Synthesis of β-lactams and transformation to β-amino acid ethyl ester derivatives: Theoretical calculations

Because of the important biological properties of beta-amino acids in the present work, two new beta-amino acid ethyl ester derivatives were synthesized, and their mechanistic occurrence was investigated. The title compounds were synthesized from related tetralone derivatives containing bromine and methoxy groups. Tetralone derivatives were reduced to their benzyl alcohol derivatives with NaBH4, followed by elimination with p-toluenesulfonic acid (pTSA) to give the desired 1,2-dihydronaphthalene derivatives. The reactions of 1,2-dihydronaphthalenes with chlorosulfonyl isocyanate (CSI) afforded beta-lactams. beta-Amino acids were obtained from the reaction of beta-lactams with EtOH in HCl. Computational studies are concerned with synthesizing four-membered lactams (beta-lactam) formed by the reaction between 1,2-dihydronaphthalene derivatives and CSI. The mechanism of the formation of compounds has been elucidated using DFT at M06-2X.