The mono- Mannich bases 2-diethylaminomethyl-, 2-t-butylaminomethyl-, 2-(pyrrolidin-1-ylmethyl)-, 2-(piperidin-1-ylmethyl)-, 2-(3-and 4-methylpiperidin-1-ylmethyl)-, 2-(4-benzylpip- eridin-1-ylmethyl)- and 2-(4-benzylpiperazin-1-ylmethyl)-4-[7-bromo (and 7-trifluoromethyl)- 1,5-naphthyridin-4-ylamino]-5,6,7,8-tetrahydronaphthalen-1-ols have been prepared from 4- acetamido-5,6,7,8-tetrahydronaphthalen-1-ols by Mannich reactions followed by hydrolysis to the 4-amino compounds and condensation with the relevant 4-chloro heterocycle.

The antimalarial activities of these compounds against the chloroquine -sensitive isolate (FCQ-27) of Plasmodium falciparum in vitro are reported; 4-(7-bromo-1,5-naphthyridin-4-yl)amino-2-(t- butylaminomethyl )-5,6,7,8-tetrahydronaphthalen-1-ol was about twice as active as chloroquine . In in vivo tests against Plasmodium vinckei vinckei in mice this compound exhibited significant activity. The 7-bromo compounds were more active than their 7-trifluoromethyl analogues.