M. Aljazrozic et al., THE TRANSFORMATIONS OF 4-HETEROARYLAMINOMETHYLENE-5(4H)-OXAZOLONES INTO DEHYDROPEPTIDE DERIVATIVES, Journal of heterocyclic chemistry, 32(5), 1995, pp. 1605-1611
Phenyl-4-heteroarylaminomethylene-5(4H)-oxazolones 3, which were prepa
red from the corresponding N,N-dimethyl-N'-heteroarylformamidines 1 an
d hippuric acid 2 in acetic anhydride, react with amino acids giving d
ehydropeptide derivatives 4, 5, and 6 as products. Dehydration of N-pr
otected peptides 7-10, containing glycine at the C-terminal, followed
by the reaction with formamidines 1 gave ituted-4-heteroarylaminomethy
lene-5(4H)-oxazolones 11-14.