| 20120065406 | Improved Preparation Method for D-Biotin - The invention discloses the improved preparation method for D-Biotin. If the composite method takes the malonic acid diester as the raw material, the finial biotin will be generated with impurities. The features of the invention refers to the improved preparation method for D-Biotin includes: firstly, (3aS,4S,6aR)-1,3-dibenzyl-4-(ω,ω,ω-3 -alkoxycarbonyl bytyl)-4H-1H-thiophene[3,4-d]iminazole-2,4(1H)-ketone is got after the methane tricarboxylic acid trialkyl ester and (3aR,8aS,8bS)-1,3-dibenzyl-2-oxo-10H-iminazole[3,4-d]thiophene[1,2-a]sulfuryl halide have the condensation reaction in the alkaline environment and then D-Biotin can be got after the reaction process of hydrolysis, decarboxylation and closed loop. The invention succeeds in greatly improving the biotin quality from the original basis and simultaneously avoids the generation of impurities and the occurrence of side reaction. | 03-15-2012 |
