反应详情

A mixture of 10 g of ethyl 4-hydroxybenzoate, 5 mL of acetic acid, 0.8 g of 5% rhodium on alumina, and 200 mL of ethanol was shaken under 55 psi of hydrogen for 48 h, filtered and concentrated under reduced pressure. The residue was taken up in 200 mL of toluene and again concentrated under reduced pressure to remove acetic acid. Drying under vacuum overnight gave 11 g of product, which was predominantly cis (83:17 cis: trans by HPLC), as a colorless oil: MS (m+1)=173.2; 1H NMR (400 MHz, CDCl3) 4.1 (dd, 2H), 3.9 (m, cis isomer, 0.85H), 3.6 (m, trans isomer, 0.15H), 2.4 and 2.2 (m, 1H), 2.0 (m, 2H), 1.62 (m, 6H), 1.2 (t, 3H).

1. filtrationfiltered
2. concentrationconcentrated under reduced pressure
3. concentrationagain concentrated under reduced pressure
4. customto remove acetic acid
5. customDrying under vacuum overnight