Gas-Liquid Chromatography and Mass Spectrometry of Quinoxalines Derived from Various Homoglucans by Alkalineo-Phenylenediamine Method

Quinoxaline Derivatives Derived from Isomaltooligosaccharides witho-Phenylenediamine under Deoxygenated and Heated Alkaline Conditions

“…With Cl-I,4-and f1-1 ,3-linked oligosaccharides, quinoxalines III and IV were formed from the reducing end after stepwise processing. 3 ) However, with Cl-I,6-linked isomaltooligosaccharides, these two quinoxalines were not formed. Therefore, to identify the quinoxalines formed from isomaltotetraose at an early stage of the reaction, a portion of the reaction mixture sampled with a heating time of 2 hr was analyzed by ion-exchange chromatography (Fig.…”

Structural Changes of Quinoxaline Derivatives, with Special Reference to 2-(2″,3″-Dihydroxypropyl)-3-hydroxy-methylquinoxaline in Alakaline and Acidic Solutions

“…After the pooled butanol layers had been evaporated to dryness, an aliquot (0.1 ml) of pyridine containing a small amount (0.4 Jlmol) of p-phenyl-n-glucoside was added to the residue, which was then subjected to trimethylsilylation. 6 ) For an estimation of the time-course changes of M-1 when heated, an aliquot of the reaction mixture (1 ml) was diluted IO-fold with carbonate buffer (pH 10), and analyzed by taking the polarographic limiting current due to quinoxalines, at -0.90 V vs. SCE.…”