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Carboxylic acid

About: Carboxylic acid is a research topic. Over the lifetime, 48544 publications have been published within this topic receiving 605696 citations.


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Journal ArticleDOI
TL;DR: In this paper, a mixture of cyclohexene, 1-pentene, and 1-cyclohexylborane was used for the identification of tripentylboranes.
Abstract: General Oxygenation Procedure. An apparently heterogeneous mixture of an olefin (cyclohexene, 1-pentene, or styrene, 1 g), NaBH, (300 mg, 7.9 mmol), (OEP)RhnxCl (4.0 mg, 6 pmol; [Rh] = 0.6 mM), and an internal standard (p-xylene, mesitylene, or durene, appropriate amount) in dry THF (10 mL) exposed to dry air was stirred a t 20-25 \"C. The oxygenation of 1-methylcyclohexene was carried out by using the rhodium catalyst in an amount 2 or 20 times as much as that used above ([Rh] = 1.2 or 12 mM). The electronic spectra of the reaction mixture underwent no significant change even after 100 h. The formation of oxygenation products was monitored by gas chromatography. Similarly was carried out the oxygenation of 1,5-cyclooctadiene and acetylenes (1-heptyne and 3-heptyne) by using substrate (300 mg), NaBH, (300 mg), and (OEP)RhmC1 or (TPP)RhInC1 (4.0 mg) in THF (20 mL). Reaction products, after conversion if necessary to silylated derivatives, were identified by gas chromatography on the basis of coinjection with authentic samples, and their yields determined also by gas chromatography. 2-Methylcyclohexanol as a mixture of stereoisomers arising from the oxygenation of 1-methylcyclohexene was purified by preparative gas chromatography. The stereoisomer distribution was determined by 'H NMR spectroscopy by taking advantage of the characteristic signals for hydroxymethine protons a t 6 3.1 (for E isomer) and 3.75 (for 2 isomer). The following control runs were carried out by using cyclohexene as substrate: (1) without rhodium porphyrin catalyst, (2) without 02, (3) without NaBH,, and (4) with NaBH(OCHJ3 in place of NaBH,. In neither case was detected oxygenation of substrate to any significant extent. Another control run using cyclohexene oxide in place of cyclohexene under otherwise identical oxygenation conditions did not give cyclohexanol. Borane Transfer. A mixture of (0EP)Rh\"'Cl (40 mg, 0.06 mmol), NaBH4 (100 mg, 2.64 mmol), and 1-pentene (70 mg, 1.0 mmol) in T H F (2 mL) in a vessel sealed with a rubber septum was degassed by freezepumpthaw cycles and was stirred a t room temperature for 19 h. The electronic spectrum of the mixture showed A, a t 395,514, and 545 nm, indicating the formation of (OEP)RhH? Following the standard procedure for the analysis of organoboranes,28 the mixture was then subjected to gas chromatography at 170 OC on a column of silicone SE-30 (2 m), which had been treated with Silyl-8 (Pierce Chemical Co.) to mask protic sites with trimethylsilyl groups. The product was readily identified as tripentylborane on the basis of coinjection with the authentic sample prepared by hydroboration of olefin with diborane under standard conditions. The mixture was exposed to air, stirred for 20 min, and then analyzed by gas chromatography to show the formation of 1-pentanol and 2-pentanol (94:6, in a total yield of 45% based on mol of Rh complex used). Oxidation of Alkylborane. A T H F solution of (E)-bis(2methy1cyclohexyl)borane\" was prepared by the hydroboration of 1-methylcyclohexene (96 mg, 1.0 mmol) with borane-THF (1 M) (0.5 mL, 0.5 mmol) in THF (1 mL) under nitrogen. To this was added 1 N aqueous NaOH (0.5 mL), and the mixture was stirred under air atmosphere for 20 h. Gas chromatographic analysis using silicone DCQF-1 showed the formation of 2methylcyclohexanol with the stereoisomer ratio of E / Z = 7624. Another control run for the oxidation of alkylborane with O2 was carried out in the presence of NaBH, (38 mg, 1.0 mmol) instead of aqueous NaOH under otherwise identical conditions and gave the isomer ratio of E / Z = 81:19. A solution of (E)-bis(2-methylcyclohexyl)borane in THF (0.21 mL) was prepared as above starting from the olefin (15.4 mg, 0.16 mmol). This solution was added to (OEP)RhH15 (100 mg, 0.16 mmol) under nitrogen. The mixture was then allowed to contact with a gentle stream of THF-saturated air for 20 h. Gas chromatography coupled with 'H NMR analysis indicated almost exclusive formation of (E)-2-methylcyclohexanol.

746 citations

Journal ArticleDOI
TL;DR: Dendrimers up to the fourth generation were successfully prepared via the divergent growth strategy using a combination of thiol-ene "click" chemistry and traditional esterification reactions to functionalize with carboxylic acid, pyrene, and Fmoc-protected cysteine moieties via thiol -ene reactions.
Abstract: Dendrimers up to the fourth generation were successfully prepared via the divergent growth strategy using a combination of thiol-ene “click” chemistry and traditional esterification reactions. The thiol-ene reactions were conducted under solvent-free, ambient conditions at room temperature by irradiating with UV light. The fourth-generation dendrimers were subsequently functionalized with carboxylic acid, pyrene, and Fmoc-protected cysteine moieties via thiol-ene reactions.

740 citations

Journal ArticleDOI
TL;DR: Hydrogels with two different types of carboxyl group locations were employed as substrates containing the carboxylic acid, while ethylenediamine and benzylamine were used as amine to study the mechanism of amide formation between carboxYlic acid and amine in aqueous media using 1-ethyl-3-(3-(dimethylamino)propyl)carbodiimide hydrochloride.

707 citations

Journal ArticleDOI
TL;DR: In this article, the reaction of carboxylic acid with triphenyl phosphine and diethyl azodicarboxylate in the presence of an alcohol has been studied.
Abstract: When n-valeric acid was treated with allyl diethyl phosphite and diethyl azodicarboxylate, allyl valeriate and diethyl N-(diethyl)phosphoryl hydrazodicarboxylate were obtained in good yields. Similarly ethyl benzoate was obtained in a nearly quantitative yield by the reaction of benzoic acid with triethyl phosphite and diethyl azodicarboxylate. The reaction of carboxylic acid with triphenyl phosphine and diethyl azodicarboxylate in the presence of an alcohol resulted in the formation of the corresponding esters of the carboxylic acid, triphenyl phosphine oxide, and diethyl hydrazodicarboxylate. The mechanisms of these reactions are also discussed.

704 citations

Journal ArticleDOI
TL;DR: In this paper, a synthesis of low molecular weight carboxylic acids in tropospheric aqueous and gaseous phases and in aerosol particles for different environments is presented.

696 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023198
2022457
2021459
2020738
2019842
2018813