Reaction of Ethyl 3,3‐Diaminopropenoate with Isocyanates and Isothiocyanates

Abstract

Abstract The title compound 1 reacts with alkyl (or phenyl) isocyanates 2 in a molar ratio of 1:1 to give the N ‐monoadducts 3 which cyclize readily to yield the 6‐aminouracils 4 , whereas in a molar ratio of 1:2 mainly N,N ′‐bisadducts 6 and, in two cases, small amounts of C,N ′‐bisadducts 5 are formed. The N,N ′‐bisadducts 6 are extremely sensitive to water giving the ureido esters 7 , but can be converted into substituted uracils 8 under basic conditions. The addition of 1 to isothiocyanates 9 yields mainly the C ‐monoadducts 10 and, as minor products, the 6‐amino‐2‐thiouracils 11 .