Functionalization of the position 5 of thiopyran fragment of 4-(diethoxyphosphoryl)-4,7-dihydro-5 Н-thiopyrano[3,4-b]furan

Abstract

Alkaline hydrolysis of ethyl 4-(diethoxyphosphoryl)-4,7-dihydro-5 Н -thiopyrano[3,4- b ]furan-5-carboxylate proceeded selectively at the ester group. The acid obtained formed the corresponding acid chloride when treated with thionyl chloride. The acid chloride was used for acylation of glycine, α- and β-alanine esters. Under the conditions of phase transfer catalysis this acid chloride formed acyl azide which under mild conditions undergoes rearrangement to isocyanate. The latter reacted with primary amines to give ureas, and with the amino acid esters in forms ureidoesters. Reducing of acid chloride with sodium borohydride led to the corresponding alcohol. It was converted to chloride which in the reactions with sodium azide and iodide gives usual substitution products. When treated with potassium thiocyanate it formed thiocyanate. Iodide in the reaction with triethyl phosphite gave the corresponding phosphonate. Oxidation of alcohols with Collins reagent and acetic acid-DMSO system was studied.