2438 J ournal of Medicinal Chemistry, 1998, Vol. 41, No. 13
Notes
1
(2) Cynamon, M. H.; Klemens, S. P.; Chou, T.-S.; Gimi, R. H.; Welch,
J . T. Antimycobacterial Activity of a Series of Pyrazinoic Acid
Esters. J . Med. Chem. 1992, 35, 1212-5.
J ) 5.6 Hz), 9.21 (s, 1H). 14: yield 44%; H NMR (CDCl3) δ
2.10 (s, 3H), 3.69 (s, 2H), 7.75 and 8.82 (AA′BB′, 4H, J ) 5.7
Hz).
(3) Cynamon, M. H.; Gimi, R. H.; Gyenes, F.; Sharpe, C. A.;
Bergmann, K. E.; J an, H.-J .; Gregor, L. B.; Rapolu, R.; Luciano,
G.; Welch, J . T. Pyrazinoic Acid Esters with Broad Spectrum in
vitro Antimycobacterial Activity. J . Med. Chem. 1995, 38, 3902-
7.
(4) Speirs, R. J .; Welch, J . T.; Cynamon, M. H. Activity of n-Propyl
Pyrazinoate against Pyrazinamide Resistant Mycobacterium
tuberculosis: Investigations into Mechanism of Action of and
Mechanism of Resistance to Pyrazinamide. Antimicrob. Agents
Chemother. 1995, 39, 1269-71.
(5) Yamamoto, S.; Toida, I.; Watanabe, N.; Ura, T. In Vitro Anti-
mycobacterial Activities of Pyrazinamide Analogues. Antimicrob.
Agents Chemother. 1995, 39, 2088-91.
(6) Heifets, L. B.; Flory, M. A.; Lindholm-Levy, P. J . Does Pyrazinoic
Acid as an Active Moiety of Pyrazinamide Have Specific Activity
against Mycobacterium tuberculosis? Antimicrob. Agents Chemoth-
er. 1989, 33, 1252-4.
(7) Butler, W. R.; Kilburn, J . O. Susceptibility of Mycobacterium
tuberculosis to Pyrazinamide and its Relationship to Pyrazina-
midase Activity. Antimicrob. Agents Chemother. 1983, 24, 600-
1.
(8) Heym, B.; Zhang, Y.; Poulet, S.; Young, D.; Cole, S. T. Charac-
terization of the KatG Gene Encoding a Catalase-Peroxidase
Required for the Isoniazid Susceptibility of Mycobacterium
tuberculosis. J . Bacteriol. 1993, 175, 4255-9.
(9) Kobayashi, S.; Nakano, M.; Goto, T.; Kimura, T.; Schaap, A. P.
An Evidence of the Peroxidase Dependent Oxygen Transfer from
Hydrogen Peroxide to Sulfides. Biochem. Biophys. Res. Commun.
1986, 135, 166-71.
(10) McManus, J . M.; Herbst, R. M. Tetrazole Analogues of Pyridi-
necarboxylic Acids. J . Org. Chem. 1959, 24, 1462-3.
(11) Kushner, S.; Dalalian, H.; Sanjurjo, J . L.; Bach, F. L., J r.; Safir,
S. R.; Smith, V. K., J r.; Williams, J . H. Experimental Chemo-
therapy of Tuberculosis. II. The Synthesis of Pyrazinamides and
Related Compounds. J . Am. Chem. Soc. 1952, 74, 3617-21.
(12) Butler, R. N. Tetrazoles. In Comprehensive Heterocyclic Chem-
istry; Katriztky, A. R., Rees, C. W., Potts, K. T., Eds.; Pergamon
Press Inc.: New York, 1984; Part 4A, Vol. 5, pp 791-838.
(13) Freedman, H. H.; Fox, A. E.; Shavel, J ., J r.; Morrison, G. C.
Oxisuran: A Differential Inhibitor of Cell Mediated Hypersen-
sitivity. Proc. Soc. Exp. Biol. Med. 1972, 139, 909-12.
(14) Alvarez-Ibarra, C.; Cuervo-Rodrigues, R.; Fernandes-Monreal,
M. C.; Ruiz, M. P. Synthesis, Configurational Assignment, and
Conformational Analysis of â-Hydroxy Sulfoxides, Bioisosteres
of Oxisuran Metabolites, and Their O-Methyl Derivatives. J .
Org. Chem. 1994, 59, 7284-91.
2-(Meth ylth ioa cetyl)p yr a zin e, 15. R-Bromoacetylpyra-
zine was prepared from acetylpyrazine by bromination in
glacial acetic acid at 50 °C. The crude product was chromato-
graphed on silica gel with a CH2Cl2/EtOAc mixture; 1.18 g (5.9
mmol) of this material was dissolved in 4 mL of MeOH, and a
solution of 413 mg (5.9 mmol) of sodium methylthiolate in 4
mL of MeOH was added at room temperature. After 1 h 10
mL of water was added, and the product was extracted with
CH2Cl2. The crude product was chromatographed on silica gel
with a CH2Cl2/MeOH mixture. Recrystallization from hexanes
gave the product as pale-yellow crystals: yield 25%; 1H NMR
(CDCl3) δ 2.15 (s, 3H), 3.90 (s, 2H), 8.65 (s, 1H), 8.75 (s, 1H),
9.32 (s, 1H).
