Hydrochloric Acid → 6-ethyl-5,7-dimethyl-2,3-dihydro-1H-2,4,7a,8-tetraaza-cyclopenta[a]indene

Beteiligte Stoffe

Reaktionsschritte

A mixture of 3-amino-2,6-dihydro-4H-pyrrolo[3,4-c]pyrazole-5-carboxylic acid tert-butyl ester (0.6 g; 2.68 mmol; 1 eq.) and 3-ethyl-2,4-pentanedione (0.36 mL; 2.68 mmol; 1 eq.) in AcOH (8 mL) was stirred at room temperature for 32 hours. Aq. 32% HCl (1.05 mL; 10.7 mmol; 4 eq.) was added and the resulting mixture stirred for a further 16 hours. After concentration in vacuo, the residue was triturated in MTBE and the precipitate filtered off and dried. The solid was taken up in ethyl acetate and washed with 1M aq. NaOH (2×), dried over magnesium sulfate and concentrated in vacuo to afford the title compound (450 mg, 94%) as a beige solid. 1H NMR (DMSO-d6) δ 4.05-4.00 (m, 4H), 2.73-2.63 (m, 5H), 2.51 (s, 3H), 1.12 (t, J=7.4 Hz, 3H). UPLC/MS: (MS+) 217.3 ([M+H]+).

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