHz, CDCl₃) δ

166.7, 158.1, 157.2, 148.5, 148.0, 142.5, 137.6, 133.6, 132.1,

131,5, 127.4, 124.9, 124.0, 121.8, 112.5, 110.7, 61.4, 61.2, 55.7,

55.6, 51.9, 44.0, 43,7, 27.6, 15.9; ESIMS m/z (rel intensity) 478

(MNa⁺, 100). Anal. (C₂₅H₂₉NO₇) C, H, N.

(E)-5-[1-(3,4-Dimethoxyphenyl)-4-(2-oxo-oxazolidin-3-

yl)-but-1-enyl]-2-methoxy-3-methyl-benzoic Acid Methyl

Ester (3). Method I: A mixture of the vinylstannane 31 (100

mg, 0.164 mmol), aryl iodide 33 (44.7 mg, 0.169 mmol),

triphenylarsine (21.3 mg, 0.068 mmol), copper(I) iodide (10.0

mg, 0.053 mmol), and tris(dibenzylideneacetone)dipalladium

(15 mg, 0.016 mmol) in 1-methyl-2-pyrrolidinone (NMP) (4 mL)

was heated at 80 °C under argon atmosphere for 14 h, cooled

to room temperature, filtered through a pad of Celite, and

washed with ethyl acetate and dichloromethane. The filtrate

was concentrated to afford a residue. The residue was purified

by column chromatography on silica gel (50 g) using ethyl

acetate in hexanes (0-30%) to afford the product 3 (32 mg) in

43% yield.

(E)-5-[1-(3-Fluoro-5-trifluoromethylphenyl)-4-(2-oxo-

oxazolidin-3-yl)-but-1-enyl]-2-methoxy-3-methylbenzo-

ic Acid Methyl Ester (7). The general procedure was followed

using the vinylstannane 31 (323 mg, 0.531 mmol), bromide

38 (219 mg, 0.874 mmol), cesium fluoride (280 mg, 1.825

mmol), and Pd(PBu^t₃)₂(28.4 mg, 0.054 mmol) in toluene (1

mL). The mixture was stirred at room temperature for 24 h,

at 60 °C for 25 h and at 110 °C for 22 h. The residue was

purified by column chromatography on silica gel (30 g), eluting

with EtOAc-hexanes (0-50%) to afford the product 7 (82.5

mg) as an oil in 32% yield. IR (KBr) 2952, 1752, 1600, 1482,

1438, 1351, 1264, 1236, 1205, 1171, 1128, 1094, 1034, 1008,

939, 875, 801, 762, 700 cm^-^{1 1}H NMR (300 MHz, CDCl₃) δ

;

7.40 (d, J ) 2.4 Hz, 1 H), 7.17 (d, J ) 8.1 Hz, 1 H), 7.09 (d, J

) 1.8 Hz, 1 H), 7.03 (d, J ) 9.6 Hz, 1 H), 6.08 (t, J ) 7.5 Hz,

1 H), 4.24 (t, J ) 7.8 Hz, 2 H), 3.89 (s, 3 H), 3.84 (s, 3 H),

3.40-3.31 (m, 4 H), 2.38 (m, 2 H), 2.31 (s, 3 H); ¹³C NMR (75

MHz, CDCl₃) δ 166.5, 158.4, 157.9, 145.2, 140.9, 136.0, 133.5,

130.1, 128.8, 124.8, 119.7, 118.0, 111.9, 61.6, 52.4, 44.4, 43.8,

28.1, 16.2; ESIMS m/z (rel intensity) 504.09 (MNa⁺, 50). Anal.

(C₂₄H₂₃F₄NO₅) C, H, F, N.

Method II: A mixture of the vinyl iodide 32 (353 mg, 0.793

mmol), palladium acetate (9.0 mg, 0.039 mmol), 2-(di-tert-

butylphosphine)biphenyl (24.2 mg, 0.080 mmol), potassium

fluoride (147 mg, 2.48 mmol), and 3,4-dimethoxyphenylboronic

acid (321 mg, 1.764 mmol) in THF (4.0 mL) was stirred at room

temperature for 14 h and at 60 °C for 8.5 h. The reaction

mixture was cooled to room temperature. Ethyl ether (30 mL)

was added to dilute the mixture. The mixture was washed with

aqueous 10% potassium hydroxide (2 × 20 mL). The organic

phase was collected and washed with brine (30 mL). The

aqueous solution was extracted with ethyl acetate (3 × 15 mL),

washed with brine (20 mL), and then combined with the ether

solution, dried over anhydrous sodium sulfate, and concen-

trated. The residue was purified by column chromatography

on silica gel (40 g) using ethyl acetate in hexanes (0-50%) to

afford the product 3 (0.224 g) as an oil in 62% yield. IR (KBr

film): 2926, 2851, 1751, 1729, 1599, 1580, 1513, 1481, 1438,

(E)-3-[4-(3-Fluoro-5-trifluoromethylphenyl)-4-(3,4-

dimethoxyphenyl)-but-3-enyl]-oxazolidin-2-one (8). The

general procedure was followed using the vinylstannane 35

(178.4 mg, 0.315 mmol), bromide 38 (130 mg, 0.519 mmol),

cesium fluoride (179 mg, 1.17 mmol), and Pd(PBu^t₃)₂(17.8 mg,

0.034 mmol) in toluene (1 mL). After the mixture was stirred

at room temperature for 18 h and at 90 °C for 4 h, more

bromide 38 (147.6 mg, 0.589 mmol) and Pd(PBu^t₃)₂(8.8 mg,

0.017 mmol) were added. The mixture was heated at 90 °C

for 22.5 h and at 115 °C for 26 h. The residue was purified by

column chromatography on silica gel (25 g) using ethyl acetate

in hexanes (0-50%) to afford the product 8 (45.2 mg) as an oil

in 33% yield. IR (KBr) 2917, 2849, 1751, 1600, 1582, 1514,

1484, 1466, 1441, 1350, 1255, 1232, 1200, 1169, 1130, 1093,

1378, 1262, 1142, 1025, 804, 762 cm^-^{1 1}H NMR (300 MHz,

;

CDCl₃) δ 7.42 (d, J ) 2.4 Hz, 1 H), 7.12 (d, J ) 1.5 Hz, 1 H),

6.80 (d, J ) 2.1 Hz, 1 H), 6.74 (d, J ) 8.4 Hz, 1 H), 6.63 (dd,

J ) 2.1 Hz, J ) 8.4 Hz, 1 H), 5.92 (t, J ) 7.5 Hz, 1 H), 4.23 (t,

J ) 8.1 Hz, 2 H), 3.88 (s, 3 H), 3.86 (s, 3 H), 3.37 (t, J ) 6.9

Hz, 2 H), 3.32 (t, J ) 8.1 Hz, 2 H), 2.37 (m, 2 H), 2.30 (s, 3 H);

¹³C NMR (75 MHz, CDCl₃) δ 166.8, 158.5, 157.5, 148.6, 142.7,

136.3, 135.1, 135.0, 132.8, 130.2.124.4, 120.3, 110.7, 110.5,

61.6, 56.0, 55.9, 52.2, 44.2, 44.0, 27.9, 16.1; ESIMS m/z (rel

intensity) 478 (MNa⁺, 100). Anal. (C₂₅H₂₉NO₇) C, H, N.

General Procedure for Synthesis of Alkenyldiaryl-

methanes by the Cross-Coupling Reaction of Vinylstan-

nanes with Aromatic Iodides or Bromides. A mixture of

vinylstannane (1 equiv), iodide or bromide (1.2-1.5 equiv),

cesium fluoride (3.0-4.5 equiv), and Pd(PBu^t₃)₂(10 mol %) in

toluene (1 mL) under argon was stirred at room temperature

for 7.3-24 h and at 90-110 °C for 9.5-43 h. The reaction

mixture was cooled to room temperature and filtered through

a short column of silica gel (5 g), and the column was washed

with ethyl acetate. The organic solution was concentrated.

(Z)-5-[1-(3,4-Dimethoxyphenyl)-4-(2-oxo-oxazolidin-3-

yl)-but-1-enyl]-2-methoxy-3-methyl-benzoic Acid Methyl

Ester (4). The general procedure was followed using the

vinylstannane derivative 35 (367.7 mg, 0.649 mmol), iodide

29 (209.6 mg, 0.685 mmol), cesium fluoride (306 mg, 2.0 mmol),

and Pd(PBu^t₃)₂(53 mg, 0.102 mmol) in toluene (3 mL). After

the mixture was stirred at room temperature for 22 h, and at

80 °C for 5.5 h, compound 29 (103.5 mg, 0.34 mmol) and

Pd(PBu^t₃)₂(9.7 mg, 0.019 mmol) were added. The mixture was

1

1027, 971, 927, 868, 814, 763, 700 cm^-1; H NMR (300 MHz,

CDCl₃) δ 7.25 (s, 1 H), 7.17 (d, J ) 8.1 Hz, 1 H), 7.10 (d, J )

9.9 Hz, 1 H), 6.89 (d, J ) 8.4 Hz, 1 H), 6.71 (dd, J ) 2.1 Hz, J

) 8.1 Hz, 1 H), 6.60 (d, J ) 1.8 Hz, 1 H), 6.064 (t, J ) 7.5 Hz,

1 H), 4.22 (t, J ) 7.8 Hz, 2 H), 3.91 (s, 3 H), 3.82 (s, 3 H), 3.38

(t, J ) 6.9 Hz, 2 H), 3.32 (t, J ) 7.8 Hz, 2 H), 2.43 (q, J ) 7.2

Hz, J ) 6.9 Hz, 2 H); ¹³C NMR (75 MHz, CDCl₃) δ 164.0, 160.7,

158.3, 149.0, 148.6, 145.8, 141.9, 130.6, 127.7, 122.1, 119.7,

117.8, 117.5, 112.5, 111.4, 111.1, 61.5, 55.9, 55.8, 44.2, 43.8,

27.9; ESIMS m/z (rel intensity) 440 (MH⁺, 48). Anal. (C₂₂H₂₁F₄-

NO₄) C, H, F, N.

(E)-3-[4-(5-Fluoro-2-trifluoromethylphenyl)-4-(3,4-

dimethoxyphenyl)-but-3-enyl]-oxazolidin-2-one (9). The

general procedure was followed using the vinylstannane 35

(84 mg, 0.148 mmol), bromide 39 (0.032 mL, 0.224 mmol),

cesium fluoride (84 mg, 0.55 mmol), and Pd(PBu^t₃)₂(8.9 mg,

0.017 mmol) in toluene (1 mL). The mixture was stirred at

room temperature for 19 h and at 90 °C for 22 h. The residue

was purified by column chromatography on silica gel (25 g)

using ethyl acetate in hexanes (0-50%) to afford the product

9 (14.7 mg) as an oil in 23% yield and the starting materials

35 (16.3 mg) in 19.4% yield. IR (KBr) 2929, 1751, 1611, 1583,

1514, 1428, 1364, 1310, 1260, 1234, 1160, 1137, 1104, 1047,

1026, 826, 763 cm^-1; ¹H NMR (300 MHz, CDCl₃) δ 7.62 (dd, J

6148 Journal of Medicinal Chemistry, 2005, Vol. 48, No. 19

Deng et al.

) 5.4 Hz, J ) 8.7 Hz, 1 H), 7.06-6.96 (m, 2 H), 6.81 (d, J )

8.1 Hz, 1 H), 6.72 (dd, J ) 2.1 Hz, J ) 8.4 Hz, 1 H), 6.65 (d, J

) 1.8 Hz, 1 H), 5.63 (t, J ) 7.2 Hz, 1 H), 4.22 (t, J ) 7.8 Hz,

2 H), 3.86 (s, 3 H), 3.80 (s, 3 H), 3.40-3.31 (m, 4 H), 2.57 (q,

J ) 7.2 Hz, J ) 6.9 Hz, 2 H); ESIMS m/z (rel intensity) 440

(MH⁺, 100). Anal. (C₂₂H₂₁F₄NO₄) C, H, N.

