Synthesis of benzyl bromides with hexabromoacetone: an alternative path to drug intermediates

A series of benzyl bromides were efficiently prepared from the corresponding alcohols with Br₃CCOCBr₃/PPh₃ at low temperatures and under neutral conditions. The present protocol was applied to the heterocyclic analogues and to the successful synthesis of the precursor of the antiulcer drug omeprazole, thus furnishing an alternate, mild method for the preparation of these drug intermediates. A significant steric factor was observed throughout both series supporting a S_N2 mechanism.     

Hexabromoacetone as tribromoacetylating agent of alcohols and amines and as mediator in the conversion of carboxylic acids into amides in the presence of triphenylphosphine

Hexabromoacetone has been used as an alternative tribromoacetylating agent of primary alcohols and amines and as mediator in the conversion of carboxylic acids into amides in the presence of triphenylphosphine. The reactions have been performed under mild conditions with moderate to good yields. All the products have been adequately characterized by their physical and spectroscopic properties.     

Hexabromoacetone and ethyl tribromoacetate: a highly efficient reagent for bromination of alcohol

A new and efficient method for the bromination of alcohols utilizing Br₃CCOCBr₃/PPh₃ and Br₃CCO₂Et/PPh₃ is described. Various alcohols can be converted smoothly into their corresponding alkyl bromides in high yields under mild conditions with short reaction times. Based upon ¹H NMR studies using competitive reactions between selected brominating agents and Cl₃CCN, Br₃CCOCBr₃ displays the highest reactivity approximately nine times that of CBr₄.