Thiophene-3,4-diamine → 2-butyl-1H-thieno[3,4-d]imidazole

A mixture of 3,4-diaminothiophene (1.7 g) and ethyl valeroimidate hydrochloride (3.0 g) in ethanol (30 ml) was stirred at room temperatures for 1.5 hour. 10 The reaction mixture was concentrated and the residue was dissolved in a mixture of ethyl acetate and a saturated aqueous solution of sodium hydrogencarbonate. The organic layer was washed with water, dried and concentrated to dryness. The concentrate was purified by silica gel column chromatography to give crystals. Recrystallization from isopropyl ether afforded colorless crystals (0.72 g, 27%), m.p. 118°-120° C. 1H-NMR(200 MHz, CDCl3)δ: 0.95(3H,t), 1.35-1.54(2H,m), 1.73-1.88(2H,m), 2.79(2H,t), 6.75(2H,br s), 8.50(1H,br s). IR(KBr)cm-1 :3200-2200, 1530, 1480, 1440, 1390, 1240, 1230, 1160, 830, 815, 760, 740.

1. concentration10 The reaction mixture was concentrated
2. dissolutionthe residue was dissolved in a mixture of ethyl acetate
3. washThe organic layer was washed with water
4. customdried
5. concentrationconcentrated to dryness
6. customThe concentrate was purified by silica gel column chromatography
7. customto give crystals
8. customRecrystallization from isopropyl ether afforded colorless crystals (0.72 g, 27%), m.p. 118°-120° C

ORD record

ord-dae19dc00e32474e9d22ba7144a993ae

Source dataset

uspto-grants-1995_10

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05463073