GB974137A - New isoquinolines and process for their manufacture - Google Patents

Abstract

The invention comprises 1-(pyridyl-lower alkyl)-7-R1-6-R2-4-R3-3, 4-dihydroisoquinolines containing a 2-methyl group or a 1, 2-double bond, the lower alkyl group containing 2 to 4 carbon atoms and separating the pyridine ring from the isoquinoline ring by at least 2 carbon atoms, in which the pyridyl group may be substituted by an alkyl, alkoxy or phenyl group, and in which R1 and R2 are each hydroxy, lower alkoxy or phenyl-lower alkoxy or R1 and R2 together are lower alkylenedioxy and R3 is hydrogen or lower alkyl, the word "lower" meaning an upper limit of 5 carbon atoms; and their acid-addition salts and quaternary ammonium derivatives; and their preparation by cyclizing an N-(pyridyl-lower alkyl-carbonyl) -2-(p-R1-m-R2-phenyl)-2-R3-ethylamine and, if desired, reducing the 1-pyridyl-lower-alkyl-7-R1-6-R2-4-R3-3, 4-dihydroisoquinoline so-formed to give the corresponding 1, 2, 3, 4-tetrahydroisoquinoline and methylating this. Racemic products can be resolved. Examples are given and extensive lists of salt-forming acids and quaternizing agents are provided. N-3-(4-pyridyl)-propionyl-N-[2-(3, 4-dimethoxyphenyl) -ethyl]-amine is prepared by refluxing 2-(3, 4-dimethoxy-phenyl)-ethylamine with ethyl 3-(4-pyridyl)-propionate. The corresponding 3-pyridyl compound is prepared similarly. The isoquinolines of the invention, which are stated to be analgetic agents, may be made up into pharmaceutical compositions with suitable carriers. These may take the form of capsules, tablets, dragees, solutions, suspensions or emulsions, and may contain preserving, stabilizing, wetting or emulsifying agents, salts for varying the osmotic pressure, or buffers.