Synthesis of sugar N-(2-thiazolin-2-yl)thioureas

Abstract

1,3,4,6-Tetra- O-acetyl-2-deoxy-2-isothiocyanato-α- or -β- d-glucopyranose ( 4 or 5) was condensed with 2-chloroethylamine hydrochloride in pyridine to afford N,N′-bis(1,3,4,6-tetra- O-acetyl-2-deoxy-α- or -β- d-glucopyranos-2-yl)- N-(2-thiazolin-2-yl)thiourea ( 2 or 3). When the reactions were carried out in ether, 1,3,4,6-tetra- O-acetyl-2-deoxy-2-(2-thiazolin-2-yl)amino-α- and -β- d-glucopyranose ( 6 and 7) were isolated and converted into the mixed N-(2-thiazolin-2-yl)-urea and -thioureas ( 9–12) by reaction with iso(thio)cyanates. Bromine-promoted cyclisation of 1,3,4,6-tetra- O-acetyl-2-( N′-allylthioureido)-2-deoxy-α- d-glucopyranose ( 13) gave a mixture of the diastereomers 1,3,4,6-tetra- O-acetyl-2-[5( R and S)-5-bromomethyl-2-thiazolin-2-yl]amino-2-deoxy-α- d-glucopyranose hydrobromides ( 14 and 15), which was transformed into the analogous N-(2-thiazolin-2-yl)thioureas ( 16–18).