Ethanol → HCID 13321941, compound

Participants

Reaction Steps

Under argon, 0.2 g of 6,8-dinitro-5H-pyrimido[5,4-b]indole-2-carboxylic acid (Example 8) is refluxed in 20 ml of ethanol with the addition of 1 ml of concentrated sulfuric acid for 8 hours. Subsequently the solution is concentrated to half the quantity and dissolved in methylene chloride. The solution is washed first with water, then with sodium bicarbonate solution, and finally again with water, dried, and concentrated, yielding 0.18 g of 6,8-dinitro-5H-pyrimido[5,4-b]indole-2-carboxylic acid ethyl ester, mp 295°-299° C.

Provenance & Evidence