Pd(PBu^t₃)₂(31 mg, 0.059 mmol) in toluene (1 mL). The mixture

was stirred at room temperature for 23 h, at 60 °C for 24 h,

and at 100 °C for 24 h. The residue was purified by column

chromatography on silica gel (20 g), eluting with EtOAc-

hexanes (0-5%) to afford the product 13 (13.2 mg) as an oil

in 5% yield. IR (KBr) 2953, 1737, 1599, 1478, 1438, 1374, 1314,

1264, 1207, 1171, 1131, 1093, 1000, 929, 878, 797, 744, 702

(Z)-3-Chloro-5-[1-(5-chloro-2-methoxyphenyl)-5-meth-

oxycarbonyl-pent-1-enyl]-2-methoxybenzoic Acid Meth-

yl Ester (10). The general procedure was followed using the

vinylstannane 51 (283.8 mg, 0.509 mmol), iodide 55 (254.4 mg,

0.779 mmol), cesium fluoride (355 mg, 2.314 mmol), and

Pd(PBu^t₃)₂(32.2 mg, 0.062 mmol) in toluene (1 mL). The

mixture was stirred at room temperature for 7.3 h and at 110

°C for 24 h. The residue was purified by column chromatog-

raphy on silica gel (25 g), eluting with EtOAc-hexanes (0-

5%) to afford the product 10 (28 mg) as an oil in 12% yield. IR

(KBr) 2950, 1735, 1487, 1436, 1248, 1208, 1130, 1000, 810

1

cm^-1; H NMR (300 MHz, CDCl₃) δ 7.46 (d, J ) 2.4 Hz, 1 H),

7.30 (m, 2 H), 7.26 (d, J ) 7.26, 1 H), 7.18 (s, 1 H), 6.09 (t, J

) 7.5 Hz, 1 H), 3.91 (s, 3 H), 3.87 (s, 3 H), 3.60 (s, 3 H), 2.28

(t, J ) 7.5 Hz, 2 H), 2.14-2.07 (q, J ) 7.5 Hz, 2 H), 1.82-1.72

(m, 2 H); ESIMS m/z (rel intensity) 511.18 (MNa⁺, 100). Anal.

(C₂₃H₂₁ClF₄O₅) C, H, Cl, F.

(E)-5-[1-(5-Chloro-2-methoxyphenyl)-5-methoxycar-

bonyl-pent-1-enyl]-2-methoxy-3-methylbenzoic Acid Meth-

yl Ester (14). The general procedure was followed using the

vinyl tributylstannane 52 (166 mg, 0.279 mmol), bromide 47

(111 mg, 0.50 mmol), cesium fluoride (122 mg, 0.787 mmol),

and Pd(PBu^t₃)₂(13.2 mg, 0.025 mmol) in toluene (1 mL). The

mixture was stirred at room temperature for 2 h and at 110

°C for 27.5 h. The residue was purified by column chromatog-

raphy on silica gel (25 g), eluting with EtOAc-hexanes (0-

5%) to afford the product 14 (50.1 mg) as an oil in 40% yield.

IR (KBr) 2950, 1732, 1591, 1484, 1436, 1366, 1291, 1252, 1231,

1

cm^-1; H NMR (300 MHz, CDCl₃) δ 7.52 (d, J ) 2.4 Hz, 1 H),

7.27 (dd, J ) 2.7 Hz, J ) 8.7 Hz, 1 H), 7.25 (d, J ) 2.4 Hz, 1

H), 6.99 (d, J ) 2.7 Hz, 1 H), 6.85 (d, J ) 9.0 Hz, 1 H), 6.10 (t,

J ) 7.5 Hz, 1 H), 3.88 (s, 6 H), 3.67 (s, 3 H), 3.60 (s, 3 H), 2.25

(t, J ) 7.5 Hz, 2 H), 2.02-1.95 (m, 2 H), 1.77-1.70 (m, 2 H);

¹³C NMR (75 MHz, CDCl₃) δ 173.8, 166.0, 155.6, 154.4, 138.0,

135.5, 131.6, 130.8, 129.2, 128.9, 127.1, 126.4, 125.5, 112.4,

61.9, 55.7, 52.4, 51.5, 33.3, 29.3, 24.3; ESIMS m/z (rel intensity)

466.78 /468.83 (MH⁺, 85/51). Anal. (C₂₃H₂₄Cl₂O₆) C, H, Cl.

1195, 1170, 1124, 1010, 883, 808 cm^-^{1 1}H NMR (300 MHz,

;

CDCl₃) δ 7.39 (d, J ) 2.1 Hz, 1 H), 7.16 (dd, J ) 2.7 Hz, J )

8.7 Hz, 1 H), 7.10 (d, J ) 2.7 Hz, 1 H), 7.07 (d, J ) 2.1 Hz, 1

H), 6.72 (d, J ) 8.7 Hz, 1 H), 3.87 (s, 3 H), 3.79 (s, 3 H), 3.61

(s, 3 H), 3.55 (s, 3 H), 2.29 (m, 2 H), 2.26 (s, 3 H), 2.19 (m, 2

H), 1.75 (m, 2 H); ESIMS m/z (rel intensity) 469 (MNa⁺, 100),

471 (MNa⁺, 39). Anal. (C₂₄H₂₇ClO₆) C, H, Cl.

(Z)-5-[1-(5-Chloro-2-methoxyphenyl)-5-methoxycar-

bonyl-pent-1-enyl]-2-methoxy-3-methylbenzoic Acid Meth-

yl Ester (11). The general procedure was followed using the

vinylstannane 51 (260 mg, 0.466 mmol), iodide 29 (219 mg,

0.715 mmol), cesium fluoride (222 mg, 1.447 mmol), and

Pd(PBu^t₃)₂(21.7 mg, 0.042 mmol) in toluene (1 mL). The

mixture was stirred at room temperature for 7.3 h and at 110

°C for 24 h. The residue was purified by column chromatog-

raphy on silica gel (20 g), eluting with EtOAc-hexanes (0-

5%) to afford the product 11 (29 mg) as an oil in 14% yield. IR

(E)-5-[1-(3-Fluoro-5-trifluoromethylphenyl)-5-methoxy-

carbonyl-pent-1-enyl]-2-methoxy-3-methylbenzoic Acid

Methyl Ester (15). The general procedure was followed using

the vinylstannane 52 (365 mg, 0.613 mmol), bromide 38 (268

mg, 1.07 mmol), cesium fluoride (358 mg, 2.33 mmol), and

Pd(PBu^t₃)₂(34.2 mg, 0.066 mmol) in toluene (1 mL). The

mixture was stirred at room temperature for 5.5 h, at 60 °C

for 16 h and at 100 °C for 26 h. The residue was purified by

column chromatography on silica gel (25 g), eluting with

EtOAc-hexanes (0-5%) to afford the product 15 (210.5 mg)

as an oil in 73% yield. IR (KBr) 2952, 1734, 1600, 1437, 1350,

(KBr) 2949, 1731, 1486, 1436, 1248, 1121, 1008, 884, 810 cm^-1

;

¹H NMR (300 MHz, CDCl₃) δ 7.47 (d, J ) 2.4 Hz, 1 H), 7.27

(dd, J ) 1.2 Hz, J ) 10.2 Hz, 1 H), 7.09 (d, J ) 2.4 Hz, 1 H),

7.00 (d, J ) 2.7 Hz, 1 H), 6.86 (d, J ) 8.7 Hz, 1 H), 6.08 (t, J

) 7.5 Hz, 1 H), 3.87 (s, 3 H), 3.78 (s, 3 H), 3.68 (s, 3 H), 3.61

(s, 3 H), 2.27 (t, J ) 7.5 Hz, 2 H), 2.23 (s, 3 H), 2.02-1.94 (q,

J ) 7.5 Hz, 2 H), 1.78-1.68 (m, 2 H); ¹³C NMR (75 MHz,

CDCl₃) δ 173.9, 167.0, 157.3, 155.7, 136.6, 136.4, 132.8, 132.3,

130.8, 130.2, 129.8, 128.5, 126.7, 125.4, 124.2, 112.3, 61.5, 55.8,

52.2, 51.5, 33.4, 29.3, 24.5, 16.2; ESIMS m/z (rel intensity)

469.12 (MNa⁺, 100), 471.04 (MNa⁺, 34). Anal. (C₂₄H₂₇ClO₆) C,

H, Cl.

1

1257, 1201, 1169, 1128, 1094, 1009, 873 cm^-1; H NMR (300

MHz, CDCl₃) δ 7.38 (d, J ) 2.1 Hz, 1 H), 7.28 (s, 1 H), 7.16 (d,

J ) 8.1 Hz, 1 H), 7.07 (d, J ) 2.1 Hz, 1 H), 6.96 (d, J ) 9.9 Hz,

1 H), 6.09 (d, J ) 7.5 Hz, 1 H), 3.89 (s, 3 H), 3.86 (s, 3 H), 3.61

(s, 3 H), 2.31 (s, 3 H), 2.27 (m, 2 H), 2.14 (m, 2 H), 1.77 (m, 2

H); ESIMS m/z (rel intensity) 491 (MNa⁺, 100). Anal.

(C₂₄H₂₄F₄O₅) C, H, F.

(Z)-5-[1-(3-Fluoro-5-trifluoromethylphenyl)-5-methoxy-

carbonyl-pent-1-enyl]-2-methoxy-3-methylbenzoic Acid

Methyl Ester (12). The general procedure was followed using

the vinylstannane 43 (250 mg, 0.43 mmol), iodide 29 (201.8

mg, 0.66 mmol), cesium fluoride (230 mg, 1.5 mmol), and

Pd(PBu^t₃)₂(25 mg, 0.048 mmol) in toluene (1 mL). The mixture

was stirred at room temperature for 7 h and at 110 °C for 24

h. The residue was purified by column chromatography on

silica gel (20 g), eluting with EtOAc-hexanes (0-10%) to

afford the product 12 (118 mg) as an oil in 58% yield. IR (KBr)

2953, 1734, 1599, 1481, 1437, 1375, 1320, 1264, 1234, 1209,

1170, 1130, 1090, 1008, 937, 882, 800, 770, 702 cm^-1; ¹H NMR

(300 MHz, CDCl₃) δ 7.42 (d, J ) 2.4 Hz, 1 H), 7.28 (m, 1 H),

7.19 (s, 1 H), 7.05-7.02 (m, 2 H), 6.04 (t, J ) 7.5 Hz, 1 H),

3.88 (s, 3 H), 3.80 (s, 3 H), 3.61 (s, 3 H), 2.28 (t, J ) 7.5 Hz, 2

H), 2.24 (s, 3 H), 2.13-2.06 (q, J ) 7.5 Hz, 2 H), 1.82-1.72

(m, 2 H); ¹³C NMR (75 MHz, CDCl₃) δ 173.6, 166.8, 164.0,

160.7, 157.7, 142.8, 139.2, 136.6, 133.6, 132.8, 130.9, 127.5,

124.6, 122.3, 120.4, 120.1, 111.9, 111.6, 61.5, 52.2, 51.5, 33.3,

29.0, 24.8, 16.1; ESIMS m/z (rel intensity) 491.13 (MNa⁺, 100).

Anal. (C₂₄H₂₄F₄O₅) C, H, F.

