Simple and convenient preparation method of key intermediate (2-methyl-4-amino-5-amino methyl pyrimidine) for vitamin B1
A technology of formamidomethylpyrimidine and aminomethylpyrimidine is applied in the field of production of vitamin B1 and derivatives thereof, can solve the problems of high reaction temperature, low yield, unfavorable environmental protection and the like, and achieves a simple and convenient operation with few steps. Effect
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[0037] A simple and convenient preparation method of vitamin B1 key intermediate 2-methyl-4-amino-5-aminomethylpyrimidine, comprising the following steps:
[0038] (1) Add 3-formylaminopropionitrile 2 to the reactor, add organic solvent to dissolve; add catalytic amount of Lewis acid; The molar ratio of acetamidine to 3-formylaminopropionitrile is (1-2): 1, and the molar ratio of acetamidine to 3-formylaminopropionitrile (1.1-1.3): 1 is preferred; Detection of 3-formamidopropionitrile reaction is complete; then continue,
[0039] (2) Add anisole internal standard and orthoformate triester 5, the molar ratio of the amount of orthoformate triester to the 3-formamidopropionitrile used in step (1) is (2-3):1, React at a temperature of 65-105°C, and use the gas phase to detect that the reaction is complete; 2-methyl-4-formylamino-5-formylaminomethylpyrimidine 6 is obtained; then continue,
[0040] (3) Directly add an aqueous solution of inorganic alkali, hydrolyze at 80-100°C to ...
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[0054] According to the present invention, a preferred embodiment is as follows:
[0055] A kind of convenient preparation method of vitamin B1 key intermediate 2-methyl-4-amino-5-aminomethylpyrimidine, the steps are as follows:
[0056] a. Add 104.5 grams of acetamidine hydrochloride and 220 grams of 27wt% sodium methoxide methanol solution in a 1000 ml glass reaction vessel, react at 10-20°C for 30 minutes, filter, and the filtrate is a methanol solution of acetamidine;
[0057] b. Add 98 grams of 3-formylaminopropionitrile, 520 grams of toluene, and 27.2 grams of anhydrous zinc chloride into a 1000 milliliter four-necked flask; heat, and the internal temperature rises to 75-80 ° C; dropwise add the above-mentioned Acetamidine alcohol solution; stirring reaction, the use of gas phase detection 3-formamidopropionitrile reaction is complete. Then add 1 gram of anisole internal standard and 254.4 grams of trimethyl orthoformate; react at 95 to 100 ° C, and use gas phase detect...
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