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Synthesis of the 3 H‐labelled 5‐HT 3 antagonist (RS‐25259‐197) at high specific activity
Author(s) -
Gong Leyi,
Parnes Howard
Publication year - 1996
Publication title -
journal of labelled compounds and radiopharmaceuticals
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.432
H-Index - 47
eISSN - 1099-1344
pISSN - 0362-4803
DOI - 10.1002/(sici)1099-1344(199605)38:5<425::aid-jlcr860>3.0.co;2-b
Subject(s) - chemistry , amide , antagonist , stereochemistry , labelling , intramolecular force , tritium , organic chemistry , receptor , biochemistry , physics , nuclear physics
Abstract The preparation of the title compound, a selective 5‐HT 3 antagonist with anti‐emetic properties, is described. The key intermediate involved is 6‐bromo‐1,2‐dihydronaphthoic acid ( 5 ), which was synthesized from 4‐bromophenylacetic acid by Michael addition, acid‐induced ring cyclization, reduction and dehydration. Compound ( 5 ) was selected because it has two labelling sites to ensure high specific activity of the final product. Reduction of amide 6 with carrier‐free tritium gas, followed by reduction of the amide functional group with BF 3 ‐OEt 2 and intramolecular cyclization furnished the title compound having a specific activity of 70.4 Ci/mmol and >99% purity.