Title : Synthesis of moraprenyl pyrophosphate derivatives of 3-O-.alpha.-L- rhamnopyranosyl-(4-O-.alpha.-D-glucopyranosyl)-.alpha.-D-galactopyranose and 3-O-.alpha.-L- rhamnopyranosyl-(4-O-.beta.-D-glucopyranosyl)-.alpha.-D-galactopyranose and investigation of their substrate properties in the biosynthesis of O- antigenic polysaccharides from Salmonella typhimurium and Salmonella anatum