INTERACTION OF PHENYLBORONIC ACID WITH HEXOSIDES
INTERACTION OF PHENYLBORONIC ACID WITH HEXOSIDES
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DOI：
10.1039/jr9610002325
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发表时间：
1961-01-01
期刊：
影响因子：
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通讯作者：
FERRIER, RJ
中科院分区：
文献类型：
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作者：
FERRIER, RJ
甲基ad -葡萄糖吡喃苷与苯硼酸（1mol）反应生成结晶的4,6环酯，该酯与过量的试剂形成2,3 -（二苯基焦硼酸酯）（含7元环）。苯基硼酸（2摩尔）与甲基ad -甘露吡喃苷顺利缩合，生成2,3,4,6 -二酯，但与1摩尔的酸反应不能生成均相产物。报道了甲基c - d -葡萄糖苷取代苯硼酸酯，以及其他糖苷和相关化合物的苯硼酸酯。所描述的所有衍生物都是空气稳定固体，容易在水或醇中分解。酯键在酯化条件下是稳定的，但在甲基化过程中是不稳定的。硼酸在水溶液中与羟基化化合物的相互作用已被广泛研究，但对非水溶剂中发生的反应关注较少。三酯形成的可能性使二醇形成的环硼酸盐的研究变得复杂，我们在这里关注的是碳水化合物衍生物，这种二酯的缩合和二聚化已被证明会发生。为了克服这一困难，人们在模型实验中使用了苯硼酸，它可以与多羟基化合物缩合生成环酯。一些己醇的结晶苯硼酸盐已经被报道过，但是这种酸能与之反应的二醇体系的种类却鲜为人知。虽然已经发现甲基a和pd -黄豆苷能与硼酸和苯基硼酸反应，但6种不同的酯尚未被报道，酯化位点也没有很好地确定。我们研究了1mol苯基硼酸对这些糖苷的作用，并在苯的存在下通过共沸蒸馏去除水分，获得了高收率的结晶环酯。苯基硼酸的酸酐（三苯基硼酸）在合成中同样有效。
Methyl aD-glucopyranoside reacts with phenylboronic acid (1 mol.) to give a crystalline 4, 6-cyclic ester which, in turn, forms a 2, 3-(diphenylpyroboronate)(containing a 7-membered ring) with an excess of the reagent. Phenylboronic acid (2 mol.) condenses smoothly with methyl aD-mannopyranoside, to give the 2, 3: 4, 6-diester, but with 1 mol. of the acid this reaction does not give a homogeneous product. Substituted phenylboronate esters of methyl cx-D-glucopyranoside, and phenylboronates of other glycosides and related compounds, are reported. All the derivatives described are air-stable solids which readily decompose in water or alcohols. The ester linkages have been shown to be stable to esterifying conditions but unstable during methylation.THE interaction in aqueous solution of boric acid with hydroxylated compounds has been studied extensively, l but less attention has been paid to the reactions which take place in non-aqueous solvents. The possibility of triester formation complicates the investigation of the cyclic borates formed from diols, and with carbohydrate derivatives, which concern us here, condensation, with dimerisation, of such diesters has been shown to occur. 2 In an attempt to overcome this difficulty, phenylboronic acid, which is known to condense with polyhydroxy-compounds to give cyclic ester^,^ has been used in model experiments. Some crystalline phenylboronates of hexitols have already been reported, but little is known of the kinds of diol system with which the acid will react. Although methyl a-and pD-ghcopyranoside have been found to react with both boric acid5 and phenylboronic acid, 6 discrete esters have not been reported and the sites of esterification have not been well defined. We have examined the action of 1 mol. of phenylboronic acid on these glycosides, and by azeotropic distilIation in the presence of benzene to remove water have been able to obtain crystalline cyclic esters in high yield. The anhydride of phenylboronic acid (triphenylboroxole) was equally effective in the syntheses.