Synthesis and antirhinovirus activity of 3-(diethylamino)-5-phenylisoxazole derivatives.

Previous studies showed that some 2'-alkyloxyisoxazoles 2b-d obtained from 3-(diethylamino)-5-(2'hydroxy-4'-methoxyphenyl)isoxazole 2a were endowed with an interesting anti-group B rhinovirus activity (action on HRV-2 serotype). Other isoxazoles (WIN compounds) are well known to have anti-group A rhinovirus activity (action on HRV-14 serotype). To obtain an action similar to that of WIN compounds, starting from 2a, the 2'-acyl (3,4,5) and 2'alkyl (6,8) derivatives were synthesized. Also some Mannich bases (9,10) and bisisoxazoles (7,11,13,14) were studied. Though some of the tested compounds mainly exhibited anti-group B rhinovirus activity, their potency was less intense with respect to the above mentioned compounds 2b-d. The only N-methylpiperazinomethyl derivative 10 was slightly active against both tested serotypes.