- In a 500-ml round-bottomed flask fitted with a reflux condenser is suspended pyridinium chlorochromate [PCC, 32.3 g, 150mmol] in 200ml of anhydrous dichloromethane. Heptan-1-ol (11.6 g, lOOmmol) in 20 ml of dichloromethane is added in one portion to the magnetically stirred solution.
- After 1.5 hours, 200 ml of dry ether is added and the supernatant solution decanted from the black gum.
- The insoluble residue is washed thoroughly with three 50-ml portions of anhydrous ether whereupon it becomes a black granular solid.
- The combined organic solutions are passed through a short pad of Florosil and the solvent removed by distillation.
- Distillation of the residual oil through a short Vigreux column gives 8.87 g (78%) of heptanal, b.p. 59-62 °C/30mmHg (1).
Notes to keep in mind:
1. These reaction conditions are used for the oxidation of decan-1-ol, hexane-1,6-diol and oct-2-yn-l-ol. In the case of alcohols where acid-sensitive groups are also present (e.g. tetrahydropyranyl ethers), sodium acetate is added to buffer the reaction mixture; alternatively pyridinium dichromate may be used."
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