(E)-5-[5-Carboxy-1-(3-cyanophenyl)-pent-1-enyl]-2-meth-

oxy-3-methyl benzoic Acid Methyl Ester (16). The general

procedure was followed using the vinylstannane 44 (212 mg,

0.409 mmol), iodide 29 (197.5 mg, 0.645 mmol), cesium fluoride

(190 mg, 1.24 mmol), and Pd(PBu^t₃)₂(23 mg, 0.044 mmol) in

toluene (1 mL). The mixture was stirred at room temperature

for 65 h, at 65 °C for 8.5 h and at 110 °C for 22 h. The residue

was purified by column chromatography on silica gel (25 g),

eluting with EtOAc-hexanes (0-10%) to afford the product

16 (98 mg) as an oil in 59% yield. IR (KBr) 2951, 2230, 1731,

1645, 1480, 1436, 1318, 1263, 1201, 1124, 1007, 770 cm^-1; ¹H

NMR (300 MHz, CDCl₃) δ 7.58 (d, J ) 7.8 Hz, 1 H), 7.46 (t, J

) 7.8 Hz, 1 H), 7.40-7.34 (m, 3 H), 7.03 (d, J ) 2.4 Hz, 1 H),

6.02 (t, J ) 7.5 Hz, 1 H), 3.84 (s, 3 H), 3.77 (s, 3 H), 3.58 (s, 3

H), 2.25 (t, J ) 7.5 Hz, 2 H), 2.21 (s, 3 H), 2.06 (q, J ) 7.5 Hz,

2 H), 1.78-1.69 (m, 2 H); ¹³C NMR (75 MHz, CDCl₃) δ 173.5,

166.6, 157.5, 140.7, 139.2, 136.8, 134.2, 133.5, 133.1, 132.6,

130.8, 130.5, 129.2, 127.4, 126.6, 124.4, 118.6, 112.5, 61.4, 52.1,

51.4, 33.2, 28.9, 24.7, 16.0; ESIMS m/z (rel intensity) 407.58

(MH⁺, 46). Anal. (C₂₄H₂₅NO₅) C, H, N.

(E)-3-Chloro-5-[1-(3-fluoro-5-trifluoromethylphenyl)-5-

methoxycarbonyl-pent-1-enyl]-2-methoxy-benzoic Acid

Methyl Ester (13). The general procedure was followed using

the vinylstannane 43 (337 mg, 0.58 mmol), iodide 55 (289 mg,

0.885 mmol), cesium fluoride (300 mg, 1.96 mmol), and

(E)-3-Chloro-5-[1-(3-cyanophenyl)-5-methoxycarbonyl-

pent-1-enyl]-2-methoxybenzoic Acid Methyl Ester (17).

The general procedure was followed using the vinylstannane

44 (247 mg, 0.477 mmol), iodide 55 (246.7 mg, 0.756 mmol),

cesium fluoride (220 mg, 1.45 mmol), and Pd(PBu^t₃)₂(25.2 mg,

Alkenyldiarylmethane HIV-1 NNRTIs

Journal of Medicinal Chemistry, 2005, Vol. 48, No. 19 6149

0.048 mmol) in toluene (1 mL). The mixture was stirred at

room temperature for 18 h, at 60 °C for 23.5 h and at 110 °C

for 23 h. The residue was purified by column chromatography

on silica gel (15 g), eluting with EtOAc-hexanes (0-5%) to

afford the product 17 (60 mg) as an oil in 29% yield. IR (KBr)

2952, 2230, 1736, 1597, 1576, 1477, 1436, 1403, 1362, 1303,

1264, 1201, 1162, 1095, 999, 969, 884, 849, 800, 744, 706, 634

Hz, 2 H), 1.82-1.72 (m, 2 H); ¹³C NMR (75 MHz, CDCl₃) δ

173.6, 167.3, 162.8, 141.2, 139.9, 137.5, 134.3, 133.2, 130.9,

130.6, 130.2, 129.3, 120.8, 118.6, 116.6, 113.7, 112.7, 57.3, 51.6,

33.3, 29.1, 24.9, 14.7; ESIMS m/z (rel intensity) 391.03 (MH⁺,

100). Anal. (C₂₃H₂₂N₂O₄) C, H, N.

(Z)-6-(5-Chloro-2-methoxyphenyl)-6-(2,3-dihydro-2,7-

dimethyl-3-oxo-benzo[d]isoxazol-5-yl)-hex-5-enoic Acid

Methyl Ester (21). The general procedure was followed using

the vinylstannane 51 (360 mg, 0.645 mmol), iodide 58 (272

mg, 0.941 mmol), cesium fluoride (349 mg, 2.27 mmol), and

Pd(PBu^t₃)₂(36 mg, 0.07 mmol) in toluene (1 mL). The mixture

was stirred at room temperature for 22 h, at 60 °C for 23.5 h

and at 110 °C for 23.4 h. The residue was purified by column

chromatography on silica gel (25 g), eluting with EtOAc-

hexanes (0-20%) to afford the product 21 (91 mg) as an oil in

33% yield. ¹H NMR (300 MHz, CDCl₃) δ 7.21 (s, 1 H), 7.19 (s,

1 H), 7.13 (dd, J ) 2.7 Hz, J ) 9.0 Hz, 1 H), 6.87 (d, J ) 2.7

Hz, 1 H), 6.72 (d, J ) 9.0 Hz, 1 H), 5.97 (t, J ) 7.5 Hz, 1 H),

3.53 (s, 3 H), 3.50 (s, 3 H), 3.48 (s, 3 H), 2.19 (s, 3 H), 2.12 (t,

J ) 7.5 Hz, 2 H), 1.90-1.84 (m, 2 H), 1.66-1.56 (m, 2 H);

ESIMS m/z (rel intensity) 452.09 (MNa⁺, 88), 454.09 (MNa⁺,

28). Anal. (C₂₃H₂₄ClNO₅) C, H, Cl, N.

1

cm^-1; H NMR (300 MHz, CDCl₃) δ 7.58 (dt, J ) 1.5 Hz, J )

7.8 Hz, 1 H), 7.45 (t, J ) 7.6 Hz, 1 H), 7.40-7.37 (m, 2 H),

7.32 (dt, J ) 1.5 Hz, J ) 7.8 Hz, 1 H), 7.20 (m, 1 H), 6.04 (t,

J ) 7.5 Hz, 1 H), 3.86 (s, 3 H), 3.84 (s, 3 H), 3.57 (s, 3 H), 2.23

(t, J ) 7.2 Hz, 2 H), 2.04 (q, J ) 7.5 Hz, 2 H), 1.76-1.66 (m,

2 H); ¹³C NMR (75 MHz, CDCl₃) δ 173.5, 165.7, 154.9, 140.0,

138.3, 138.1, 134.2, 133.1, 132.3, 132.0, 131.2, 129.5, 128.0,

126.7, 118.5, 112.9, 62.0, 52.5, 51.6, 33.3, 29.1, 24.7; ESIMS

m/z (rel intensity) 450.13/452.11 (MNa⁺, 86/33), 427.94/429.94

(M⁺, 37/12). Anal. (C₂₃H₂₂ClNO₅) C, H, Cl, N.

(E)-6-(5-Chloro-2-methoxyphenyl)-6-(3-cyanophenyl)-

hex-5-enoic Acid Methyl Ester (18). The general procedure

was followed using the vinylstannane 44 (250 mg, 0.48 mmol),

bromide 47 (185 mg, 0.835 mmol), cesium fluoride (235 mg,

1.532 mmol), and Pd(PBu^t₃)₂(27.6 mg, 0.053 mmol) in toluene

(1 mL). The mixture was stirred at room temperature for 13

h, at 60 °C for 23.5 h and at 110 °C for 9.5 h. The residue was

purified by column chromatography on silica gel (15 g), eluting

with EtOAc-hexanes (0-5%) to afford the product 18 (67 mg)

as an oil in 38% yield. IR (KBr) 2949, 2230, 1735, 1644, 1484,

(Z)-6-(2,3-Dihydro-2,7-dimethyl-3-oxo-benzo[d]isoxazol-

5-yl)-6-(3-fluoro-5-trifluoromethylphenyl)-hex-5-enoic Acid

Methyl Ester (22). The general procedure was followed using

the vinylstannane 43 (310 mg, 0.535 mmol), the iodide 58 (239

mg, 0.827 mmol), cesium fluoride (262 mg, 1.71 mmol), and

Pd(PBu^t₃)₂(29 mg, 0.056 mmol) in toluene (1 mL). The mixture

was stirred at room temperature for 18 h, at 60 °C for 8 h and

at 100 °C for 45 h. The residue was purified by column

chromatography on silica gel (20 g), eluting with EtOAc-

hexanes (0-20%) to afford the product 22 (101 mg) as a white

solid in 42% yield. The solid was recrystallized with ethyl

acetate and hexanes to afford a colorless needle crystal for

X-ray crystallography: mp 97.5-98.5 °C. IR (KBr) 2952, 1738,

1694, 1616, 1599, 1492, 1470, 1438, 1377, 1318, 1228, 1171,

1319, 1240, 1127, 1027, 807, 707 cm^-^{1 1}H NMR (300 MHz,

;

CDCl₃) δ 7.52-7.49 (m, 1 H), 7.42-7.37 (m, 3 H), 7.21 (dd, J

) 2.4 Hz, J ) 8.4 Hz, 1 H), 7.15 (d, J ) 2.4 Hz, 1 H), 6.71 (d,

J ) 8.7 Hz, 2 H), 5.84 (t, J ) 7.5 Hz. 1 H), 3.62 (s, 3 H), 3.52

(s, 3 H), 2.30 (t, J ) 7.5 Hz, 2 H), 2.23-2.15 (q, J ) 7.2-7.8

Hz, 2 H), 1.82-1.72 (m, 2 H); ¹³C NMR (75 MHz, CDCl₃) δ

173.6, 155.5, 141.4, 137.4, 133.4, 132.5, 130.3, 128.6, 125.4,

118.9, 112.5, 111.9, 55.6, 51.5, 33.3, 28.5, 24.8; ESIMS m/z (rel

intensity) 391.95/393.96 (MNa⁺, 39/12). Anal. (C₂₁H₂₀ClNO₃)

C, H, Cl, N.

1131, 1090, 1001, 934, 875, 854, 772, 786, 712, 698, 631 cm^-1

;

¹H NMR (300 MHz, CDCl₃) δ 7.35 (d, J ) 1.2 Hz, 2 H), 7.28

(dt, J ) 8.4 Hz, 1 H), 7.21 (br, 1 H), 7.17 (br, 1 H), 7.02 (dt, J

) 8.7 Hz, 1 H), 6.54 (s, 1 H), 6.06 (t, J ) 7.5 Hz, 1 H), 3.64 (s,

3 H), 3.60 (s, 3 H), 2.33 (s, 3 H), 2.29 (t, J ) 7.5 Hz, 2 H),

2.15-2.08 (q, J ) 7.2-7.5 Hz, 2 H), 1.82-1.72 (m, 2 H); ¹³C

NMR (75 MHz, CDCl₃) δ 173.6, 164.1, 162.9, 158.3, 143.0,

139.3, 137.5, 132.9, 131.2, 122.3, 120.3, 120.0, 116.1, 111.7,

51.5, 33.3, 32.7, 29.1, 24.8, 14.1; ESIMS m/z (rel intensity)

451.99 (MH⁺, 100). Anal. (C₂₃H₂₁F₄NO₄) C, H, F, N.

Determination of the Structure of (Z)-6-(2,3-Dihydro-

2,7-dimethyl-3-oxo-benzo[d]isoxazol-5-yl)-6-(3-fluoro-5-

trifluoromethylphenyl)-hex-5-enoic Acid Methyl Ester

(22) by X-ray Crystallography. DATA COLLECTION: A

colorless needle of C₂₃H₂₁F₄NO₄having approximate dimen-

sions of 0.44 × 0.29 × 0.13 mm was mounted on a glass fiber

in a random orientation. Preliminary examination and data

collection were performed Mo KR radiation (λ ) 0.71073 Å on

a Nonius KappaCCD equipped with a graphite crystal, incident

beam monochromator.

Cell constants for data collection were obtained from least-

squares refinement, using the setting angles of 12884 reflec-

tions in the range 2 < θ < 27°. The triclinic cell parameters

and calculated volume are: a ) 8.8822(7), b ) 9.7444(9), c )

12.9675(17) Å, R ) 76.306(4), â )72.480(6), γ ) 89.873(5)°, V

) 1036.98(19) Å³. For Z ) 2 and FW ) 451.42 the calculated

density is 1.45 g/cm³. The refined mosaicity from DENZO/

SCALEPACK was 0.39° indicating good crystal quality. The

space group was determined by the program ABSEN.²⁹There

were no systematic absences; the space group was determined

to be P-1(#2). The data were collected at a temperature of 150

(1) K. Data were collected to a maximum 2θ of 55.8°.

Data Reduction. A total of 12884 reflections were collected,

of which 4884 were unique. Lorentz and polarization correc-

tions were applied to the data. The linear absorption coefficient

is 1.2 /cm for Mo K_aradiation. An empirical absorption

correction using SCALEPACK³⁰was applied. Transmission

coefficients ranged from 0.940 to 0.986. Intensities of equiva-

(Z)-6-(3-Fluoro-5-trifluoromethylphenyl)-6-(3-methoxy-

7-methylbenzo[d] isoxazol-5-yl)-hex-5-enoic Acid Methyl

Ester (19). The general procedure was followed using the

vinylstannane 43 (305 mg, 0.526 mmol), iodide 59 (200 mg,

0.692 mmol), cesium fluoride (245 mg, 1.6 mmol), and

Pd(PBu^t₃)₂(28 mg, 0.054 mmol) in toluene (1 mL). The mixture

was stirred at room temperature for 19 h, at 60 °C for 8 h and

at 100 °C for 22 h. The residue was purified by column

chromatography on silica gel (20 g), eluting with EtOAc-

hexanes (0-2%) to afford the product 19 (112 mg) as an oil in

47% yield. IR (KBr) 2949, 1736, 1599, 1549, 1496, 1438, 1376,

1329, 1220, 1171, 1130, 1047, 934, 874, 765, 701 cm^-1; ¹H NMR

(300 MHz, CDCl₃) δ 7.29 (d, J ) 7.8 Hz, 1 H), 7.20 (s, 1 H),

7.13 (d, J ) 8.4 Hz, 2 H), 7.05 (d, J ) 8.7 Hz, 1 H), 6.06 (t, J

) 7.5 Hz, 1 H), 4.12 (s, 3 H), 3.62 (s, 3 H), 2.45 (s, 3 H), 2.30

(t, J ) 7.5 Hz, 2 H), 2.17-2.09 (q, J ) 7.2-7.5 Hz, 2 H), 1.84-

1.74 (m, 2 H); ¹³C NMR (75 MHz, CDCl₃) δ 173.6, 167.3, 164.0,

162.8, 160.7, 143.3, 139.7, 137.3, 132.8, 130.9, 130.2, 122.3,

120.8, 120.4, 120.1, 116.6, 113.8, 111.9, 111.6, 57.3, 51.5, 33.3,

29.1, 24.8, 14.7; ESIMS m/z (rel intensity) 451.97 (MH⁺, 100).

Anal. (C₂₃H₂₁F₄NO₄) C, H, F, N.

(E)-6-(3-Cyanophenyl)-6-(3-methoxy-7-methylbenzo[d]-

isoxazol-5-yl)-hex-5-enoic Acid Methyl Ester (20). The

general procedure was followed using the vinylstannane 44

(232 mg, 0.448 mmol), iodide 59 (195 mg, 0.675 mmol), cesium

fluoride (245 mg, 1.6 mmol), and Pd(PBu^t₃)₂(22 mg, 0.043

mmol) in toluene (1 mL). The mixture was stirred at room

temperature for 19 h, at 60 °C for 8 h and at 100 °C for 43 h.

The residue was purified by column chromatography on silica

gel (20 g), eluting with EtOAc-hexanes (0-20%) to afford the

product 20 (72 mg) as an oil in 41% yield. IR (KBr) 2949, 2230,

1738, 1615, 1548, 1495, 1394, 1315, 1169, 1047, 910, 804, 765,

1

695 cm^-1; H NMR (300 MHz, CDCl₃) δ 7.61 (dt, J ) 1.5 Hz,

J ) 7.8 Hz, 1 H), 7.48 (t, J ) 7.48 Hz, 1 H), 7.43 (br, 1 H),

7.38 (dt, J ) 1.5 Hz, J ) 7.8 Hz, 1 H), 7.13 (br, 1 H), 7.09 (br,

1 H), 6.06 (t, J ) 7.5 Hz, 1 H), 4.11 (s, 3 H), 3.61 (s, 3 H), 2.43

(s, 3 H), 2.29 (t, J ) 7.5 Hz, 2 H), 2.14-2.07 (q, J ) 7.2-7.8

6150 Journal of Medicinal Chemistry, 2005, Vol. 48, No. 19

Deng et al.

lent reflections were averaged. The agreement factor for the

averaging was 3.8% based on intensity.

extracted ethyl acetate (4 × 200 mL). The organic solution was

washed with brine, dried over Na₂SO₄, and concentrated to

afford a residue, which was purified by column chromatogra-

phy on silica gel (40 g), eluting with EtOAc-hexanes (0-30%),

to afford the product 25 as an oil (2.197 g) in 83% yield. IR

(KBr film) 3286, 2919, 2118, 1744, 1485, 1429, 1366, 1271,

Structure Solution and Refinement. The structure was

solved by direct methods using SIR2002.³⁶The remaining

atoms were located in succeeding difference Fourier syntheses.

Hydrogen atoms were included in the refinement but re-

strained to ride on the atom to which they are bonded. The

structure was refined in full-matrix least-squares where the

1

1236, 1093, 1042, 970, 763 cm^-1; H NMR (300 MHz, CDCl₃)

δ 4.32 (t, J ) 7.8 Hz, 2 H), 3.70 (t, J ) 7.8 Hz, 2 H), 3.42 (t, J

) 6.6 Hz, 2 H), 2.45 (dt, J ) 2.7 Hz, J ) 6.6 Hz, 2 H), 2.00 (t,

J ) 2.7 Hz, 1 H); ¹³C NMR (75 MHz, CDCl₃) δ 157.9, 80.6,

70.0, 61.5, 44.5, 42.5, 17.4; ESIMS m/z (rel intensity) 139.98

(100). Anal. (C₇H₉NO₂) C, H, N.

function minimized was Σw(|F_o| - |F_c| )²and the weight w is

2

defined as 1/[σ²(F_o) + (0.0722P)²+ 0.0000P] where P ) (F_o

+ 2F_c²)/3. Scattering factors were taken from the “Interna-

tional Tables for Crystallography”.³²4884 reflections were used

2

in the refinements. However, only the 3461reflections with F_o

2-Hydroxy-5-iodo-3-methylbenzoic Acid Methyl Ester

(28).¹⁰Tetrabutylammonium bromide (0.9 g, 2.764 mmol) was

added to a stirred solution of 3-methylsalicylic acid 26 (4.634

g, 29.85 mmol) in dichloromethane (50 mL). A solution of

potassium carbonate (13.433 g, 97.34 mmol) in water (25 mL)

was added. Dimethyl sulfate (6.0 mL, 62.77 mmol) was added

to afford a clear solution. The resulting solution was stirred

at room temperature for 4 h. The organic layer was separated,

and the aqueous layer was diluted with water (40 mL) and

extracted with dichloromethane (2 × 20 mL). The combined

organic solutions were washed with sat. ammonium chloride

(30 mL) and brine (2 × 30 mL), dried over sodium sulfate, and

concentrated to afford crude methyl ester 27 as an oil. ¹H NMR

(300 MHz, CDCl₃) δ 10.99 (s, 1 H), 7.67 (dd, J ) 1.5 Hz, J )

8.1 Hz, 1 H), 7.30 (d, J ) 7.5 Hz, 1 H), 6.76 (t, J ) 7.5 Hz, 1

H), 3.94 (s, 3 H), 2.25 (s, 3 H). The crude methyl ester 27 was

dissolved in methanol (80 mL), sodium iodide (5.526 g, 36.86

mmol) and sodium hydroxide (1.489 g, 36.86 mmol) were

added, and the solution was cooled to 0 °C. Aqueous sodium

hypochlorite (62.5 mL, 36.86 mmol, 4%) was added dropwise.

The resulting brown mixture was stirred for 4.5 h at 0-3 °C

and then treated with 10% sodium thiosulfate (60 mL). The

pH of the mixture was adjusted to 5-6 using 1 N HCl. Ether

(200 mL) was added, and the layers were separated. The

aqueous layer was extracted with ether (3 × 200 mL). The

combined organic solution was washed with brine (300 mL),

dried over anhydrous Na₂SO₄, and concentrated to afford crude

28 (8.52 g) as colorless crystals in 98% yield: mp 94-95.5 °C

(lit.¹⁰mp 82-84 °C). ¹H NMR (300 MHz, CDCl₃) δ 10.80 (s, 1

H), 7.83 (d, J ) 2.4 Hz, 1 H), 7.43 (d, J ) 2.4 Hz, 1 H), 3.80 (s,

3 H), 2.07 (s, 3 H).

Methyl 5-Iodo-2-methoxy-3-methylbenzoate (29). The

methyl ester (28) (8.52 g, 29.17 mmol) was dissolved in

dichloromethane (100 mL). Then tetrabutylammonium bro-

mide (958 mg, 2.94 mmol) was added. A solution of sodium

hydroxide (3.4 g, 85 mmol) in water (50 mL) was added,

followed by dimethyl sulfate (5.5 mL, 57.55 mmol). The

resulting solution was stirred at room-temperature overnight

and quenched with solid ammonium chloride (6 g), and the

pH was adjust to 5-6 with 1 N HCl. The organic layer was

separated, and the aqueous layer was extracted with di-

chloromethane (3 × 100 mL). The combined organic solution

was washed with brine (200 mL), dried over sodium sulfate,

and concentrated to afford a solid, which was purified by

column chromatography on silica gel (40 g) using hexanes and

5% ethyl acetate in hexanes to afford 29 (7.69 g) as white

crystals in 86% yield: mp 66-67.5 °C (lit.¹⁰mp 55-57 °C). ¹H

NMR (300 MHz, CDCl₃) δ 7.93 (d, J ) 2.4 Hz, 1 H), 7.66 (d, J

) 2.4 Hz, 1 H), 3.90 (s, 3 H), 3.81 (s, 3 H), 2.27 (s, 3 H).