Gen er a l P r oced u r e for th e P r ep a r a tion of th e 4-Su b-
stitu ted 7-Aza cou m a r in s 17-19. 4-Hydroxy-7-azacoumarin
was obtained according to Dejardin and Lapiere;18 3.3 mmol
of triethylamine was added to a suspension of 3.0 mmol of 16
in 15 mL of CH2Cl2. After the starting material was dissolved
completely, 10 mL of petroleum ether was added, and the
mixture was cooled on an ice bath; 3.6 mmol of acetyl chloride
or benzoyl chloride in 3 mL of cold petroleum ether was added
slowly. The resulting slurry was stirred for 30 min, then the
ice bath was removed, and stirring was continued for another
30 min. The solvents were removed in vacuo, and the residue
was stirred with 50 mL of ice water. The crude product was
obtained by filtering. It was dried over CaCl2 and recrystal-
lized from EtOAc or EtOAc/petroleum ether. For the synthesis
of 19: The reaction with ethyl chloroformate was carried out
at - 20 °C; 100 mL of cold diethyl ether was added to the
mixture which was then slowly brought to room temperature.
After filtration the residue was treated with water and
extracted with diethyl ether. The combined ethereal solutions
were dried, concentrated to 40 mL, and left in the freezer for
15 h. The solution was filtered; evaporation of the filtrate gave
the slightly yellow product. 17: yield 74% (EtOAc); 1H NMR
(CDCl3) δ 2.48 (s, 3H), 6.80 (s, 1H), 7.52 (d, 1H, J ) 5.1 Hz),
8.57 (d, 1H, J ) 5.1 Hz), 8.78 (s, 1H). 18: yield 86% (EtOAc/
PE); 1H NMR (CDCl3) δ 6.90 (s, 1H), 7.57-7.65 (m, 4H), 7.73-
7.77 (m, 1H), 8.20-8.26 (m, 1H), 8.59 (d, 1H, J ) 5.2 Hz), 8.83
1
(s, 1H). 19: yield 38%; H NMR (CDCl3) δ 1.46 (t, 3H, J )
7.2 Hz), 4.44 (q, 2H, J ) 7.2 Hz), 6.94 (s, 1H), 7.63 (d, 1H, J )
5.2 Hz), 8.58 (d, 1H, J ) 5.2 Hz), 8.78 (s, 1H).
Deter m in a tion of Biologica l Activity. The compounds
were tested for inhibition of M. tuberculosis H37Rv ATCC 27294
using the BACTEC 460 system as previously described.18
Percent inhibition was calculated as 1 - (growth index of test
sample/growth index of control) × 100. The minimum inhibi-
tory concentration is defined as the lowest concentration which
inhibited 99% of the inoculum.
(15) Russel, G. A.; Sabourin, E. T. â-Keto-Sulfoxides. IV. Conversion
into â-Keto Sulfides, Vinyl Ethers, and Enol Acetates. J . Org.
Chem. 1969, 34, 2336.
(16) Garc´ıa-Ruano, J . L.; Pedregal, C.; Rodriguez, J . H. Synthesis
and Conformational Analysis of some Oxisuran Metabolites and
their O-Methylderivatives. Tetrahedron 1987, 43, 4407-16.
(17) Dejardin, J .-V.; Lapiere, C.-L. Synthesis in the Domain of the
Azacoumarins III. Hydroxy-4-aza-5-coumarin and hydroxy-4-
aza-7-coumarin. Bull. Soc. Chim. Fr. 1979, 279-98.
(18) Collins, L. A.; Franzblau, S. G. Microplate Alamar Blue Assay
versus BACTEC 460 System for High Throughput Screening of
Compounds Against Mycobacterium tuberculosis and Mycobac-
terium avium. Antimicrob. Agents Chemother. 1997, 41, 1004-
9.
Ack n ow led gm en t. This work was funded by the
Arizona Disease Control Research Commission, Phoe-
nix, AZ, Contract 9617, and Intraagency Agreement
Y-02-AI-30123 with the National Institutes of Allergy
and Infectious Disease, National Institutes of Health.
The authors thank Anita Biswas for her reliable techni-
cal assistance in the determination of the bioactivities.
(19) Browner-Van Stratten, B.; Solinger, D.; Van de Westeringh, C.;
Veldstra, H. Tetrazole Analogues of Physiologically or Pharma-
cologically Active Carboxylic Acids. Recl. Trav. Chim. Pays Bas
1958, 77, 1129-34.
Refer en ces
(1) CDC. Tuberculosis Morbidity-United States, 1994. MMWR -
Morbidity and Mortality Weekly Report 1995, 44, 387-9 and 395.
J M9708745