Na. Hassan, Syntheses of furo[3,2-e][1,2,4]triazolo[1,5-c]pyrimidines and furo[2 ',3 ': 5,6]-pyrimido[3,4-b][2,3-elindolo[1,2,4]triazine as a new ring system, MOLECULES, 5(6), 2000, pp. 826-834
2-Amino-4,5-di-(2-furyl)furan-3-carbonitriie (1) reacted with triethyl orth
oacetate to afford the corresponding 2-ethoxyimine derivative (2). The latt
er compound reacted with phenyl hydrazine, p-fluorobenzylamine and sodium h
ydrogen sulfide, respectively, to afford the corresponding furo[2,3-d]pyrim
idine derivatives (3-5). Compound 1 also reacted with carbon disulfide and
phenyl isocyanate to afford 5,6-di-(2-furyl)-1H-4H-furo[2,3-d]-[1,3-thiazin
]-4-imino-2-thione (6) and 5,6-di-(2-furyl)-1H-3H-3-phenylfuro[2,3-d]pyrimi
din-4- imine-2-one (7), respectively. Treatment of compound 2 with hydrazin
e hydrate at 0 degrees C afforded compound 8, while on boiling 5,6-di-(2-fu
ryl)-3H,4H-4-imino-2-methylfuro-[2,3-d]pyrimidin-3-amine (9) was isolated.
Treatment of 9 with carbon disulfide, cyanogen bromide, ethyl cyanoacetate,
diethyloxalate and triethyl orthoformate gave the corresponding furo[3,2-e
][1,2,4]triazolo[1,5-c]pyrimidines (10-14). Reaction of 9 with isatin and N
-acetyl isatin gave the condensation products 15 and 16 respectively.