Studies with tetrazole derivatives; some pharmacologic properties of aliphatic substituted pentamethylene tetrazole derivatives.

A few generalizations can be made from the data in Table 2. The introduction of a single substituent, R 4 , into the pentamethylene tetrazole structure will enhance the analeptic and convulsant activity of the parent substance only when the group is small, or closely packed as in the case of methyl, isopropyl or tert.butyl. Substitution of alkyl groups in positions other than R 4 , di- and trisubstitutions, or the formation of quaternary salts decreased the activity of the compounds studied. The isopropyl group appeared to be unique in the latter groups, since in any given case it was generally associated with the most active compounds. None of the new compounds appears to have advantages over the parent compound when toxicity and solubility are considered.