Magda A. Barsy

Microwave-assisted reactions: Part 2 One-pot synthesis of pyrimido[1,2-a]pyrimidines

A simple route for the synthesis of pyrimido[1,2-a]pyrimidines by condensation of 2-aminopyrimidine 1, aromatic aldehydes 2 and active methylene reagents 3 under microwave irradiation is reported.

NOVEL SYNTHESIS OF POLYFUNCTIONALISED BIARYL, PYRIDAZINE, AND PHTHALAZINE DERIVATIVES

A variety of new biaryl, pyridazine and phthalazine derivatives have been synthesized by reacting ethyl 2-arylhydrazono-3-oxobutyrate with α,β-unsaturated nitriles including acrylonitrile and crotononitrile derivatives.

Ring-Opening Ringn-Closure of 4-Phenyl-1,2-Dithiole-3-Thione. Novel Synthesis of Thio-Pyrano[2,3-B]Pyrane Derivatives

Abstract 1,2-Dithiole-3-thione (1) react with a number of selected α, β-unsaturated nitriles to give thiopyrano(2,3-b]pyrane (3 a,b) and/or pyridine (3c) derivatives in excellent yields. The products result from a ring-opening ring-closure reaction and a concomitant nucleophilic attack at the 5-position of the dithiole ring.

Ring opening-ring closure of 4-phenyl-1,2-dithiole-3-thione: Reaction with α, β-unsaturated nitriles

4-Phenyl-1,2-dithiole-3-thione ( 1 ) reacts with unsaturated nitriles including g -arylacrylo-nitrile and crotonitrile derivatives. Thiinthione ( 8 ) was the only product obtained in all cases, which resulted from initial nucleophilic attack at C-5 of the dithiole ring. On the other hand compound ( 1 ) reacted with bromine followed by some selected amino- f , g -unsaturated nitriles to afford isothiazolo[3,2-b]-[1,3]thiazine derivatives mainly from nucleophilic attack at either C-3 or ring sulfur atom.

Photoinduced reaction of polyfunctional nitroaromatics: photoreduction versus photosubstitution reaction of nitrobenzylidene malonic derivatives with triethylamine

Broad band irradiation of nitrobenzylidene malonic derivatives in benzene solution in the presence of triethylamine leads to two types of photochemical reactions, photoreduction of the nitro group predominantly, and photosubstitution of the cyano group. The formation of the products is suggested to proceed through a radical ion pair via initial electron transfer, followed by proton transfer, and finally through a sequence of ground state reactions leading to different products.

New Routes for Novel Pyrazolo[3,4- b ][1,6]-naphthyridine, Pyrazolo[3,4- b ]pyridine and Pyrazolo[3,4:2,3]pyrido[6,1- a ]benzimidazole Derivatives

Pyrazolo[3,4-b][1,6]naphthyridine, pyrazolo[3,4-b]pyridine and pyrazolo[3,4:2,3]pyrido[6,1-a]benzimidazole derivatives are synthesized starting from the isomeric 3-substituted 5-chloro-1-phenylpyrazole-4-carbaldehyde.

Ring opening–ring closure of 4-phenyl-1,2-dithiole-3-thione: convenient route to novel thiinethione derivatives by the reaction with active methylene nitriles

4-Phenyl-1,2-dithiole-3-thione (1) reacts with active methylene nitriles in the presence of triethylamine to afford fused and isolated thiine derivatives, mainly from initial nucleophilic attack of methylene group at C-5 of the dithiole ring.

Studies on Polyfunctionalised Heteroaromatics: a Novel Synthesis of Polyfunctionalised Pyridine, Pyridazine and Pyrido[2,3-c]pyridazine Derivatives

Ethyl 2-arylhydrazono-3-oxobutyrates react with α,β-unsaturated nitriles to afford either pyridopyridazine or pyridine derivatives depending on the structure of the unsaturated nitrile.