Ashraf A. F. Wasfy

Simple synthesis of novel diphenylsulfapyrimidine acetates from chalcones and their antimicrobial activity

Given the significant low yield (19–43 %) in reported results on the cyclocondensation of sulfaguanidine acetate with chalcones, a careful reinvestigation was carried out. A new series of chalcones, bearing electron-attracting groups in the aromatic moiety, have been used as precursors in the synthesis of diphenylsulfapyrimidine acetates with good yield. All synthesized compounds were active against G+- and G−-bacteria, and fungi. Combination of substituents (Cl, OMe, NO2,etc.) enhanced antimicrobial activity. Derivative with two NO2 groups exhibits an activity comparable with sulfadiazine.

γ-Oxo Carboxylic Acids in Heterocyclic Synthesis IV. Synthesis of Some Pyridazines Containing Phthalyl and Tosyl Amino Acids Using Dcc as the Condensing Agent

The 3(2H)-oxo-, 3(2H)-thioxo- or 3-amino-pyridazine derivatives 4, 6 and 7 were coupled with N-phthalyl- or N-tosyl-amino acids in one-step using N,N′-dicyclohexyl-carbodiimide as the condensing agent to furnish the corresponding 3-(N-phthalyl- or N-tosyl-aminoacyl)pyridazine derivatives 8–10 respectively. Hydrazinolysis of the N-phthalyl derivatives in methanol yielded the corresponding unprotected derivatives 11–13. The antibacterial activities of the prepared compounds were tested. The authors are grateful to Dr. M. Amer, Botany Department, Faculty of Science, Benha University, for biological screening.

Studies on Quinazolines. Part III. Synthesis of Some Fused-Ring Cationic and Mesoionic Derivatives of the 1,3-Thiazolo[3,2-c]quinazoline Ring System

4-Allylthio-2-arylquinazolines 4a–c undergo cyclization by action of bromine to furnish 5-aryl-3-bromomethyl-2,3-dihydrothiazolo[3,2-c]quinazolin-4-ium bromide 5a–c. Compounds 5a–c undergo ring opening by action of water under acid catalysis to afford the corresponding dibromide derivatives 6a–c. Bromination of 3-allyl-2-aryl-4(3H)quinazolinethiones 7a–c leads to 5-aryl-2-bromomethyl-2,3-dihydrothiazolo[3,2-c]quinazolin-4-ium bromides 8a–c. However, 5-aryl-1,3-thiazolo[3,2-c]quinazolinium-3-olate 10a–c were prepared by the cyclodehydration of the corresponding thioglycolic acids 9a–c with Ac2O.

α,β-Unsaturated γ-Oxo Carboxylic Acids in Heterocylic Synthesis II. Behavior of 4-(5,5-Dioxodibenzothiophen-2-yl)-4-oxo-2-butenoic Acid Towards Carbon Nucleophiles under Michael Reaction Condition

4-(5,5-Dioxodibenzothiophen-2-yl)-4-oxo-2-butenoic acid ( 1 ) was condensed with compounds containing active methylene groups under Michael reaction conditions to form the Michael adducts 2a-c , 3a-c , and 4a-b . The behavior of Michael adduct towards the action of hydrazine hydrate was investigated. The compounds were tested for biological properties.

γ-Oxo Carboxylic Acids in Heterocyclic Synthesis, III. Synthesis of Biologically Active 4-Benzylamino-6-(5,5-dioxodibenzothiophen- 2-yl)-2,3,4,5-tetrahydropyridazin-3-ones

α-Benzylamino-β-(5,5-dioxodibenzothiophen-2-carbonyl)propionic acid (1) has been synthesized by treating the corresponding β-aroylacrylic acid with benzylamine in dry benzene. On treatment with hydrazine hydrate the keto acid 1 furnishes the corresponding pyridazinone derivative 2. The behaviour of 2 towards carbon electrophiles, namely, ethyl chloroacetate, acrylonitrile, formaldehyde and secondary amines (under Mannich reaction conditions), aromatic aldehydes and carbon nucleophiles, namely, POCl3/PCl3 and P2S5 has been investigated. The 3-chloropyridazine derivative 13 reacts with hydrazine hydrate to give the 3-hydrazino derivative 14. On treatment with ethyl acetoacetate and/or acetylacetone the hydrazine 14 undergoes cyclization to afford pyrazolone derivative 16 and 3-(3,5-dimethylpyrazol- 1-yl)pyridazine derivative 17, respectively. On reaction with acetylhydrazine in boiling butanol and/or sodium azide in DMF the 3-chloropyridazine derivative 13 affords the triazolo[4,3-b]pyridazine 18 and the tetrazolo[1,5-b]pyridazine 19, respectively. The anti-microbial activity of the synthesized derivatives has been investigated.

α,β-unsaturated 4-oxo acids in heterocyclic synthesis

Abstract3-(1,1-Dioxadibenzothien-4-oyl)acrylic acid (1) was condensed with compounds containing active methylene groups under Michael reaction conditions to furnish the Michael adducts (lactones,2a–c, lactams,3a–c, ketones4a, b). The behavior of these adducts toward the action of hydrazine hydrate were investigated. The compounds were tested for their biological properties.