Mahmoud A. El-Gendy

Design, synthesis and molecular modeling study of acylated 1,2,4-triazole-3-acetates with potential anti-inflammatory activity

The present investigation is concerned with the synthesis of different acylated 1,2,4-triazole-3-acetates with the objective of discovering novel and potent anti-inflammatory agents. Structures of the synthesized compounds were elucidated by spectral and elemental analyses. The obtained compounds were evaluated for their anti-inflammatory activites as well as gastric ulcerogenic effects and acute toxicity. Results showed that 1-acylated-5-amino-1,2,4-triazole-3-acetates 3a-e showed higher anti-inflammatory activity than the corresponding 5-acylamino derivatives 4a-e in carageenan-induced rat paw edema test with low gastric ulcerogenicity compared with indomethacin. Furthermore, molecular modeling studies were performed in order to rationalize the obtained biological results.

Synthesis and Three-dimensional Qualitative Structure Selectivity Relationship of 3,5-Disubstituted-2,4-Thiazolidinedione Derivatives As COX2 Inhibitors

In our effort for synthesis of selective COX2 inhibitors, certain new 2,4-thiazolidinedione derivatives were synthesized. It necessitates preparation of potassium salt of 2,4-thiazolidinedione 2, which condensed with intermediate 4a. The resulting 3-[2-(4-methylphenyl)-2-oxo-1-phenylethyl]-2,4-thiazolidinedione 8 was condensed with appropriate aldehyde to afford compounds 10a, 10i-l, 10o and 10p. Compounds (9a-l, 10a-n, 10p, 11 and 12) were obtained through the preparation of 5-arylmethylidene-2,4-thiazolidinediones 6a-p and reaction of its potassium salt 7a-p with compounds 4a, 4b, and 5. Some compounds displayed significant analgesic activity as compared to reference standards. The anti-inflammatory activity of the synthesized compounds revealed that intermediate 8 and compounds 9c, 10c and 10d showed good results. Compound 10c produced no significant mucosal injury. HipHop methodology of Catalyst program was used to build up hypothetical model of selective COX2 inhibitors followed by fitting the synthesized compounds to this model. Compounds 10c and 10d were suspected to be promising selective COX2 inhibitors. Also, compounds (6c, 8, 9a,c,d,k, 10a,c,d,k, 11 and 12) were docked into COX1 and COX2 X-ray structures, using DOCK6 program. Docking results suggested that several of these derivatives are active COX inhibitors with a significant preference for COX2.

Design, synthesis and evaluation against Mycobacterium tuberculosis of azole piperazine derivatives as dicyclotyrosine (cYY) mimics

Three series of azole piperazine derivatives that mimic dicyclotyrosine (cYY), the natural substrate of the essential Mycobacterium tuberculosis cytochrome P450 CYP121A1, were prepared and evaluated for binding affinity and inhibitory activity (MIC) against M. tuberculosis. Series A replaces one phenol group of cYY with a C3-imidazole moiety, series B includes a keto group on the hydrocarbon chain preceding the series A imidazole, whilst series C explores replacing the keto group of the piperidone ring of cYY with a CH2-imidazole or CH2-triazole moiety to enhance binding interaction with the heme of CYP121A1. The series displayed moderate to weak type II binding affinity for CYP121A1, with the exception of series B 10a, which displayed mixed type I binding. Of the three series, series C imidazole derivatives showed the best, although modest, inhibitory activity against M. tuberculosis (17d MIC = 12.5 μg/mL, 17a 50 μg/mL). Crystal structures were determined for CYP121A1 bound to series A compounds 6a and 6b that show the imidazole groups positioned directly above the haem iron with binding between the haem iron and imidazole nitrogen of both compounds at a distance of 2.2 Å. A model generated from a 1.5 Å crystal structure of CYP121A1 in complex with compound 10a showed different binding modes in agreement with the heterogeneous binding observed. Although the crystal structures of 6a and 6b would indicate binding with CYP121A1, the binding assays themselves did not allow confirmation of CYP121A1 as the target.