Acetic Acid → HCID 70202500, compound

Participants

Reaction Steps

to a solution, cooled to 19° C. and under cover of nitrogen, of 9 g of 5H,10H-imidazo[1,2-a]indeno[1,2-e]pyrazin-4-one in 180 ml of dimethyl sulphoxide are added 4 g of 60% sodium hydroxide portionwise with stirring. The stirring is continued for 35 minutes and 7.8 g of tert-butyl glyoxylate are added dropwise. After stirring for 18 hours the reaction mixture is treated with 9 ml of acetic acid and 150 ml of water. The suspension is filtered and the insoluble material is washed with water (2×200 ml) and then with acetone (3×100 ml) and dried at 80° C. under reduced pressure. The crude product obtained (5.85 g) is heated to about 90°-10° C. in 300 ml of dimethylformamide and filtered immediately, and 150 ml of methanol and 200 ml of water are added to the filtrate, which is left in the ice compartment of a refrigerator overnight. The crystals formed are filtered off, washed with 20 ml of water and dried at 80° C. under vacuum (2 mmHg; 0.26 kPa) to give 3.4 g of 10-(tert-butoxycarbonylmethylene)-5H,10H-imidazo-[1,2-a]indeno[1,2-e]pyrazin-4-one, in the form of a red solid melting above 260° C. (Analysis % calculated C: 68.05, H: 5.11, N: 12.53, O: 14.31, % found C: 68.0, H: 5.6, N: 12.5, O: 14.3).

Provenance & Evidence