Reference of 193274-02-1 , The common heterocyclic compound, 193274-02-1, name is tert-Butyl 3a-benzyl-2-methyl-3-oxo-3a,4,6,7-tetrahydro-2H-pyrazolo[4,3-c]pyridine-5(3H)-carboxylate, molecular formula is C19H25N3O3, its traditional synthetic route has been very mature, but the traditional synthetic route has various shortcomings, such as complicated route, low yield, poor purity, etc., below Introduce a new synthetic route.
Step D. 3a(R)-Benzyl-2-methyl-2,3,3a,4,6,7-hexahydro-pyrazolo[4,3-c]pyridin-3-one (L)-tartrate To a 2 liter, round bottom flask, equipped with a mechanical stirrer, addition funnel, and a thermocouple was added, sequentially, 3a-(R,S)-benzyl-2-methyl-3-oxo-2,3,3a,4,6,7-hexahydro-pyrazolo[4,3-c]-pyridine-5-carboxylic acid tert-butyl ester (prepared according to Step C, 51.5 g, 0.15 moles, 1.0 equivalents) and methylene chloride (515 ml, 10 volumes). The mixture was agitated to form a solution which was then cooled to an internal temperature of 0 C.-5 C. To the cooled mixture was added trifluoroacetic acid (TFA, 130 ml, 192 g, 1.68 moles, 11.2 eq., 2.5 volumes). The TFA was added via the addition funnel over 15 minutes while maintaining an internal temperature of 0 C.-5 C. The reaction mixture was warmed to about 20 C. over 3 hours and then the reaction mixture was cooled to 10 C.-15 C. To the cooled reaction mixture was added sodium carbonate (92 g, 0.868 moles) in water (920 mL) over 20 minutes. The pH was 7.5. The reaction mixture was transferred to a 2 liter separatory funnel and allowed to settle. The organic portion was decanted and the aqueous portion was extracted with methylene chloride (130 ml, 2.5 volumes). The combined organic portions were transferred back to the 2 liter reactor and to it was added L-tartaric acid (24.77 g, 0.165 moles, 1.1 equivalents) dissolved in acetone (354 ml, about 7 volumes) and water (44 mL, about 1 volume). The reaction mixture was agitated and heated at about 38 C. overnight. The resultant slurry was cooled to 0 C.-5 C., granulated for 1 hour, then filtered. The solids were washed with 100 ml of cold acetone and then dried in vacuo at 40 C.-50 C. for 16 hours to afford 51.86 g (87.9% yield) of the title compound of Step D.
The synthetic route of 193274-02-1 has been constantly updated, and we look forward to future research findings.
Reference:
Patent; Busch, Frank R; Chiu, Charles K; Meltz, Clifford N; Post, Ronald J; Rose, Peter R; US2002/2283; (2002); A1;,
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem