Sulfuryl chloride, reaction with pyruvic

Sulfuryl chloride, reaction with pyruvic acid to yield chloropyruvic acid, 40,54... 

The inner disaccharide unit of the trisaccharide hapten of the M. avium serovar 8 GPL148 was assembled in a manner similar to that of the serovar 20, but with reaction of the rhamnosyl trichloroacetimidate (80b) with the benzylidene acetal (81). O-Deacetylation of the product yielded the disaccharide acceptor (84) for the next glycosylation. Incorporation of the pyruvate acetal moiety into the terminal 3-O-methyl-D-glucose residue of 85 was achieved by transacetalation with methyl pyruvate diethyl dithioacetal, with sulfuryl chloride-triflic acid as catalyst. From the mixture of products the desired diastereomer was separated and converted by successive O-debenzylation, acetylation, selective 1-O-deacetylation, and reaction with trichloroacetonitrile into the trichloroacetimidate 86. Reaction of glycosyl donor 86 with acceptor 84, with trimethylsilyl triflate as promoter, afforded fully... 

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