Convenient Synthesis of Tolcapone, a Selective Catechol‐O‐methyltransferase Inhibitor
摘要:
A convenient and efficient synthesis of tolcapone from commercial 4-benzyloxy-3-methoxybenzaldehyde is presented. Grignard reaction of 4-benzyloxy-3-methoxybenzaldehyde (1) with p-tolylmagnesium bromide followed by Oppenauer oxidation of the hydroxyl functionality and subsequent O-debenzylation gave phenol 5. Compound 5 was regioselectively nitrated and then subjected to O-demethylation to produce tolcapone in 60% overall yield.
Catechol derivatives of the formula ##STR1## wherein Ra, Rb and Rc have the significance given herein, the ester and ether derivatives thereof which are hydrolyzable under physiological conditions and the pharmaceutically acceptable salts thereof are described and possess valuable pharmacological properties. In particular, they inhibit the enzyme catechol-O-methyltransferase (COMT), a soluble, magnesium-dependent enzyme which catalyses the transference of the methyl group of S-adensoylmethionine to a catechol substrate, whereby the corresponding methyl ethers are formed. Suitable substrates which can be O-methylated by COMT and which can thus be deactivated are, for example, extraneuornal catecholamines and exogeneously-administered therapeutically active substances having a catechol structure. Formula Ia above embraces not only compounds which form part of the invention, but also known compounds; the compounds which form part of the invention can be prepared according to known methods.
Process for the preparation of benzophenone derivatives
申请人:Hoffmann-La Roche Inc.
公开号:US05877353A1
公开(公告)日:1999-03-02
The present invention relates to a process for the preparation of benzophenone derivatives and comprises a selective crystallization of alkali salts of compounds of formula (I) ##STR1## wherein R.sup.1 is lower-alkyl and R.sup.2 is hydrogen, lower-alkyl or halogen, from the isomeric alkali salts of the 3-hydroxy compounds of formula (II), ##STR2## wherein R.sup.1 and R.sup.2 are as defined above.
Methods for the preparation of benzophenones derivatives
申请人:F. HOFFMANN-LA ROCHE AG
公开号:EP0855379A1
公开(公告)日:1998-07-29
The present invention relates to a process for the manufacture of benzophenone derivatives and is based on the separation of compounds of formula (I),
from corresponding isomeric compounds of formula (II),
by selective crystallization of corresponding salts of compounds of formula (I).