New tetrahydro-pyrido-[4,3-d]-pyrimidines and processes for their preparation

摘要

The invention comprises 5,6,7,8-tetrahydropyrido-[4,3-d]-pyrimidines of the formula in which R represents a hydrogen atom, or an alkyl group in the 7- or 8-position, R1 represents an aminoalkyl (including a mono- or di-substituted aminoalkyl), alkoxyalkyl, cycloalkyl, aryl or aralkyl group, and R2 represents a hydrogen atom, a hydroxy, alkyl, aryl or aralkyl group, a free or mono- or di-substituted amino group, a nitrogen-containing saturated heterocyclic ring (which may contain a further hetero atom and/or be alkyl- or hydroxyalkyl-substituted) linked to the 2-position of the pyrimidine ring via the nitrogen atom, or an alkylthio or aralkylthio group; non-toxic acid addition salts thereof; and a process for their preparation comprising reacting a piperidone carboxylic acid ester of the formula in which Alk is an alkyl group, or an acid addition salt thereof, with a compound of the formula or an acid addition salt thereof, and, if desired' converting the compound thus formed to non-toxic acid addition salt of a compound of Formula I. The compounds in which R2 represents a free or mono- or di-substituted amino group, or a saturated heterocyclic ring as defined above, may also be prepared by reacting a compound of Formula I in which R2 represents a mercapto, alkylthio, aralkylthio or halo-aralkylthio group with ammonia or an appropriate primary or secondary amine, and, if desired, the compound of Formula I thus formed may be converted to a non-toxic acid addition salt thereof. Piperidone carboxylic acid esters of Formula II are prepared by the Dieckmann condensation of an ester of the formula Pharmaceutical compositions having anti-pyretic, antiphlogistic, diuretic, bacteriostatic, sedative or coronary-dilatory activity for oral, rectal or parenteral administration comprise a compound of the invention together with a pharmaceutical carrier or excipient. The compositions may be formulated as tablets, coated tablets, capsules, suspensions, ampoules or suppositories.