Process for R (+) 1,2,3,6-tetrahydro-4-phenyl-1-›(3-phenyl-3-cyclohexen-1-yl)methyl!pyridi ne, a central nervous system agent

A process for the preparation of the compound of Formula VI ##STR48## which comprises:

• Step (a) treating the racemic compound of Formula VIII ##STR49## with cinchonidine in a solvent to afford the compound of Formula VII ##STR50## and Step (b) treating the compound of Formula VII with a base in a solvent to afford after acidification the compound of Formula VI.

A process for the preparation of the compound of Formula VI ##STR51## which comprises treating the racemic compound of Formula IX ##STR52## in a solvent at about pH 5 with .alpha.-chymotrypsin to afford after separation of unreacted ester and acidification the compound of Formula VI.

A process for the preparation of the compound of Formula II ##STR53## which comprises:

• Step (a) treating the racemic compound of Formula VIII ##STR54## with cinchonidine in a solvent to afford the compound of Formula VII ##STR55## Step (b) treating the compound of Formula VII with a base in a solvent to afford after acidification the compound of Formula VI ##STR56## Step (c) treating the compound of Formula VI with the compound of Formula V ##STR57## in the presence of a coupling reagent and a solvent to afford the compound of Formula IV ##STR58## Step (d) treating the compound of Formula IV with a reducing reagent in a solvent to afford a mixture of compounds of Formula IIIa and Formula IIIb ##STR59## Step (e) treating the mixture of compounds of Formula IIIa and Formula IIIb with a mixture of zinc chloride, and sodium cyanoborohydride in a solvent followed by a solution of a carboxylic acid in a solvent to afford the compound of Formula II.

A process for the preparation of the compounds of Formula IIIa and Formula IIIb ##STR60## which comprises:

• Step (a) treating the racemic compound of Formula VIII ##STR61## with cinchonidine in a solvent to afford the compound of Formula VII ##STR62## Step (b) treating the compound of Formula VII with a base in a solvent to afford after acidification the compound of Formula VI ##STR63## Step (c) treating the compound of Formula VI with the compound of Formula V ##STR64## in the presence of a coupling reagent and a solvent to afford the compound of Formula IV ##STR65## and Step (d) treating the compound of Formula IV with a reducing reagent in a solvent to afford a mixture of compounds of Formula IIIa and Formula IIIb.

A process for the preparation of the compound of Formula IV ##STR66## which comprises:

• Step (a) treating the racemic compound of Formula VIII ##STR67## with cinchonidine in a solvent to afford the compound of Formula VII ##STR68## Step (b) treating the compound of Formula VII with a base in a solvent to afford after acidification the compound of Formula VI ##STR69## and Step (c) treating the compound of Formula VI with the compound of Formula V ##STR70## in the presence of a coupling reagent and a solvent to afford the compound of Formula IV.

The compound of Formula IX ##STR71##

A compound selected from the group consisting of Formula IIIa and Formula IIIb ##STR72##

The compound of Formula IV ##STR73##

The optically pure compound of Formula VI ##STR74##

The compound of Formula VII ##STR75##