- Method for preparing aminobenzoic acid or ester thereof
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The invention discloses a method for preparing aminobenzoic acid or ester thereof. The method comprises the following steps: S1, sequentially adding nitrobenzoic acid or ester, a solvent and an active nickel catalyst in a reactor; S2, while stirring, introducing hydrogen gas to replace air in a system for 3-4 times, controlling the pressure of the hydrogen gas, and performing a stirring reaction at preset temperature for a scheduled time so as to realize catalytic hydrogenation; S3, performing filtration under reduced pressure, washing filter cakes with a solvent which is the same as the solvent in S1, and collecting the active nickel catalyst; S4, performing reduced-pressure concentration on filtrate obtained in the S3 to obtain a solid namely the product of the aminobenzoic acid or the ester thereof. The method disclosed by the invention can be performed in neutral condition, normal temperature, low pressure or normal pressure, is high in synthetizing yield and low in cost, and has commercial value and environmental protection efficacy; the yield of the obtained product can be 95% or above, and the purity of the product can be 98.5% or above.
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Paragraph 0022
(2017/07/21)
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- Competitive homolytic and heterolytic decomposition pathways of gas-phase negative ions generated from aminobenzoate esters
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An alkyl-radical loss and an alkene loss are two competitive fragmentation pathways that deprotonated aminobenzoate esters undergo upon activation under mass spectrometric conditions. For the meta and para isomers, the alkyl-radical loss by a homolytic cleavage of the alkyl-oxygen bond of the ester moiety is the predominant fragmentation pathway, while the contribution from the alkene elimination by a heterolytic pathway is less significant. In contrast, owing to a pronounced charge-mediated ortho effect, the alkene loss becomes the predominant pathway for the ortho isomers of ethyl and higher esters. Results from isotope-labeled compounds confirmed that the alkene loss proceeds by a specific γ-hydrogen transfer mechanism that resembles the McLafferty rearrangement for radical cations. Even for the para compounds, if the alkoxide moiety bears structural motifs required for the elimination of a more stable alkene molecule, the heterolytic pathway becomes the predominant pathway. For example, in the spectrum of deprotonated 2-phenylethyl 4-aminobenzoate, m/z 136 peak is the base peak because the alkene eliminated is styrene. Owing to the fact that all deprotonated aminobenzoate esters, irrespective of the size of the alkoxy group, upon activation fragment to form an m/z 135 ion, aminobenzoate esters in mixtures can be quantified by precursor ion discovery mass spectrometric experiments.
- Xia, Hanxue,Zhang, Yong,Pavlov, Julius,Jariwala, Freneil B.,Attygalle, Athula B.
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p. 245 - 253
(2016/03/15)
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- Synthesis and cytotoxicity of some d-mannose click conjugates with aminobenzoic acid derivatives
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Two sets of new conjugates obtained from d-mannose derivatives and o-, m-, and p-substituted benzoic acid esters interconnected through a triazole ring were synthesized by Cu(I) catalyzed azide-alkyne cycloaddition. All synthesized compounds were tested for their in vitro cytotoxic activity against seven cancer cell lines with/without multidrug resistance phenotype as well as non-tumor MRC-5 and BJ fibroblasts. Butyl ester of 4-aminobenzoic acid 6c showed the highest activity among all tested compounds, however, it was active only against K562 myeloid leukemia cells. N-Glycosyltriazole conjugates, both acetylated and nonacetylated at mannose moiety, were almost completely inactive. In contrast, some of the acetylated O-glycosyl conjugates showed cytotoxic activity which was cell line dependent and strongly affected by position of benzoic acid substitution as well as a length of its ester alkyl chain; the most potent compound was acetylated mannoside conjugated with octyl ester of m-substituted benzoic acid. However, deacetylation resulting in hydrophilicity increase of the glycosides almost completely abolished their cytotoxic potency.
- Hradilová, Ludmila,Poláková, Monika,Dvo?áková, Barbora,Hajdúch, Marián,Petru?, Ladislav
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- Thermosensitive recording material and novel color developer compounds
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Disclosed is a thermosensitive recording material comprising a sheet-shaped support and a thermosensitive recording layer which is formed on at least one surface of the support and comprises a colorless or light-colored dye precursor and a color developer capable of reacting with the dye precursor and inducing color formation therein upon application of heat thereto, the color developer comprising a compound represented by the following formula (I) or analog thereof:: The thermosensitive recording material has high sensitivity and can prevent white background portions from coloring and recorded images from decolorizing in an environmental resistance test.
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- An efficient general method for esterification of aromatic carboxylic acids
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Treatment of a variety of aromatic carboxylic acids with alcohols in the presence of thionyl chloride results in excellent yields of corresponding esters. This esterification system is compatible with a wide assortment of functional groups.
- Hosangadi, Bhaskar D.,Dave, Rajesh H.
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p. 6375 - 6378
(2007/10/03)
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