Succinimidinium hydrogensulfate ([H-Suc]HSO4) as a new, green and efficient ionic liquid catalyst for the synthesis of tetrahydrobenzimidazo[2,1-b]quinazolin-1(2H)-one, 1-(benzothiazolylamino)phenylmethyl-2-naphthol, 1, 8-dioxo-octahydroxanthene and bis(indolyl)methane derivatives