| |
[摘要]：A new class of C-glycosyl a-amino acids featuring a nitrogenated heterocycle ring holding the carbohydrate and glycinyl moiety was designed in this work. Having previously prepd. isoxazole-, 1,2,3-triazole-, and pyridine-tethered compds., the family has now been enlarged by a group of newcomers represented by tetrazole derivs. Two sets of compds. have been prepd., one being constituted of C-galactosyl and C-ribosyl O-tetrazolyl serines while the other contains S-tetrazolyl cysteine derivs. In both cases, the synthetic scheme involved a two-step route, the first one being the thermal cycloaddn. of a sugar azide with p-toluenesulfonyl cyanide (TsCN) to give a 1-substituted 5-sulfonyl tetrazole and the second the replacement of the tosyl group with a serine or cysteine residue. For the high efficiency and operational simplicity, the azide-TsCN cycloaddn. appears to be a true click process. Finally, one of the amino acids prepd. was incorporated into a tripeptide. |
|
