alpha-Amino-(2-chlorophenyl)acetic acid prepd. in 90% yield by boiling 2-chlorobenzaldehyde with NaCN and (NH4)(2)CO3 for 16 h was esterified with thionyl chloride in MeOH to yield Me alpha-amino-(2-chlorophenyl)acetate which was converted into the amine in 73%. The ester was alkylated with 2-(2-thienylethanol) tosylate to yield the aminoester in 60%. This was cyclized with paraformaldehyde to yield, via crystn of the hydrochloride, high-purity Me alpha-(4,5,6,7-tetrahydrothieno[3,2-b]pyrid-5-yl)-(2-chlorophenyi)acetate in 75% yield. The resulting racemate was sepd. by the use of (-)-camphorsulfonic acid to prep. 99% pure enantiomer and the (+)-camphorsulphonate was converted into the optically active base which was treated with H2SO4 to give clopidogrel hydrosulfate.