| 78% |
With 1-ethyl-(3-(3-dimethylamino)propyl)-carbodiimide hydrochloride; In acetonitrile; at 80℃; for 5h; |
Compound 6 (0.6 g, 1.95 mmol),1-ethyl-(3-dimethylaminopropyl)carbonic acid diimine hydrochloride (EDCI, 0.51 g, 2.65 mmol),2,4-difluorobenzylamine (0.29 ml, 2.44 mmol) in acetonitrile (10 ml) was heated to 80 C for 5 h.The reaction was quenched by the addition of 6 ml of water, the lower layer was a viscous yellow oily liquid, and the upper layer was suspended.The solvent of acetonitrile was evaporated under reduced pressure and suction filtered to give a crude material (yel.The crude product was recrystallized from AcOEt/petroleum ether = 4/1 solvent 15 ml to give compound 7 0.66 g(Rf = 0.25, TLC developer: AcOEt),The yield was 78%. |
| 85 g |
|
(3S,11aR)-3-methyl-6-(methyloxy)-5,7-dioxo-2,3,5,7,11,11a- hexahydro[1,3]oxazolo [3,2-a]pyrido[1,2-d]pyrazine-8-carboxylic acid (100 gm) and carbonyldimidazole (78.89 gm) were suspended in acetonitrile (1000 mL). The mixture was heated to a temperature of 75C and stirred for 1 hour. The resulting solution was cooled to a temperature of 20C and treated with 2,4- difluorobenzyl amine solution (55.2 gm was dissolved in 200 mL of acetonitrile). The reaction mixture was maintained for 2 hours, concentrated and the compound was extracted with ethyl acetate (1000 mL). Isopropyl alcohol (500 mL) was added at a temperature of 40C, stirred the reaction mass for 30 minutes at a temperature of 50C and the cooled the reaction mass to 25C. The reaction mixture was maintained for 8 hours at the same temperature. The product was collected by filtration and dried under vacuum (85 gm). |
|
With 4-methyl-morpholine; chloroformic acid ethyl ester; In dichloromethane; at 0℃;Flow reactor; Large scale; |
A solution of l-(2,2-dimethoxyethyl)-5-methoxy-6-(methoxycarbonyl)-4-oxo-l,4- dihydropyridine-3 -carboxylic acid (V) in acetic acid / Dimethyl carbonate ( 5.0Kg, 15.8 moles) and methane sulfonic acid (533.0 g, 5.6 moles) were introduced in micro channel reactor. After residence time of 9 mins at l30C gives 5-methoxy- 6-(methoxycarbonyl)-4-oxo- 1 -(2-oxoethyl)- 1 ,4-dihydropyridine-3 -carboxylic acid (IVa). The reaction mixture was further introduced in a Tube Flow reactor and cyclised with solution of R-3 amino butanol ( 1.97 kg, 22.2 moles) in Dimethyl carbonate at l00C at a residence time of 5.15 mins followed by quenching with Aq HC1 solution. The organic layer containing (4S,l2aR)-7-methoxy-4-methyl- 6,8-dioxo-3,4,6,8,l2,l2a-hexahydro-2H-pyrido[r,2':4,5]pyrazino[2,l- b][l,3]oxazine-9-carboxylic acid (III) was separated and introduced in a Tube Flow Reactor with a solution of N-Methyl Morpholine (2.25 Kg, 22.22 moles) and a solution of 2,4-diflurobenzylamine(3.l8 kg, 22.2 moles) in MDC solvent and reacted in presence of Ethyl chloroformate (1.73 Kg, 20.63 moles) at 0C. After a residence time of l. l5mins yields (4S,l2aR)-N-(2,4-Difluorobenzyl)-7-methoxy- 4-methyl-6,8-dioxo-3,4,6,8,l2,l2a-hexahydro-2H-pyrido[r,2':4,5]pyrazino[2,l- b][l,3]oxazine-9-carboxamide (Ila) which was isolated in IPA after acid base workup. (0250) HPLC purity: 99.0% (0251) Yield: 80.0%. |
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