http://rdf.ncbi.nlm.nih.gov/pubchem/patent/CA-2059908-A1
Outgoing Links
| Predicate | Object |
|---|---|
| assignee | http://rdf.ncbi.nlm.nih.gov/pubchem/patentassignee/MD5_5c24684033fba97d1ad845ce453a57e3 |
| classificationCPCInventive | http://rdf.ncbi.nlm.nih.gov/pubchem/patentcpc/C07D217-02 http://rdf.ncbi.nlm.nih.gov/pubchem/patentcpc/C07D217-26 |
| classificationIPCInventive | http://rdf.ncbi.nlm.nih.gov/pubchem/patentipc/C07D217-26 |
| filingDate | 1992-01-23-04:00^^<http://www.w3.org/2001/XMLSchema#date> |
| inventor | http://rdf.ncbi.nlm.nih.gov/pubchem/patentinventor/MD5_219f1e76f889ad5664fde752883146ed http://rdf.ncbi.nlm.nih.gov/pubchem/patentinventor/MD5_9f85766661877ddfac058404a2cc3b02 |
| publicationDate | 1992-07-25-04:00^^<http://www.w3.org/2001/XMLSchema#date> |
| publicationNumber | CA-2059908-A1 |
| titleOfInvention | Process for the preparation of racemic and optically active 1,2,3,4-tetrahydroisoquinoline-3-carboxylic acid and its precursors |
| abstract | A process for the preparation of racemic and optically active 1,2,3,4-tetrahydroisoquinoline-3-carboxylic acid is described, in which dihalo-o-xylylenes are cyclized to dicarboxylic acid esters in basic medium using dialkyl N-acylamidomalonates of the formula (CO2R1)2CHNHCOR2, in which R1 is (C1-C4)-alkyl and R2 is H, (C1-C4)-alkyl or (C6-C12)-aryl, decarboxylated by basic hydrolysis and subsequent acid work-up and then reacted in acid medium to give (D,L)-1,2,3,4-tetrahydroisoquinoline-3-carboxylic acid, or dihalo-o-xylylenes are cyclized in basic medium to give the dicarboxylic acid esters and these are reacted directly without isolation in a one-pot process to give (D,L)-1,2,3,4-tetrahydroisoquinoline-3-carboxylic acid, if desired the racemic 1,2,3,4-tetrahydroisoquinoline-3-carboxylic acid is reacted with (-)menthol and p-toluenesulfonic acid to give (-)menthyl (D)- or (L)-1,2,3,4-tetrahydroisoquinoline-3-carboxylate, then the diastereomers are separated by column chromatography and subjected to basic hydrolysis to give (D)- or (L)-1,2,3,4-tetrahydroisoquinoline-3-carboxylic acid, or (D,L)-1,2,3,4-tetrahydroisoquinoline-3-carboxylic acid is esterified by means of benzyl alcohol and p-toluenesulfonic acid, reacted with D(-)mandelic acid to give benzyl (D)-1,2,3,4-tetrahydroisoquinoline-3-carboxylate (D)-mandelate and benzyl (L)-1,2,3,4-tetrahydroisoquinoline-3-carboxylate (D)-mandelate or with L(+)mandelic acid to give benzyl (D)-1,2,3,4-tetrahydroisoquinoline-3-carboxylate (L)-mandelate and benzyl (L)-1,2,3,4-tetrahydroisoquinoline-3-carboxylate (L)-mandelate and then the compounds obtained are separated into the optical antipodes by fractional crystallization in an inert solvent and the enantiomers (D)- or (L)-1,2,3,4-tetrahydroisoquinoline-3-carboxylic acid are liberated by basic hydrolysis, the chiral auxiliary reagent being recovered. |
| priorityDate | 1991-01-24-04:00^^<http://www.w3.org/2001/XMLSchema#date> |
| type | http://data.epo.org/linked-data/def/patent/Publication |
Incoming Links
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