Question

Procyclidine is a drug that has been used to treat the uncontrolled body movements associated with Parkinson’s disease. Draw three different methods to prepare procyclidine using a Grignard reagent

Short answer

Three methods for preparing procyclidine are:

Method 1

Method 2

Method 3

Step-by-step solution

Procyclidine 

Procyclidine is a centrally acting anticholinergic drug. It is tertiary alcohol formed from the ketone and Grignard reagents.

Retroanalysis mechanism

The three different methods for the preparation are:

Method 1.

(2-(pyrrolidine-1-yl) ethyl) magnesium bromide reacts with cyclohexyl(phenyl)methanone in the presence of water to give 1-cyclohexyl-1-phenyl-3-(pyrrolidine-1-yl) propan-1-ol

Using (2-(pyrrolidine-1-yl) ethyl) magnesium bromide and cyclohexyl(phenyl)methanone.

Method 2.

Cyclohexyl magnesium bromide reacts with 1-phenyl-3-(pyrrolidine-1-yl) propan-1-one in the presence of water to give 1-cyclohexyl-1-phenyl-3-(pyrrolidine-1-yl) propan-1-ol

Using cyclohexyl magnesium bromide and 1-phenyl-3-(pyrrolidine-1-yl) propan-1-one.

Method 3.

Phenyl magnesium bromide reacts with 1-cyclohexyl-3-(pyrrolidine-1-yl) propan-1-one in the presence of water to give 1-cyclohexyl-1-phenyl-3-(pyrrolidine-1-yl) propan-1-ol

Using Phenyl magnesium bromide and 1-cyclohexyl-3-(pyrrolidine-1-yl) propan-1-one.