193824-05-4

Upstream product

• 3187-83-5 (R,R)-N,N'-bis(salicylidene)-1,2-cyclohexanediamine 
• 215057-24-2 2,2'-(1E,1'E)-(1R,2R)-cyclohexane-1,2-diylbis(azan-1-yl-1-ylidene)bis(methan-1-yl-1-ylidene)diphenol 
• 89-95-2 2-methyl-benzyl alcohol 
• 1121-22-8 trans-1,2-Diaminocyclohexane 
• 10027-80-2 (1R,2R)-1,2-dicyclohexane-1,2-diamine dihydrochloride 
• 90-02-8 salicylaldehyde 
• 20439-47-8 (1R,2R)-1,2-diaminocyclohexane 
• 1160221-09-9 C₃₂H₄₆N₂O₁₂ 

Downstream Products

• 193824-04-3 2,2'-[trans-(R,R)-1,2-cyclohexanediylbis(N-methylaminomethyl)]-diphenol 
• 1065518-60-6 (R,R)-N,N'-dibenzyl-N,N'-bis(2-hydroxybenzyl)-1,2-cyclohexanediamine 

Relevant academic research and scientific papers

Stereoselective protonation of 2-methyl-1-tetralone lithium enolate catalyzed by salan-type diamines

Asymmetric protonation of ketone enolates is a convenient alternative to asymmetric alkylation of enolates that allows to convert racemic ketones into their optically active form. Here, we have reported an efficient enantioselective protonation of 2-methyl-1-tetralone lithium enolate catalyzed by salan-type diamines. A broad series of salan-type catalysts were synthesized, including several previously unknown, and subsequently tested in the title reaction. For the first time, a chiral amine used as organocatalyst has shown better results than as stoichiometric protonating agent. Application of only 10 mol% of salan allows to obtain the title ketone with high yield and enantiomeric excess up to 75%. The DFT calculations of the structure of the catalyst and its complex with lithium enolate were conducted, which makes it possible to propose a likely reaction mechanism.

Synthesis of N,N′-Dialkylated Cyclohexane-1,2-diamines and Their Application as Asymmetric Ligands and Organocatalysts for the Synthesis of Alcohols

A series of N,N′-dialkylated derivatives of (1R,2R)-cyclohexane-1,2-diamine were synthesized, and a new approach to the one-pot preparation of this type of amine was demonstrated. The prepared diamines were used as organocatalysts for the two-step synthesis of α-hydroxy γ-keto esters from arenes, chlorooxoacetates, and ketones; they were also used as chiral ligands for Meervein-Ponndorf-Verley reductions and Henry reactions.

Glycosylated tetrahydrosalens as multifunctional molecules for Alzheimer's therapy

The tetrahydrosalens N,N′-bis(2-hydroxybenzyl)-ethane-1,2-diamine (H2L1), N,N′-bis(2-hydroxybenzyl)-(-)-1,2- cyclohexane-(1R,2R)-diamine (H2L2), N,N′-bis(2- hydroxybenzyl)-N,N′-dimethyl-ethane-1,2-diamine (H2L 3), N,N′-bis(2-hydroxybenzyl)-N,N′-dibenzyl-ethane-1,2- diamine (H2L4), and N,N′-bis(2-(4-tert-butyl) hydroxybenzyl)-ethane-1,2-diamine (H2L5), as well as their prodrug glycosylated forms, GL1-5, have been prepared and evaluated in vitro for their potential use as Alzheimer's disease (AD) therapeutics. Dysfunctional interactions of metal ions, especially those of Cu, Zn, and Fe, with the amyloid-β (Aβ) peptide are hypothesised to play an important role in the aetiology of AD, and disruption of these aberrant metal-peptide interactions via chelation therapy holds considerable promise as a therapeutic strategy. Tetrahydrosalens such as H2L1-5 have a significant affinity for metal ions, and thus should be able to compete with the Aβ peptide for Cu, Zn, and Fe in the brain. This activity was assayed in vitrovia a turbidity assay; H2L1 and H2L 3 were found to attenuate Aβ1-40 aggregation after exposure to Cu2+ and Zn2+. In addition, H 2L1-5 were determined to be potent antioxidants on the basis of an in vitro antioxidant assay. GL1-5 were prepared as metal binding prodrugs; glycosylation is intended to prevent systemic metal binding, improve solubility, and enhance brain uptake. Enzymatic (β-glucosidase) deprotection of the carbohydrate moieties was facile, with the exception of GL4, demonstrating the general feasibility of this prodrug approach. Finally, a representative prodrug, GL3, was determined to be non-toxic over a large concentration range in a cell viability assay.

