| abstract |
A process for producing a cyclic compound, i.e., a ß-lactam compound, represented by the following formula (3), which comprises the step of reacting a compound represented by the following formula (1) with 2 to 5 mol of a trialkyl phosphite represented by the formula (R5O)3P (wherein R5 represents ethyl, etc.) per mol of that compound and the step of heating the resultant reaction mixture in a diluent, characterized by including before the heating step a step in which the trialkyl phosphite remaining unreacted is completely removed from the reaction mixture. (1) → (2) → (3) In the formulae, X represents sulfur, etc.; Y represents nitrogen, etc.; n is 0 or 1; R1 represents optionally substituted C1-10 alkyl, etc.; R2 and R3 each represents an optionally substituted alkyl or heterocyclic group, etc.; R4 represents C1-6 alkenyloxy, etc.; and R1 and R2 may be bonded to form a ß-lactam ring, etc. |