Sodium Hydroxide → 4-Chloro-5,6,10,11-tetrahydro-8-methylbenz[g]pyrazino[1,2-a]indole fumarate

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Reaction Conditions

Reaction Steps

N-[2-(6-Chloro-4,5-dihydro-1H-benz[g]indol-1-yl)ethyl]acetamide (6.0 g) was treated with 30 ml of phosphorus oxychloride and the mixture was stirred at 100° C. for 30 minutes. The cooled mixture was added to 2500 g of ice-water and treated with 100 ml of 2N sodium hydroxide solution and 200 ml of 28% sodium hydroxide solution. The mixture was extracted once with 300 ml of methylene chloride and twice with 100 ml of methylene chloride each time, the organic phases were combined, dried with MgSO4 and freed from solvent. 5.7 g of residue were dissolved in a 20-fold amount of hot ethanol and treated while hot with 1.1 equivalents of a saturated solution of fumaric acid in ethanol. There were obtained 6.6 g (82%) of 4-chloro-5,6,10,11-tetrahydro-8-methylbenz[g]pyrazino[1,2-a]indole fumarate (1:1); m.pt.: 191°-192° C. (dec.).

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