Novel Spectrophotometric Method for Determination of Macro-paracetamol via Reaction with Bromine

The reaction between Br2 and paracetamol(p-AAP) leads to the formation of a coloured product, which can be used for spectrophotometric determination of the p-AAP content in its pure form and in different pharmaceutical preparations with p-AAP. The stoichiometric composition of the reaction was found to be n(p-AAP)∶n(bromine)=1∶3. The effects of pH and time on the spectra of p-AAP-bromine redox reaction product were studied. The interference of different additives on the measured spectra of the obtained product was also studied. The results obtained by the present method were compared with those obtained by the standard method. The F- and t- test values were calculated for both of the applied procedures and they met a confidence level of 99%. The proposed procedure actually needs no separation of these drugs from their sources before analysis and was unaffected by interference of other phenolic compounds. The proposed method is simpler and faster than the repoeted ones.     

Copper(ii) ketimides in sp3 C–H amination

Commercially available benzophenone imine (HN CPh₂) reacts with β-diketiminato copper(ii) tert-butoxide complexes [Cu^II]–O^tBu to form isolable copper(ii) ketimides [Cu^II]–N CPh₂. Structural characterization of the three coordinate copper(ii) ketimide [Me₃NN]Cu–N CPh₂ reveals a short Cu-N_ketimide distance (1.700(2) Å) with a nearly linear Cu–N–C linkage (178.9(2)°). Copper(ii) ketimides [Cu^II]–N CPh₂ readily capture alkyl radicals R˙ (PhCH(˙)Me and Cy˙) to form the corresponding R–N CPh₂ products in a process that competes with N–N coupling of copper(ii) ketimides [Cu^II]–N CPh₂ to form the azine Ph₂C N–N CPh₂. Copper(ii) ketimides [Cu^II]–N CAr₂ serve as intermediates in catalytic sp³ C–H amination of substrates R–H with ketimines HN CAr₂ and ^tBuOO^tBu as oxidant to form N-alkyl ketimines R–N CAr₂. This protocol enables the use of unactivated sp³ C–H bonds to give R–N CAr₂ products easily converted to primary amines R–NH₂via simple acidic deprotection.

Commercially available benzophenone imine (HN CPh₂) reacts with β-diketiminato copper(ii) tert-butoxide complexes [Cu^II]–O^tBu to form isolable copper(ii) ketimides [Cu^II]–N CPh₂ that serve as intermediates in catalytic sp³ C−H amination via radical relay.