767340-03-4, name is (2Z)-4-Oxo-4-[3-(trifluoromethyl)-5,6-dihydro[1,2,4]triazolo[4,3-a]pyrazine-7(8H)-yl]-1-(2,4,5-trifluorophenyl)but-2-en-2-amine, belongs to Pyrazines compound, is considered to be a conventional heterocyclic compound, which is widely used in drug synthesis. The chemical synthesis route is as follows. 767340-03-4
Into a 500 ml flask were charged chloro(l,5-cyclooctadiene)rhodium(I) dimer {[Rh(cod)Cl]2}(292 mg, 1.18 mmol) and (R,S) f-butyl Josiphos (708 mg, 1.3 mmol) under a nitrogen atmosphere. Degassed MeOH was then added (200 mL) and the mixture was stirred at room temperature for 1 h. Into a 4 L hydrogenator was charged the enamine amide 2Lambda (118 g, 0.29 mol) along with MeOH (1 L). The slurry was degassed. The catalyst solution was then transferred to the hydrogenator under nitrogen. After degassing three times, the enamine amide was hydrogenated under 200 psi hydrogen gas at 50 0C for 13 h. Assay yield was determined by EtaPLC to be 93% and optical purity to be 94% ee.The optical purity was further enhanced in the following manner. The methanol solution from the hydrogenation reaction (18 g in 180 mL MeOH) was concentrated and switched to methyl t- butyl ether (MTBE) (45 mL). Into this solution was added aqueous Eta3PO4 solution (0.5 M, 95 mL).After separation of the layers, 3NNaOH (35 mL) was added to the water layer, which was then extracted with MTBE (180 mL + 100 mL). The MTBE solution was concentrated and solvent switched to hot toluene (180 mL, about 75 0C). The hot toluene solution was then allowed to cool to 0 0C slowly (5 – 10 h). The crystals were isolated by filtration (13 g, yield 72%, 98 – 99% ee); m.p. 114.1 – 115.7 0C. lH NMR (300 MHz, CD3CN): delta 7.26 (m), 7.08 (m), 4.90 (s), 4.89 (s), 4.14 (m), 3.95 (m), 3.40 (m), 2.68(m), 2.49 (m), 1.40 (bs).Compound 2-5 exists as amide bond rotamers. Unless indicated, the major and minor rotamers are grouped together since the carbon-13 signals are not well resolved: 13c NMR (CD3CN): delta 171.8, 157.4 (ddd , JCF = 242.4, 9.2, 2.5 Hz), 152.2 (major), 151.8 (minor), 149.3(ddd; JCF = 246.7, 14.2, 12.9 Hz), 147.4 (ddd, JCF = 241.2, 12.3, 3.7 Hz), 144.2 (q, JCF = 38.8 Hz), 124.6 (ddd , JCF = 18.5, 5.9, 4.0 Hz), 120.4 (dd , JCF = 19.1, 6.2 Hz), 119.8 (q, JCF = 268.9 Hz), 106.2 (dd , JCF = 29.5, 20.9 Hz), 50.1, 44.8, 44.3 (minor), 43.2 (minor), 42.4, 41.6 (minor), 41.4, 39.6, 38.5 (minor), 36.9. The crystalline free base 2^ can also be isolated as follows:(a) The reaction mixture upon completion of the hydrogenation step is charged with 25 wt% of Ecosorb C-941. The mixture is stirred under nitrogen for one h and then filtered. The cake is washed with 2L/kg of methanol. Recovery of free base is about 95% and optical purity about 95% ee.(b) The freebase solution in methanol is concentrated to 3.5-4.0 L/kg volume (based on free base charge) and then solvent-switched into isopropanol (IPA) to final volume of 3.0 L/kg IPA.(c) The slurry is heated to 40 0C and aged 1 h at 4O0C and then cooled to 25 0C over 2 h. EPO
Statistics shows that 767340-03-4 is playing an increasingly important role. we look forward to future research findings about (2Z)-4-Oxo-4-[3-(trifluoromethyl)-5,6-dihydro[1,2,4]triazolo[4,3-a]pyrazine-7(8H)-yl]-1-(2,4,5-trifluorophenyl)but-2-en-2-amine.
Reference:
Patent; MERCK & CO., INC.; WO2006/33848; (2006); A1;,
Pyrazine – Wikipedia,
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