110851-12-2

A simple and cheap oxidative procedure using 30% H2O2 and catalytic SeO2 allows to transform 2-aralkylidenecycloalkanones and hydroxy- or alkoxybenzaldehydes to give, in high yields, enollactones and arylformates, respectively.

In SbF5-HF, hydrogen peroxide reacts on the aromatic ring of esters 1a-5a and anilides 11a-15a to give monohydroxylated derivatives in good yields.With compounds 2a, 4a and 5a, meta or para isomers are by far the major products, whereas with formate 1a and benzoate 3a, the proportion of the ortho isomer is more important.With anilides, the reaction is less selective, the three isomers being obtained in comparable amounts.Thus, the relative proportions of ortho, meta and para-hydroxylated derivatives obtained using 70 percent H2O2 with acetate 2a and acetanilide 12a are 6/51/43 and 36.5/30/33.5, respectively.The important proportion of meta hydroxylation is the result of the reaction of protonated hydrogen peroxide H3O2+ on the protonated substrate.

By the photolysis of the ozonide derived from 1,4-benzodioxins, o-benzoquinones were obtained in moderate yields independent of the stability of o-benzoquinones and of the substituent groups, except the nitro group.Through the mechanistic studies, it was indicated that o-benzoquinones were formed through a radical decomposition pathway, while catechols were formed through an ionic decomposition pathway induced by acidic impurities.