222835-30-5

Upstream product

• 107-15-3 ethylenediamine 
• 405202-99-5 (2,4-di-tert-butyl-6-({2-[(3,5-di-tert-butyl-2-hydroxy-benzylidene)-amino]-phenylimino}-methyl)-phenol) 
• 37942-07-7 3,5-di-tert-butyl-2-hydroxybenzaldehyde 

Relevant academic research and scientific papers

Synthesis, spectroscopy and electrochemical behaviors of nickel(II) complexes with tetradentate shiff bases derived from 3,5-Bu2 t-salicylaldehyde

Nickel(II) complexes of a series of N,N′-polymethylenebis(3,5-Bu2t- salicylaldimine) ligands containing 2,4-di-Bu2t-phenol arms, NiLx, were synthesized and their spectroscopic and redox properties were examined. The UV-vis, 1H NMR sp

Site-Selective Copper-Catalyzed Azidation of Benzylic C-H Bonds

Site selectivity represents a key challenge for non-directed C-H functionalization, even when the C-H bond is intrinsically reactive. Here, we report a copper-catalyzed method for benzylic C-H azidation of diverse molecules. Experimental and density functional theory studies suggest the benzyl radical reacts with a CuII-azide species via a radical-polar crossover pathway. Comparison of this method with other C-H azidation methods highlights its unique site selectivity, and conversions of the benzyl azide products into amine, triazole, tetrazole, and pyrrole functional groups highlight the broad utility of this method for target molecule synthesis and medicinal chemistry.

Vanadium-catalyzed solvent-free synthesis of quaternary α-trifluoromethyl nitriles by electrophilic trifluoromethylation

The direct electrophilic trifluoromethylation of silyl ketene imines (SKIs) with hypervalent iodine reagents leads to the formation of quaternary α-trifluoromethyl nitriles in good yields. This new reaction has been carried out with a variety of substitut

Salophen and salen oxo vanadium complexes as catalysts of sulfides oxidation with H2O2: Mechanistic insights

The application of V(V) catalysts in oxidation of sulfides with peroxides offers an efficient procedure, that is compatible with different functional groups, and leads to good yields and selectivities. However, the understanding of the factors affecting the reactivity of different catalysts is still far to be complete. An experimental and theoretical study on a series of V(V) complexes containing variously substituted salen and salophen ligands is reported with the aim to correlate the activity of the catalysts with the electronic character of the vanadium center. The results obtained indicate that steric factors play a major role in determining the outcome of the reaction, often overcoming the electronic effects. Theoretical results suggest the intervention in the catalytic cycle of an hydroperoxo vanadium species.

Salen manganese (III) complexes as catalysts for R-(+)-limonene oxidation

The epoxidation of R-(+)-limonene using in situ generated dimethyldioxirane (DMD) as the oxidizing agent and four Jacobsen-type catalysts ((R,R)-Jacobsen, (S,S)-Jacobsen, racemic Jacobsen and achiral Jacobsen) was examined. The effect of the amount of KHSO5 and acetone in the catalyzed and un-catalyzed reaction was also assessed. The main reaction products were diepoxide and endocyclic monoepoxide. In the absence of catalyst, the amount of KHSO5 did not significantly influence conversion and selectivity. The catalyst can be segregated to a different phase and separated from the reaction media when the amount of KHSO5 is above the stoichiometric ratio, R-(+)-limonene/KHSO5 = 0.5 mmol/mmol, and acetone/mmol R-(+)-limonene = 2 mL/mmol. However, when the amount of KHSO5 is below the stoichiometric ratio (R-(+)-limonene/KHSO5 = 1.5 mmol/mmol) the catalyst is difficult to separate. Under the reaction conditions of this study, when the catalyst is segregated, no effect of the catalyst chiral center, (R,R)-Jacobsen or (S,S)-Jacobsen, was found on conversion and selectivity. Additionally, the (R,R)-Jacobsen's catalyst proved to be very stable to oxidative degradation.

Hydroxy- and alkoxy-bridged dinuclear uranyl-Schiff base complexes: Hydrolysis, transamination and extraction studies

