518-05-8Relevant academic research and scientific papers
Mechanism of intramolecular catalysis in the hydrolysis of alkyl monoesters of 1,8-naphthalic acid
Souza, Bruno S.,Yunes, Santiago F.,Lima, Marcelo F.,Gesser, Jose C.,Sa, Marcus M.,Fiedler, Haidi D.,Nome, Faruk
, p. 6163 - 6170 (2011)
Hydrolysis of alkyl 1,8-naphthalic acid monoesters 1a-d is subject to highly efficient intramolecular nucleophilic catalysis by the neighboring COOH group. The reactivity for the COOH reaction depends on the leaving group pK a, with values of βLG of -0.50, consistent with a mechanism involving rate determining breakdown of tetrahedral addition intermediates. The release of the steric strain of the peri-substitiuents in the highly reactive alkyl 1,8-naphthalic acid monoesters is fundamental to understand the observed special reactivity in this intramolecular reaction. DFT calculations show how the proton transfers involved in the cleavage of the neutral ester can be catalyzed by solvent water, thus facilitating the departure of poor alkoxide leaving groups.
Use of fourier transform infrared spectroscopy to follow the heterocumulene aided thermal dehydration of phthalic and naphthalic acids
Rigout, Muriel L. A.,Lewis, David M.
, p. 1405 - 1413 (2006)
Fourier transform infrared (FT-IR) spectroscopy has been successfully employed to follow the formation of phthalic anhydride and 1,8-naphthallc anhydride on heating their corresponding acids. The effects of three heterocumulenes, cyanamide, dicyandlamide, and sodium cyanate, on the temperature of formation of the anhydrides were also investigated using this method. It was found that the carbodlimides cyanamide and dicyandiamide dramatically lowered the temperature at which thermal dehydration of the acid led to anhydride formation. It was noted that cyanamide had a stronger catalytic effect than dicyandiamide, presumably due to the electron-withdrawing effect of the amidine group. Sodium cyanate was also found to promote the thermal dehydration of the acids to form the corresponding anhydrides. Under more severe conditions, phthalic acid anhydride formed is seen to react further, leading to the formation of phthalimide. The discrepancy between the products obtained with cyanamide and sodium cyanate leads to the conclusion that, unlike earlier claims, imide formation is not due to the reaction of the anhydride with the urea formed but with sodium cyanate itself. However, only the phthalic anhydride flve-membered ring system is sufficiently reactive towards the CNO- nucleophile to form the imide; the six-membered 1,8-naphthalic anhydride system does not react in this way.
In situ generation of hydroperoxide by oxidation of benzhydrols to benzophenones using sodium hydride under oxygen atmosphere: Use for the oxidative cleavage of cyclic 1,2-diketones to dicarboxylic acids
Kang, Sunhae,Lee, Soyoung,Jeon, Minju,Kim, Sun Min,Kim, Young Sug,Han, Hogyu,Yang, Jung Woon
, p. 373 - 376 (2013/02/23)
A facile oxidative cleavage of cyclic 1,2-diketones 1 to dicarboxylic acids 3 with hydroperoxide generated in situ has been developed. In situ generation of hydroperoxide was effected by the oxidation of 4,4′-dichlorobenzhydrol 2f to 4,4′-dichlorobenzophenone 4f using sodium hydride under oxygen atmosphere.
Organocatalytic aerobic oxidative cleavage of cyclic 1,2-diketones
Gundala, Sivaji,Fagan, Claire-Louise,Delany, Eoghan G.,Connon, Stephen J.
supporting information, p. 1225 - 1228 (2013/07/19)
The first organocatalytic aerobic oxidative cleavage of cyclic 1,2-diketones is reported. The reaction occurs in either aqueous or alcoholic media and is promoted by a simple N-heterocyclic carbene catalyst derived from a 1,2,4-triazolium ion. No strong oxidants are required. The application of the process in a one-pot synthesis of a cyclic anhydride is also possible. Georg Thieme Verlag Stuttgart. New York.
Pd(OAc)2-catalyzed oxidative carbonylation of aromatics: Synthesis of naphthalenecarboxylic acids
Elman, Alexander R.
, p. 5527 - 5531 (2013/09/23)
The liquid-phase oxidative carbonylation of aromatics leading to aromatic carboxylic acids is studied to develop new approaches to 2,6- naphthalenedicarboxylic acid (NDA) preparation. It is shown that the catalytic system Pd(OAc)2/K2S2O8 allows the synthesis of naphthalic anhydride (NAn) by direct oxidative carbonylation of naphthalene under mild conditions (25 C, 2 atm CO). The subsequent alkaline hydrolysis of NAn and isomerization of the obtained 1,8-naphthalenedicarboxylic acid salt is known to lead to NDA.
