O-Nitro Complexed Lewis Acid Promoted Selective Dealkylation Of P-Dialkoxylbenzene

The o-nitro group complexing effect was demonstrated for the first time in theselective dealkylation of dialkoxylbenzene. Among the Lewis acids screened wereAlCl3, ZrCl4, BF3, ZnCl2, CuCl2 and NiCl2. AlCl3 was found to be generally effective,although other Lewis acids worked well. Anhydrous 1,2-dichloroethane was used assolvent. The reaction conditions were optimized according to different o-alkyl groups.When the alkyl group was benzyl, the reaction went smoothly in ice salt bathtemperature (0~-5℃). When the alkyl group was s-butyl or i-propyl or acetyl, thereaction proceeded at room temperature. When the alkyl group was methyl or ethyl or3-chloropropyl or n-butyl, the reaction was carried out at reflux temperature (83℃).The reaction is high-yielding (87~98%) and the reaction time short (1.5~13h), thereaction conditions mild (-5~83℃). The structures of the products were fullycharacterized by IR, HNMR, GC and GC-MS. 1 The mechanism of the reaction was proposed and alkyl halide, which is oneexpected product of the reaction, was identified by GC-MS.