Facile and Selective <i>O</i>-Alkyl Transesterification of Primary Carbamates with Titanium(IV) Alkoxides

Shapiro, Gideon; Marzi, M.

doi:10.1021/jo971498z

Cited by 64 publications

(26 citation statements)

References 11 publications

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“…M.p. 168-170 8C; 4'-Nitro-1,1'-biphenyl-4-carboxylic acid benzyl ester (2): Titanium(IV) isopropoxide (0.7 mL, 2.3 mmol) was added to 4'-nitro-1,1'-biphenyl-4-carboxylic acid methyl ester (1, 1.393 g, 5.7 mmol) in a mixture of benzyl alcohol (11.8 mL, 114 mmol) and toluene (90 mL) and the mixture was heated to reflux at 150 8C for 10 h. [46] Then, the solution was allowed to cool to room temperature and was concentrated under reduced pressure, followed by purification on a silica column with n-hexane/ethyl acetate 4'-Amino-1,1'-biphenyl-4-carboxylic acid benzyl ester (3): A mixture of 4'-nitro-1,1'-biphenyl-4-carboxylic acid benzyl ester (2, 500 mg, 1.5 mmol) and ethanol was heated to reflux (95 8C). After about 10 min, iron powder (837 mg, 0.015 mol) and 1 m aqueous HCl solution (0.95 mL) were added.…”

Section: Methodsmentioning

confidence: 99%

Dynamics of the Glycosidic Bond: Conformational Space of Lactose

Erdélyi

d’Auvergne

Navarro‐Vázquez

et al. 2011

Chemistry A European J

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The dynamics of the glycosidic bond of lactose was studied by a paramagnetic tagging-based NMR technique, which allowed the collection of an unusually large series of NMR data for a single compound. By the use of distance- and orientation-dependent residual dipolar couplings and pseudocontact shifts, the simultaneous fitting of the probabilities of computed conformations and the orientation of the magnetic susceptibility tensor of a series of lanthanide complexes of lactose show that its glycosidic bond samples syn/syn, anti/syn and syn/anti ϕ/ψ regions of the conformational space in water. The analysis indicates a higher reliability of pseudocontact shift data as compared to residual dipolar couplings with the presently available weakly orienting paramagnetic tagging technique. The method presented herein allows for an improved understanding of the dynamic behaviour of oligosaccharides.

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Section: Methodsmentioning

confidence: 99%

Dynamics of the Glycosidic Bond: Conformational Space of Lactose

Erdélyi

d’Auvergne

Navarro‐Vázquez

et al. 2011

Chemistry A European J

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“…Various catalysts for the transesterification reaction were screened. Boronic acid [91] and indium(III) iodide [92] yielded no transesterification product with propargyl alcohol, while Ti(OiPr) 4 [93] gave only a trace of the desired product, with mostly detosylation resulting. Otera’s catalyst [94] proved to be optimal, giving cycloaddition precursors 17a and 17b in excellent yields (84% and 87%, respectively).…”

Section: Resultsmentioning

confidence: 99%

An intramolecular inverse electron demand Diels–Alder approach to annulated α-carbolines

Feng²,

Woo³

et al. 2012

Beilstein J. Org. Chem.

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SummaryIntramolecular inverse electron demand cycloadditions of isatin-derived 1,2,4-triazines with acetylenic dienophiles tethered by amidations or transesterifications proceed in excellent yields to produce lactam- or lactone-fused α-carbolines. Beginning with various isatins and alkynyl dienophiles, a pilot-scale library of eighty-eight α-carbolines was prepared by using this robust methodology for biological evaluation.

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“…The introduction of N -nitroso ( 27 ) [ 77 , 78 ], N -nitro ( 28 ) [ 79 ], N -(tosyl) ( 29 ) [ 80 ], N -(trifluoromethanesulfonyl) (30) [ 80 ], or N -acyl (31) [ 81 , 82 , 83 ] amides are the most relevant examples. The following step describes how these activated amides (27–31) could react with, e.g., dimethylamine, to yield the desired and exemplified amide product 26.…”

Section: Discussionmentioning

confidence: 99%

Amide Activation in Ground and Excited States

et al. 2018

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Not all amide bonds are created equally. The purpose of the present paper is the reinterpretation of the amide group by means of two concepts: amidicity and carbonylicity. These concepts are meant to provide a new viewpoint in defining the stability and reactivity of amides. With the help of simple quantum-chemical calculations, practicing chemists can easily predict the outcome of a desired process. The main benefit of the concepts is their simplicity. They provide intuitive, but quasi-thermodynamic data, making them a practical rule of thumb for routine use. In the current paper we demonstrate the performance of our methods to describe the chemical character of an amide bond strength and the way of its activation methods. Examples include transamidation, acyl transfer and amide reductions. Also, the method is highly capable for simple interpretation of mechanisms for biological processes, such as protein splicing and drug mechanisms. Finally, we demonstrate how these methods can provide information about photo-activation of amides, through the examples of two caged neurotransmitter derivatives.

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Facile and Selective O-Alkyl Transesterification of Primary Carbamates with Titanium(IV) Alkoxides

Cited by 64 publications

References 11 publications

Dynamics of the Glycosidic Bond: Conformational Space of Lactose

Dynamics of the Glycosidic Bond: Conformational Space of Lactose

An intramolecular inverse electron demand Diels–Alder approach to annulated α-carbolines

Amide Activation in Ground and Excited States

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