One-Pot Synthesis of 1-[(1-Phenyl-1-Dialkoxyphosphoryl)-Methyl]-2- Pyrrolidinone

A novel one-pot method to 1-[(1-phenyl-1-dialkoxyphosphoryl)-methyl]-2-pyrrolidinones (1a-c), where R=Me, Et, n-Hex, from the benzaldehyde (2), 4-aminobutyric acid (3) and dialkyl phosphite (4a-c) has been developed with reasonable 61-80% yields. Preparation of 4-{[(dimethoxyphosphoryl)-phenyl-methyl]- amino}-butyric acid (5) with high 85% yield is also described. Unexpected large 5JHP coupling constants 3.35, 3.37 and 3.15 Hz for compounds 1a-c, respectively, were observed.