Novel stilbene compounds: process for their manufacture and their use as optical brighteners

A compound of the formula ##STR18## wherein A is a benzene or naphthalene ring which is unsubstituted or substituted by non-chromophoric substituents, B is a group of the formulae ##STR19## and R is a straight-chain or branched alkyl group with 1-18 C-atoms, preferably 1-6 C-atoms, which is unsubstituted or substituted by hydroxyl groups, halogen atoms, lower alkoxy, dialkylamino, lower alkylmercapto, chloroaryloxy, aryloxy, arylmercapto, aryl, morpholine, piperidine or piperazine groups, or R is a group of the formula--(CH.sub.2 CH.sub.2 O).sub.n --R.sup.1 with n being 1, 2 or 3 and R.sup.1 being H, lower alkyl or R is dialkylaminoalkoxyalkyl, alkylthioalkoxyalkyl, piperidine-alkoxyalkyl, hexamethylenimine-alkoxyalkyl, morpholine-alkoxyalkyl or piperazine-alkoxyalkyl or R is a group of the formula ##STR20## wherein R.sub.2 and R.sub.3 are identical or different and are selected from the group consisting of hydrogen, fluorine, chlorine, phenyl, lower alkyl, lower alkoxy, lower acylamino, or two adjacent radicals R.sub.4 and R.sub.5 form together a lower alkylene group, a fused benzene ring or a 1,3-dioxapropylene group.