2

> 2σ(F_o) were used in, calculating R1. The final cycle of

refinement included 292 variable parameters and converged

(largest parameter shift was <0.01 times its su) with un-

weighted and weighted agreement factors of:

R1 ) Σ|F_o- F_c|/Σ F_o) 0.046

2 2

R2 ) SQRT (Σ w(F_o²- F_c) /Σw(F_o) ) ) 0.117

The standard deviation of an observation of unit weight was

1.03. The highest peak in the final difference Fourier had a

height of 0.27 e/A³. The minimum negative peak had a height

of -0.36 e/A³. Refinement was performed on a LINUX PC

using SHELX-97.³³Crystallographic drawings were done using

programs ORTEP³⁴and PLUTON.³⁵

Butynyl 1-Tosylate (24). Method I: A mixture of p-

toluenesulfonyl chloride (62.21 g, 0.323 mol) and pyridine (31

mL, 0.383 mol) was warmed to get a colorless solution and

then cooled to get small crystals. 3-Butyn-1-ol (23) (23 mL,

0.29 mol) was added dropwise by syringe during about 20 min

with stirring at 15 °C. The resulting mixture was stirred below

20 °C under nitrogen atmosphere for 20 h. Water was added

with cooling. The mixture was extracted with ethyl acetate (4

× 120 mL). The organic solution was washed with 5% aqueous

sulfuric acid (3 × 120 mL), water (100 mL), 10% aqueous

sodium hydrogen carbonate, and brine, dried over sodium

sulfate, and concentrated. The crude product was purified by

flash column chromatography on silica gel (800 g), eluting with

ethyl acetate-hexanes (0-10%) to afford the tosylate 24 (56.13

g) as colorless oil in 85% yield.^{11 1}H NMR (300 MHz, CDCl₃) δ

7.79 (d, J ) 8.4 Hz, 2 H), 7.33 (d, J ) 8.1 Hz, 2 H), 4.08 (t, J

) 6.9-7.2 Hz, 2 H), 2.54 (dt, J ) 2.7 Hz, J ) 6.9-7.2 Hz, 2

H), 2.43 (s, 3 H), 1.94 (t, J ) 2.7 Hz, 1 H).

Method II: A solution of sodium hydroxide (22.53 g, 0.563

mol) in water (200 mL) was added to a mixture of 3-butyn-1-

ol (23) (26.76 g, 0.370 mol) and p-toluenesulfonyl chloride (86.3

g, 0.448 mol) in THF (500 mL). The resulting mixture was

stirred at room temperature for 50.5 h and concentrated to

remove the organic solvent. The residue was extracted with

ethyl acetate (3 × 100 mL). The combined organic solution was

washed with brine, dried over Na₂SO₄, and concentrated to

afford a residue. The residue was purified by column chroma-

tography on silica gel (200 g), eluting with 0-10% EtOAc in

hexanes, to afford the tosylate 24 (68.70 g) as an oil in 77%

yield.

3-(But-3-ynyl)-1,3-oxazolidin-2-one (25). A flask was

charged with 2-oxazolidinone (1.721 g, 19.17 mmol), tetra-

butylammonium bromide (715 mg, 2.20 mmol), potassium

carbonate (19.09 g, 138 mmol), and toluene (90 mL). 3-Butynyl

1-tosylate (24) (11.72 g, 52.26 mmol) was added. After the

resulting mixture was stirred at 100 °C for 4 h, more tosylate

24 (10.62 g, 47.35 mmol) was added. After stirring overnight,

more potassium carbonate (7.52 g, 54.41 mmol) and tosylate

24 (11.94 g, 53.24 mmol) were added. The resulting mixture

was stirred at 105 °C for 5.5 h, and potassium carbonate (10.00

g, 72.35 mmol) and tosylate 24 (11.312 g, 50.44 mmol) were

added. The mixture was heated at 105 °C overnight, and more

tosylate 24 (10.70 g, 47.71 mmol) and potassium carbonate

(9.29 g, 67.22 mmol) were added. The mixture was heated to

reflux for another 5 h and then cooled to room temperature.

Water was added to quench the reaction. The mixture was

2-Methoxy-3-methyl-5-[4-(2-oxo-oxazolidin-3-yl)-but-1-

ynyl]benzoic Acid Methyl Ester (30). Triethylamine (1.35

mL, 9.69 mmol) and Pd(PPh₃)Cl₂(139 mg, 0.19 mmol) were

added to a mixture of the iodide 29 (1.310 g, 4.28 mmol) and

the alkyne 25 (536 mg, 3.86 mmol) in THF (25 mL) at room

temperature, and then Cu(I)I (75 mg, 0.40 mmol) was added.

The resulting mixture was stirred at room temperature for

22 h. The reaction was quenched with water (20 mL) and

concentrated to remove the organic solvents. The residue was

extracted with ethyl acetate (3 × 50 mL). The organic layer

was separated and washed with brine (60 mL), dried over

sodium sulfate, and concentrated. The residue was purified

by column chromatography on silica gel (35 g), eluting with

Alkenyldiarylmethane HIV-1 NNRTIs

Journal of Medicinal Chemistry, 2005, Vol. 48, No. 19 6151

EtOAc-hexanes (0-50%) to afford the product 30 (981 mg)

J ) 8.4 Hz, 1 H), 4.32 (t, J ) 7.8 Hz, 2 H), 3.86 (s, 3 H), 3.85

(s, 3 H), 3.73 (t, J ) 7.8 Hz, 2 H), 3.51 (t, J ) 6.6 Hz, 2 H),

2.67 (t, J ) 6.6 Hz, 2 H); ESIMS m/z (rel intensity) 276.05

(MH⁺, 94), 298.05 (MNa⁺, 98). Anal. (C₁₅H₁₇NO₄) C, H, N.

1

as brown oil in 80% yield. H NMR (300 MHz, CDCl₃) δ 7.63

(d, J ) 2.1 Hz, 1 H), 7.34 (d, J ) 1.5 Hz, 1 H), 4.33 (t, J ) 7.8

Hz, 2 H), 3.89 (s, 3 H), 3.80 (s, 3 H), 3.73 (t, J ) 7.8 Hz, 2 H),

3.50 (t, J ) 6.6 Hz, 2 H), 2.66 (t, J ) 6.6 Hz, 2 H), 2.26 (s, 3

H); ESIMS m/z (rel intensity) 340.10 (MNa⁺, 100). Anal. Calcd

for (C₁₇H₁₉NO₅) C, H, N.

3-[4-(Tributylstannanyl)-4-(3,4-dimethoxyphenyl)-but-

3-enyl]-1,3-oxazolidin-2-one (35). The intermediate 34 (254

mg, 0.923 mmol) was dissolved in THF (20 mL), and then

tetrakis(triphenylphosphine)palladium (9.4 mg, 8.13 µmol) was

added. The mixture was cooled to 0 °C, degassed by gently

bubbling argon through for 15 min and then tributyltin

hydride (0.4 mL, 1.44 mmol) was added dropwise over 70 min.

After the mixture was stirred at room temperature for 3.5 h,

it was concentrated to yield a residue. The residue was purified

by column chromatography on silica gel (30 g) using hexane

and EtOAc-hexane (0-30%) to afford the vinylstannanes 35

(415 mg) in 79% yield and 37 as an oil (39.2 mg) in 8% yield.

Spectral data of 35: IR (KBr) 2954, 2926, 1755, 1508, 1463,

2-Methoxy-3-methyl-5-[1-(tributylstannanyl)-4-(2-oxo-

oxazolidin-3-yl)-but-1-enyl]benzoic Acid Methyl Ester

(31). Compound 30 (945 mg, 0.945 mmol) was dissolved in

THF (20 mL), and then tetrakis(triphenylphosphine)palladium

(7.0 mg, 6.05 µmol) was added. The mixture was cooled to 0

°C, degassed by gently bubbling argon through for 15 min, and

then tributyltin hydride (0.4 mL, 1.44 mmol) was added

dropwise over 60 min. After the mixture was stirred at room

temperature for 3 h, it was concentrated to yield a residue.

The residue was purified by column chromatography on silica

gel (40 g) using hexanes and EtOAc-hexanes (5-15%) to

afford the vinylstannanes 31 (437 mg) as an oil in 76% yield

and 36 (53 mg) in 9% yield. Spectral data of 31: IR (KBr) 2926,

1756, 1435, 1257, 1197, 1126 cm^-1; ¹H NMR (300 MHz, CDCl₃)

δ 7.15 (d, J ) 2.4 Hz, 1 H), 6.86 (d, J ) 2.1 Hz, 1 H), 5.71 (t,

J ) 6.9 Hz, 1 H), 4.22 (t, J ) 7.8 Hz, 2 H), 3.87 (s, 3 H), 3.79

(s, 3 H), 3.34 (t, J ) 7.8 Hz, 2 H), 3.27 (t, J ) 7.2 Hz, 2 H),

2.26 (m, 5 H), 1.42-1.34 (m, 6 H), 1.29-1.17 (m, 6 H), 0.88-

0.78 (m, 9 H); ESIMS m/z (rel intensity) 633.33 (MNa⁺, 77),

632.20 (MNa⁺, 100). Anal. (C₂₉H₄₇NO₅Sn) C, H, N, Sn.

1254, 1233, 1136, 1028, 865, 761 cm^-^{1 1}H NMR (300 MHz,

;

CDCl₃) δ 6.77 (m, 1 H), 6.45-6.42 (m, 2 H), 5.68 (t, J ) 6.9

Hz, 1 H), 4.19 (t, J ) 8.1 Hz, 2 H), 3.84 (s, 3 H), 3.82 (s, 3 H),

3.32 (t, J ) 8.1 Hz, 2 H), 3.27 (t, J ) 7.2 Hz, 2 H), 2.32 (m, 2

H), 1.49-1.38 (m, 6 H), 1.34-1.18 (m, 6 H), 0.95-0.76 (m, 14

H); ¹³C NMR (75 MHz, CDCl₃) δ 158.1, 148.6, 148.4, 146.4,

137.1, 136.8, 118.5, 111.0, 110.1, 61.4, 55.7, 55.6, 44.1, 43.8,

28.8, 27.1, 13.5, 9.8; ESIMS m/z (rel intensity) 588.45 (MNa⁺,

80.4), 590.19 (MNa⁺, 100). Anal. (C₂₇H₄₅NO₄Sn) C, H, N, Sn.

3-[3-(Tributylstannanyl)-4-(3,4-dimethoxyphenyl)-but-

3-enyl]-1,3-oxazolidine-2-one (37). ¹H NMR (300 MHz,

CDCl₃) δ 6.83 (m, 2 H), 6.74 (s, 1 H), 6.64 (s, 1 H), 4.20 (t, J )

7.5-8.4 Hz, 2 H), 3.89 (s, 3 H), 3.87 (s, 3 H), 3.38 (t, J ) 7.5-

8.4 Hz, 2 H), 3.31 (t, J ) 7.5-8.1 Hz, 2 H), 2.74 (t, J ) 7.5-

8.1 Hz, 2 H), 1.59-1.49 (m, 6 H), 1.40-1.28 (m, 6 H), 1.02-

0.96 (m, 6 H), 0.090 (t, J ) 7.1 Hz, 9 H); ESIMS m/z (rel

intensity) 564.30 (M⁺, 12), 566.25 (M⁺, 23), 568.26 (M⁺, 28),

586.32 (MNa⁺, 42), 588.31 (MNa⁺, 77), 590.26 (MNa⁺, 100).

2-Methoxy-3-methyl-5-[2-(tributylstannanyl)-4-(2-oxo-

oxazolidin-3-yl)-but-1-enyl]benzoic Acid Methyl Ester

(36). IR (KBr) 2955, 2926, 2871, 1756, 1732, 1480, 1424, 1377,

1360, 1315, 1263, 1232, 1201, 1128, 1102, 1051, 1010, 881, 799,

1

762, 695 cm^-1; H NMR (300 MHz, CDCl₃) δ 7.47 (d, J ) 2.1

Hz, 1 H), 7.24 (d, J ) 2.1 Hz, 1 H), 6.61 (s, 1 H), 4.21 (t, J )

7.8 Hz, 2 H), 3.90 (s, 3 H), 3.81 (s, 3 H), 3.42 (t, J ) 7.8 Hz, 2

H), 3.30 (t, J ) 7.2 Hz, 2 H), 2.70 (t, J ) 7.2 Hz, 2 H), 2.31 (s,

3 H), 1.58-1.47 (m, 6 H), 1.39-1.27 (m, 6 H), 1.00-0.96 (m, 6

H), 0.89 (t, J ) 7.2 Hz, 9 H); ESIMS m/z (rel intensity) 552.17

([M-Bu]⁺, 38.5), 608.09 (M⁺, 12), 610.07 (M⁺, 18). Anal.

