Ethylenediamine → Pyrazino[2,3-b]pyrazine, decahydro-

To an ice-cold solution of 206 grams of 70% aqueous ethylenediamine (144 grams, 2.4 moles) was added dropwise 115 grams of a 30% aqueous solution of glyoxal (34.8 grams, 0.6 mole). When the addition was completed, the solution was stirred at room temperature for 30 minutes, then concentrated by removing approximately 75 ml of water at 150 mm Hg. The mixture was cooled in an ice bath and the precipitated solid was filtered, stirred in 100 ml of 50% ethanol-isopropanol, and again filtered. The yield of product was 50.6 grams (59%), m.p. 222°-225° C. (dec; literature m.p. 230°-232° C.).

1. additionWhen the addition
2. concentrationconcentrated
3. customby removing approximately 75 ml of water at 150 mm Hg
4. temperatureThe mixture was cooled in an ice bath
5. filtrationthe precipitated solid was filtered
6. stirringstirred in 100 ml of 50% ethanol-isopropanol
7. filtrationagain filtered

ORD record

ord-dea5ac2bbf11438ba905f40648dfb6ee

Source dataset

uspto-grants-1980_08

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04218559