The reaction of uranyl nitrate with 1,3-bis(salicylideneamino)-2-propanol (H3L1) and 1,3-bis(3,5-di-tert-butylsalicylideneamino)-2-propanol (H3L2) in the presence of triethylamine (Et3N) yielded hydroxy- and alkoxy-bridged dinuclear complexes; [(UO2) 2(L1)(OH)(MeOH)2]?(MeOH)2 (1?(MeOH)2) and [(UO2)2(L2)(OH)(MeOH) 2]?(MeOH)2 (2?(MeOH)2). The crystal structures of 1?(DMF)2 and 2?(DMF)2 exhibit an unsymmetrical central U2O2 core involving bridging alkoxy- and hydroxy-oxygen atoms. The geometry around the uranium center in 1?(DMF)2 and 2?(DMF)2 is that of a distorted pentagonal bipyramid with the solvent molecule occupying the fifth coordination site. The flexible nature of the ligand backbone is more pronounced in 2?(DMF)2 compared to 1?(DMF)2, yielding two molecules per unit cell in different conformations. Under similar reaction conditions, using ethylenediamine as a base, the respective Salen-based uranyl compounds, [UO2(Salen)(MeOH)] (3) and [UO2(Bu t2-Salen)(MeOH)] (4) are obtained due to transamination of the ligand backbone. Complexes 1?(MeOH)2 and 2?(MeOH) 2 when reacted with an excess of ethylenediamine failed to yield the respective Salen-based complexes, 3 and 4, respectively. The new compounds have been characterized using solution (NMR and UV-Vis) and solid-state (IR, X-ray crystallography) techniques. Hydrolysis of 1?(MeOH)2 and 2?(MeOH)2 in the pH range 1-14 was studied using UV-Vis spectroscopy and compared with the hydrolysis of 3 and [UO2(Salophen) (MeOH)] (5). A two-phase extraction study suggests quantitative removal of uranyl ions from the aqueous phase at higher pH conditions. The Royal Society of Chemistry 2008.

Stereoselective ring-opening polymerization of a racemic lactide by using achiral salen- and homosalen-aluminum complexes

Highly isotactic polylactide or poly(lactic acid) is synthesized in a ring-opening polymerization (ROP) of racemic lactide with achiral salen- and homosalen-aluminum complexes (salenH2 = N,N′-bis(salicylidene) ethylene-1,2-diamine; homosalenH2 = N,N′-bis(salicylidene) trimethylene-1,3-diamine). A systematic exploration of ligands demonstrates the importance of the steric influence of the Schiff base moiety on the degree of isotacticity and the backbone for high activity. The complexes prepared in situ are pure enough to apply to the polymerizations without purification. The crystal structures of the key complexes are elucidated by X-ray diffraction, which confirms that they are chiral. However. analysis of the 1H and 13C NMR spec tra unambiguously demonstrates that their conformations are so flexible that the chiral environment of the complexes cannot be maintained in solution at 25°C and that the complexes are achiral under the polymerization conditions. The flexibility of the back-bone in the propagation steps is also documented. Hence, the isotacticity of the polymer occurs due to a chain-end control mechanism. The highest reactivity in the present system is obtained with the homosalen ligand with 2.2-dimethyl substituents in the backbone (ArCH=NCH2CMe2CH2N=CHAr), whereas tBuMe2Si substituents at the 3-positions of the salicylidene moieties lead to the highest selectivity (Pmeso,= 0.98; T m = 210°C). The ratio of the rate constants in the ROPs of racemic lactide and L-lactide is found to correlate with the stereoselectivity in the present system. The complex can be utilized in bulk polymerization, which is the most attractive in industry, although with some loss of stereoselectivity at high temperature, and the afforded polymer shows a higher melting temperature (Pmeso = 0.92, Tm up to 189°C) than that of homochiral poly(L-lactide) (Tm = 162-180°C). The "livingness" of the bulk polymerization at 130°C is maintained even at a high conversion (97-98%) and for an extended polymerization time (1-2 h).

Titanium-salen complexes as initiators for the ring opening polymerisation of rac-lactide

A family of bis(iso-propoxide) titanium(iv) complexes supported by tetradentate Schiff base (salen) ligands has been synthesised and characterised, including a structural determination of N,N′-bis(6′-methylenimino- 2′,4′-di-tert-butylphenoxy)cyclohexyl-(1

Direct observation of enantiomer discrimination of epoxides by chiral salen complexes using ENDOR

Electron nuclear double resonance (ENDOR) spectroscopy was used to investigate the weak enantioselective binding between chiral salen complexes [VO(1)] ((R,R)- and (S,S)-vanadyl N,N-bis(3,5-di-tert-butylsalcylidene)-1,2-cyclohexanediamine) and chiral epoxides (e.g., (R)-/(S)-propylene epoxide, 5) in frozen (10 K) solution. Differences in epoxide binding by enatiomers of [VO(1)] was evidenced by changes to the 1H epoxide derived peaks in the ENDOR spectra, such that (R,R)-[VO(1)] + (R)-5 and (R,R)-[VO(1)] + (S)-5 yield noticeably different spectra. These changes were assigned to the small structural differences between the diastereomeric metal-epoxide adducts. Simulation of the spectra revealed differences in the VO...1Hepoxide distances for the diastereomeric pairs, which was confirmed by a complementary set of density functional theory (DFT) calculations. While the epoxide molecule is very weakly coordinated, ENDOR measurements of the racemic complex in racemic epoxide nevertheless indicated the preferential coordination of the (R)-5 to (R,R)-[VO(1)] (likewise (S)-(5) to (S,S)-[VO(1)]), which is favored over the binding of (S)-5 epoxide to (R,R)-[VO(1)] (and likewise (R)-5 epoxide to (S,S)-[VO(1)]). This demonstrates the unique power of the ENDOR technique to resolve weak chiral interactions for which EPR spectroscopy alone lacks sufficient resolution. Copyright