Attempted synthesis of a 2,3,6-trisubstituted 5-pyranone

Abstract

Carbohydrate analogues are of great interest for the development of new pharmaceutical products. These compounds are attached to the macromolecule via glycosidic linkages, and then influence directly the overall biological activity. The goal of this project was to synthesize 2,3,6-trisubstituted-5-pyranone (10) from 1,1- diethoxy-3-(1,3-dithian-2-yl)-prpan-2-ol (7) which can undergo further reaction to synthesize carbohydrate analogues and great interest in the development of new pharmaceutical drugs. In this project, 3,3,4,4-tetraethoxy-1-butyne (TEB) was investigated as a starting material, further deprotection reaction and double Michael addition has also been carried out. Chain elongation of β-hydroxy dithiane has been also done to synthesize the target compound, which was prepared by treating compound 1,1-diethoxy-3-(1,3-dithan-2-yl)propan-2-ol with n-butyllithium followed by benzaldehyde. The target compound (8) has further been reacted to form carbohydrate analogues by cyclization and then hydrolysis of dithiane. Preparation of compound 8-Oxa-7-phenyl-1,5-dithiaspiro[5.5]undecane-9,10-diol acetonide (9) in a satisfactory yield is an important step in this project. The yield of compound 9 could be increased by repeating the attempt, from 48% to 59% respectively, and then furnished 2,3,6-trisubstituted-5-pyranone as the main product in this study.