Formation and decomposition of N-alkylnaphthalimides: Experimental evidences and ab initio description of the reaction pathways
De Barros, Teresa Cristina,Filho, Pedro Berci,Loos, Michel,Politi, Mario Jose,Chaimovich, Hernan,Cuccovia, Iolanda Midea
, p. 385 - 397 (2011/11/06)
The kinetics of hydrolysis of 1,8-N-butyl-naphthalimide (1,8-NBN) to 1,8-N-butyl-naphthalamide (1,8-NBAmide) and of 2,3-N-butyl-naphthalimide (2,3-NBN) to 2,3-N-butyl-naphthalamide (2,3-NBAmide), as well as the formation of the respective anhydrides from the amides were investigated in a wide acidity range. 1,8-NBN equilibrates with 1,8-NBAmide in mild alkali. Under the same conditions 2,3-NBN quantitatively yields 2,3-NBAmide. Over a wide range of acidities the reactions of the 1,8- and 2,3-N-butyl-naphthalamides (or imides) yield similar products but with widely different rates and at distinct pH's. Anhydride formation in acid was demonstrated for 1,8-NBAmide. The reactions mechanisms were rationalized in the manifold pathways of ab initio calculations. The differences in rates and pH ranges in the reactions of the 1,8- and 2,3-N-butyl-naphthalamides were attributed to differences in the stability of the tetrahedral intermediates in alkali as well as the relative stabilities of the five and six-membered ring intermediates. The rate of carboxylic acid assisted 1,8-N-Butyl-naphthalamide hydrolysis is one of the largest described for amide hydrolysis models. Copyright
Electron transfer in the cathodic reduction of α-dicarbonyl compounds
Batanero, Belén,Barba, Fructuoso
, p. 1834 - 1838 (2008/09/18)
Electron transfer processes take place during the cathodic reduction, under an argon atmosphere, of different α-dicarbonyl substrates. Carboxylic acids or methylene diesters are obtained from benzil or furil after electron transfer to the oxygen in the air, during the workup, or after electron transfer to the solvent. Involving an electron transfer to dichloromethane, 2-hydroxy-2-hydroxymethyl-2H-acenaphtylen-1-one or benzo[1,3]dioxin-8-one are formed when acenaphthenequinone or 1,2-cyclohexanedione are, respectively, reduced.
Reaction of azulenes with derivatives of aromatic dicarboxylic acids
Razus, Alexandru C.,Surugiu, Nina Mirela,Cristian, Liliana,Negoescu, Alina,Zaharia, Oana,Birzan, Liviu
, p. 601 - 608 (2007/10/03)
The reaction of azulenes with phthalic and naphthalene-1,8-dicarboxylic acid derivatives was investigated. Working with acids dichloride in the presence of Lewis acids (SnCl4 and AlCl3) the obtained products were gem-di-(azulen-1-yl)-lactones, di-(1-azulenoyl) ketones and (1-azulenoyl)-carboxylic acids. The reaction of phthalic anhydride in the same conditions occurred with low yields affording only corresponding lactone whereas the naphthalic anhydride was recovered unreacted. The Vilsmeier reaction of azulenes with both diamides failed. The reaction route starting from the dichloride was discussed.
Hydrolysis of 1,8- and 2,3-naphthalic anhydrides and the mechanism of cyclization of 1,8-naphthalic acid in aqueous solutions
Barros, Teresa C.,Yunes, Santiago,Menegon, Guilherme,Nome, Faruk,Chaimovich, Hernan,Politi, Mario J.,Dias, Luis G.,Cuccovia, Iolanda M.
, p. 2342 - 2350 (2007/10/03)
Naphthalene-1,8-dicarboxylic acid, 1,8-Acid, cyclizes spontaneously in acidic aqueous solution to naphthalene-1,8-dicarboxylic anhydride, 1,8-An, and here we Present an ab initio study of the reaction pathway. The effect of pH on the hydrolysis of 1,8-An was analysed and compared with the hydrolysis of naphthalene-2,3-dicarboxylic anhydride, 2,3-An, to naphthalene-2,3-dicarboxylic acid, 2,3-Acid. The values of the pKa's of 1,8-Acid and 2,3-Acid were ca. 3.5 and 3.0, for monoanion formation, pKa1, and 5.5 and 5.0 for dianion formation, pKa2, respectively. Fluorimetric titration demonstrated that the diprotonated 2,3-Acid. AH2, was further protonated to yield AH3+. The pH-rate constant profile for 2,3-An hydrolysis showed a water reaction between pH's 1.0 and 6.0 and a base catalysed hydrolysis above pH 7.0. Under no condition was 2,3-An formed from 2,3-Acid. The pH dependent decomposition kinetics of 1,8-An is complex and, below pH 6.0, the pH-rate constant profile was fitted by assuming that both AH2 and AH3+ are in equilibrium with 1,8-An. The values of the equilibrium constants for 1,8-An formation from AH2 and AH3+ were ca. 4 and 100 in dilute and concentrated acid, respectively. Ab initio calculations for a possible reaction pathway connecting the undissociated 1,8-Acid to 1,8-An show a transition state where an intramolecular proton transfer is concerted with oxygen alignment towards the carbonyl centre. The planar intermediate is then dehydrated yielding a complex between water and 1,8-An.
New antiferromagnetic dinuclear complexes of manganese(II) with 1,8-naphthalato as bridging ligand: Synthesis, spectrum and magnetism
Gao,Ma,Liao
, p. 839 - 843 (2007/10/03)
Three manganese(II) binuclear complexes have been synthesized, namely [Mn2(NAPH)(L)4(ClO4)2, L is bpy (2,2′-bipyridyl), phen (1,10-phenanthroline) or NO2-phen (5-nitro-1,10-phenanthroline), NAPH denotes the 1,8-naphthalate dianion. Based on IR, elemental analyses and conductivity measurement, these complexes are proposed to have extended NAPH-bridged structures and consist of two manganese(II) in a distorted octahedron environment. The temperature dependence of magnetic susceptibilities of manganese(II) complexes have been studied, giving the exchange integral J = -0.36 cm-1 (bpy); J = -0.49 cm-1 (phen), respectively. These results indicate a weak antiferromagnetic coupling between the paramagnetic ions in the complexes.
