Alcohol to Aldehyde/Ketone using PDC (Pyridinium Dichromate)

General Procedure:

Pyridinium Dichromate (2.5 eq.) was added portion wise to a stirred suspension of Substrate (alcohol, 1 eq.) and molecular sieves in dichloromethane (20 Vol)) at room temperature under nitrogen atmosphere and the mixture stirred overnight

During the reaction progress, a brown tar-like material slowly gets precipitated out. The reaction mixture containing solids is filtered through Celite bed and the bed washed with CH₂Cl₂. The organic layers are combined, and washed with water (10 Vol) and brine solution (5 Vol). The resultant organic layer is dried over Na₂SO₄ and concentrated. The crude product shall be used for next reaction or if required, is purified by column chromatography

Note:

• The most preferable solvent is DCM

• PDC oxidation reaction is to be performed under anhydrous condition

• The addition of Celite or Molecular sieves helps in PDC reaction to make the brown tar-like material (side products from the reagent) not sticking to the bottom of the flask.

• PDC is a toxic reagent

For more details on reactions and reagents, 
refer to the tab "Reaction, Reagents and Mechanism"

Typical Procedure:

• PDC oxidation of an alkynol (ChemSpider) — Open access

For more details on large-scale reactions and OPRD procedures, 
refer to the tab "Scale-up & Green Chem"

WO2010045258, page no. 347