(C₂₉H₄₇NO₅Sn) C, H, N, Sn.

6-(3-Fluoro-5-trifluoromethylphenyl)-hex-5-ynoic Acid

Methyl Ester (41). Pd(PPh₃)₂Cl₂(236 mg, 0.336 mmol) was

added to a mixture of bromide 38 (1.677 g, 6.70 mmol) and

methyl 5-hexynoate (1.025 g, 8.12 mmol) in triethylamine (5.0

mL) at room temperature. Cu(I)I (136 mg, 0.714 mmol) was

added. The resulting mixture was stirred at room temperature

for 1.5 h and at 80 °C for 22.5 h. The reaction mixture was

cooled to room temperature and filtered through a short

column of silica gel (5 g), and the column was washed with

ethyl acetate. The organic solution was concentrated. The

residue was purified by column chromatography on silica gel

(40 g), eluting with EtOAc-hexanes (2%) to afford the product

41 (1.564 g) as a white solid in 81% yield: mp 44-45 °C. IR

(KBr) 3084, 2955, 2848, 2238, 1740, 1619, 1599, 1467, 1439,

1363, 1253, 1240, 1224, 1171, 1133, 1093, 1046, 995, 973, 924,

5-[1-Iodo-4-(2-oxo-oxazolidin-3-yl)-but-1-enyl]-2-meth-

oxy-3-methylbenzoic Acid Methyl Ester (32). The vinyl

tributylstannane 31 (157 mg, 0.258 mmol) was dissolved in

dry CH₂Cl₂(6 mL). Finely divided I₂(80 mg, 0.315 mmol) was

added, and the mixture was stirred vigorously at room

temperature for 50 min. Saturated aqueous Na₂S₂O₃(15 mL)

was added, the phases were separated, and the aqueous phase

was extracted with CH₂Cl₂(3 × 10 mL). The combined organic

extracts were dried (Na₂SO₄) and concentrated. The residue

was purified by flash chromatography on silica gel (20 g, 30%

EtOAc-hexanes as eluent) to afford the vinyl iodide as an oil

(114 mg, 99%): ¹H NMR (CDCl₃) δ 7.46 (d, J ) 2.1 Hz, 1 H),

7.20 (d, J ) 1.5 Hz, 1 H), 6.40 (t, J ) 7.5 Hz, 1 H), 4.23 (t, J

) 7.8 Hz, 2 H), 3.86 (s, 3 H), 3.78 (s, 3 H), 3.36 (t, J ) 7.8 Hz,

2 H), 3.24 (t, J ) 6.9 Hz, 2 H), 2.25 (s, 3 H), 2.19 (t, J ) 7.2

Hz, 2 H); ¹³C NMR (CDCl₃) δ 166.1, 158.2, 158.0, 139.4, 136.5,

134.9, 133.1, 128.8, 124.1, 95.5, 61.5, 61.4, 52.2, 44.5. 43.1, 30.1,

16.0; ESIMS m/z (rel intensity) 467.85 (MNa⁺, 100). Anal.

(C₁₇H₂₀INO₅) C, H, I, N.

3-[4-(3,4-Dimethoxyphenyl)-but-3-ynyl]-1,3-oxazolidin-

2-one (34). Triethylamine (0.08 mL, 0.574 mmol) and

Pd(PPh₃)Cl₂(8.0 mg, 0.011 mmol) were added to a mixture of

3,4-dimethoxyphenyl iodide (33) (64 mg, 0.242 mmol) and

alkyne 25 (34 mg, 0.245 mmol) in THF (3 mL) at room

temperature. Then Cu(I)I (5 mg, 0.026 mmol) was added. The

resulting mixture was stirred at room temperature for 4 h.

The reaction was quenched with water (10 mL) and concen-

trated to remove the organic solvents. The residue was diluted

with ethyl acetate (15 mL). The organic layer was separated

and washed with brine (2 × 10 mL), dried over sodium sulfate,

and concentrated. The residue was purified by column chro-

matography on silica gel (25 g), eluting with EtOAc-hexanes

(10-50%) to afford the product 34 (54 mg) as solid in 80%

yield: mp 78-79 °C. ¹H NMR (300 MHz, CDCl₃) δ 6.95 (dd, J

) 2.1 Hz, J ) 8.4 Hz, 1 H), 6.88 (d, J ) 1.8 Hz, 1 H), 6.76 (d,

911, 875, 695 cm^-^{1 1}H NMR (300 MHz, CDCl₃) δ 7.40 (s, 1

;

H), 7.21 (m, 2 H), 3.66 (s, 3 H), 2.47 (t, J ) 7.2 Hz, 4 H), 1.90

(m, 2 H); ¹³C NMR (75 MHz, CDCl₃) δ 173.3, 163.7, 160.4,

132.8, 132.3, 126.8, 126.7, 124.7, 124.3, 121.8, 121.5, 112.3,

111.9, 79.1, 51.6, 32.7, 23.5, 18.7; ESIMS m/z (rel intensity)

288.96 (MH⁺, 51). Anal. (C₁₄H₁₂F₄O₂) C, H, F.

6-(3-Cyanophenyl)-hex-5-ynoic Acid Methyl Ester (42).

Pd(PPh₃)₂Cl₂(223 mg, 0.315 mmol) was added to a mixture of

3-bromobenzonitrile (40) (832 mg, 6.43 mmol) and methyl

5-hexynoate (970 mg, 7.69 mmol) in triethylamine (4.5 mL)

at room temperature, and then Cu(I)I (122 mg, 0.64 mmol)

was added. The resulting mixture was stirred at room tem-

perature for 1 h and at 80 °C for 22 h. The reaction mixture

was cooled to room temperature and filtered through a short

column of silica gel (5 g), and the column was washed with

ethyl acetate. The organic solution was concentrated. The

residue was purified by column chromatography on silica gel

(30 g), eluting with EtOAc-hexanes (3-5%) to afford the

product 42 (1.117 g) as an oil in 76% yield. IR (KBr) 3069,

2952, 2232, 1737, 1597, 1572, 1479, 1436, 1416, 1370, 1316,

1222, 1160, 1057, 894, 799, 684 cm^-^{1 1}H NMR (300 MHz,

;

CDCl₃) δ 7.64 (m, 1 H), 7.58 (dt, J ) 1.2 Hz, J ) 7.8 Hz, 1 H),

7.53 (dt, J ) 1.2 Hz, J ) 7.8 Hz, 1 H), 7.38 (t, J ) 7.5 Hz, 1

H), 3.68 (s, 3 H), 2.48 (m, 4 H), 1.92 (m, 2 H); ¹³C NMR (75

6152 Journal of Medicinal Chemistry, 2005, Vol. 48, No. 19

Deng et al.

MHz, CDCl₃) δ 173.4, 135.6, 134.9, 130.9, 129.1, 125.3, 118.1,

112.6, 91.7, 79.3, 51.6, 32.8, 23.6, 18.8; EIMS m/z (rel intensity)

227 (M⁺, 29), CIMS m/z (rel intensity) 228 (MH⁺, 100). Anal.

(C₁₄H₁₃NO₂) C, H, N.

was then added to the flask via syringe. The reaction mixture

was heated at reflux temperature for 26 h. The mixture was

cooled to room temperature and filtered, and the inorganic

salts were washed with methylene chloride (20 mL). The

solution was evaporated to yield the crude product. The crude

product was purified by flash column chromatography on silica

gel (60 g) using 3-30% ethyl acetate in hexanes as the eluent

to yield the product 48 as a crystallizing oil (7.4 g) in

quantitative yield: mp 57-58.5 °C (lit.¹³mp 59-60 °C). ¹H

NMR (300 MHz, CDCl₃) δ 7.76 (d, J ) 2.58 Hz, 1 H), 7.47 (d,

J ) 2.58 Hz, 1 H), 3.91 (s, 3 H), 3.81 (s, 3 H), 2.30 (s, 3 H).

6-Tributylstannanyl-6-(3-fluoro-5-trifluoromethyl-

phenyl)-hex-5-enoic Acid Methyl Ester (43). Alkyne 41

(1.545 g, 5.36 mmol) was dissolved in THF (220 mL), and then

tetrakis(triphenylphosphine)palladium (56 mg, 48 µmol) was

added. The mixture was cooled to 0 °C, degassed by gently

bubbling argon through for 20 min, and then tributyltin

hydride (2.2 mL, 7.93 mmol) was added dropwise over 120 min.

After the mixture was stirred at room temperature for 3 h, it

was concentrated to yield a residue. The residue was purified

by column chromatography on silica gel (50 g) using hexanes

and EtOAc-hexanes (0-1%) to afford the vinylstannane 43

(2.651 g) as an oil in 90% yield. IR (KBr) 2957, 2928, 2873,

2854, 1743, 1617, 1593, 1464, 1434, 1369, 1327, 1246, 1224,

1170, 1133, 1090, 978, 903, 877, 865, 695, 706 cm^-1; ¹H NMR

(300 MHz, CDCl₃) δ 7.05 (d, J ) 8.7 Hz, 1 H), 6.92 (s, 1 H),

6.76 (t, J ) 9.3 Hz, 1 H), 5.76 (t, J ) 7.2 Hz, 1 H), 3.59 (s, 3

H), 2.23 (t, J ) 7.5 Hz, 2 H), 2.01 (m, 2 H), 1.68 (m, 2 H),

1.45-1.35 (m, 6 H), 1.30-1.18 (m, 6 H), 0.89-0.81 (m, 9 H);

¹³C NMR (75 MHz, CDCl₃) δ 173.7, 163.9, 160.6, 148.8, 148.7,

144.6, 142.2, 132.4, 132.0, 119.4, 117.0, 116.7, 109.2, 108.8,

51.4, 33.2, 29.4, 28.9, 27.2, 24.6, 13.5, 10.0; ESIMS m/z (rel

intensity) 523.15 (M-Bu⁺, 64). Anal. (C₂₆H₄₀F₄O₂Sn) C, H, F,

Sn.

6-(5-Chloro-2-methoxyphenyl)-hex-5-ynoic Acid Meth-

yl Ester (49). Pd(PPh₃)₂Cl₂(76 mg, 0.106 mmol) was added

to a mixture of bromide 47 (498 mg, 2.25 mmol) and methyl

5-hexynoate (440 mg, 3.48 mmol) in triethylamine (3.0 mL)

at room temperature, and then Cu(I)I (45 mg, 0.235 mmol)

was added. The resulting mixture was stirred at room tem-

perature for 8 h, and at 80 °C for 21 h. The reaction mixture

was cooled to room temperature and filtered through a short

column of silica gel (5 g), and the column was washed with

ethyl acetate. The organic solution was concentrated. The

residue was purified by column chromatography on silica gel

(25 g), eluting with EtOAc-hexanes (3-5%) to afford the

product 49 (589 mg) as a slightly yellow oil in 98% yield. IR

(KBr) 2950, 2844, 2234, 1736, 1591, 1490, 1460, 1439, 1397,

1370, 1313, 1287, 1266, 1229, 1180, 1161, 1138, 1095, 1026,

935, 882, 807, 709, 647 cm^-^{1 1}H NMR (300 MHz, CDCl₃) δ

;

7.30 (d, J ) 2.4 Hz, 1 H), 7.17 (dd, J ) 2.7 Hz, J ) 8.7 Hz, 1

H), 6.74 (d, J ) 8.0 Hz, 1 H), 3.83 (s, 3 H), 3.67 (s, 3 H), 2.52

(m, 4 H), 1.92 (m, 2 H); ESIMS m/z (rel intensity) 289.04

(MNa⁺, 4.5). Anal. (C₁₄H₁₅ClO₃) C, H, Cl.

