Regioselective bromination of 1,4-dimethoxy-2,3-dimethylbenzene and conversion into sulfur-functionalised benzoquinones

First synthesis of novel 2,4-bis((E)-styryl)quinoline-3-carboxylate derivatives and their antitumor activity

“…Further varying the amount of NBS used resulted in no improvement as well. Recently, Aitken et al 21 reported the application of benzotrifluoride as the solvent in the NBS bromination reaction of 2,3-dimethylbenzene for the efficient preparation of 2,3-bis(bromomethyl)benzene. Disappointly, by employing this method the reaction always proceeded heterogeneously and no desired product could be obtained.…”

Synthesis of Electro-active Compounds Suitable for Adsorption on Metal Surfaces

“…An example of such work towards adsorbing a quinone (Scheme 13) shows a further method 33 of forming the dithiin ring by reduction of a bis(thiocyanate), but also emphasizes the pitfalls inherent in such an approach. 34 the dibromide 51 is readily converted into the bis(thiocyanate) 52 and this reacts with sodium borohydride to generate the dihydrobenzo-1,2-dithiin 53. However attempted deprotection of the dimethoxybenzene to give the corresponding quinone 56 using ceric ammonium nitrate failed, and instead resulted in formation of the monosulfoxide of 53.…”

“…On the other hand, deprotection at the bis(thiocyanate) stage readily gave 54, but reductive cyclization of either this, or its Diels-Alder adduct 55 with cyclopentadiene, resulted in undesired reduction at the carbonyl groups and 56 remains elusive. 34…”