Design and synthesis of some substituted thiazolo[3,2-a]pyrimidine derivatives of potential biological activities.

In continuation to our previous work, thiazolopyrimidines 2a-x were synthesized through intramolecular cyclization of 2-phenacylthio-dihydropyrimidine hydrobromides 1a-x using polyphosphoric acid. On the other hand, thiazolo[3,2-a]pyrimidine-3-one 3 was coupled with aryldiazonium salts or condensed with isatin to afford compounds 4a-c or 5, respectively. Chemical structure of the target compounds was substantiated by IR, FT-IR, (1)H-, (13)C and DEPT-(13)C NMR, MS as well as microanalyses. Moreover, the lipophilicity of the target compounds is expressed as Clog P. The antimicrobial screening of the test compounds 2a-x, 4a-c and 5 revealed moderate activity in comparison to reference drugs. Compounds 2a-c, 2e, 2o and 2v showed a gradual increase in their anti-inflammatory activity reaching its maximum at 5 h compared to indomethacin. Furthermore, the analgesic activity of compounds 2a-c, 2e, 2o and 2v revealed a maximum activity after 5 h of injection compared to aspirin and the LD50 of compounds 2e and 2v was determined.

Synthesis and antimicrobial activity of certain new 1,2,4-triazolo[1,5-a]pyrimidine derivatives.

Certain new derivatives of 1,2,4-triazolo[1,5-a]pyrimidines were synthesized through the reaction of 1,2,4-triazolo[1,5-a]pyrimidine-7-ol with ethyl bromoacetate to afford the ethyl acetate ester, which upon hydrazinolysis gives the corresponding hydrazide. The hydrazide is the key intermediate which was used for the synthesis of the target compounds. The structures of the new compounds were assigned by spectral and elemental methods of analyses. The synthesized compounds were tested for their in vitro antibacterial and antifungal activities. Most of the tested compounds showed comparable results with those of ampicillin and fluconazole reference drugs.

Synthesis of 1-acyl-2-alkylthio-1,2,4-triazolobenzimidazoles with antifungal, anti-inflammatory and analgesic effects.

Some new derivatives of 1,2,4-triazolo[2,3-a]benzimidazoles were synthesized through the reaction of 1,2-diaminobenzimidazole with carbon disulfide. The resulting 1,2,4-triazolo[2,3-a]benzimidazole-2-thione intermediate reacted with one equivalent of the alkyl halide to give the corresponding 2-alkylthio derivative 3a-g. The latters were acylated to afford the 1-acyl-2-alkylthio-1,2,4-triazolo[2,3-a]-benzimidazole derivatives 4-10 in good yields. Structures of the new compounds were verified on the basis of spectral and elemental methods of analyses. Fourteen of the prepared compounds were tested for their possible antifungal activities. Most of the tested compounds showed activity against Candida albicans and Fusarium oxysporum comparable to that of fluconazole as a reference drug. Compounds 8a, 9a, and 10d are the most active ones against most of the fungi used. Compounds 3e, 4d, 5d, 6d, 7d, 8c, 8d, 9d, and 10d were tested for their anti-inflammatory and analgesic effects; most of these compounds showed potent and significant results compared to indomethacin. Moreover, ulcerogenicity and the median lethal dose (LD(50)) of the most active compound 8d were determined in mice; LD(50) was found to be 275 mg kg(-1) (i.p.).

Design, synthesis and molecular docking of some new 1,2,4-triazolobenzimidazol-3-yl acetohydrazide derivatives with anti-inflammatory-analgesic activities.

The present work describes the synthesis and evaluation of some new acetohydrazones, 1,3,4-oxadiazoles and 1,2,4-triazoles of 1,2,4-triazolo[1,5-a]benzimidazole as anti-inflamm atory-analgesic agents. Structure elucidation of these compounds was confirmed by IR, (1)H NMR, and mass spectrometry along with elemental microanalyses. Most compounds exhibited significant anti-inflammatory activity in comparison to indomethacin. Further, some compounds were tested for their analgesic effects where two compounds showed results comparable to indomethacin at 4 h interval. The most active anti-inflammatory and analgesic compounds (4c and 11a) were examined on gastric mucosa and didn't show any gastric ulcerogenic effect compared with the reference indomethacin. Moreover, LD50 of compounds (4c and 11a) were determined in mice; they were found non toxic up to 240 and 300 mg/kg (i.p.). Also, docking simulation of some compounds into COX active sites was studied.

Synthesis, anti-inflammatory, analgesic, and antibacterial activities of some triazole, triazolothiadiazole, and triazolothiadiazine derivatives.

This study is concerned with the synthesis of new 1,2,4-triazoles, 1,3,4-thiadiazoles, and 1,3,4-thiadiazines derivatives. Derivatives 3a-i were obtained by condensation of 4-amino-3-(4-pyridine)-5-mercapto-1,2,4-triazole 1 with the appropriate aldehyde. Compounds 4a-i were synthesized in a one pot reaction involving compounds 3a-i, formaldehyde, and morpholine. Condensation of compound 1 with the appropriate acids or 4-substituted phenacyl bromide gave compounds 6a-d and 8a-f respectively. The chemical structures of the newly synthesized derivatives were elucidated using different spectral and elemental methods of analysis. All compounds were evaluated for their anti-inflammatory activity and the most potent derivatives were tested for their analgesic activity using indomethacin as a reference drug. In addition, ulcerogenicity and LD(50) for the most active compounds were evaluated. Moreover, the antibacterial activities of the newly synthesized derivatives were investigated.

Synthesis and biological activities of new substituted thiazoline-quinoline derivatives.

