Process for the preparation of isoquinoline compounds
AssigneeRoche Vitamins Inc.
InventorChristof Wehrli
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Abstract
(Z)-11-(4-Methoxybenzylidene)-1,2,3,4,5,6,7,8-octahydro-isoquinolin-2-yl!a lkanones of the formula ##STR1## wherein R is lower alkanoyl, can be produced under specific reaction conditions in a one-pot process in an advantageous manner by a Bischler-Napieralski cyclization of N-(2-cyclohex-1-enylethyl)-2-(4-methoxyphenyl)-acetamide and subsequent lower-alkanoylation of the resulting 1-(4-methoxybenzyl)-3,4,5,6,7,8-hexahydro-isoquinoline of the formula ##STR2## under an inert gas atmosphere and, if desired converted to dextomethorphan in a known manner.
Claims16
A process for the production of (Z)-1-1-(4-methoxybenzylidene)-1,2,3,4,5,6,7,8-octahydro-isoquinolin-2-yl !alkanones of the formula ##STR10## wherein R is lower alkanoyl, which process comprises cyclizing by a Bischler-Napieralski reaction N-(2-cyclohex-1-enylethyl)-2-(4-methoxyphenyl)acetamide of the formula ##STR11## to produce 1-(4-methoxybenzyl)-3,4,5,6,7,8-hexahydro-isoquinoline of the formula ##STR12## under an inert gas atmosphere, and further comprising carrying out the Bischler-Napieralski reaction in the presence of 0.45 to 0.8, molar equivalents of phosphorus oxychloride;
- and lower-alkanoylating the resulting 1-(4-methoxybenzyl)-3,4,5,6,7,8-hexahydro-isoquinoline in situ, in the presence of a weak organic base which is inert under the reaction conditions.
Dependencies are inferred from the claim text.