Clinical application | 1-Methyl-L-4, 5-dihydroorotic acid can be used as a pharmaceutical synthesis intermediate, if it can be used to prepare tatirellin, tatirellin is a pituitary hormone releasing stimulant, successfully developed by Japan's Tanabe Mitsubishi Pharmaceutical Co., Ltd., with a Taltirelin trade name, and belongs to the 3.1 category of new chemical drugs, at present, it is the most effective drug for improving motor disorders in patients with spinal cerebellar degeneration. |
preparation | 1) preparation of Boc-Asn(Me)-OBzl: dissolve the Boc-Asp-OBzl in tetrahydrofuran, add 1.5 times the molar amount (based on the Boc-Asp-Obzl molar amount, then the same) HOSu, add 1.2 times the molar amount DCC dropwise, and cool to 2 ℃; drop 2 times the molar amount of methylamine tetrahydrofuran solution into the reaction solution; react for 2 hours; add a small amount of water to the reaction solution, filter DCU, spin evaporate tetrahydrofuran, dissolve ethyl acetate, filter insoluble matter, dilute acid washing, Water washing, sodium bicarbonate solution washing, water washing, drying, and evaporation to obtain Boc-Asn(Me)-OBzl. 2) Preparation of 1-methyl-L-4, 5-dihydroorotic acid: Dissolve Boc-Asn(Me)-OBzl in ethanol, add sodium ethoxide, reflux for 4 hours, cool and add dilute hydrochloric acid for neutralization, vacuum distillation of ethanol, petroleum ether washing, the water layer is extracted from ethyl acetate, the ethyl acetate layer is washed with saturated salt water, the ethyl acetate anhydrous magnesium sulfate is dried, filtered, and rotated to obtain 3-methyl-L-4,5-dihydroorotinate; 3-methyl-L-4,5-dihydroorotinate benzyl ester is dissolved in methanol, and it is catalyzed by 5% Pb-C hydrogenolysis, temperature at room temperature, reaction overnight, filter the catalyst, and evaporate the methanol to obtain 1-methyl-L-4, 5-dihydroorotinate solid. |