REACTION OF O-BENZYLIDENE SUGARS WITH N-BROMOSUCCINIMIDE .2. SCOPE AND SYNTHETIC UTILITY IN METHYL 4,6-O-BENZYLIDENEHEXOPYRANOSIDE SERIES
REACTION OF O-BENZYLIDENE SUGARS WITH N-BROMOSUCCINIMIDE .2. SCOPE AND SYNTHETIC UTILITY IN METHYL 4,6-O-BENZYLIDENEHEXOPYRANOSIDE SERIES
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DOI：
10.1021/jo01256a059
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发表时间：
1969-01-01
影响因子：
3.6
通讯作者：
PLESSAS, NR
中科院分区：
文献类型：
--
作者：
HANESSIAN, S;PLESSAS, NR
ResultsA general procedure for this reaction involves the interaction of thebenzylidene acetal with NBS in refluxing carbon tetrachloride in the presence of barium carbonate. In those cases where the starting acetals are insoluble inhot carbon tetrachloride or benzene, complete solution can be effected by the addition of dry 1, 1, 2, 2-tetrachloroethane. The presence of excess bar-ium carbonate as a scavenger for hydrogen bromide may be desirable, although not necessary. The reaction is invariably complete within 2-2.5 hr and is characterized in some cases by the appearance of colors ranging from orange to brick red during the initial stages of refluxing. The ring opening of the acetal and the incorporation of a benzoate function in the molecule can be readily recognized from the absence of the benzylic proton and the characteristic splitting pattern of the aromatic ring hydrogens in the nmr spectrum of the product. In several cases, the products could be crystallized directly from the crude residues. In the case of methyl 4, 6-O-benzylidene-aD-gluco-pyranoside6· 7 (la)(Scheme I), an ether-soluble crystal-(. 1)(a) Portions oC this work were presented at the 152nd National Meeting of the American Chemical Society, New York, NY, Sept 1966, D29, and the 154th National Meeting, Chicago, III., Sept 1967, D16.(b) To whom correspondence should be addressed at the Department of Chemistry, University of Montreal, Montreal 3, Quebec, Canada.(2) S. Hanessian, Carbohydrate Rea., 2, 86 (1966).(3) S. Hanessian, Advan. Carbohydrate Chem., 21, 146 (1966).(4) S. Hanessian, Advances in Chemistry Series, No. 74, American Chemical Society, Washington, D. C., 1968, p 159.(5) S. Hanessian and NR Plessas, J. Org. Chem., 34, 1045, 1053 (1969), papers III and IV in this series.
