Phthalic Anhydride → 1-Cyclohexyl-5-ethyl-5-phthalimidobarbituric acid

Participants

Reaction Steps

A mixture of about 500 mg (about 2 mmol) of 5-amino-1-cyclohexyl-5-ethylbarbituric acid available from 5-azido-1-cyclohexyl-5-ethylbarbituric acid as described in Guetschow, M. et al., Synthesis, 1999, 410-414 (incorporated herein by reference) and about 300 mg (about 2 mmol) of phthalic anhydride and about 20 mL of glacial acetic acid was refluxed for about 5 hours. The mixture was cooled to room temperature and the precipitate was filtered off. The precipitate was next washed with H2O and dried to give about 470 mg of 1-cyclohexyl-5-ethyl-5-phthalimidobarbituric acid (a yield of about 61%). The 1-cyclohexyl-5-ethyl-5-phthalimidobarbituric acid had a melting point of about 248 to about 253° C.

Provenance & Evidence