Synthesis of Cypridina Luciferin and Related Compounds. II. : Synthesis of Etioluciferamine

Abstract

2-Amino-5-benzamidovaleramidine dihydrobromide (X) was synthesized from 4-benzamidobutyraldehyde diethyl acetal. Using the similar procedure reported in the previous paper for the preparation of 2-amino-5- (3-indolyl) pyrazine, X and 3-indolylglyoxal were condensed to afford benzoyletioluciferamine (XII), which in turn was hydrolyzed with methanolic KOH to give etioluciferamine (I). Synthetic I was proved to be identical with I obtained from natural luciferin.