Synthesis of 1-Amino-2-naphthalenecarboxylic Acid Derivatives via the Intramolecular Cyclization of 4-(2-Cyanophenyl)-2-butenoic Acid Derivatives and Its Application to the One-Pot Preparation of Benzo[h]quinazoline-2,4(1H,3H)-diones

Abstract

Abstract The reaction of 2-(lithiomethyl)benzonitrile with 2-phenylthio-2-alkenoic acid derivatives in diglyme at −78 °C, followed by oxidation with sodium metaperiodate in aqueous MeOH at room temperature and the subsequent elimination reaction in refluxing toluene, gave 4-(2-cyanophenyl)-2-butenoic acid derivatives in moderate-to-fair overall yields. Intramolecular cyclization of these products using NaH in DMF at 0 °C gave 1-amino-2-naphthalenecarboxylic acid derivatives almost quantitatively. Successive treatments with an isocyanate without isolation of the aminonaphthalenecarboxylates under reflux afforded benzo[h]quinazoline-2,4(1H,3H)-diones in moderate-to-good yields.