反应详情

A mixture of 4.0 grams of 2-anilino-3-hydroxy-4-(phenylimino)-2-cyclobuten-1-one and 3.4 grams of 1-ethylpiperazine is heated at 194°-198° C. in an atmosphere of dry nitrogen for 30 minutes. The cooled solid is comminuted, washed with anhydrous ethyl ether, and dried and the resulting solid is then extracted with 50 ml. of anhydrous benzene. The benzene solution is treated with activated carbon, filtered, concentrated and cooled. A crystalline solid forms and this is separated by filtration and dissolved in distilled water at room temperature and the solution is filtered and concentrated. A precipitate forms and is separated by filtration to give 1-[2-hydroxy-3-(4-ethyl-1-piperazinyl)-4-oxo-2-cyclobuten-1-ylidene]-4-ethylpiperazinium hydroxide inner salt melting at about 179.5°-183° C.

1. temperatureis heated at 194°-198° C. in an atmosphere of dry nitrogen for 30 minutes
2. customThe cooled solid is comminuted
3. washwashed with anhydrous ethyl ether
4. customdried
5. extractionthe resulting solid is then extracted with 50 ml
6. additionThe benzene solution is treated with activated carbon
7. filtrationfiltered
8. concentrationconcentrated
9. temperaturecooled
10. customA crystalline solid forms and this is separated by filtration
11. dissolutiondissolved in distilled water at room temperature
12. filtrationthe solution is filtered
13. concentrationconcentrated
14. customA precipitate forms and is separated by filtration