| abstract |
Cyclobutene derivs. of formula (I) are used in prepn. of cyclobutene derivs. of formula (V), or their non-toxic pharmaceutically acceptable salts, by (a) reacting (I) with a phenol deriv. of formula (III) in an inert solvent, or mixed aq./organic solvent, in presence of a base and opt. a catalyst to give a cpd. of formula (IV); and (b) reacting with an amine of formula R1NH2. - In formulae, R1 = H or lower alkyl; R2 and R3 = lower alkyl; or NR2R3 = pyrrolidino, methylpyrrolidino, piperidino, methylpiperidino, homopiperidino, heptamethyleneimino, or octamethyleneimino; R = lower alkyl or cyclohexyl; and X = leaving gp. |