- Hydrogenolysis of Amide Acetals and Iminium Esters
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Amide acetals and iminium esters were hydrogenated into amines under very mild reaction conditions over common hydrogenation catalysts. This finding provides a new strategy for the selective reduction of amides. The synthetic utility of this approach was demonstrated by the selective reduction of amides bearing ester and nitrile groups.
- Kadyrov, Renat
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p. 170 - 172
(2017/12/26)
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- Catalytic Hydrogenation for Producing Amines from Carboxylic Acid Amides, Carboxylic Acid Diamides, Di-, Tri-, or Polypeptides, or Peptide Amides
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The present invention relates to a process for the preparation of amines, comprising the following steps: a. reaction of a (i) carboxylic acid amide of the general formula (I), or (ii) carboxylic acid diamide of the general formula (II), or (iii) di-, tri- or polypeptide, or (iv) peptide amide with carboxy-terminal amide function with an alkylating agent, b. addition of a hydrogenation catalyst to the reaction mixture in a molar ratio of from 1:10 to 1:100 000, based on carboxylic acid amide, carboxylic acid diamide, di-, tri- or polypeptide or peptide amide, c. reaction of the reaction mixture with hydrogen, where a hydrogen pressure of from 0.1 bar to 200 bar is established and where a temperature in a range of from 0° C. to 250° C. is established.
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Paragraph 185-186
(2016/10/11)
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- Chemoselective Reduction of Tertiary Amides to Amines Catalyzed by Triphenylborane
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Triphenylborane (BPh3) was found to catalyze the reduction of tertiary amides with hydrosilanes to give amines under mild condition with high chemoselectivity in the presence of ketones, esters, and imines. N,N-Dimethylacrylamide was reduced to provide the α-silyl amide. Preliminary studies indicate that the hydrosilylation catalyzed by BPh3may be mechanistically different from that catalyzed by the more electrophilic B(C6F5)3.
- Mukherjee, Debabrata,Shirase, Satoru,Mashima, Kazushi,Okuda, Jun
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supporting information
p. 13326 - 13329
(2016/10/30)
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- Characterization of N-methylated amino acids by GC-MS after ethyl chloroformate derivatization
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Methylation is an essential metabolic process in the biological systems, and it is significant for several biological reactions in living organisms. Methylated compounds are known to be involved in most of the bodily functions, and some of them serve as biomarkers. Theoretically, all α-amino acids can be methylated, and it is possible to encounter them in most animal/plant samples. But the analytical data, especially the mass spectral data, are available only for a few of the methylated amino acids. Thus, it is essential to generate mass spectral data and to develop mass spectrometry methods for the identification of all possible methylated amino acids for future metabolomic studies. In this study, all N-methyl and N,N-dimethyl amino acids were synthesized by the methylation of α-amino acids and characterized by a GC-MS method. The methylated amino acids were derivatized with ethyl chloroformate and analyzed by GC-MS under EI and methane/CI conditions. The EI mass spectra of ethyl chloroformate derivatives of N-methyl (1–18) and N,N-dimethyl amino acids (19–35) showed abundant [M-COOC2H5]+ ions. The fragment ions due to loss of C2H4, CO2, (CO2 + C2H4) from [M-COOC2H5]+ were of structure indicative for 1–18. The EI spectra of 19–35 showed less number of fragment ions when compared with those of 1–18. The side chain group (R) caused specific fragment ions characteristic to its structure. The methane/CI spectra of the studied compounds showed [M + H]+ ions to substantiate their molecular weights. The detected EI fragment ions were characteristic of the structure that made easy identification of the studied compounds, including isomeric/isobaric compounds. Fragmentation patterns of the studied compounds (1–35) were confirmed by high-resolution mass spectra data and further substantiated by the data obtained from 13C2-labeled glycines and N-ethoxycarbonyl methoxy esters. The method was applied to human plasma samples for the identification of amino acids and methylated amino acids. Copyright
- Reddy, B. Sudarshana,Chary, V. Naresh,Pavankumar,Prabhakar
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p. 638 - 650
(2016/09/28)
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- SUBSTITUTED INDAZOLE COMPOUNDS, COMPOSITIONS THEREOF, AND METHODS OF TREATMENT THEREWITH
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Provided herein are methods for treating and preventing malaria and/or Babesiosis, the methods comprising administering an effective amount of Indazole Compounds having the formulas: (I)[Formula (I) should be inserted here] or (II)[Formula (II) should be inserted here] wherein R1, R2, R3 and Y are as defined herein.
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Paragraph 00184
(2016/06/28)
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- Borohydride reductions in dichloromethane: A convenient, environmentally compatible procedure for the methylation of amines
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The combination of zinc chloride and sodium borohydride in dichloromethane is used to effect reductive aminations of formaldehyde with a variety of primary and secondary amines containing potentially acid-sensitive functional groups in good to excellent yields.
- Bhattacharyya
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p. 2061 - 2069
(2007/10/02)
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- Use of Zinc Borohydride in Reductive Amination: An Efficient and Mild Method for N-Methylation of Amines
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An efficient method for the reductive methylation of amines using paraformaldehyde, zinc chloride and zinc borohydride is described.
- Bhattacharyya, Sukanta,Chatterjee, Arindam,Duttachowdhury, Shiti, Kantha
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- Titanium(IV) Isopropoxide and Sodium Borohydride: A Reagent of Choice for Reductive Amination
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The preliminary results on the novel use of titanium(IV) isopropoxide and sodium borohydride in reductive amination reactions are reported.A highly efficient and mild procedure for reductive aminations of formaldehyde with a variety of primary and secondary amines is described.
- Bhattacharyya, Sukanta
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p. 2401 - 2404
(2007/10/02)
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- Substituent Effects on the Strength of C-C-Bonds. IX. Thermolability of 2,3-Di(N,N-dialkylamino)-diethyl-succinates
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The title compounds meso and D,L 3a-c have been prepared from R,R'N-CH2-COOEt (5), R,R'=CH3 (a), C2H5 (b) and i-C3H7 (c), by lithiation followed by oxydation with I2.The thermolysis of (3) above 140 deg C in solution generates the radicals 1, which could be detected by e.s.r.Kinetic measurements are performed in the presence of phenylthiol as a scavenger and the activation parameters are determined. - The steric acceleration of the cleavage reaction is separated using the correlation , whereby the strain values are taken from force field calculations.The obtained strain free barrier to dissociation b = 37.4 kcal/mol is considerably lower than the value for the thermolysis reaction of tetraalkyl ethanes (b=66.2 kcal/mol). The decrease of the activation enthalpy (ΔΔH(excit.) = 35.4 kcal/mol) is mainly caused by stabilisation of 1 compared to sec. alkyl radicals; heats of formation of meso-3a and 5a support this conclusion. Furthermore, the decrease of bond strength in 3 by the two geminal capto-dative substituents exceeds the sum of the effect of one ester group (ΔΔH(excit.)=4 kcal/mol and one amino group (ΔΔH(excit.)=9.5 kcal/mol), drawn from the thermolysis of 1,2-(N,N-Dimethylamino)-1,2-diphenylethane (4)) by about 4 kcal/mol.
- Schulze, Rainer,Beckhaus, Hans-Dieter,Ruechardt, Christoph
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p. 325 - 330
(2007/10/02)
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