Acetaldehyde → 3-(5-Ethylamino-3H-isobenzofuran-1-ylidene)-1,3-dihydro-indol-2-one

Reaction equation

[NH2:1][C:2]1[CH:3]=[C:4]2[C:8](=[CH:9][CH:10]=1)[C:7](=[C:11]1[C:19]3[C:14](=[CH:15][CH:16]=[CH:17][CH:18]=3)[NH:13][C:12]1=[O:20])[O:6][CH2:5]2.[CH:21](=O)[CH3:22].C(O[BH-](OC(=O)C)OC(=O)C)(=O)C.[Na+]>>[CH2:21]([NH:1][C:2]1[CH:3]=[C:4]2[C:8](=[CH:9][CH:10]=1)[C:7](=[C:11]1[C:19]3[C:14](=[CH:15][CH:16]=[CH:17][CH:18]=3)[NH:13][C:12]1=[O:20])[O:6][CH2:5]2)[CH3:22]

Participants

Reactant 3

HCID 177Acetaldehyde

HCID 5049666Sodium triacetoxyborohydride

HCID 696596273-(5-Amino-2-benzofuran-1(3H)-ylidene)-1,3-dihydro-2H-indol-2-one

Product 1

HCID 696602193-(5-Ethylamino-3H-isobenzofuran-1-ylidene)-1,3-dihydro-indol-2-oneYield 25.5%

Procedure

A mixture of 3-(5-Amino-3H-isobenzofuran-1-ylidene)-1,3-dihydro-indol-2-one (50.0 mg, 0.189 mmol), acetaldehyde (10.0 mg, 0.227 mmol), and sodium triacetoxyborohydride (52.1 mg, 0.246 mmol) was stirred at room temperature for 50.5 h. The reaction was then partitioned between EtOAc and H2O. The organic phase was washed with H2O, brine and then dried with Na2SO4. The solvent was removed in vacuo and the solid chromatographed (CHCl3/MeOH, 97.5:2.5) to afford the title compound (14.1 mg, 25%) as a yellow solid.