Triethylamine → HCID 66581099, compound

Participants

Reaction Steps

To a solution of 4-[3-(ethoxycarbonyl)-5,5-dioxidothiochromeno[4,3-c]pyrazol-1 (4H)-yl]benzoic acid (21.88 g; 53.05 mmol; 1 eq.) in THF (350 ml) is added triethylamine (14.71 ml; 106.11 mmol; 2 eq.) followed by isobutyl chloroformate (13.83 ml; 106.11 mmol; 2 eq.) at 0° C. under nitrogen. The reaction mixture is stirred at rt for 30 min then cooled at 0° C. Sodium borohydride (10 g; 265.27 mmol; 5 eq.) is added portionwise. After 5 h, THF (100 mL) is added and the reaction mixture is heated at 35° C. for 1 day then at rt for 2 days. Sodium borohydride is added (1 eq) and after 6 h stirring the reaction is quenched by dropwise addition of water at 0° C. over 2 h. The product is extracted with EtOAc, the organic layers washed with HCl 1 m (2×) and brine then dried over MgSO4. After evaporation of the solvent, the residue is taken up in DCM and HCl 1 m. The precipitate formed is filtered off and recrystallized in DCE to afford the title compound as a white solid. 1H NMR (DMSO-d6) δ 8.05-8.02 (m, 1H), 7.68-7.48 (m, 6H), 6.88-6.84 (m, 1H), 5.76 (s, 2H), 4.99 (s, 2H), 4.37 (q, J=7.1 Hz, 2H), 3.90 (s, 1H), 1.35 (t, J=7.1 Hz, 3H). HPLC (max plot) 68.2%; Rt 3.02 min. MS (ESI+): 398.9

Provenance & Evidence