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V J Lee

Publications and source records attributed to V J Lee.

4 recordsLinked to original sources
PubMed1991

Structural studies on tazobactam.

Tazobactam (3, C10H12N4O5S) is an effective inhibitor of bacterial beta-lactamases. It crystallizes with unit cell dimensions a = 10.230 (2) A, b = 14.396 (2) A, and c = 17.291 (2) A in space group P2(1)2(1)2(1). Compared to the related inhibitor sulbactam (2), which lacks the triazole ring, crystalline tazobactam exhibits very similar beta-lactam geometry and the same S(1) envelope conformation of the thiazolidine ring. However, in both independent molecules of 3 a triazole ring nitrogen atom accepts an intermolecular hydrogen bond; similar interaction by this moiety of 3 with a hydrogen-bond donor on the enzyme, which is impossible for 2, could account for its enhanced inhibitory power. Semiempirical molecular orbital calculations show pronounced negative potential there. Molecular mechanics supports the hypothesis that the carboxyl group can rotate freely and the triazole ring can "flip".

Computer Simulation↗
PubMed1989

Pyrido[3,4-e]-1,2,4-triazines and related heterocycles as potential antifungal agents.

The preparation and biological activities of a series of pyrido[3,4-e]-1,2,4-triazines, 1,2,4-triazino[5,6-c]quinolines, and related fused triazines are described. Methyl, amino, and acylamino substituents were placed in the pyridyl ring of the former system. Other structural modifications included various alkyl, cycloalkyl, substituted phenyl, and heterocyclic groups in the 3-position of these ring systems. In agar dilution assays, actives in this series inhibited strains of Candida, Aspergillus, Mucor, and Trychophyton species at MIC's of less than or equal to 16 micrograms/mL.

Antifungal Agents↗
PubMed1988

N-azamonobactams. 1. The synthesis of some 3-substituted N-azamonobactam derivatives.

Ring closure of the N-(tert-butyloxycarbonyl)-L-serine 2-(diphenylmethylene)hydrazide (10a) and the corresponding L-threonine derivative (10b) gave good yields of the beta-lactams 11a and 11b. Catalytic hydrogenation afforded the corresponding N-amino beta-lactams 12a and 12b. These compounds were then further transformed into 3-(S)-[[(2-amino-4-thiazolyl)-(Z)-(methoxyimino)acetyl]amino-2-oxo-1- azetidinyl]sulfamic acid analogs 18, 23, and 30a and 30b. None of these compounds exhibited any interesting biological activity.

Aztreonam↗