L. N. Borisova

New method for the reduction of benzofurans

A new method for the reduction of benzofurans with potassium and sodium borohydrides in CF3COOH was developed. It is shown by gas-liquid chromatography and PMR spectroscopy that mixtures (∼2∶3) of the cis and trans isomers of dihydro derivatives of benzofuran are formed in the reduction. The mechanism of the reduction includes intermolecular transfer of a hydride ion to the protonated form of the benzofuran.

Synthesis of thieno[2,3-d]thia[1]pyrano[4,3-b]pyrrole derivatives

It is shown that 2-methyl-3-carbethoxy-4H,8H,5,6-dihydrothieno[2,3-d]thia[1]pyrano [4,3-b]pyrrole and 8-methyl-9-carbethoxy-10H,5,6-dihydrothieno[2,3-d]thia[1]chromeno[4,3-b]pyrrole and their S,S-dioxides, respectively, are obtained in the reaction of 2-methyl-3-carbethoxy-4-thienylhydrazine with tetrahydro-4-thiopyrone, tetrahydro-4-thiopyrone S, S-dioxide, 4-thiochromanone, and 4-thiochromanone S,S-dioxide in the presence of an acid catalyst.