title: Noncatalytic reaction of isonitriles and carboxylic acids en route to amide-type linkages.
abstract: This protocol describes the preparation of an N-methyl-asparagine-linked glycosyl amino acid, on the basis of a reaction between carboxylic acids and isonitriles. Under microwave/thermolysis, carboxylic acids can couple with isonitriles without an external catalyst to form N-formyl-amides, which may be further advanced to the corresponding amides, N-methyl amide and N-methyloyl amide. The example reaction of beta-galactopyranosyl isonitrile (7) with a protected aspartic acid under microwave condition in 30 min stereoselectively leads to a beta-galactopyranosyl-N-formyl-asparagine (9). Further chemical transformations readily convert 9 into beta-galactopyranosyl-N-methyl-asparagine (11).
authors.affiliation: Laboratory for Bioorganic Chemistry, Sloan-Kettering Institute for Cancer Research, New York, NY 10065, USA.
authors.forename: Xuechen
authors.initials: X
authors.lastname: Li
authors.forename: Samuel J
authors.initials: SJ
authors.lastname: Danishefsky
mesh_terms: D000577:Amides / Q000737:chemistry*; D002264:Carboxylic Acids / Q000737:chemistry*; D006860:Hydrogen Bonding; D015394:Molecular Structure; D009570:Nitriles / Q000737:chemistry*
chemical_list: D000577:Amides; D002264:Carboxylic Acids; D009570:Nitriles