A kind of preparation method of nicotinic acid derivative
A technology of derivatives and nicotinic acid, which is applied in the field of medicine and chemical industry, can solve the problems of many by-products, unfavorable environmental protection, unfavorable industrial production, cumbersome preparation process, etc., and achieve the effect of green and convenient industrial production, less three wastes, and short process flow
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Embodiment 1
[0060] Embodiment 1: the preparation of piperidin-4-ketone-3-formic acid methyl ester
[0061] Add 300 grams of methanol, 49.5 grams (0.2 moles) of methyl N-benzylpiperidin-4-one-3-carboxylate in a 500 milliliter stainless steel autoclave, 0.9 grams of 5% palladium-carbon catalyst, nitrogen replacement three times, pass into Hydrogen, keep the system pressure at 0.2-0.3MPa, react at 40-45°C for 4 hours. Nitrogen was replaced three times, the palladium carbon was removed by filtration, the filter cake was washed twice with methanol, 30 grams of methanol each time, and the filtrates were combined. The solvent was recovered by distilling the filtrate to obtain 30.9 g of methyl piperidin-4-one-3-carboxylate, with a yield of 98.3% and a gas phase purity of 99.7%.
Embodiment 2
[0062] Embodiment 2: the preparation of piperidin-4-ketone-3-formic acid ethyl ester
[0063] Add 280 grams of acetonitrile, 52.2 grams (0.2 moles) of ethyl N-benzylpiperidin-4-one-3-formate in 500 milliliters of stainless steel autoclave, 5.0 grams of 50% Raney nickel catalyst, after nitrogen replacement three times, pass Inject hydrogen, keep the system pressure at 0.3-0.4MPa, and react at 45-50°C for 4 hours. Nitrogen was replaced three times, the catalyst was removed by filtration, the filter cake was washed twice with acetonitrile, 30 grams each time, the filtrate was combined, the filtrate was distilled to recover the solvent, and 33.5 grams of ethyl piperidine-4-one-3-carboxylate was obtained, with a yield of 98.0%. 99.6% purity.
Embodiment 3
[0064] Embodiment 3: Preparation of 3,5-dichloropiperidin-4-one-3-methyl carboxylate
[0065] In the 500 milliliter four-necked flask that is connected with stirring, thermometer, reflux condenser, 200 grams of chloroform, 31.4 grams (0.2 mole) are prepared by the method of embodiment 1 piperidin-4-ketone-3-methyl carboxylate, 43.0 grams (0.41 mol) 35% hydrochloric acid, add 51.0 (0.45 mol) 30% hydrogen peroxide dropwise at 30-35°C, drop it in about 3 hours, after that, stir and react at 45-50°C for 3 hours, cool to 20-25°C, Catch residual chlorine and hydrogen chloride gas for 1 hour, add 50 grams of water, adjust the pH value to 7 with 5% aqueous sodium bicarbonate solution, separate layers, wash the organic phase once with 20 grams of saturated aqueous sodium chloride solution, separate layers, and recover the solvent by distillation , to obtain 45.1 g of yellow liquid 3,5-dichloropiperidin-4-one-3-carboxylic acid methyl ester, which was directly used in related elimination...
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