ReFlux 

A Better method for oxidation of the alcohol is using in-situ prepared
Chromium Trioxide-Pyridine complex in methylene chloride. For best results
use 6:1 molar excess of reagent @ room temp. General proc. as follows:

6.00g (60 mmol) of Cr03 is added at room temp. to a stirring soln. of 9.49g
(120 mmol) of Pyridine in 150ml of methylene chloride (DCM). After approx.
15 min of stirring a soln of the Alcohol (10 mmol) in a small volume of DCM
is added in one portion. A tarry black deposit seperated immediately. After
stirring for an additional 15 min. at room temp, the soln. is decanted from
the residue, which is washed with 200ml of ether. The combined organic
soln. are washed successively w/ 5% aq. NaOH, HCl, Sodium Bicarbonate, and
NaCl. It is then dried over anhydrous Magnesium Sulphate. Evap. of the
solvent at reduced pressure affords crude aldehyde.

Notes: If large scale rxns are attempted then use ice-bath cooling during
the Cr03 addition and mechanical stirring.

The advantages are that there is no risk of explosion/fire and the yields
are extremely high. If the reaction is allowed to continue for 24-48hrs
then near quantitative yeilds of the aldehyde can be obtained. Also,
over-oxidation to a carboxalic acid will not occur.

