Patent GB-916507-A (GB)
Title: Process for the production of dehydroquinolizinium compounds
IPC: C07D491/14
Filed: 1960-06-13
Abstract: Dehydroquinolizinium compounds are prepared by condensing a compound having two adjacent oxo groups with an N-(CH2-X)-a picolinium compound or a di- or tetra-hydroderivative thereof, X being a group which activates the adjacent methylene group.  The picolinium compound may contain inert substituents (including fused on rings) in the nucleus or the methylene group, such as alkyl, aryl or aralkyl groups, and they include in particular N-(CH2-X)-quinaldinium, -1-methylisoquinolinium and -3-methyl-isoquinolinium compounds, X being preferably a carbalkoxy, alkoyl, aroyl, carbamido or cyano group.  The dioxo compound is preferably an aliphatic, mixed aliphatic-aromatic or aromatic diketone or orthoquinone, suitable compounds being diacetyl, benzil, anisil, furil, pyridil and phenanthrene quinone.  The condensation is preferably effected in an inert solvent such as a lower aliphatic alcohol, a lower ketone, a cyclic ether, water or mixtures of two or more of these solvents, and preferably in the presence of condensation initiators such as aliphatic amines, alkali metal bicarbonates and alkaline earth metal carbonates.  In Examples (1) and (45) N-carbethoxymethyl(or N-phenacyl- or N-acetonyl-)-a -picolinium bromide and diacetyl give 2,3-dimethyldehydroquinolizinium bromide; (2) to (5) and (46) the corresponding 2,3-diphenyl-, 2,3-dianisyl-, 2,3-difuryl- and 2,3-di-(a -pyridyl)-compounds are prepared similarly; (6) Ncarbethoxymethyl-a -picolinium bromide and phenanthrene quinone give 2,3;91,101-phenanthrodehydroquinolizinium bromide; (7) to (10) furil and N-carbethoxymethyl-a -ethylpyridinium, -2,6-lutidinium, -2,4-lutidinium and -2-methyl-5-ethyl-pyridinium bromides give, respectively, 1-methyl-, 6-methyl-, 8-methyl-and 7-ethyl-2,3-(di-a -furyl)-dehydroquinolizinium bromides; (11) to (19) by similar methods are prepared 2,3-dimethyl-8,9-benzo-, 2,3-dimethyl-8,9-(31,41-dimethoxybenzo)-, 2,3-dimethyl-8,9-(31,41-methylenedioxybenzo)-, 2,3-dimethyl-4-carbethoxy-6,7-benzo-, 1,9-trimethylene-2,3-dimethyl-, 2,3-dimethyl-4-benzoyl-6,7-dihydro-8, 9-(benzo- and 31,41-dimethoxybenzo)-, 2,3-dimethyl - 4 - carbethoxy-6,7-dihydro-8, 9-(31,41-dimethoxybenzo)-, and 2,3-dimethyl-4-cyano-dehydroquinolizinium bromides; (20) to (32) N - cyanomethyl-a -picolinium, -2,6-lutidinium and -a -ethyl-pyridinium bromides with the appropriate 1,2-dioxo compounds give compounds of the formulae <FORM:0916507/IV (b)/1> wherein R1 and R2 are variously hydrogen, methyl, phenyl, furyl, pyridyl or together, diphenylene; (33) to (44) N-(1-carbethoxy)-ethyla -picolinium bromide, N-(1-carbethoxyethyl)2-ethyl-pyridinium bromide and N-(1-carbethoxypropyl)-a -picolinium bromide with the appropriate 1,2-dioxo compounds give, respectively, 4-methyl-, 1,4-dimethyl- and 4-ethyl-2,3-disubstituted-dehydroquinolizinium bromides wherein the substituents have the values for R1 and R2 given above; (47) the product of (5) is prepared from pyridil and dicarbethoxymethyl-a -picolinium bromide; and (48), (49) and (50) 2,3-diphenyl-4-anilinocarbonyl-, 2,3-dimethyl-4-phenyl- and 2,3-difuryl-4-styryldehydroquinolizinium bromides are prepared from the appropriate N-substituted a -picolinium bromides and the appropriate diketones.  N-(CH2-X)-a -picolinium bromides are prepared from a -picoline and compounds Br-CH2-X.  Other N-(CH2-X)-substituted pyridinium, 1 - methyl - isoquinolinium, 6,7 - dimethoxy-1-methyl-isoquinolinium, 6,7-methylenedioxy - 1 - methyl - isoquinolinium, quinaldinium, 5,6,7,8 - tetrahydroquinolinium, 1-methyl-3,4-dihydro-isoquinolinium and 6,7-dimethoxy - 1 - methyl - 3,4-dihydro-isoquinolinium bromides are prepared similarly.