Reaction #47225

Reaction equation

3,5-bis[2-(3,5-di-tert-butylphenyl)ethyl)benzyl alcohol

pyridinium chlorochromate

KBr

→

15

Yield 99.1%

3,5-Bis[2-(3,5-di-tert-butylphenyl)ethyl)benzaldehyde

Yield 99.1%

Solvents

dichloromethane

Conditions

Workup

1. 1
   Otherthe solvent was removed
2. 2
   Otherthe residue purified by column chromatography over silica with dichloromethane-light petroleum (2:3) as eluent

Procedure

Hydroxylamine hydrochloride (77.66 g, 1.117 mol) was dissolved in N,N-dimethylformamide (216 cm3). Powdered potassium hydroxide (73.45 g, 1.309 mol) was added and the solution stirred for 10 min, evolving heat and giving a white precipitate. The suspension was filtered, the solid washed with N,N-dimethylformamide (40 cm3) and the filtrates combined and cooled to 0° C. Ethyl acetate (48.6 cm3) was added to give a stock solution which was stirred at 0° C. A suspension of 3,5-bis(3,5-di-tert-butylphenyl-E-vinyl)benzyl alcohol 13 (1.00 g, 1.86 mmol) and stock solution (20 cm3) was heated to 100° C. Stock solution was added in 20 cm3 portions at 20 min intervals with heating maintained at 100° C., and the mixture, which had turned into a homogeneous solution, heated to 100° C. for a further 1 h then allowed to cool. Water (100 cm3) was added and the product extracted into ether (2×100 cm3). The extracts were washed with aqueous hydrochloric acid (3 M, 2×75 cm3) and brine (75 cm3), dried over anhydrous magnesium sulphate, filtered and the solvent removed. The residue was purified by column chromatography over silica with dichloromethane as eluent to leave 3,5-bis[2-(3,5-di-tert-butylphenyl)ethyl)benzylalcohol (957 mg, 95%) as a white solid, mp 101° C. (Found: C, 86.7; H, 10.4. C39H56O requires C, 86.6; H, 10.4%); νmax (KBr)/cm−1 3401 (OH) and 1600 (C═C); λmax(CH2Cl2)/nm 265 (log(ε/dm3mol−1cm−1) 2.95), 269 sh (2.93), 305 (2.57), 317 (2.56) and 330 sh (3.37); δH(400 MHz, CDCl3) 1.34 (36H, s, t-butyl), 1.57 (1H, s, OH), 2.92 (8H, s, CH2CH2), 4.68 (2H, d, J 6, CH2OH), 7.03 (1H, s, bp-H), 7.07 (4H, d, J 2, sp-H), 7.09 (2H, d, J 1, bp-H) and 7.29 (2H, dd, J 2, sp-H); δC(100.6 MHz, CDCl3) 31.5, 34.8, 38.3, 38.7, 65.5, 119.9, 122.6, 124.7, 128.1, 140.85, 140.90, 142.6 and 150.7; m/z (APCI+) 523.4 ((M-OH)+, 100%) and 558.4 (MNH4+, 54%). A solution of 3,5-bis[2-(3,5-di-tert-butylphenyl)ethyl)benzyl alcohol (914 mg, 1.69 mmol) and pyridinium chlorochromate (729 mg, 3.38 mmol) in dichloromethane (4 cm3) was stirred at room temperature for 18 h, the solvent was removed and the residue purified by column chromatography over silica with dichloromethane-light petroleum (2:3) as eluent to leave 15 (902 mg, 99%) as a viscous oil, mp 74-75° C. (Found: C, 86.8; H, 10.1. C39H54O requires C, 86.9; H, 10.1%); νmax(KBr)/cm−1 1702 (C═O) and 1599 (C═C); λmax(CH2Cl2)/nm 258 (log(ε/dm3 mol−1cm−1) 4.18) and 300 (3.45); δH(400 MHz, CDCl3) 1.38 (36H, s, t-butyl), 2.95 (8H, m, CH2CH2), 7.03 (4H, d, J 2, sp-H), 7.25 (1H, s, bp-H), 7.30 (2H, dd, J 2, sp-H), 7.57 (2H, s, J 1.5, bp-H) and 9.98 (1H, s, CHO); δC(100.6 MHz, CDCl3) 31.5, 34.8, 37.9, 38.4, 120.1, 122.7, 127.5, 135.3, 136.7, 140.2, 143.0, 150.8 and 192.8; m/z (EI+) 538.3 (M+, 18%).

Source