GB1399469A - Amino derivatives of pyrazolopyridine ketones - Google Patents

Abstract

1399469 Amino derivatives of pyrazolopyridine ketones E R SQUIBB & SONS Inc 23 May 1972 [25 May 1971] 24223/72 Heading C2C Novel compounds of the Formula I wherein R 1 is hydrogen, alkyl, phenyl or phenyl alkylene, R 2 is hydrogen or alkyl, R 3 and R 4 each is hydrogen, alkyl, alkanoyl, haloalkanoyl, R 7 ,R 8 -phenyl, phenylalkylene, dialkylaminoalkylene or R 3 and R 4 together with the nitrogen to which they are attached form R 9 ,R 10 - aziridinyl, -pyrrolidino, -piperidino, -pyrazolyl, -hexahydropyrimidinyl, -hexahydropyridazinyl or -piperazinyl, R 5 is alkyl, C 3-7 -cycloalkyl, phenyl, R 7 ,R 8 -phenyl, R6 is hydrogen, alkyl or phenyl, R 7 and R 8 each is hydrogen, halogen or trifluoromethyl and R 9 and R 10 each is hydrogen, alkyl or hydroxyalkyl where all alkyl, alkylene and alkanoyl radicals have up to 8 carbon atoms and acid addition salts thereof may be prepared by reacting either of the compounds VI or VIII with an amine R 3 R 4 NH, optionally followed where R 3 and/or R 4 is alkanoyl or haloalkanoyl by acylating the product I in which at least one of R 3 and R 4 is hydrogen. Compounds of the Formula VIII are the subject of the divided Specification 1,399,470. 5 - Acetyl - 4 - ethoxy - 1 - ethylpyrazolo[3,4- b]pyridine may be prepared by condensing 1- ethyl-5-aminopyrazole with ethoxymethylene acetoacetic acid ethyl ester to form (1-ethyl-5- pyrazolyl)aminomethylene - acetoacetic acid ethyl ester followed by pyrolysis to 5-acetyl-1-ethyl-4- hydroxypyrazolo[3,4-b]pyridine followed by alkylation of the hydroxy group. 5 - Acetyl - 4 - chloro - 1 - ethylpyrazolo[3,4 - b]- pyridine may be prepared by chlorinating the 4-hydroxy compound above. 5 - Benzoyl - 4 - chloro - 1 - ethylpyrazolo[3,4- b]pyridine may be prepared by reacting 5- amino-1-ethyl pyrazole with ethoxymethylene benzoylacetic acid ethyl ester, and pyrolysing the reaction mixture to form 5-benzoyl-1-ethyl- 4-hydroxpyrazolo[3,4-b]pyridine which gives the required intermediate on treatment with phosphorus oxychloride. Pharmaceutical compositions of the compounds I with the usual excipients show antiinflammatory, and CNS depressant activity and may be used to treat asthma when administered orally or parenterally (and topically for anti-inflammatory activity).