76019-90-4

Upstream product

• 51953-02-7 racemic 3-cyclohexyl-2-methylpropanoic acid 
• 20514-52-7 3-Cyclohexyl-2-methylpropanal 
• 67-56-1 methanol 
• 1124-63-6 3-cyclohexylpropan-1-ol 
• 201230-82-2 carbon monoxide 
• 2114-42-3 allylcyclohexane 
• 22436-06-2 2-methyl-3-phenylpropanol 
• 100597-39-5 diethyl 2-(cyclohexylmethyl)-2-methylmalonate 
• 2550-36-9 Cyclohexylmethyl bromide 

Downstream Products

• 21782-55-8 (-)(S)-(γ-bromo-isobutyl)-cyclohexane 

Relevant academic research and scientific papers

Synthesis of β-Chiral Amines by Dynamic Kinetic Resolution of α-Branched Aldehydes Applying Imine Reductases

Imine reductases (IREDs) allow the one-step preparation of optically active secondary and tertiary amines by reductive amination of ketones. Until now, mainly α-chiral amines have been prepared by this route. In this study, we explored the possibility of synthesizing β-chiral amines, a class of compounds which is also frequently found as structural motif in pharmaceuticals but much more challenging to prepare due to the following reasons: (i) The aldehyde substrate already contains the chiral center and needs to be racemized to enable full conversion. (ii) Because the intermediate imine bears the stereo center two carbon atoms remote to the imine nitrogen, it is more challenging to achieve high enantioselectivity compared to α-chiral amine synthesis. For investigating the proof of concept, we first confirmed that different IREDs are able to convert a variety of α-branched aldehydes when combined with five different amine substrates. The IRED from Streptomyces ipomoeae was a suitable enzyme facilitating the dynamic kinetic resolution of 2-phenylpropanal and a substituted 2-methyl-3-phenylpropanal: the corresponding N-methylated β-chiral amines were obtained with '95 % conversion and 78 and 95 %ee. Other amines were formed with low to moderate enantiomeric excess. This exemplifies the potential of IREDs for the one-step synthesis of secondary β-chiral amines, but also the challenge to identify highly selective enzymes for a desired amine product.

C -Methylation of Alcohols, Ketones, and Indoles with Methanol Using Heterogeneous Platinum Catalysts

A versatile, selective, and recyclable heterogeneous catalytic method for the methylation of C-H bonds in alcohols, ketones, and indoles with methanol under oxidant-free conditions using a Pt-loaded carbon (Pt/C) catalyst in the presence of NaOH is reported. This catalytic system is effective for various methylation reactions: (1) the β-methylation of primary alcohols, including aryl, aliphatic, and heterocyclic alcohols, (2) the α-methylation of ketones, and (3) the selective C3-methylation of indoles. The reactions are driven by a borrowing-hydrogen mechanism. The reaction begins with the dehydrogenation of the alcohol(s) to afford aldehydes, which subsequently undergo a condensation reaction with the nucleophile (aldehyde, ketone, or indole), followed by hydrogenation of the condensation product by Pt-H species to yield the desired product. In all of the methylation reactions explored in this study, the Pt/C catalyst exhibits a significantly higher turnover number than other previously reported homogeneous catalytic systems. Moreover, it is demonstrated that the high catalytic activity of Pt can be rationalized in terms of the adsorption energy of hydrogen on the metal surface, as revealed by density functional theory calculations on different metal surfaces.

From alkenes to alcohols by cobalt-catalyzed hydroformylation-reduction

The cobalt-catalyzed hydroformylation of alkenes in the presence of a range of novel cyclic phosphine ligands was investigated. The effect of various parameters such as solvents, additives, cobalt/phosphine ratio, CO/H2 (1:2), and nature of the alkenes was examined. The results revealed that both terminal and internal alkenes are hydroformylated in high yields to give mainly linear products at moderate temperature and syn gas pressure. The linearity ranges from 43 to 85%, with Lim-10 giving the highest proportion of linear product.

Fragrance materials

The use of 2-methyl-3-cyclohexylpropanol, esters thereof or mixtures thereof as fragrance materials is disclosed. The subject materials possess unique fragrance notes and are cost-effective materials. The esters are novel compounds.

Kinetic resolution of primary 2-methyl-substituted alcohols via Pseudomonas cepacia lipase-catalysed enantioselective acylation

The enantioselectivities of lipases from Pseudomonas cepacia (PFL, Amano PS, etc.) towards a series of primary 2-methyl-substituted alcohols using vinyl acetate as the acyl donor in transesterifications in organic solvents were studied. In terms of enantioselectivity, the best results were found for 3-aryl-2-methylpropan-1-ols with enantiomeric ratios (E-values) over 100 in most cases, whereas other 3-substituted primary 2-methylpropan-1-ols generally displayed lower enantioselectivities: 3-cycloalkyl-2-methylpropan-1-ols (E ≈ 20) and 2-methylalkan-1-ols (E ≈ 10). Moving the aryl group closer or further away from the chiral centre resulted in low enantioselectivities: 2-arylpropan-1-ols (E 10), 2-methyl-4-(2-thienyl)butan-1-ol (E = 12), 2-methyl-5-(2-thienyl)pentan-1-ol (E = 3.2) and 2-methyl-6-(2-thienyl)hexan-1-ol (E = 3.8).

2-Substituted histamines with G-protein-stimulatory activity

The cationic-amphiphilic 2-substituted histamines, 2-(2-chlorophenyl)histamine (2-ethanamine) and 2-(2-cyclohexylethyl)histamine, activate pertussis toxin-sensitive guanine nucleotide-binding proteins (G-proteins) of the Gi-subfamily by a receptor-independent mechanism.We studied structure-activity relationships of 2-substituted histamine derivatives for this G-protein activation using six known and 12 newly synthesized compounds.Elongation of the alkyl chain between imidazole and the ring system enhanced the potency and efficiency of substances in activating high-affinity GTP hydrolysis, ie the enzymatic activity of G-protein α subunits, in membranes of HL-60 leukemic cells.Cyclopentyl-, cyclohexyl- and norbornyl-substituted histamines were more effective and potent than phenyl-substituted histamines in mediating G-protein activation in HL-60 membranes and in activating reconstituted bovine brain Gi/Go-proteins.Our data show that the chain length and the type of ring system are important determinants for receptor-independent G-protein activation by 2-substituted histamines.With respect to histamine H1-receptors, most of the substances studied displayed weak antagonistic activity.

Benzopyranoisoxazolidine als Auxiliare fuer die asymmetrische Synthese

Stichworte: Alkylierungen * Asymmetrische Synthesen * Chirale Hilfsstoffe * Isoxazolidine