DEGRADATION OF METHYL BETA-D-RIBOPYRANOSIDE AND METHYL BETA-D-XYLOPYRANOSIDE BY OXYGEN IN AQUEOUS SODIUM-HYDROXIDE SOLUTION

被引:6
作者
HEARNE, DO [1 ]
THOMPSON, NS [1 ]
SCHROEDER, LR [1 ]
机构
[1] SUNY COLL ENVIRONM SCI & FORESTRY,EMPIRE STATE PAPER RES INST,SYRACUSE,NY 13210
关键词
D O I
10.1080/02773819108050277
中图分类号
TB3 [工程材料学]; TS [轻工业、手工业、生活服务业];
学科分类号
0805 ; 080502 ; 0822 ;
摘要
Methyl beta-D-ribopyranoside (1) and methyl beta-D-xylopyranoside (2) were degraded by oxygen (0.682 MPa partial pressure) in 1.25 M sodium hydroxide at 120-degrees-C. The degradations of 1 and 2 were similar to the previously reported degradations of 1,5-anhydroribitol (3) and 1,5-anhydroxylitol (4), respectively.4 Both hydrogen peroxide and stable organic peroxides were detected in the reactions of 1 and 2. The riboside 1 degraded faster than the xyloside 2. This difference in reactivity is proposed to be a function of the relative acidity of the glycosides. Ionization of hydroxyl groups is postulated to be favored in 1, thus facilitating the initiation of the free radical degradation. The degradations of both 1 and 2 exhibited complex kinetics indicating auto-inhibited reactions. In spite of the differences in reactivity, glycosidic bond cleavage occurred in approximately 60% of the degradations for both 1 and 2. C-1 radicals, resulting from abstraction of the anomeric hydrogen atom, are proposed to cause the observed autoinhibition via termination reactions with alpha-hydroxyhydroperoxyl radicals. However, decomposition of the glycosides via C-1 radicals is not believed to constitute a major degradation pathway since the reactivities of 1 and 2 were essentially the same as the analogous 1,5-anhydroalditols, i.e. 3 and 4, respectively. The major acidic degradation products of 1 and 2 were identical, but were formed in different relative ratios. The major acidic products were methoxyacetic acid, lactic acid, glycolic acid, glyceric acid, a methyl 3-C-carboxyfuranoside, and two isomeric 2-C-carboxyfuranosides.
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页码:307 / 327
页数:21
相关论文
共 47 条
[1]  
AKIM GL, 1973, CELLUL CHEM TECHNOL, V7, P441
[2]   CONFORMATIONAL ANALYSIS IN CARBOHYDRATE CHEMISTRY .I. CONFORMATIONAL FREE ENERGIES . CONFORMATIONS AND ALPHA - BETA RATIOS OF ALDOPYRANOSES IN AQUEOUS SOLUTION [J].
ANGYAL, SJ .
AUSTRALIAN JOURNAL OF CHEMISTRY, 1968, 21 (11) :2737-&
[3]  
[Anonymous], 1950, J ORG CHEM
[4]  
[Anonymous], 1966, ADV CARBOHYD CHEM, V21, P209
[5]   LIGHT-INDUCED FREE-RADICAL REACTIONS OF 2-METHOXY-6-METHYLTETRAHYDROPYRAN - IRREVERSIBLE RING-OPENING AND MULTISITE HYDROGEN ABSTRACTION [J].
BABCOCK, BW ;
DIMMEL, DR ;
GRAVES, DP .
JOURNAL OF ORGANIC CHEMISTRY, 1981, 46 (04) :736-742
[6]  
BAUER N, 1959, WEISSBERGERS TECHN 1, V1, P136
[7]   ACID DISSOCIATION CONSTANT AND DECAY KINETICS OF PERHYDROXYL RADICAL [J].
BEHAR, D ;
CZAPSKI, G ;
RABANI, J ;
DORFMAN, LM ;
SCHWARZ, HA .
JOURNAL OF PHYSICAL CHEMISTRY, 1970, 74 (17) :3209-&
[8]   STUDY OF CH-13 COUPLING-CONSTANTS IN PENTOPYRANOSES AND SOME OF THEIR DERIVATIVES [J].
BOCK, K ;
PEDERSEN, C .
ACTA CHEMICA SCANDINAVICA SERIES B-ORGANIC CHEMISTRY AND BIOCHEMISTRY, 1975, B 29 (02) :258-264
[9]  
BROOKS RD, 1966, TAPPI, V49, P362
[10]   OXIDATION OF D-GLUCOSE AND D-FRUCTOSE WITH OXYGEN IN AQUEOUS, ALKALINE SOLUTIONS .1. INTEGRAL REACTION SCHEME [J].
DEWILT, HGJ ;
KUSTER, BFM .
CARBOHYDRATE RESEARCH, 1971, 19 (01) :5-&