PHOTOCHEMICAL ORGANIC SYNTHESES .I. PHOTOCHEMICAL ADDITION OF FORMAMIDE AND ANILINE TO CROTONIC ACID AND ITS ESTERS

In light-induced amidation of crotonic acid and its esters with formamide, yields of 60-77% of the 1-1-adducts were obtained. The distribution of the isomers of the 1-1-adducts was found to differ in the case of acid and ester. For example, crotonic acid yielded 2-, 3-, and 4-carbamoylbutyric acid in a ratio of 41:28:31, whereas in methyl crotonate the corresponding distribution was 8:41:51. It was confirmed that the γ-adduct is obtained by an addition reaction of formamide with the β,γ-unsaturated acid or ester produced by photoisomerization of the corresponding αβ-unsaturated compounds. The photoisomerization of crotonic acid and its esters was studied under varying conditions. A photochemical addition of aniline to crotonic acid and its esters gave different yields and distributions according to the conditions used. But it was found that the acid yields essentially a pure β-adduct, while the esters give an α-adduct as themain product. © 1968.