First Synthesis of 3-O-Functionalized Cellulose Ethers via 2,6-Di-O-Protected Silyl Cellulose

Abstract

The present paper describes the synthesis of 2,6-di-O-thexyldimethylsilyl cellulose as a novel 2,6-di-O-protected cellulose derivative. This material was obtained by reacting cellulose in N,N-dimethylacetamide/LiCl solution with thexyldimethylchlorosilane and imidazole for 24 h at 100°C. In a typical subsequent reaction the residual OH-group in position 3 could be completely etherified without loss of any protecting groups. Treatment with tetrabutylammonium fluoride leads to the novel compounds 3-O-allyl and 3-O-methyl cellulose. The structures of all polymers are revealed by means of one- (1H and 13C) and two-dimensional (COSY and HMQC) NMR techniques.