Abstract: The invention involves condensation of various derivatives of cyclic alkene alcohols of Formula II or Formula III where, R1 is alkyl, aryl, alkyl aryl or heterocyclic carbamoyl. R2 is either R1 as mentioned earlier or an acyl group, —C(?O)—R3 where, R3 is selected from a group comprising (subst)C1-C12 alkyl, (subst)aryl, alkyl aryl with olivetol to get (?)-trans-?9-tetrahydrocannabinol (also known as Dronabinol, Formula I). The process disclosed provides high purity of dronabinol at crude stage making it easy for purification.

Abstract: The present invention relates to a process for preparation of dexmethylphenidate hydrochloride from racemic methylphenidate. The process involves the treatment of racemic mixture of dl-threo-methylphenidate base in the presence of di-pivaloyl-D-tartaric acid (D-DPTA) in a solvent to isolate dipivaloyl tartrate salt of d-threo-methylphenidate. The dipivaloyl tartrate salt of d-threo-methylphenidate is treated with a base to obtain a d-threo-methylphenidate base, which is extracted using a suitable solvent. The d-threo-methylphenidate base is treated with hydrochloric acid-isopropyl alcohol solution to obtain slurry of d-threo-methylphenidate hydrochloride also known as dexmethylphenidate hydrochloride. The dexmethylphenidate hydrochloride slurry is filtered and washed with acetone. The invention also discloses a process for recovery of D-DPTA from the salt mother liquor and from the spent aqueous layer.

Abstract: The present invention relates to a method of enantioselective enzymatic transamination of (1R)-1-Hydroxy-1-Phenylacetone (R-PAC) to a chiral amine 1R, 2S-Norephedrine in the presence of an isopropylamine catalyzed by enantioselective transaminase. Isopropylamine is converted to acetone in the process. The transaminase used is in completely purified form, partially purified form or as whole cells. The source is microbial cells, which are genetically engineered. In the present invention, the enzyme is expressed in E. coli and used preferentially as a suspension of native cells. Transaminase comprising polypeptide sequence is obtained from Rhodobacter sphaeroides and expressed in E. coli. The nucleotide sequence of transaminase is expressed in an expression vector system pIEP/Kan/IEP AT12, which is incorporated in E. coli. The yield of 1R, 2S-1-norephedrine is greater than 87% and de % is greater than 99%.

Abstract: The present invention relates to method of production of optically active chiral amine from alpha hydroxy ketone using enzyme transaminase as the biocatalyst. In particular the present invention relates to production of (1R, 2S)-Norephedrine and its salts from R-Phenylacetylcarbinol (R-PAC) by employing S-transaminase as the biocatalyst and Isopropylamine as the amine donor.