6-(Tributylstannanyl)-6-(3-cyanophenyl)-hex-5-enoic

Acid Methyl Ester (44). Alkyne 42 (787 mg, 3.46 mmol) was

dissolved in THF (150 mL), and then tetrakis(triphenylphos-

phine)palladium (40 mg, 34.6 µmol) was added. The mixture

was cooled to 0 °C, degassed by gently bubbling argon through

for 15 min, and then tributyltin hydride (1.5 mL, 5.41 mmol)

was added dropwise over 60 min. After the mixture was stirred

at 0 °C for 15 min and at room temperature for 6 h, the mixture

was concentrated to yield a residue. The residue was purified

by column chromatography on silica gel (20 g) using hexanes

and EtOAc-hexanes (5%) to afford the vinylstannane 44

(1.696 g) as an oil in 95% yield. IR (KBr) 2955, 2927, 2871,

2853, 2230, 1740, 1607, 1590, 1571, 1474, 1457, 1436, 1417,

1376, 1313, 1292, 1247, 1217, 1161, 1074, 1048, 1074, 1022,

6-Tributylstannanyl-6-(5-chloro-2-methoxyphenyl)-hex-

5-enoic Acid Methyl Ester (51). Alkyne 49 (1.217 g, 4.63

mmol) was dissolved in THF (200 mL), and then tetrakis-

(triphenylphosphine)palladium (45 mg, 39 µmol) was added.

The mixture was cooled to 0 °C, degassed by gently bubbling

argon through for 15 min, and then tributyltin hydride (1.9

mL, 6.85 mmol) was added dropwise over 60 min. After the

mixture was stirred at 0 °C for 15 min and at room temper-

ature for 2 h, it was concentrated to yield a residue. The

residue was purified by column chromatography on silica gel

(45 g) using hexanes and EtOAc-hexanes (3%) to afford the

vinylstannane 51 (2.269 g) as an oil in 88% yield. IR (KBr)

2954, 2926, 2871, 2852, 1740, 1481, 1462, 1438, 1395, 1375,

1000, 960, 911, 875, 841, 804, 770, 697, 677 cm^-^{1 1}H NMR

;

(300 MHz, CDCl₃) δ 7.37 (dt, J ) 1.5 Hz, J ) 7.8 Hz, 1 H),

7.34 (q, J ) 7.8 Hz, 1 H), 7.14 (m, 1 H), 7.08 (dt, J ) 1.5 Hz,

J ) 7.5 Hz, 1 H), 5.75 (t, J ) 7.2 Hz, 1 H), 3.61 (s, 3 H), 2.20

(t, J ) 7.5 Hz, 2 H), 1.97 (q, J ) 7.5 Hz, 2 H), 1.64 (m, 2 H),

1.47-1.35 (m, 6 H), 1.28-1.16 (m, 6 H), 0.87-0.79 (m, 9 H);

¹³C NMR (75 MHz, CDCl₃) δ 173.7, 146.4, 144.6, 142.1, 131.3,

130.0, 128.9, 128.5, 119.0, 112.1, 51.4, 33.2, 29.3, 28.8, 27.2,

24.6, 13.6, 9.9; ESIMS m/z (rel intensity) 515.96 (M⁺, 31),

517.99 (M⁺, 49), 519.98 (M⁺, 61). Anal. (C₂₆H₄₁NO₂Sn) C, H,

N, Sn.

2-Bromo-4-chloro-1-methoxybenzene (47). A solution of

sodium hydroxide (836 mg, 20.9 mmol) in water (8.0 mL) was

added to a solution of 2-bromo-4-chlorophenol (45) (2.1 g, 9.92

mmol) and tetrabutylammonium bromide (336.4 mg, 1.03

mmol) in dichloromethane. Dimethyl sulfate (1.5 mL, 15.69

mmol) was added. The resulting mixture was stirred at room

temperature for 22 h and then 1 N aq HCl (about 2 mL) was

added to quench the reaction. The organic phase was sepa-

rated, and the aqueous phase was extracted with dichloro-

methane (2 × 15 mL). The combined organic phase was

washed with brine, dried over sodium sulfate, and concen-

trated to afford an oil. The crude product was purified by

column chromatography on silica gel (10 g) using EtOAc-

hexanes (5%) to afford the product 47 as a colorless oil (2.17

g) in 99% yield.^{28 1}H NMR (300 MHz, CDCl₃) δ 7.51 (d, J )

2.4 Hz, 1 H), 7.22 (dd, J ) 2.4 Hz, J ) 8.7 Hz, 1 H), 6.80 (d, J

) 8.7 Hz, 1 H), 3.86 (s, 3 H).

1

1290, 1240, 1173, 1128, 1079, 1030, 878, 804 cm^-1; H NMR

(300 MHz, CDCl₃) δ 7.04 (dd, J ) 2.4 Hz, J ) 8.7 Hz, 1 H),

6.80 (d, J ) 2.4 Hz, 1 H), 6.68 (d, J ) 8.7 Hz, 1 H), 5.70 (t, J

) 6.9 Hz, 1 H), 3.70 (s, 3 H), 3.59 (s, 3 H), 2.23 (t, J ) 7.5 Hz,

2 H), 2.04 (m, 2 H), 1.66 (m, 5 H), 1.40 (m, 6 H), 1.29-1.17

(m, 6 H), 0.85-0.76 (m, 9 H); ¹³C NMR (75 MHz. CDCl₃) δ

174.1, 153.9, 142.0, 141.0, 134.9, 127.7, 125.8, 125.0, 110.9,

55.2, 51.4, 33.3, 29.5, 28.9, 27.7, 27.3, 26.9, 24.7, 13.7, 10.3;

ESIMS m/z (rel intensity) 501.14 (M-Bu⁺, 100). Anal.

(C₂₆H₄₃ClO₃Sn) C, H, Cl, Sn.

Methyl 6-(Tributylstannyl)-6-[4-methoxy-5-methoxy-

carbonyl-3-methylphenyl]-hex-5-enoate (52). Aryl bromide

48 (2.25 g, 8.68 mmol), methyl 5-hexynoate (1.329 g, 10.54

mmol), and dichlorobis(triphenylphosphine)palladium(II) (307

mg, 0.437 mmol) were added to a flask under an argon

atmosphere. Triethylamine (6.5 mL) was added to the flask.

Cuprous iodide (168 mg, 0.88 mmol) was then added to the

flask. The reaction mixture was stirred at room temperature

for 0.5 h and heated at 80 °C for 21.5 h. The reaction mixture

was cooled to room temperature and filtered through a short

column of silica gel (5 g), and the column was washed with

ethyl acetate. The organic solution was concentrated. The

residue was purified by column chromatography on silica gel

(40 g), eluting with EtOAc-hexanes (2%) to afford the alkyne

50 as a crude red oil. The crude oil was dissolved in dry THF

(400 mL) and added to a flask under an argon atmosphere.

Tetrakis(triphenylphosphine)palladium(0) (100 mg, 0.0865

mmol) was added to the flask. The mixture was cooled to 0

°C, degassed by gently bubbling argon through for 20 min, and

then tributyltin hydride (3.6 mL, 12.98 mmol) was added

Methyl 5-Bromo-2-methoxy-3-methylbenzoate (48).

5-Bromo-3-methylsalicylic acid (46) (6.6 g, 28.57 mmol),¹³

potassium carbonate (19.2 g), and acetone (150 mL) were

added to an oven-dried 250 mL round-bottom flask equipped

with a stirring bar. Dimethyl sulfate (8.55 mL, 88.94 mmol)

Alkenyldiarylmethane HIV-1 NNRTIs

Journal of Medicinal Chemistry, 2005, Vol. 48, No. 19 6153

503 cm^-^{1 1}H NMR (300 MHz, DMSO-d₆) δ 12.22 (bs, 1 H),

7.90 (s, 1 H), 7.71 (s, 1 H), 2.39 (s, 3 H); ESIMS m/z (rel

intensity) 275.95 (MH⁺, 28); negative ion ESIMS m/z (rel

intensity) 274.10 (M-H⁺, 100). Anal. (C₈H₆INO₂) C, H, I, N.

dropwise over 110 min. After the mixture was stirred at room

temperature for 2 h, it was concentrated to yield a residue.

Solvent was removed in vacuo to yield a crude black oil. The

oil was purified by flash column chromatography using silica

gel (60 g) and a gradient eluant from 0 to 2% ethyl acetate in

hexanes to yield the product 52 as a colorless oil (4.64 g, 90%,

over two steps).^{13 1}H NMR (500 MHz, CDCl₃) δ 7.15 (d, J )

2.06 Hz, 1 H), 6.85 (d, J ) 2.06 Hz, 1 H), 5.69 (t, J ) 6.91 Hz,

1 H), 3.87 (s, 3 H), 3.79 (s, 3 H), 3.60 (s, 3 H), 2.26 (s, 3 H),

2.23 (t, J ) 7.68 Hz, 2 H), 2.04 (q, J ) 7.17 Hz, 2 H), 1.66 (q,

J ) 7.46 Hz, 2 H), 1.45-1.20 (m, 11 H), 0.86-0.69 (m, 16 H).

;

5-Iodo-2,7-dimethyl-benzo[d]isoxazol-3-one (58) and

5-Iodo-3-methoxy-7-methylbenzo[d]isoxazole (59). Iodo-

methane (0.34 mL, 5.46 mmol) was added to a mixture of 57

(746 mg, 2.7 mmol) and potassium carbonate (1.225 g, 8.86

mmol) in DMSO (5 mL). The resulting mixture was stirred at

room temperature for 1 day. Water (50 mL) was added to

quench the reaction. The mixture was extracted with ethyl

acetate (3 × 40 mL). The organic solution was washed with

brine (2 × 50 mL), dried over anhydrous sodium sulfate, and

concentrated to afford a residue. The residue was purified by

column chromatography on silica gel (25 g) using ethyl acetate

in hexanes (0-20%) to afford 58 (350 mg) as a white solid in

45% yield and 59 (298 mg) as white solid in 38% yield. The

product 58 was recrystallized with ethyl acetate and hexanes

to afford crystals for X-ray crystallography: mp 107-108 °C.

IR (KBr) 1694, 1398, 1368, 1297, 1267, 1218, 1007, 966, 871,

850, 831, 752, 705, 649, 595, 561, 549, 483 cm^-1; ¹H NMR (300

MHz, CDCl₃) δ 7.91 (s, 1 H), 7.61 (s, 1 H), 3.63 (s, 3 H); ¹³C

NMR (75 MHz, CDCl₃) δ 161.1, 158.2, 142.0, 130.2, 122.7,

118.2, 86.1, 32.6, 13.7; ESIMS m/z (rel intensity) 289.94 (MH⁺,

100). Anal. (C₉H₈INO₂) C, H, I, N.

