ChemInform Abstract: A Convenient Procedure for Bis‐esterification of Cyclic Anhydrides.

Jana, Amit Kumar; Karmakar, Raju; Dinda, Bidyut Kumar; Mitra, Prithiba; Ghosh, Ketaki; Mal, Dipakranjan

doi:10.1002/chin.201312044

Cited by 2 publications

(3 citation statements)

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“…The second derivatization process should be done using a different alcohol (MeOH instead of EtOH), in the presence of a catalyst/mediator, to achieve the esterification of all free carboxylic groups not involved in the first derivatization step. The preliminary functionalization test was carried out on TMA using reaction conditions found in the literature: the first step was performed by stirring for 10 min a TMA EtOH solution (1 mg/mL) using an excess of DBU, 40 and then the second step was carried out by heating for 1 h at 100 °C the reaction crude dissolved in a BF 3 •MeOH solution. 24 It was found that these conditions were not totally suitable for this analytical method, since trimethyl trimellitate (TMT) was detected in high percentage compared to the analytical target, ethyl dimethyl trimellitate (EDMT).…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“… 39 In this context, a greener method for the simultaneous recognition and quantification of any anhydride in the presence of the corresponding acid could be attractive. In this work, an innovative, fully automated, direct injection GC–MS method is presented: the sample pretreatment consists in selective esterification with absolute ethanol (EtOH), mediated by 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), on the anhydride, 40 followed by a treatment with BF 3 ·MeOH for the methylation of remaining carboxylic groups. 24 The setup of the derivatization process was optimized by experimental design to minimize the amount of tests required.…”

Section: Introductionmentioning

confidence: 99%

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Simultaneous Determination by Selective Esterification of Trimellitic, Phthalic, and Maleic Anhydrides in the Presence of Respective Acids

et al. 2023

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Trimellitic, phthalic, and maleic anhydrides are important building blocks to produce polymers and additives, such as plasticizers. In humans, the exposure to these compounds can cause several health issues. In European Union and USA, their presence in substances and mixtures is restricted by CLP Regulation (no. 1272/2008) and HCS/HazCom 2012, respectively, but no information about the corresponding acids is reported. For this reason, a selective method to determine anhydrides in mixtures, in the presence of acids, could be interesting. Nowadays, methods in the literature are either not selective or use explosive and toxic reagents (as diazomethane). In this work, an innovative, greener, and safer method for the simultaneous recognition and quantification of anhydrides and acids, via direct injection gas chromatography−mass spectrometry, is developed. The sample pretreatment consists in selective esterification with absolute ethanol on the anhydride, followed by a treatment with boron trifluoride-methanol for the methylation of remaining carboxylic groups. The optimization of the functionalization, a crucial step of the method, was optimized by experimental design. The limit of detection−limit of quantification (LOD−LOQ) values for trimellitic, phthalic, and maleic anhydrides are 0.31− 0.93, 0.47−1.41, and 0.06−0.18 μg/mL, respectively.

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Section: ■ Results and Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Simultaneous Determination by Selective Esterification of Trimellitic, Phthalic, and Maleic Anhydrides in the Presence of Respective Acids

et al. 2023

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“…The phrase "usual workup" or "worked up in the usual manner" refers to washing of the organic phase with water (2 ϫ 1/3 of the volume of the organic phase) and brine (1 ϫ 1/4 of the volume of the organic phase), drying (Na 2 SO 4 ), filtration, and concentration under reduced pressure. Known substrates 11, [22] 18d, [29] 25, [15] 29a, [30] 29b, [30] 34, [31] 43, [15] 45 [28] were prepared according to reported procedures.…”

Section: Methodsmentioning

confidence: 99%

Regiospecific Synthesis of 7‐Hydroxyindoles from Pyrroles by Anionic Benzannulation

2014

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Anionic annulation of appropriate 2,3‐disubstituted pyrroles with Michael acceptors provides an expedient route to densely substituted 7‐hydroxyindoles. Intrinsic to the methodology, the resulting substituents are disposed in a fully regiocontrolled manner. The methodology is applicable to the synthesis of 7‐hydroxybenzofurans. None of the indoles/benzofurans or pyrrole synthons synthesized in this study have hitherto been reported.

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ChemInform Abstract: A Convenient Procedure for Bis‐esterification of Cyclic Anhydrides.

Cited by 2 publications

References 0 publications

Simultaneous Determination by Selective Esterification of Trimellitic, Phthalic, and Maleic Anhydrides in the Presence of Respective Acids

Simultaneous Determination by Selective Esterification of Trimellitic, Phthalic, and Maleic Anhydrides in the Presence of Respective Acids

Regiospecific Synthesis of 7‐Hydroxyindoles from Pyrroles by Anionic Benzannulation

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