ChemInform Abstract: STEREOSELECTIVE REDUCTIONS OF SUBSTITUTED CYCLOHEXYL AND CYCLOPENTYL CARBON‐NITROGEN Π SYSTEMS WITH HYDRIDE REAGENTS

Hutchins, Robert O.; Su, Wei-Yang; Sivakumar, R; Cistone, Frank; Stercho, Yuriy P.

doi:10.1002/chin.198412133

Cited by 3 publications

(3 citation statements)

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“…Finally, we identified a stereoselective reductive amination as being the pivotal step to set the desired cis-stereochemistry, improve the yield, and avoid a tedious chromatography. 7,8 This stereoselective reductive amination could occur either early in the reaction sequence as a way to avoid the reduction and subsequent oxidation of the cyclobutanone (via intermediate 10) or as the last step (via intermediate 9) (Scheme 2). This led to identification of the key intermediate 6, which would serve as precursor to both routes.…”

Section: ■ Introductionmentioning

confidence: 99%

Scalable Synthesis of a Cis-Substituted Cyclobutyl-Benzothiazole Pyridazinone: Process Development of an Efficient Copper Catalyzed C–N Cross-Coupling Reaction

Kallemeyn

Mulhern

et al. 2013

Org. Process Res. Dev.

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A scalable process for the preparation of 2-(2-(cis-3-(piperidin-1-yl)cyclobutyl)benzothiazol-6-yl)pyridazin-3(2H)-one in multi-kilogram amounts and in high purity has been developed. The key features of this synthesis are the copper-catalyzed C–N cross-coupling reaction and the development of a highly diastereoselective reductive amination using NaBH(OPiv)3 as a reducing agent. Controls were implemented to minimize both base- and acid-catalyzed isomerization of the 1,3-cis-substituted cyclobutane ring.

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Section: ■ Introductionmentioning

confidence: 99%

Scalable Synthesis of a Cis-Substituted Cyclobutyl-Benzothiazole Pyridazinone: Process Development of an Efficient Copper Catalyzed C–N Cross-Coupling Reaction

Kallemeyn

Mulhern

et al. 2013

Org. Process Res. Dev.

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“…Amines 2-5 and 10-12 were prepared from 4-tert-butylcyclohexanone, the appropriate amine, and formic acid. 6 For 6-9, 14, and 15 NaBH3CN was the reductant, 7 and 13 was prepared from commercial 4-tert-butylcyclohexylamine (1), formaldehyde, and formic acid. 8 The cis/trans mixtures of amine stereoisomers, purified by distillation, were not separated but were characterized by 1 H and 13 C NMR, 9 and were used in whatever ratio was obtained.…”

Section: Methodsmentioning

confidence: 99%

Unusually Strong Dependence of Conformation on Solvent

1998

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Relative partition coefficients between aqueous methanol and pentane of the two stereoisomers of a series of 4-tert-butylcyclohexylamines were measured by NMR. The cis isomer shows a larger partition coefficient, with a ΔΔG°org → aq up to 1.4 kcal/mol. A thermodynamic cycle relates these values to a solvent dependence of the A value for conformational equilibrium of an amino substituent. The variation with stereoisomer is attributed to a greater hydrophilicity of a cyclohexylamine with an equatorial amino group, or equivalently to a greater steric bulk of an amino group whose lone pair is hydrogen bonded to water. The strong dependence on solvent inferred for A NMe 2 was confirmed by direct measurement of conformer populations at low temperature.

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“…Then, a solution of p-toluenesulphonic acid (15 mol% in 2 mL of THF) was added dropwise, and stirred over 2-4 h more [6]. During this time, a small portion of bromocresol green was used as indicator, maintaining the solution in an orange-yellow colour (indicating acidic pH) [7]. After that, diluted HCl (2%, 4 mL) was added and stirred for 1 h. Finally, the resulting solution was neutralized up to pH 7-8, and the corresponding amine was extracted with Et2O (3 × 3 mL).…”

Section: General Procedures For Reduction Of Imines To Aminesmentioning

confidence: 99%

Terminal Alkynes Hydroamination Catalyzed by Copper Nanoparticles

Mancebo‐Aracil

Alonso

Radivoy

2020

The 24th International Electronic Conference on Synthetic Organic Chemistry

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The copper-catalyzed regioselective intermolecular hydroamination of terminal alkynes with amines has been accomplished. The reaction was effectively catalyzed by copper nanoparticles supported on montmorillonite K10 (CuNPs/MK10), and afforded the intended imines in good conversions. Then, imines were transformed into the corresponding amines after treatment with NaBH3CN. The catalyst could be recovered and reused in several cycles.

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ChemInform Abstract: STEREOSELECTIVE REDUCTIONS OF SUBSTITUTED CYCLOHEXYL AND CYCLOPENTYL CARBON‐NITROGEN Π SYSTEMS WITH HYDRIDE REAGENTS

Abstract: Imine (I), Enamine (II) oder auch Iminiumsalze (III) werden mit verschiedenen Hydriden (IV) zu den entsprechenden gesättigten Aminen (V) reduziert.

Cited by 3 publications

References 1 publication

Scalable Synthesis of a Cis-Substituted Cyclobutyl-Benzothiazole Pyridazinone: Process Development of an Efficient Copper Catalyzed C–N Cross-Coupling Reaction

Scalable Synthesis of a Cis-Substituted Cyclobutyl-Benzothiazole Pyridazinone: Process Development of an Efficient Copper Catalyzed C–N Cross-Coupling Reaction

Unusually Strong Dependence of Conformation on Solvent

Terminal Alkynes Hydroamination Catalyzed by Copper Nanoparticles

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