Stable Thioaldehydes : Synthesis, Structure Assignment, and Stability of 6-Amino-5-thioformyluracils.

Abstract Stable 6-amino-5-thioformyluracils 3a-e were synthesized starting from 6-amino-1,3-disubstituted uracils 1a-e in 23–98 % yields. According to the x-ray crystal structure, although the thioaldehyde 3c possesses reasonable double-bond character of the C=S bond, the length of C=S bond of the thioaldehyde 3c is longer than those of the kinetically stabilized thioaldehydes due to the mesomeric effect of the 6-amino group.