Heterocyclization of 3-deoxy-D-erythro-hexos-2-ulose-1,2-bis-thiosemicarbazone. X-Ray structure of the major diastereoisomer

MARTINS ALHO MIRIAM A; BAGGIO, RICARDO; GARLAND, MARÍA T.; D'ACCORSO NORMA B.; VARELA, OSCAR

CARBOHYDRATE RESEARCH

Elsevier Science Ltd.

Lugar: Ansterdam; Año: 2002 vol. 337 p. 1397 - 1403

0008-6215

Abstract Both thiosemicarbazone groups of the derivative 1 of 3-deoxy-D-erythro-hexos-2-ulose underwent, on acetylation, a heterocyclization process to give (5R,5R)-2,2-diacetamido-4,4-di-N-acetyl-5-(1-deoxy-2,3,4-tri-O-acetyl-D-erythritol-1-yl)-5,5-bis(1,3,4- thiadiazoline) (2) as a major product. The X-ray diffraction data of a single crystal of 2 indicated the R,R configuration for the stereocenters of the thiadiazoline rings (C-5 and C-5). In the solid state, 2 adopts a sickle conformation (by clockwise rotation of the C-2?C-3 axis of the sugar chain) which has a S//O 1,3-parallel interaction. In solution, as determined by 1H NMR spectroscopy which included NOE experiments, a similar sickle conformation was observed. From the reaction mixture of acetylation of 1 was isolated the bis(thiadiazoline) 3 as a by-product . The configuration of the C-5 and C-5 stereocenters of 3 1 of 3-deoxy-D-erythro-hexos-2-ulose underwent, on acetylation, a heterocyclization process to give (5R,5R)-2,2-diacetamido-4,4-di-N-acetyl-5-(1-deoxy-2,3,4-tri-O-acetyl-D-erythritol-1-yl)-5,5-bis(1,3,4- thiadiazoline) (2) as a major product. The X-ray diffraction data of a single crystal of 2 indicated the R,R configuration for the stereocenters of the thiadiazoline rings (C-5 and C-5). In the solid state, 2 adopts a sickle conformation (by clockwise rotation of the C-2?C-3 axis of the sugar chain) which has a S//O 1,3-parallel interaction. In solution, as determined by 1H NMR spectroscopy which included NOE experiments, a similar sickle conformation was observed. From the reaction mixture of acetylation of 1 was isolated the bis(thiadiazoline) 3 as a by-product . The configuration of the C-5 and C-5 stereocenters of 3 R,5R)-2,2-diacetamido-4,4-di-N-acetyl-5-(1-deoxy-2,3,4-tri-O-acetyl-D-erythritol-1-yl)-5,5-bis(1,3,4- thiadiazoline) (2) as a major product. The X-ray diffraction data of a single crystal of 2 indicated the R,R configuration for the stereocenters of the thiadiazoline rings (C-5 and C-5). In the solid state, 2 adopts a sickle conformation (by clockwise rotation of the C-2?C-3 axis of the sugar chain) which has a S//O 1,3-parallel interaction. In solution, as determined by 1H NMR spectroscopy which included NOE experiments, a similar sickle conformation was observed. From the reaction mixture of acetylation of 1 was isolated the bis(thiadiazoline) 3 as a by-product . The configuration of the C-5 and C-5 stereocenters of 3 2) as a major product. The X-ray diffraction data of a single crystal of 2 indicated the R,R configuration for the stereocenters of the thiadiazoline rings (C-5 and C-5). In the solid state, 2 adopts a sickle conformation (by clockwise rotation of the C-2?C-3 axis of the sugar chain) which has a S//O 1,3-parallel interaction. In solution, as determined by 1H NMR spectroscopy which included NOE experiments, a similar sickle conformation was observed. From the reaction mixture of acetylation of 1 was isolated the bis(thiadiazoline) 3 as a by-product . The configuration of the C-5 and C-5 stereocenters of 3 2 adopts a sickle conformation (by clockwise rotation of the C-2?C-3 axis of the sugar chain) which has a S//O 1,3-parallel interaction. In solution, as determined by 1H NMR spectroscopy which included NOE experiments, a similar sickle conformation was observed. From the reaction mixture of acetylation of 1 was isolated the bis(thiadiazoline) 3 as a by-product . The configuration of the C-5 and C-5 stereocenters of 3 //O 1,3-parallel interaction. In solution, as determined by 1H NMR spectroscopy which included NOE experiments, a similar sickle conformation was observed. From the reaction mixture of acetylation of 1 was isolated the bis(thiadiazoline) 3 as a by-product . The configuration of the C-5 and C-5 stereocenters of 31 was isolated the bis(thiadiazoline) 3 as a by-product . The configuration of the C-5 and C-5 stereocenters of 3 were respectively assigned as S,R by comparison of the physical and spectroscopic data of this compound with those of 2. © 2002 Elsevier Science Ltd. All rights reserved. S,R by comparison of the physical and spectroscopic data of this compound with those of 2. © 2002 Elsevier Science Ltd. All rights reserved. Keywords : Sugar thiosemicarbazone; Thiadiazoline; Heterocyclization; X-ray diffraction: Sugar thiosemicarbazone; Thiadiazoline; Heterocyclization; X-ray diffraction 1. Introduction