Aminozucker‐Synthesen, XXIV. Pyrazinbildung aus Aminozuckern

Abstract

Während d-Isoglucosamin beim Erhitzen mit Diäthylamin das bereits auf anderem Wege hergestellte „Fructosazin” der Formel III liefert, erhält man durch Wasserabspaltung aus d-Glucosamin in heißem Eisessig ein um 1 Sauerstoffatom ärmeres „Desoxyfructosazin”. Für dieses wird durch hydrierend-hydrolytische Spaltung zu 1 Mol. d-Isoglucosamin und 1 Mol. 3-Desoxy-d-isoglucosamin die Struktur VII bewiesen

A Clean Conversion ofD-Glucosamine Hydrochloride to a Pyrazine in the Presence of Phenylboronate or Borate

“…The explanation for the formation of 2 during the reaction is based on a previously published mechanism, [9,12] taking into account the formation of borate (or boronate) es-ters. The reaction in the presence of borate was too fast to follow by NMR spectroscopy, and only the borate esters of the reaction product 2 could be observed and identified (see below).…”

“…[9] Better yields of compound 2 have been obtained by heating glucosamine in acetic acid. [12] The disadvantage of this procedure is that the purification of compound 2 from the brown complex reaction mixture obtained is tedious.…”

Arylboronic Acids Catalyzed Upgrade of Glucosamines for Deoxyfructosazine and Insights on Reaction Mechanism

“…3,4 Such recalcitrant structures usually lead to complex products in direct conversion of chitin into chemicals, and not surprisingly one of its hydrolysed A good conversion of D-glucosamine hydrochloride to deoxyfructosazine in the presence of excess amount (2.5 to 5 equivalents) of phenylboronic acid and excess amount of NaOH in water was initially reported by J. A. Peters et.al 13 , which was a cleaner transformation and a significant progress based on pioneer works in alkali hydroxide solution only 10 or pyridine solution only 14 . Further optimization on this conversion with phenylboronic acid as a promoter 15 or boric acid as an additive with 1-ethyl-3-methylimidazolium acetate ([C2C1Im][OAc]) as a dual solvent-catalyst 16a,b or in deep eutectic solvents 16c was also reported.…”

“…Further optimization on this conversion with phenylboronic acid as a promoter 15 or boric acid as an additive with 1-ethyl-3-methylimidazolium acetate ([C2C1Im][OAc]) as a dual solvent-catalyst 16a,b or in deep eutectic solvents 16c was also reported. However, yield of deoxyfructosazine was generally low to moderate either from selfcondensation of D-glucosamine [13][14][15][16] or other monosaccharides with ammonia acid salts 17 even though more clues were achieved in mechanism investigation 16 . In these literatures (Scheme 1), excess amount of phenylboronic acid or boric acid is still a must for achieving a good yield of deoxyfructosazine.…”

Isolation and Identification of 2-(d-threo-Trihydroxypropyl)-5-(d-glycero-2′,3′-dihydroxypropyl)pyrazine and Its 6-Isomer from the Browning Reaction between Xylose and Ammonium Formate

“…4 ) These oxidation products were chromatographed on paper by the use of n-BuOH-AcOH-H,O (5: 2: 2 v/v/v) as solvent and using ferrous ammonium sulfate reagent 5 ) as spraying reagent. The spot (blue, Rxylos.…”