Computational elucidation of the reaction mechanism for synthesis of pyrrolidinedione derivatives Nef-type rearrangement - cyclization reaction.

This paper reports a quantum chemical study of all stages of a one-pot synthesis of pyrrolidinedione derivatives from nitromethane and coumarin, which includes Michael addition, migration of an oxygen atom (Nef-type rearrangement), and cyclization to a pyrrolidine ring. The energy barrier of deprotonated nitromethane addition to coumarin is 21.7 kJ mol, while the barrier of proton transfer from the methylene to the nitro group in the nitromethyl group is notably higher, 197.

A new and efficient method for the synthesis of 3,4-disubstituted pyrrolidine-2,5-diones.

A newly found reaction for the synthesis of 3,4-disubstituted 1-hydroxy-pyrrolidine-2,5-diones from 3-substituted coumarins and nitromethane has been elaborated. The reaction involved a simple and convenient experimental procedure. The applicability of the rearrangement reaction is determined.

Esters of 1-coumarinylbenzylphosphonic acid-IR-spectroscopic and theoretical elucidation.

The IR-spectroscopic properties of three esters of 1-coumarinylbenzylphosphonic acid are elucidated both in solution and in solid-state. Linear-polarized IR-spectroscopy of oriented colloid suspensions in nematic host is used for experimental IR-characteristic band assignment in solid-state. Theoretical quantum chemical DFT calculations at B3LYP level of theory and 6-31++G** basis set are carried.