19200-32-9Relevant academic research and scientific papers
Preparation of acylated pyranoid glycals in neutral aqueous medium by using chromium(II) complexes as reagents
Kovacs, Gyoengyver,Toth, Krisztina,Dinya, Zoltan,Somsak, Laszlo,Micskei, Karoly
, p. 5253 - 5264 (2007/10/03)
Reactions of 2,3,4,6-tetra-O-acetyl-α-D-glucopyranosyl bromide (3) with chromium(II)L complexes (L = EDTA, NTA, IDA, GLY, MAL) in neutral (5 95% purity. Complexes of Cr(II) with L = EDTA, NTA were similarly efficient with 2,3,4,6-tetra-O-acetyl-α-D- glucopyranosyl chloride (2) in furnishing glucal 13, while with L = IDA, GLY, MAL hydrolysis of 2 could not be suppressed. Under the same conditions [Cr(II)(EDTA)]2- also efficiently gave the corresponding glycals 14-19 from 2,3,4,6-tetra-O-benzoyl- (4) and 2,3,4,6-tetra-O-pivaloyl-α-D-glucopyranosyl bromide (5), per-O-acetylated α-D-galactopyranosyl chloride (6) and bromide (7), α-D-mannopyranosyl chloride (8), α-D-xylopyranosyl chloride (9), and bromide (10), β-D-arabinopyranosyl bromide (11), and α-L-rhamnopyranosyl chloride (12).
EQUILIBRATION OF ALDITOL ANHYDRIDES IN ACETIC ACID
Wisniewski, Andrzej,Gajdus, Jerzy,Sokolowski, Janusz,Szafranek, Janusz
, p. 11 - 20 (2007/10/02)
Dehydration of pentitols in acetic acid containing an acidic catalyst parallels that in aqueous sulfuric acid; 1,4(2,5)-dehydration occurs with inversion of configuration at C-2 or C-4.Acetylated alditols undergo similar processes via intermediates having free hydroxyl groups.Configurational inversion of 1,4- or 1,5-anhydroalditols is attributed to intermediate acyloxonium ions that are also proposed as intermediates in the structural isomerisation.Drastic treatment of each alditol gives equilibrium mixtures.The equilibrium concentrations are used to calculate free-energy differences.
