Hafez M. El-Shaaer

Synthesis, antimicrobial activity and bleaching effect of some reaction products of 4-oxo-4H-benzopyran-3-carboxaldehydes with aminobenzothiazoles and hydrazides

The synthesis of the biologically active novel systems derived from reaction of 3-formylchromones with three types of amino derivatives, 6-R2-2-aminobenzothiazoles, 6-amino-2-R3-thiobenzothiazoles and hydrazide derivatives (derived from cyanoacetic, isonicotine, salicylic and gallic acids) was carried out. The structures of the prepared compounds have been proved by elemental analysis, 1H NMR and IR spectra. Antimicrobial activity was studied against the following microorganisms--bacteria G+ (Staphylococcus aureus 29/58, Bacillus subtilis 18/66), G- (Escherichia coli 326/71, Pseudomonas aeruginosa); yeasts: Candida albicans, Saccharomyces cerevisiae; moulds: Microsporum gypseum, Aspergillus niger, Scopulariopsis brevicaulis; and against typical and atypical mycobacteria: Mycobacterium tuberculosis (H37Rv), Mycobacterium kansasii (PFG 8), Mycobacterium avium (My 80/72), Mycobacterium fortuitum (1021). The hereditary bleaching effect on the plastid system of Euglena gracilis, a unique phenomenon of the biological activity of chromone derivatives, is reported. The bleaching test on E. gracilis is used for detecting extranuclear mutations.

Synthesis of Bioactive 4-Oxo-4H-Chromenes Bearing Heterocyclic Systems from Hydrazonecarbodithioic Acid and Thiocarbohydrazone

Condensation 4-oxo-4H-chromene-3-carboxaldehydes (1a,b) with acid hydrazine-carbodithioic acid and/or thiocarbohydrazide afforded hydrazonecarbodithioic acid 2, monothiocarbohydrazone 3a,b and bisthiocarbohydrazone 4, respectively. Heterocyclization of 2–4 via reaction with oxygen, sulfur and/or halogen reagents in different media yielded pyridazinethione 5; 1,3-thiazoles 7; pyrazoles 9–12; 1,2,4-thiadiazoles 8,13,14, and 23; 1,2,4-triazolethiones 15–17; 1,2,4-triazinethiones 18–22; imidazolethione 24 and pyrimidinethione 25 derivatives. Antifungal activity was screened for some the new synthesized compounds. Formulations of all products have been deduced by elemental analysis and spectral data (IR, 1H NMR and Mass spectroscopy).

FUSED CYANOPYRIMIDINES: PART II SYNTHESIS AND REACTIONS OF FUSED CYANOPYRIMIDINE DERIVATIVES AS AFFECTING ENZYMATIC AGENTS

Abstract Some new fused heterobicyclic systems, such as thiazolo[3,2-a]-pyrimidin-5-one (3), 2,3-tetrahydrothiazolo[3,2-a]pyrimidin-5-one (5), 2,4-tetrahydrothiazino[3,2-a]pyrimidin-3,6-dione (6), 3-dihydrothiazino[3,2-a]pyrimidin-2,4,6-trione (7), 3-arylidenethiazino[3,2-a]pyrimidin-2,4,6-trione (8) and/or the related nitrogen compounds, such as 2,3-tetrahydroimidazolo[3,2-a]-pyrimidin-5-one (9), 1-aryl-2,3-tetra-hydroimidazolo[3,2-a]pyrimidin-5-one (11), quinazolino[3,2-a]-pyrimidin-6,8-dione (12) and 3-mercapto-1,2,4-triazolo[4,3-a]pyrimidin-5-one (14) have been synthesized by the interaction of 2-mercapto-4-arylidene-5-cyanopyrimidin-6(1H)one (1) with α,β-bifunctional nitrogen, oxygen and/or sulfur compounds. The structures have been characterized by elemental analyses, IR, UV, 1H NMR and mass spectral data. Some newly prepared compounds revealed a moderate effect on the activity of cellobiase produced by Aspergillus nidulans.

Synthesis and Reactions of New 4-Oxo-4H-benzopyran-3-carboxaldehydes Containing Hydroxy Groups or 2-Oxopyran Cycles

The synthesis of eight hydroxy- and 2-oxopyranochromone-3-carboxaldehydes 3, 5 and their reactions with 2-hydroxyaniline, 2,4-dinitrophenylhydrazine and 2-benzothiazolylhydrazine were investigated. Products were confirmed by IR, NMR spectral and elemental analysis data. The semi-empirical AM1 quantum-chemical method has been used to study optimal geometries and heats of formation of synthesized 3-formylchromones.

Evaluation of Effect of Microwave Irradiation on Syntheses and Reactions of Some New 3-Acyl-methylchromones

The 3-Acyl-2-R-methylchromones (R = H, ArO, C6H4(CO)2N) were prepared in good yields by different methods from 2-hydroxyaroylacetone derivatives. Some subsequent reactions of these compounds with hydroxylamine and 3-formylchromones are described. The effect of microwave irradation on some condensation reactions was studied.

Synthesis and Reactions of Some 2-Methyl-4-oxo-4 H -1-benzopyrans and 2-Methyl-4-oxo-4 H -1-benzo[ b ]-thiopheno[3,2- b ]pyrans

2-Methyl-4-oxo-4 H -1-benzothiophenopyran ( 3 ) was prepared together with its thio analoge 4 . A facial conversion of 3 and some 2-methyl-4-oxo-4 H -1-benzopyrans ( 5 ) to 2-oxo-2 H -1-pyrans and 2(1 H )-pyridones was achieved under the influence of some carbon nucleophiles (NCCH 2 R). The behavior of the active methyl group of 3 or 5 toward benzaldehyde, ethyl oxalate, and phthalic anhydride was discussed, where the styryl derivatives 12 , 16 , the pyruvates 20 , 24 , and phthalide 33 were obtained, respectively. Bromination of 12 , 16 , followed by reaction with phenylenediamine and 2-aminothiophenol, led to the formation of quinoxalinyl and benzothiazinyl derivatives. Treatment of the pyruvic acids derived from 20 , 24 with phenylenediamine gave quinoxalinyl derivatives, but with benzaldehyde and aniline, atophan analogues were formed. In addition, compound 33 was isomerized to the corresponding phthalone derivative. Compound 3 was allowed to react with amines, hydrazine, hydroxylamine, thiourea, and guanidine, where opening of the pyrone ring was observed and alkylaminobutene, pyrazole, isoxazole, aminopyrimidine, thioxopyrimidine derivatives were obtained, respectively.

Reaction of 2-imino-2H-chromene-3-carboxamide with phosphorus sulfides: Synthesis of novel 2-sulfido-2,3-dihydro-4H-chromeno[2,3-d][1,3,2]diaza-phosphinines

Abstract Novel 2-sulfido-2,3-dihydro-4H-chromeno[2,3-d][1,3,2]diazaphosphinines are obtained in a simple one-pot procedure via treatment of 2-imino-2H-chromene-3-carboxamide with various phosphorus sulfides. Possible reaction mechanisms are proposed. The structure of the obtained products is confirmed by elemental analyses and spectral tools. Graphical Abstract