Triethylamine → 3,3-Dimethyl-8-{[(2S)-2-(phenoxymethyl)pyrrolidin-1-yl]carbonyl}-3,4-dihydropyrimido[1,2-a]indol-10(2H)-one

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Reaction Steps

To a solution of 3′,3′-dimethyl-3′,4′-dihydro-2′H-spiro[1,3-dioxane-2,10′-pyrimido[1,2-a]indole]-8′-carboxylic acid (0.090 g, 0.284 mmol) in CH2Cl2 (7 mL) was added (2S)-2-(phenoxymethyl)pyrrolidine (0.75 g, 0.427 mmol), DCC (0.082 g, 0.039 mmol), HOBT (0.038 g, 0.281 mmol) and Et3N (0.045 mL, 0.277 mmol) and the solution stirred overnight at rt. The reaction was filtered through 1 cm of silica gel washing with EtOAc. The filtrate was dried over Na2SO4, filtered, concentrated and purified on silica gel eluting with acetone/hexane (30/70). The resulting white foam was dissolved in CH2Cl2 (1.5 mL) and methanesulfonic acid (1 mL) was added and the solution was stirred at rt overnight. The reaction was poured onto ice, basified to pH 11 with ammonium hydroxide and extracted with EtOAc (3×). The combined organic extracts were dried over Na2SO4, filtered, concentrated and purified on Biotage Si 12+M cartridge silica gel eluting with acetone/hexane (35/65) to give the title compound as a yellow foam (0.021 g, 20%). NMR (400 Mz, DMSO-d6): consistent. MS (ES+) m/z 418.3 [M+H].

Provenance & Evidence