Chiral salan aluminium ethyl complexes and their application in lactide polymerization

Synthetic routes to aluminium ethyl complexes supported by chiral tetradentate phenoxyamine (salan-type) ligands [Al(OC6H 2(R-O-R4)CH2)2{CH3N(C 6H10)NCH3}-C2H5] (4, 7: R = H; 5, 8: R = Cl; 6, 9: R = CH3) are reported. Enantiomerically pure salan ligands 1-3 with (R,R) configurations at their cyclohexane rings afforded the complexes 4, 5, and 6 as mixtures of two diastereoisomers (a and b). Each diastereoisomer a was, as determined by X-ray analysis, monomeric with a five-coordinated aluminium central core in the solid state, adopting a cis-(O,O) and cis-(Me,Me) ligand geometry. From the results of variabletemperature (VT) 1H NMR in the tern-perature range of 220-335 K, 1H- 1H NOESY at 220K, and diffusion-ordered spectroscopy (DOSY), it is concluded that each diastereoisomer b is also monomeric with a five-coordinated aluminium central core. The geometry is intermediate between square pyramidal with a cis-(O,O), trans-(Me,Me) ligand disposition and trigonal bipyramidal with a rrans-(O,O) and trans(Me,Me) disposition. A slow exchange between these two geometries at 220 K was indicated by 1H-1H NOESY NMR. In the presence of propan-2-ol as an initiator, enantiomerically pure (R,R) complexes 4-6 and their racemic mixtures 7-9 were efficient catalysts in the ring-opening polymerization of lactide (LA). Polylactide materials ranging from isotactically biased (Pm up to 0.66) to medium heterotactic (P r up to 0.73) were obtained from rac-lactide, and syndiotactically biased polylactide (Pr up to 0.70) from wicso-lactide. Kinetic studies revealed that the polymerization of (S,S)-LA in the presence of 4/propan-2-ol had a much higher polymerization rate than (R,R)-LA polymerization (kss/kRR = 10.1).

Synthesis of chlorinated biphenyls by Suzuki cross-coupling using diamine or diimine-palladium complexes

Several novel diimines (Salen-type ligands) 2a-2i and their reduced diamine counterparts 3b,3d-3g and 3i form complexes 4a-4i, 5b,5d-5g, and 5i with PdCl2 in DMF or methanol. Using 1 mol-% of the isolated complexes 4e and 5f many polychlorinated biphenyls (PCBs) can be prepared in moderate to excellent yields according to the Suzuki cross-coupling protocol with contact to air. Several 4-acetylbiphenyls prepared by this method can be converted in moderate yields into the corresponding biphenylcarboxylic acids (BCAs) by alkaline cleavage. An X-ray crystal structure determination confirms the structure of complex 5f. Wiley-VCH Verlag GmbH & Co. KGaA, 2008.

Titanium-salan-catalyzed asymmetric oxidation of sulfides and kinetic resolution of sulfoxides with H2O2 as the oxidant

Asymmetric oxidation of sufides to sulfoxides by aqueous hydrogen peroxide with catalysis by titanium-salan complexes is presented. Optically active sulfoxides have been obtained with good to high enantioselectivities (up to 97% ee) by a tandem enantioselective oxidation and kinetic resolution procedure, the catalyst performing over 500 turnovers with no loss of enantioselectivity. Wiley-VCH Verlag GmbH & Co. KGaA, 2008.

Molybdenum(VI) cis-dioxo complexes with chiral schiff base ligands: Synthesis, characterization, and catalytic applications

Three optically active Molybdenum (VI) dioxo complexes with tetrahydro salen and substituted tetrahydro salen derivatives as ligands were synthesized and examined as catalysts for asymmetric epoxidation. Complexes of the type MoO2(L)(Solv) and WO2(L) (L = tridentate, trans-2-aminocyclohexanol derived chiral Schiff base, Solv = alcohol) were prepared and characterized by elemental analysis, NMR and IR spectroscopy. These complexes are applicable as catalysts for olefin epoxidation reactions with tert-butyl hydroperoxide (TBHP) being the oxidizing agent. In case of cis-β-methylstyrene moderate enantiomeric excesses of up to 26% can be reached when the reaction is carried out at 0°C.

Efficient asymmetric oxidation of sulfides and kinetic resolution of sulfoxides catalyzed by a vanadium-salan system

The asymmetric oxidation of sulfides to chiral sulfoxides with hydrogen peroxide in good yield and high enantioselectivity has been catalyzed very effectively by chiral vanadium-salan [N,N′-alkyl bis(salicylamine)] complex. The salan ligand shows results superior in terms of reactivity and enantioselectivity to those of salen [N,N′-alkylene bis(salicylideneimine) ] analogue, and provides the sulfoxide with opposite configuration. The high enantioselectivity of this reaction is the direct result of the asymmetric oxidation. The efficient kinetic resolution of racemic sulfoxides catalyzed by the vanadium-salan system is also described.