Ralf Wischnat

Synthesis of a 2-hydroxymethyl-dihydropyridone-system as a flexible building block for the preparation of azasugars

Abstract m CPBA induced oxidative cyclization of the aminoalcohol 1a under complete stereocontrol, generating after acetal formation a new diastereomerically pure key intermediate 2b for the flexible synthesis of azasugars. 2b could be converted to protected rac -mannonojirimycin, 3 in only three steps.

Improved procedure for the synthesis of thiazolium-type peptide coupling reagents: BMTB as a new efficient reagent

An efficient scalable synthesis of 2-halothiazolium-type peptide coupling reagents has been developed. The key step is the formation of the 2-bromothiazole scaffold through cyclization of α-thiocyanato ketones with hydrogen bromide. Using this method, the new coupling reagent 2-bromo-N-methylthiazolium bromide (BMTB) was synthesized. BMTB was tested in a difficult model coupling reaction of two sterically hindered N-methylated amino acids and showed higher activity than the well-established peptide coupling reagent HATU.