Process for producing cyclic compound

摘要

The present invention provides a method for preparing a beta-lactam compound of the following Formula (3), which comprises the step of reacting a compound of the following Formula (1) with a trialkyl phosphite represented by the formula (R⁵O)₃P (wherein R⁵ represents an ethyl group, etc.) in an amount of 2 to 5 moles per mole of the compound and the step of heating the resulting reaction mixture in a diluent, wherein said method is characterized by having the step of completely removing unreacted trialkyl phosphite from the reaction mixture prior to the step of heating. (wherein X represents S, etc., Y represents N, etc., n represents 0 or 1, R¹ represents an optionally substituted alkyl group containing 1 to 10 carbon atoms, etc., R² and R³ each represent an optionally substituted alkyl or heterocyclic group, etc., and R⁴ represents an alkenyloxy group containing 1 to 6 carbon atoms, etc., provided that R¹ and R² may together form a beta-lactam ring, etc.)