Sodium Hydroxide → 3,4-Dihydro-1-methyl-6-[4-(trifluoro-methyl)phenyl]pyrrolo[1,2-a]pyrazine fumarate

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Reaction Steps

N-[2-[2-[4-(Trifluoromethyl)phenyl]-pyrrol-1-yl]ethyl]acetamide (5.4 g) was treated with 25 ml of phosphorus oxychloride under argon and boiled for 1 hour while stirring. The reaction mixture was hydrolyzed at 0° C. with 100 ml of 2N sodium hydroxide solution and 150 ml of 28% sodium hydroxide methylene chloride (1×300 ml, 2×100 ml). The organic extracts were combined, dried with MgSO4 and freed from solvent. 2.5 g of a total of 5.0 g of crude product was dissolved in a 30-fold amount of ethanol and treated with 1.1 equivalents of a saturated solution of fumaric acid in ethanol. There was obtained 2.7 g (76%) of 3,4-dihydro-1-methyl-6-[4-(trifluoro-methyl)phenyl]pyrrolo[1,2-a]pyrazine fumarate (1:1); m.pt.: 165°-167° C. (dec.).

Provenance & Evidence