Triethylamine → 8-chloro-2-methyl-5-((6-(trifluoromethyl)pyridin-3-yl)ethynyl)-2,3,4,5-tetrahydro-1H-pyrido[4,3-b]indole

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Reaction Conditions

Reaction Steps

A mixture of 5-bromo-2-(trifluoromethyl)pyridine (4.6 g, 0.02 mol), triphenylphosphine (0.053 g, 0.00020 mol), triethylamine (1.7 mL, 0.01227 mol) and 8-chloro-5-ethynyl-2-methyl-2,3,4,5-tetrahydro-1H-pyrido[4,3-b]indole (1 g, 0.00409 mol) was dissolved in acetonitrile (30 mL) and heated by microwave at 80° C. for 30 min. The reaction was monitored by TLC. After completion of reaction, the mixture was cooled to RT and diluted with water (100 mL). The mixture was extracted with EtOAc (3×100 mL), and the organic layer was dried over anhydrous sodium sulfate and concentrated under reduced pressure to obtain product. Product was purified by column chromatography using silica (100-200 mesh) and 3% MeOH:DCM as eluent, diameter of column—5 cm, height of silica—approx. 5 inch) then further purified by preparative TLC to give the desired compound as a yellow colored solid (0.06 g, 4% yield). The product (0.02 g, 0.000051 mol) was dissolved in THF (1.0 mL). A solution of oxalic acid dihydrate (0.007 g, 0.000055 mol) in THF (2 mL) was added and stirred for 30 min at RT. The precipitate was filtered and dried to give oxalate salt as an off-white solid (0.015 g, 60% yield). 1H NMR (CD3OD, oxalate salt) δ (ppm): 8.90 (s, 1H), 8.25 (d, 1H), 7.85 (d, 1H), 7.70 (d, 1H), 7.60 (s, 1H), 7.40 (d, 1H), 4.50 (m, 2H), 3.80 (m, 2H), 3.40 (m, 1H), 3.18 (m, 1H), 3.10 (s, 3H).

Provenance & Evidence