Pyridine → HCID 86737370, compound

Participants

Reaction Conditions

Reaction Steps

A solution of pyridine (70.3 g, 0.89 mol) and chromium trioxide (44.5 g, 0.445 mol) in methylene chloride (1.8 l) in a nitrogen atmosphere is stirred for 45 minutes. Celite (180 g) is added followed by (2S*, 3R*)-3-benzyloxy-1,1-ethylenedioxy-2-methyl-2-(4'-hydroxypentyl)-cyclohexane (25.8 g, 0.074 mol) in methylene chloride (100 ml). The mixture is stirred for 90 minutes at 23° C. The mixture is then filtered and the celite cake is washed with methylene chloride (10×200 ml). The filtrate and washings are combined and the solvents are removed under reduced pressure to give a dark oil, which is diluted with ether (750 ml) and filtered. The ether phase is dried (MgSO4) and the solvents are removed at reduced pressure. The crude product (21 g) is chromatographed on SilicAR CC-7 (300 g, Mallinckrodt) in hexane. Elution with 6% ethyl acetate/hexane gives (2S*, 3R*)-3-benzyloxy-1,1-ethylenedioxy-2-methyl-2-(4'-oxopentyl)-cyclohexane as a clear colorless oil (15.7 g, 61%): ir (neat) 1712 cm-1 (CO); nmr (CDCl3)δ 1.06 (s, 3H, CH3), 2.04 (s, 3H, ##STR4## 2.30 (m, 2H, --CH2 --CO), 3.50 (m, 1H, --CH--OCH2Ph), 3.98 (s, 4H, ketal), 4.55 (d of d, J=10 Hz, 2H, --O--CH2Ph), 7.20 (s, 5H, aromatic).

Provenance & Evidence