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4-甲基伞形酮基-β-D-吡喃半乳糖苷(MUGal)是食品安全中重要指示菌大肠菌群的特异性快速检测荧光底物。本文采用相转移催化方法使4-甲基伞形酮(4-MU)和四乙酰基-α-D-吡喃溴代半乳糖缩合生成保护的糖苷,再在碳酸钠的水/甲醇溶液中去保护生成4-甲基伞形酮基-β-D-吡喃半乳糖苷。通过对温度、时间和催化剂用量对糖苷化一步产率的研究发现,当温度为30℃,反应时间为16 h时,产率最高可达73.12%。醇解反应一步以碳酸钠为碱产率可达91.01%。在对产物进行IR和1HNMR结构表征后,进一步将产物应用于大肠菌群显色培养基,并和进口底物比较,其产荧光管数经X2检验无显著性差异(P>0.05),在实际样品检测中,采用GB4789.3-2010(48 h)和MUGal方法(24 h)的阳性检出率均为80%,MUGal方法的检出时间明显缩短。因此,本研究制备的荧光底物能和进口产品相媲美,可以作为进口底物的替代品。
4-methylumbelliferyl-β-D-galactopyranoside (MUGal) is a fast and sensitive fluorescent substrate for the detection of coliforms, an important indicator organism in food safety. In this paper, 4-methylumbelliferone (4-MU) and tetraacetyl-α-D-galactopyranosyl bromide were condensed to form protected glycosides by phase-transfer catalysis, and then hydrolyzed in water / methanol solution of sodium carbonate Deprotection to generate 4-methylumbelliferyl-β-D-galactopyranoside. The research on the one-step yield of glycosylation by temperature, time and amount of catalyst found that when the temperature was 30 ℃ and the reaction time was 16 h, the yield reached 73.12%. Alcoholysis reaction step with sodium carbonate as a base rate of up to 91.01%. The products were further characterized by IR and 1HNMR. The products were further applied to the coloration medium of coliforms. Compared with the imported substrates, the number of fluorescent tubes produced by the two methods showed no significant difference (P> 0.05) In the real sample test, the positive detection rate was 80% using GB4789.3-2010 (48 h) and MUGal method (24 h), and the detection time of MUGal method was significantly shortened. Therefore, the fluorescent substrates prepared in this study are comparable to imported products and can be used as substitutes for imported substrates.