FromCorydalisincisa (+)-corynoline (2) was isolated together with (±)-corynoline (2'), which has been reported to be the major alkaloid. Optical resolution of 2' was achieved by resolving the corresponding diastereomeric esters with (-)-menthoxyacetic acid. The quaternary hydroxide of (+)-corynoline-O-acetate (3) was subjected to Emde degradation to afford the hydromethine base (5), the methiodide