Method for preparing allolactose

Abstract

The invention discloses a method for preparing allolactose. According to the method, 1,2-O-(1-methyl ethylidene)-3-O-acetyl-alpha-D-furan glucose is used as an initial raw material, a glycosyl receptor 1,2-O-(1-methyl ethylidene)-3-O-acetyl-5-O-benzoyl-alpha-D-furan glucose midbody is obtained through three steps of reaction, the yields and the purities of each step of reaction are all high (the yield is respectively 97%, 100% and 95%, and the purities are respectively 99.5%, 99.2% and 99.8%). Therefore, midbodies IV and V can be applied to next step of reaction without being purified in large-scale preparation, a compound formula VII is obtained by coupling a midbody formual VI and a midbody formula V, the reaction condition is obtained through optimization, the yield is high (80%), the stereoselectivity is good (no isomer is detected), purification can be easily achieved, the total yield that a disaccharide formula VII is prepared from a compound formula II through four steps of reaction is 74%, the purity is 99.8%, and the purity of a final product of the invention is high, that is, the purity is not less than 98%.

Description

technical field [0001] The invention relates to a preparation method of allolactose. Background technique [0002] Allolactose is an isomer of lactose, and its chemical structure is β-D-galactosyl-(1→6)-D-glucose, which is a reducing disaccharide. Under the action of β-galactosidase, lactose can be converted into allolactose, which is the inducer of the lactose operon and plays a very important biological role in the metabolic process of bacteria. For example, in Escherichia coli, allolactose is involved in regulating the activity of the lactose operon, which contains three structural genes (LacZ, LacY and LacA), which are mainly responsible for absorbing and hydrolyzing lactose as a carbon source for the life activities of Escherichia coli. If lactose is absent in the bacterial growth environment, the repressor protein binds tightly to a short DNA sequence (called the lactose operator) located downstream of the promoter near LacZ. The repressor protein bound to the operat...

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Problems solved by technology

[0004] The synthesis methods disclosed in the above-mentioned documents have the following problems: First, the chemical synthesis methods reported in the existing literature have long routes (8 to 15 steps of reaction), low yields (the highest total yield is 12%), and reproducibility Not good (the bromogalactose or chlorogalactose donors are not stable enough to be purified), separation and purification are difficult (the impurity content is too large), and it is not suitable for the large-scale preparation of isolactose; second, the existing The yield of allolactose synthesized by enzymatic method is extremely low, and the obtained allolactose is at the milligram level, which cannot be used for the large-scale synthesis of allolactose

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