Substituted 1-Phenyl-2-alkylaminoethanols and -propanols<sup>1</sup>

Corrigan, John R.; Sullivan, Marie-Jo; Bishop, Howard W.; Ruddy, A. Wayne

doi:10.1021/ja01120a045

Cited by 12 publications

(3 citation statements)

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“…In 1953, Ruddy and co-workers reported the synthesis of benzylcyclopentylamine via a two-step procedure (Scheme 110). 208 They used Raney Ni as the catalyst for the first step, the reductive amination of cyclopentanone with NH 3 . Cyclopentylamine was obtained in a yield of 84%.…”

Section: Use Of Several Catalysts For Reductive Aminationmentioning

confidence: 99%

Transition-Metal-Catalyzed Reductive Amination Employing Hydrogen

2020

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The reductive amination, the reaction of an aldehyde or a ketone with ammonia or an amine in the presence of a reducing agent and often a catalyst, is an important amine synthesis and has been intensively investigated in academia and industry for a century. Besides aldehydes, ketones, or amines, starting materials have been used that can be converted into an aldehyde or ketone (for instance, carboxylic acids or organic carbonate or nitriles) or into an amine (for instance, a nitro compound) in the presence of the same reducing agent and catalyst. Mechanistically, the reaction starts with a condensation step during which the carbonyl compound reacts with ammonia or an amine, forming the corresponding imine followed by the reduction of the imine to the alkyl amine product. Many of these reduction steps require the presence of a catalyst to activate the reducing agent. The reductive amination is impressive with regard to the product scope since primary, secondary, and tertiary alkyl amines are accessible and hydrogen is the most attractive reducing agent, especially if large-scale product formation is an issue, since hydrogen is inexpensive and abundantly available. Alkyl amines are intensively produced and use fine and bulk chemicals. They are key functional groups in many pharmaceuticals, agro chemicals, or materials. In this review, we summarize the work published on reductive amination employing hydrogen as the reducing agent. No comprehensive review focusing on this subject has been published since 1948, albeit many interesting summaries dealing with one or the other aspect of reductive amination have appeared. Impressive progress in using catalysts based on earth-abundant metals, especially nanostructured heterogeneous catalysts, has been made during the early development of the field and in recent years.

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Section: Use Of Several Catalysts For Reductive Aminationmentioning

confidence: 99%

Transition-Metal-Catalyzed Reductive Amination Employing Hydrogen

2020

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“…204−206 °C with decomp.). 54 1 H NMR (500 MHz, CD 3 OD): δ (ppm) 1.36 (t, 6H, J = 7.3 Hz), 3.33 (q, 4H, J = 7.3 Hz), 4.86 (s, 2H), 6.97 (d, 2H, J = 8.8 Hz), 7.95 (d, 2H, J = 8.8 Hz) (Figure S8). 13 S10).…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

4-Hydroxyphenacyl Ammonium Salts: A Photoremovable Protecting Group for Amines in Aqueous Solutions

Bownik¹,

Šebej²,

Literák³

et al. 2015

J. Org. Chem.

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Irradiation of N-protected p-hydroxyphenacyl (pHP) ammonium caged derivatives at 313 nm releases primary and secondary amines or ammonia in nearly quantitative yields via the photo-Favorskii reaction when conducted in acidic or neutral aqueous buffered media. The reaction efficiencies are strongly dependent on the pH with the most efficient and highest yields obtained when the pH of the media maintains the ammonium and p-hydroxyl groups as their conjugate acids. For example, the overall quantum yields of simple secondary amines release are 0.5 at acidic pH from 3.9 to 6.6 dropping to 0.1 at neutral pH 7.0 and 0.01 at pH 8.4. Speciation studies provide an acid-base profile that helps define the scope and limitations of the reaction. When the pKa of the ammonium group is lower than that of the phenolic hydroxyl group, as is the case for the α-amino-protected amino acids, the more acidic ammonium ion deprotonates as the media pH is changed from acidic toward neutral or basic, thus diminishing the leaving group ability of the amino group. This, in turn, lowers the propensity for the photo-Favorskii rearrangement reaction to occur and opens the reaction pathway to alternative competing photoreduction process.

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“…Calc. for C11HnKO: C, 73.69; H, 9 A mixture of oil and cyclopentylamine hydrochloride was obtained from the acidic aqueous washings of the ether extract. The crystals (m.p.…”

Section: Attempt To Prepare Cyclopentyl 2-carboxycyclopentylaminementioning

confidence: 99%

Condensation of Alicyclic Ketones With Urea and Thiourea

McKay¹,

Podešva²,

Tarlton³

et al. 1964

Can. J. Chem.

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The previous assignment of a cis conforination to cyclohexyl 2-carbamylcyclohexylamine, which was prepared by the condensation of urea with cyclohexanone, has been confirmed by equilibration in the presence of potassiutn t-butoxide. The failure of 4-t-butylcyclohexyl 2-carbamyl-4-t-butylcyclohexylamine to equilibrate under the same conditions is discussed in relation to its structure. 1,2,3,4,5,6,7,8-Octahydroacridine was prepared by the condensation of 2,2'-methylene-bis-cyclohexanone with urea.The product from the condensation of cyclohexanone with urea in alkaline medium was assigned (1) structure I on the basis of its analysis, infrared spectrum, and hydrogenation to cq-clohexyl 2-carba~~~ylcyclohexylamine (11). Later Scarborough and Gould (2) reported an improved procedure for the preparation of compound I. During the present investigation a new process (cf. Experimental) was developed which gives high yields of this condensation product. T h e latter procedure was used in the preparation of the compounds listed in Table I. Cyclohexylidene 2-thiocarbamylcyclohex-1-enylamine was prepared from the condensation of cyclohexanone with thiourea. The infrared and ultraviolet absorption bands listed in Tables I1 and I11 respectively show that these condensation products have the same general structure. If the imino nitrogen in structure I is assumed t o be equivalent t o carbon for calculating the ultraviolet absorption maximum then the calculated (3) value of 308 mp is in good agreement with the observed value of 305 mp (Table 111).Cyclohexylidene 2-carbamylcyclohex-1-enylamine (I) was considered (1) t o be formed by the carbamylation of an enamine intermediate and the reaction sequence may be represented as follows:The previous (I) scheme showed the addition of HNCO to 1-aminocyclohexene instead of cyclohexylidene cyclohex-1-enylamine. Isocyanic acid would be expected t o add more readily to the latter compound because of its closer structural relationship to typical

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Substituted 1-Phenyl-2-alkylaminoethanols and -propanols¹

Cited by 12 publications

References 1 publication

Transition-Metal-Catalyzed Reductive Amination Employing Hydrogen

Transition-Metal-Catalyzed Reductive Amination Employing Hydrogen

4-Hydroxyphenacyl Ammonium Salts: A Photoremovable Protecting Group for Amines in Aqueous Solutions

Condensation of Alicyclic Ketones With Urea and Thiourea

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Substituted 1-Phenyl-2-alkylaminoethanols and -propanols1

Cited by 12 publications

References 1 publication

Transition-Metal-Catalyzed Reductive Amination Employing Hydrogen

Transition-Metal-Catalyzed Reductive Amination Employing Hydrogen

4-Hydroxyphenacyl Ammonium Salts: A Photoremovable Protecting Group for Amines in Aqueous Solutions

Condensation of Alicyclic Ketones With Urea and Thiourea

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Substituted 1-Phenyl-2-alkylaminoethanols and -propanols¹