Green protocol for conjugate addition of amines to p-quinones accelerated by water

On-Water Reactivity and Regioselectivity of Quinones in C–N Coupling with Amines: Experimental and Theoretical Study

“…[18] In view of the latter, new methodologies without catalysts, using water as reaction medium have been developed in recent years. [19,20] In addition to its positive environmental properties, water presents unique reactivity and selectivity that cannot be achieved by conventional organic solvents. [21,22] On the other hand, several descriptors derived from conceptual density functional theory (DFT) [23] and approaches of pure electrostatic nature, such as molecular electrostatic potentials, [24] have been used to assess chemical reactivity.…”

Enhanced Hydrogen Production from DNA‐Assembled Z‐Scheme TiO2–CdS Photocatalyst Systems

“…BQ was attached to DNA-3 strands through aM ichael addition. [43,44] Mass spectrometric analysis confirmed the successful conjugation of BQ to the DNA-3 strand ( Supporting Information, Figure S10). Cyclic voltammetry (CV) studies revealed that amine functionalization of BQ altered its reduction potential to circa 0.073 Vv sN HE at pH 7( Supporting Information, Figure S11), which is still in between the CB and VB of TiO 2 and CdS,respectively.Wenext hybridized equimolar amounts of the DNA-1-Pt@CdS,DNA-2-TiO 2 ,and the DNA-3-BQ to make 43 nm concentrations of the Pt@CdS-BQ-TiO 2 and H 2 production was measured.…”

“…[43,44] Mass spectrometric analysis confirmed the successful conjugation of BQ to the DNA-3 strand ( Supporting Information, Figure S10). Benzoquinone (BQ) was chosen as ac andidate because its reduction potential of 0.283 Vv s. NHE at pH 7lies between the conduction band (CB) of TiO 2 NP and the valence band (VB) of CdS NR.…”

Amine Functionalization through Sequential Quinone‐Catalyzed Oxidation/Nucleophilic Addition

“…Important trends can be inferred from analysis of these data. Quinones that are prone to 1,4‐addition ( 5 and 6 ) or addition/elimination processes ( 10 , 14 , and 15 ) are ineffective catalysts. Additionally, very sterically encumbered ( 7 and 11 ) and electron‐rich quinones ( 8 and 12 ) that likely fail to undergo amine condensation are generally ineffective.…”