L-1-Methylproline Monohydrate

The title compound, C₆H₁₁NO₂.H₂O, crystallizes in the zwitterion form with methyl and carboxyl substituents anti to each other. The pyrrolidine ring displays the unusual half-chair conformation C₂—C^δ-endo (N-exo). In the crystal, symmetry related mol­ecules form zigzag chains extending along the a axis. Water molecules connect pairs of these chains by forming two hydrogen bonds.