Methyl 5-Iodo-2-methoxybenzoate (54). To a solution of

5-iodosalicyclic acid (53) (25.20 g, 90.67 mmol) in dichloro-

methane (200 mL) was added tetrabutylammonium bromide

(3.1 g, 9.52 mmol). A solution of sodium hydroxide (14.66 g,

0.367 mol) in water (60 mL) was added, followed by an addition

of dimethyl sulfate (26 mL, 0.272 mol). The resulting mixture

was stirred at room temperature for 53 h. 1 N HCl was added

until the pH was about 5 to quench the reaction. The organic

phase was separated and the aqueous phase was extracted

with dichloromethane (60 mL). The combined organic solution

was washed with brine (80 mL), dried over anhydrous sodium

sulfate, and concentrated. The residue was purified by column

chromatography on silica gel (100 g) using hexanes and 1%

ethyl acetate in hexanes to afford the product 54 (20.02 g) as

a white solid in 76% yield: mp 57-57.5 °C (lit.²⁵mp 48-50

5-Iodo-3-methoxy-7-methylbenzo[d]isoxazole (59): mp

1

°C). H NMR (300 MHz, CDCl₃) δ 8.04 (d, J ) 2.1 Hz, 1 H),

79 °C. IR (KBr) 2921, 1603, 1546, 1481, 1453, 1422, 1407, 1366,

1311, 1260, 1228, 1205, 1038, 986, 951, 908, 866, 760 cm^-1

;

7.70 (dd, J ) 8.7, 2.4 Hz, 1 H), 6.73 (d, J ) 8.7 Hz, 1 H), 3.86

¹H NMR (300 MHz, CDCl₃) δ 7.76 (s, 1 H), 7.56 (s, 1 H), 4.13

(s, 3 H); ¹³C NMR (75 MHz, CDCl₃) δ 166.1, 162.8, 139.1, 127.0,

123.2, 115.9, 85.7, 57.5, 14.3; ESIMS m/z (rel intensity) 289.94

(MH⁺, 24). Anal. (C₉H₈INO₂) C, H, I, N.

(s, 6 H).

Methyl 3-Chloro-5-iodo-2-methoxybenzoate (55). A mix-

ture of the iodide 54 (4.331 g, 14.83 mmol) and SO₂Cl₂(5.1

mL, 61.58 mmol) was heated at 50 °C for 20 h and then cooled

to room temperature. It was poured into ice (20 g) and

extracted with CH₂Cl₂(3 × 80 mL). The CH₂Cl₂extracts were

combined, washed with brine, dried over Na₂SO₄, and evapo-

rated in vacuo. The residue was further purified by flash

chromatography on silica gel (50 g, hexanes and 3% EtOAc in

hexanes as eluent) and was recrystallized with ethyl acetate

and hexanes to afford white crystals (4.60 g, 95%): mp 48-

Determination of the Structure of 5-Iodo-2,7-dimeth-

yl-benzo[d]isoxazol-3-one (58) by X-ray Crystallography.

Data Collection. A colorless needle of C₉H₈INO₂having

approximate dimensions of 0.50 × 0.19 × 0.10 mm was

mounted on a glass fiber in a random orientation. Preliminary

examination and data collection were performed Mo K_aradia-

tion (λ ) 0.71073Å) on a Nonius KappaCCD equipped with a

graphite crystal, incident beam monochromator. Cell constants

for data collection were obtained from least-squares refine-

ment, using the setting angles of 6370 reflections in the range

2 < θ < 27°. The monoclinic cell parameters and calculated

volume are: a ) 4.1515(5), b ) 16.0162(12); c ) 14.1406(11)

Å, â ) 97.411(5)°, V ) 932.37(15)Å³. For Z ) 4 and FW )

289.07 the calculated density is 2.06 g/cm³. The refined

mosaicity from DENZO/SCALEPACK was 0.70° indicating

moderate crystal quality. The space group was determined by

the program ABSEN.²⁹From the systematic presences of: h0l

l ) 2n; 0k0 k ) 2n, and from subsequent least-squares

refinement, the space group was determined to be P2₁/c(# 14).

The data were collected at a temperature of 150(1)K. Data

were collected to a maximum 2θ of 55.7°.

1

48.5 °C (lit.⁷mp 41-43 °C); H NMR (CDCl₃) δ 7.97 (d, J )

2.1 Hz, 1 H), 7.83 (d, J ) 2.1 Hz, 1 H), 3.91 (s, 6 H).

2,N-Dihydroxy-5-iodo-3-methylbenzamide (56). A mix-

ture of ester 28 (2.0 g, 6.86 mmol), hydroxylamine hydrochlo-

ride (967 mg, 13.74 mmol), and potassium hydroxide (1.91 g,

30.0 mmol) in methanol (40 mL) was heated to reflux for 6 h

and then cooled to room temperature. The mixture was

acidified with acetic acid until the pH was about 6 and

concentrated to remove the solvents. The residue was mixed

with EtOAc (100 mL), and water (80 mL) was added to get a

clear solution. The organic solution was separated, and the

aqueous solution was extracted with EtOAc (2 × 50 mL). The

combined organic solution was washed with brine, dried over

anhydrous sodium sulfate, and concentrated to afford a white

solid residue, which was purified by column chromatography

on silica gel (35 g) using EtOAc-hexanes (0-20%) to afford

the product 56 (1.688 g) in 84% yield: mp 151-152.5 °C (dec).

¹H NMR (300 MHz, acetone-d₆) δ 12.60 (s, 1 H), 11.12 (s, 1

H), 8.61 (s, 1 H), 7.81 (d, J ) 1.8 Hz, 1 H), 7.59 (d, J ) 1.8 Hz,

1 H), 2.20 (s, 3 H); ESIMS m/z (rel intensity) 293.87 (MH⁺,

45); negative ion ESIMS m/z (rel intensity) 292.03 (M - H⁺,

100). Anal. (C₈H₈INO₃) C, H, I, N.

Data Reduction. A total of 6370 reflections were collected,

of which 2194 were unique. Lorentz and polarization correc-

tions were applied to the data. The linear absorption coefficient

is 33.6 /cm for Mo K radiation. An empirical absorption

correction using SCALEPACK³⁰was applied. Transmission

coefficients ranged from 0.623 to 0.715. Intensities of equiva-

lent reflections were averaged. The agreement factor for the

averaging was 3.7% based on intensity.

5-Iodo-7-methylbenzo[d]isoxazol-3-one (57). A solution

of carbonyldiimidazole (2.243 g, 13.83 mmol) in THF (40 mL)

was added to a boiling solution of 56 (2.022 g, 6.9 mmol) in

THF (20 mL). The resulting solution was then heated under

reflux for 2 h, cooled, and evaporated. The residue was mixed

with water to afford a precipitate. The precipitate was collected

and washed with water and then dissolved in ethyl acetate

(150 mL), washed with brine (3 × 50 mL) dried over Na₂SO₄,

and concentrated. The residue was recrystallized with ethyl

acetate to afford the product 57 (1.879 g) as a white solid in

99% yield: mp 232-233 °C. IR (KBr) 2927, 2760, 2672, 2613,

1726, 1702, 1608, 1564, 1510, 1465, 1384, 1345, 1296, 1260,

1198, 1176, 1122, 1019, 967, 742, 864, 806, 763, 721, 612, 559,

Structure Solution and Refinement. The structure was

solved using the structure solution program PATTY in

DIRDIF99.³¹The remaining atoms were located in succeeding

difference Fourier syntheses. Hydrogen atoms were included

in the refinement but restrained to ride on the atom to which

they are bonded. The structure was refined in full-matrix least-

2

squares where the function minimized was ∑w(|F_o| - |F_c| )²

and the weight w is defined as 1/[σ²(F_o) + (0.0384P)²

+

2

0.7511P] where P ) (F_o+2 F_c²)/3. Scattering factors were

taken from the “International Tables for Crystallography”.³²

2194 reflections were used in the refinements. However, only

2

the 1876 reflections with F_o>2σ(F_o) were used in, calculating

R1. The final cycle of refinement included 120 variable

6154 Journal of Medicinal Chemistry, 2005, Vol. 48, No. 19

Deng et al.

Reverse Transcriptase Inhibitors. J. Med. Chem. 1998, 41,

2076-2089.

(7) Cushman, M.; Casimiro-Garcia, A.; Williamson, K.; Rice, W. G.

Synthesis of a Non-Nucleoside Reverse Transcriptase Inhibitor

in the Alkenyldiarylmethane (ADAM) Series with Optimized

Potency and Therapeutic Index. Bioorg. Med. Chem. Lett. 1998,

8, 195-198.

(8) Casimiro-Garcia, A.; Micklatcher, M.; Turpin, J. A.; Stup, T. L.;

Watson, K.; Buckheit, R. W.; Cushman, M. Novel Modifications

in the Alkenyldiarylmethane (ADAM) Series of Non-Nucleoside

Reverse Transcriptase Inhibitors. J. Med. Chem. 1999, 42,

4861-4874.

(9) Xu, G.; Micklatcher, M.; Silvestri, M.; Hartman, T. L.; Burrier,

J.; Osterling, M. C.; Wargo, H.; Turpin, J. A.; Buckheit, R. W.,

Jr.; Cushman, M. The Biological Effects of Structural Variation

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parameters and converged (largest parameter shift was <0.01

times its su) with unweighted and weighted agreement factors

of:

R1 )

|F_o- F_c|/

F_o) 0.029

∑

2 2

R2 ) SQRT (

w(F_o²- F_c) /

w(F_o) ) ) 0.071

∑

The standard deviation of an observation of unit weight was

1.07. The highest peak in the final difference Fourier had a

height of 0.62 e/A³. The minimum negative peak had a height

of -1.58 e/A³. Refinement was performed on a LINUX PC

using SHELX-97.³³Crystallographic drawings were done using

programs ORTEP³⁴and PLUTON.³⁵

RT Inhibition Assay. Analysis of the effects of the

compounds on recombinant HIV-1 RT enzyme (p66/51 dimer)

was performed as previously described.³⁷Briefly, inhibition of

purified recombinant reverse transcriptase enzyme was mea-

sured by the incorporation of [³²P]GTP into poly(rC)/oligo(dG)

(rCdG) homopolymer template primers.⁵

In Vitro Antiviral Assays. Evaluation of the antiviral

activity of compounds against HIV-1_RFinfection in CEM-SS

cells was performed using the MTS cytoprotection assay as

previously described.³⁸Evaluation of the antiviral activity of

the compounds against HIV-1 strain IIIB and HIV-2 strain

(ROD) in MT-4 cells was performed using the MTT assay as

previously described.^13,39

In Vitro Hydrolytic Stability Study in Rat Plasma. The

alkenyldiarylmethanes 3, 4, 8-11, 14-18, 20, 21 (4.3-9.3 mg)

(1,1-diphenylethylene (2.1-5.1 mg) or benzophenone (2.1 mg)

as internal standard) were tested for their hydrolytic stability,

utilizing rat plasma in vitro using methods as previously

described.¹³

(10) Xu, G.; Loftus, T. L.; Wargo, H.; Turpin, J. A.; Buckheit, R. W.;

Cushman, M. Solid-Phase Synthesis of the Alkenyldiaryl-

methane (ADAM) Series of Non-Nucleoside Reverse Tran-

scriptase Inhibitors. J. Org. Chem. 2001, 66, 5958-5964.

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W., Jr.; Cushman, M. Synthesis of Alkenyldiarylmethane (ADAM)

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Non-Identical Aromatic Rings. Bioorg. Med. Chem. 2002, 10,

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spray Ionization. Rapid Commun. Mass Spectrom. 2003, 17 ,

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Cushman, M. Design, Synthesis, Anti-HIV Activities, and

Metabolic Stabilities of Alkenyldiarylmethane (ADAM) Non-

nucleoside Reverse Transcriptase Inhibitors. J. Med. Chem.

2004, 47, 3149-3162.

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Acknowledgment. This investigation was made

possible by Grant RO1-AI-43637, awarded by the Na-

tional Institutes of Health, DHHS. This research was

conducted in a facility constructed with support from

Research Facilities Improvement Program Grant Num-

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Resources of the National Institutes of Health.

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Supporting Information Available: Elemental analyses

of compounds 3, 4, 7-22, 25, 30-32, 34-36, 41-44, 49, 51,

56-59. X-ray crystal structures of 22 and 58 in cif format,

and elemental analyses. This material is available free of

charge via the Internet at http://pubs.acs.org.

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JM050452S

Article Doi

Synthesis, anti-HIV activity, and metabolic stability of new alkenyldiarylmethane HIV-1 non-nucleoside reverse transcriptase inhibitors

DOI: 10.1021/jm050452s

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