5-Acyl-8-hydroxyquinoline-2-(3'-substituted-4'-aryl-2,3-dihydrothiazol-2'-ylidene)hydrazones, 5a-e to 10a-c, were prepared by the reaction of appropriate 5-acyl-8-hydroxyquinoline-4-substituted thiosemicarbazones 3a-e and phenacyl bromides 4a-e. Structures of the new compounds were verified on the basis of spectral and elemental analyses. Twenty-eight new compounds were tested for their possible antimicrobial activities. Most of the tested compounds showed weak to moderate antibacterial activity against most of the bacterial strains used in comparison with gatifloxacin as a reference drug. The test compounds showed weak to moderate antifungal activity against tested fungi in comparison with ketoconazole as a reference drug. On the other hand, the newly synthesized compounds were tested for their anti-inflammatory effects and most of them showed good to excellent anti-inflammatory activity compared to indomethacin. Moreover, ulcerogenicity and the median lethal dose (LD(50)) of the most active anti-inflammatory compounds 6b and 9e were determined in mice; they were non-toxic at doses up to 400 mg kg(-1) after i.p. administration.

Synthesis of new 3-substituted-5-(2-hydroxyethyl)-3,4,5,6-tetrahydro-2H-l,3,5-thiadiazine-2-thione derivatives with potential antimicrobial activity.

The purpose of this study is based upon design and synthesis of a new series of flexible molecules of 3,4,5,6-tetrahydro-2H-1,3,5-thiadiazine-2-thione (THTT) derivatives depending upon incorporation of 2-aminoethanol as a part of the polar moiety in this nucleus. Thirteen derivatives of 3-substituted-5-(2-hydroxyethyl)-3,4,5,6-tetrahydro-2H-1,3,5-thiadiazine-2-thione were synthesized by reaction of the appropriate alkyl, cycloalkyl, aralkyl amine, or glycine with carbon disulphide, formaldehyde, and 2-aminoethanol. The structures of the target compounds were elucidated using spectral methods as well as elemental analyses. A mass-spectrometry study was carried out on representatives of the synthesized derivatives. The title compounds were tested for their antibacterial activity in vitro against some gram positive and gram negative bacteria. The in-vitro antifungal activity was tested against dermatophytic, saprophytic, phytopathogenic, and antagonistic fungi. In most cases, the newly synthesized compounds 4-16 exhibited a considerable inhibitory effect on the growth of some of the tested organisms in comparison to that of ampicillin or muconazole as reference drugs. Moreover, the results indicated that the polar hydroxyethyl group at the N5- and the lipophilic one at the N3-positions are essential for the antimicrobial activity of the tested compounds.

Selenium-containing heterocycles: synthesis and pharmacological activities of some new 4-methylquinoline-2(1H) selenone derivatives.

Several selenolo[2,3-b]quinolines and pyrimido[4',5':4,5]selenolo[2,3-b]quinolines were prepared by annulations via reaction of NaSeH with 2-chloro-3-cyano-4-methylquinoline 1 followed by reactions with aromatic aldehydes, cycloalkanones, and acetic anhydride. Spectroscopic (IR, 1H-NMR, and MS) properties of the synthesized compounds are reported. Some selected compounds 5a, 7b, 7c, 8b-d, 9a, 11b, and 11d were investigated for their anti-inflammatory and analgesic activities; in addition, the most active compounds were tested for their ulcerogenicity and acute toxicity. Moreover, some of the test compounds 7c, 9a, 11b, and 11d were screened for their antibacterial and antifungal activities.

Synthesis of beta-hydroxypropanoic acid derivatives as potential anti-inflammatory, analgesic and antimicrobial agents.

A series of new 3-(substituted) 3-hydroxy-propanoic acid ethyl esters 1a-c, hydrazides 2a-c, thiosemicarbazides 3a-f, and semicarbazides 3g, 3h has been synthesized. Cyclization of compounds 3a-d in basic medium yielded 1,2,4-triazole-5-thiones 4a-d. On the other hand, reaction of hydrazides 2a-c with CS(2 )in basic medium afforded 1,3,4-oxadiazole-5-thiones 5a-c. All the synthesized compounds were characterized by their physical and spectral analyses data. The newly synthesized compounds were evaluated for their anti-inflammatory, analgesic, and antimicrobial activities. Compounds 1c, 3g, 4a, 4b, 4c, and 5c exhibited comparable anti-inflammatory activity to that of indomethacin and compounds 1c, 4c, and 5c were more analgesics than acetyl salicylic acid. Compounds 4b, 4c, and 5c showed superior GI safety profile (33.3%, 33.3% and 50.0% ulceration) than that of indomethacin (100% ulceration) at 100 mg/kg oral dose. Compounds 4b, 4c, and 5c were also non-toxic with a median lethal dose (LD(50)) up to 200 mg/kg. The antibacterial and antifungal screenings identified compounds 3c, 4b, 4d, 5a, and 5b as the most effective against a variety of tested microorganisms.

New 2H-tetrahydro-1, 3, 5-thiadiazine-2-thiones incorporating glycine and glycinamide as potential antifungal agents.

The new title derivatives (4b-h and 5a-i) were synthesized by reaction of the appropriate primary amine, carbon disulphide, and formaldehyde. These derivatives were prepared in order to study the effects of introducing polar groups at N3 or N5 or at both positions on the biological activity. The compounds were tested for their antifungal activity in vitro against pathogenic (Trichophyton rubrum and Candida albicans), phytopathogenic (Penicillum expansum, Trichoderma hazianum, and Fasarium oxysporum), and aflatoxin-producing (Aspergillus flavus) fungi. These compounds exhibited varied inhibitory effects on growth or sporulation of some tested fungal species.