Synthesis of 2-fluoro and 4-fluoro galactopyranosyl phosphonate analogues of UDP-Gal
摘要:
Two novel nonisosteric UDP-Gal analogues, (2-deoxy-2-fluoro- and 4-deoxy-4-fluoro-alpha-D-galactopyranosyl) phosphonoyl phosphates, were synthesized by optimized multistep procedures starting from 3,4,6-tri-O-benzyl-D-galactal and allyl 2,3,6-tri-O-benzyl-alpha-D-glucopyranoside, respectively. The key steps were a Michaelis-Arbuzov reaction of respective deoxy-fluoro-D-galactopyranosyl acetate with triethyl phosphite followed by a Moffatt-Khorana coupling reaction with UMP-morpholidate. The structure of all new compounds was confirmed by NMR and mass spectroscopies. (C) 2012 Elsevier Ltd. All rights reserved.
Highly efficient synthesis of 1-thioglycosides in solution and solid phase using iminophosphorane bases
作者:Weizheng Xu、Shawn A. Springfield、John T. Koh
DOI:10.1016/s0008-6215(99)00327-4
日期:2000.4
Disaccharides of l-thioglycosides, an important class of glycomimics, can be synthesized by direct S-alkylation in exceptionally high yields when iminophosphorane bases are employed. The reaction conditions employed appear to be general and stereospecific. Axial and equatorial 4-triflates and primary tosylates of alkyl pyranosides provided excellent yields of thio-disaccharides without substantial elimination products. The iminophosphorane bases also proved to be useful in solid support-bound couplings of thioglycosides though with lower efficiency. (C) 2000 Elsevier Science Ltd. All rights reserved.