Balkis Al-Saleh

Studies with condensed thiophenes: reactivity of condensed aminothiophenes toward carbon and nitrogen electrophiles

The condensed aminothiophenes 5–7a,b react with 1,4-naphthoquinone in refluxing ethanol to yield products of addition followed by hydrogen sulfide elimination in a Diels–Alder type reaction. When the reaction is carried out under microwave irradiation a dipolar addition occurred affording products of substitution at C-l. Compounds 5–7a,b coupled with aromatic diazonium salts to yield arylazo derivatives 15 and 16 where coupling occurred at C-1. The condensed aminothiophenes 5–7a,b reacted with dimethylformamide dimethylacetal to yield amidines 17–19.

Studies with 2H pyranones: Synthesis of new 3-substituted-4-hydroxy-2H-pyran-2-ones

3-Acetyl-4-hydroxy-6-methyl-2H-pyran-2-one 1a condensed with N,N-dimethylformamide dimethyl acetal yielding the enaminone 3a. The latter reacted with a variety of reagents affording pyridine derivatives 11, benzofuranoylpyranes 14 and 17, pyranylpyranes 22, pyranylpyrazole 29a,b and pyranylisoxazole 33.

Synthetic approaches towards [1]benzopyrano [4,3-b]thieno[2,3-e]pyridines via intramolecular Diels-Alder reactions of 1,2,4-triazines

Efficient syntheses are reported of [1]benzopyrano[4,3-b]thieno[2,3-e]pyridines (20), by the application of an intramolecular Diels–Alder reaction employing the intermediate appropriately designed functionalised thieno [3,2-e][1,2,4]triazines.

Studies with Heteroaromatic Amines: the Reaction of SomeHeteroaromatic Amines with 1-Substituted3-Dimethylaminopropanones, Enaminones andCinnamonitriles†

Heteroaromatic amines react with 1-substituted 3-dimethylaminopropanones, with enaminones and with cinnamonitriles to yield azolopyrimidines or azolopyridines.

Synthesis of New Azoloazine Derivatives: New Routes to 1,2,4-Triazolo[4,3-a]pyrimidines, Pyrazolo[1,5a]pyridines and Pyrazolo[3,4-b]-pyridinones

Azoloazines are produced via the reaction of aminoazoles with enaminones, enaminonitriles and ethyl alkylidene cyanoacetate.