麦芽酚-β-D-葡萄糖苷的便捷合成及加香应用

Facile Preparation of Maltol Alcohol-β-D-Glucopyranoside and its application

摘要:

为了改进糖苷化反应的合成工艺，以D-葡萄糖为原料，合成了糖基供体溴代四乙酰葡萄糖(Ⅱ)，再与麦芽酚(I)进行糖苷化反应，分别采用相转移催化法和Koenigs-Knorr法，合成了麦芽酚-2, 3, 4, 6-四-O-乙酰基-β-D-葡萄糖苷(Ⅲ)；最后，将化合物Ⅲ进行水解，得到目标产物麦芽酚-β-D-葡萄糖苷(Ⅳ)。所得产物结构经1HNMR、13CNMR、IR、HRMS 确证，并研究了目标糖苷Ⅳ的热裂解和加香评吸效果。结果表明: 两种糖苷化方法所得到的产物均为化合物Ⅲ，相转移催化法更优。相转移催化法的反应条件为：以丙酮为溶剂，无水K2CO3为缚酸剂，四丁基溴化铵（TBAB）为相转移催化剂，n（麦芽酚）∶n（溴代四乙酰葡萄糖）=1: 1.2，室温反应4 h，化合物Ⅲ的产率为 75.6%。用甲醇钠/甲醇体系将化合物Ⅲ水解得到化合物Ⅳ。目标糖苷Ⅳ受热裂解能够释放出麦芽酚等特征香味成分，将其添加于卷烟中能够改善香气品质。

Abstract:

Abstract: To improve the synthetic process of glycosylation, 2, 3, 4, 6-tetra-O-acetyl-α-D-glucopyranosyl bromide (Ⅱ) was firstly synthesized from D-glucose. Then, a glycosylation reaction between compounds Ⅱ and maltol (I) led to maltol-2, 3, 4, 6-tetra-O-acetyl-β-D-glucoside (Ⅲ) by phase transfer catalysis method and Koenigs-Knorr method, respectively. Finally, the target compound maltol-β-D-glucoside (Ⅳ) was obtained by hydrolysis of compound Ⅲ. These compounds were confirmed by 1HNMR, 13CNMR, IR and HRMS. The effects of pyrolysis and aroma evaluation of target glycoside Ⅳ were studied. The results indicated that the compound Ⅲ synthesized by the two above-mentioned methods was target product, the phase transfer catalysis method was better than Koenigs-Knorr method. The optimal conditions for the preparation of compound Ⅲ by phase transfer catalysis method were as follows: acetone was used as the solvent, anhydrous potassium carbonate was used as acid binding agent, and tetrabutyl ammonium bromide (TBAB) was used as phase transfer catalyst, n (maltol): n (2, 3, 4, 6-tetra-O-acetyl-α-D-glucopyranosyl bromide)=1:1.2, reaction at room temperature for 4 h. Under these optimal conditions, the yield of compound Ⅲ reached 75.6%. Hydrolysis of compound III to compound IV in sodium methoxide/methanol system. The target glycoside Ⅳ can release characteristic flavor components such as maltol by pyrolysis, and can be added to cigarettes to improve the aroma quality.