Formic Acid → 5-Formylamino-2,2,4,6,7-pentamethyl-2,3-dihydrobenzofuran
Reaction equation
[NH2:1][C:2]1[C:3]([CH3:15])=[C:4]([CH3:14])[C:5]2[O:9][C:8]([CH3:11])([CH3:10])[CH2:7][C:6]=2[C:12]=1[CH3:13].[CH:16](O)=[O:17]>>[CH:16]([NH:1][C:2]1[C:3]([CH3:15])=[C:4]([CH3:14])[C:5]2[O:9][C:8]([CH3:10])([CH3:11])[CH2:7][C:6]=2[C:12]=1[CH3:13])=[O:17]Participants
3
Procedure
5-Amino-2,2,4,6,7-pentamethyl-2,3-dihydrobenzofuran (1.00 g, 4.87 mmol) was dissolved in formic acid (20 ml) and the solution was heated under reflux for 48 hours. The reaction mixture was concentrated under reduced pressure. Saturated sodium bicarbonate solution was added to the residue and the mixture was extracted with chloroform. The extract was washed with saturated saline, dried and then concentrated under reduced pressure. The residue was purified by column chromatography on silica gel (chloroform-methanol, 97:3) to obtain the desired compound (1.06 g, yield: 93.3%). A part of it was recrystallized from dichloromethan-isopropyl ether to obtain white prisms, m.p. 177°-179° C.