Identification of Side Products From The Hydrogenation Reaction of Bis(substitutedbenzylidene)cyclopentanone/- cyclohexanone by Using Palladium/Carbon Catalyst

Abstract

Synthesis of some curcumin analogs which are categorised as bis(substitutedbenzylidene)cyclopentanone/cyclohexanone have been published and patented by Faculty of Pharmacy, Universitas Gadjah Mada, Indonesia, few years ago. One of the main identity of the curcumin analogs that discussed is the use of cyclopentanone and cyclohexanone on its synthesis instead of 1,3-diketone as on curcumin’s. The tetrahydrocurcumin as metabolite of curcumin also has been successfully synthesised through the hydrogenation reaction of curcumin. This research was aimed to synthesise the tetrahydroform of bis(substituted-dibenzylydene)cyclopentanone/cyclohexanone (analog curcumins). Hydrogenation reaction was applied in this synthesis which carried out by using palladium on carbon as catalyst and hydrogen gas as source of hydrogen at room temperature for 2 – 3.5 hours and this reaction is an auto-indicator type reaction. The recation gave not only the hydrogenation products which were found in moderate yield but also gave other three side poducts. All their structures have been characterised by spectroscopic method and the side products are in alkane and alcohol form of the cyclopentane ring.

Keywords: hydrogenation,  bis(substitutedbenzylidene)cyclopentanone/cyclohexanone,  bis-(substitutedbenzyl)cyclopentanone/cyclohexanone, side product