Condensation of 4-benzamido-3-oxothiophan with acrolein. synthesis of 1-benzamido-4-hydroxy-6-thiabicyclo[3.2.1]-octan-8-one and 6-benzoyl-7-hydroxy-2-thia-6-azaspiro[4.4]-nonan-4-one

It is shown that acrolein adds to the 4 position (rather than to the 2 position) of 4-benzamido-3-oxothiophan under the influence of catalysts with basic character; the aldehyde group of the intermediate compound reacts with the amino group (if the reaction is carried out in chloroform) to give 6-benzoyl-7-hydroxy-2-thia-6-azaspiro[4.4]nonan-4-one or (if the reaction is carried out in a mixture of alcohol and chloroform) 1-benzamido-4-hydroxy-6-thiabicyclo-[3.2.1]octan-8-one as a result of intramolecular aldol condensation.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1620–1624, December, 1978.