Formaldehyde → (S)-7-Chloro-10-[3-(2-methoxy-ethyl)-4-methyl-piperazin-1-yl]-2-methyl-4H-3-thia-4,9-diaza-benzo[f]azulene

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Reaction Steps

Combine (S)-7-chloro-10-[3-(2-methoxy-ethyl)-piperazin-1-yl]-2-methyl-4H-3-thia-4,9-diaza-benzo[f]azulene (33.3 g, 85.2 mmol) and 1,2-dichloroethane (DCE, 500 mL). Add formaldehyde (37% wt. in water, 6.91 g solution, 2.56 g, 85.2 mmol) in one portion and stir at ambient temperature for 5 minutes. Add sodium triacetoxyborohydride (3.41 g, 16.1 mmol) in portions over 5-10 minutes, keeping the pot temperature below 25° C. Stir at ambient temperature overnight. Add saturated aqueous sodium bicarbonate (333 mL). Stir for 15 minutes, and then separate layers. Extract the aqueous layer with methylene chloride (250 mL). Wash the combined organic layers with water (3×333 mL), dry over sodium sulfate, and then concentrate ins vacuo to a residue (>100% recovery). Purify the residue by flash column chromatography, eluting with (100% CH2Cl2 to 93/7 CH2Cl2/MeOH) 91.2% recovery of the title compound. 1H NMR (500 MHz, DMSO-d6) δ 1.49 (m, 1H), 1.82 (m, 1H), 2.13 (m, 2H), 2.20 (s, 3H), 2.27 (s, 3H), 2.74 (m, 2H), 2.98 (bt, 1H), 3.19 (s, 3H), 3.32 (m, 2H), 3.77 (bm, 2H).

Provenance & Evidence