Cyclic α-amino acids as precursors for synthesis of 2-amino-3-hetarylpyrrolin-4-ones and their spiro derivatives

Abstract

a-Aminoisobutanoic acid and some representatives of cyclic a-amino acids were converted to corresponding 1-phthalimido-and N-trifluoroacylated acid chlorides. Treatment of 2-(1H-benzimidazol-2-yl)acetonitrile with 1-phthalimidoacid chlorides in DMF unexpectedly gaveOn the other hand, the reaction of hetarylacetonitriles with N-trifluoroacylated acid chlorides gave the desired (3-cyano-2-oxo-3-hetarylpropyl)-2,2,2-trifluoroacetamides that upon detrifluoroacetylation provided the target 2-amino-3-hetarylpyrrolin-4-ones. The acylation of benzoimidazolylaminopyrrolinones by benzoyl chloride leads to formation of 3-benzoyl-2,3-dihydro-5-phenyl-1H-benzo [4,5]imidazo [1,2-c] pyrrolo[3,2-e]pyrimidin-1-ones.