2169-87-1Relevant articles and documents
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Schoenberg,Fayez
, p. 104 (1958)
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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 (2001)
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.
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Scott
, p. 6332 (1953)
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New Derivatizing Agents for Amino Acids and Peptides. 1. Facile Synthesis of N-Substituted 1-Cyanobenzisoindoles and Their Spectroscopic Properties
Carlson, R. G.,Srinivasachar, K.,Givens, R. S.,Matuszewski, B. K.
, p. 3978 - 3983 (1986)
2,3-Naphthalenedicarboxaldehyde (NDA) is shown to be a very useful reagent for the derivatization of primary amines, amino acids, and small peptides.The reaction of these amino compounds with NDA and cyanide ion produces highly fluorescent 2-substituted 1-cyanobenzisoindoles that are relatively stable.The physical and fluorescent properties of a variety of 1,2-disubstituted benzisoindoles are presented.
"release and catch" catalysis by tungstate species for the oxidative cleavage of olefins
Yoshimura, Yu,Ogasawara, Yoshiyuki,Suzuki, Kosuke,Yamaguchi, Kazuya,Mizuno, Noritaka
, p. 1662 - 1670 (2017/07/22)
The oxidative cleavage of olefins produces valuable carbonyl compounds, and thus, the development of green catalytic methods using H2O2 as an oxidant is highly desired. In this work, we have successfully developed an efficient catalytic system for the oxidative cleavage of olefins and related compounds using H2O2. In the presence of tungstate species supported on zinc-modified tin dioxide (W/Zn-SnO2), the oxidative cleavage of 1-methyl-1-cyclohexene proceeds efficiently through multistep reaction pathways involving oxygenation, hydrolysis, perhydrolysis, and isomerization reactions. In this reaction system, active peroxotungstate species, generated by the reaction of the supported tungstate species with H2O2, are released into the solution during the course of the reaction. At the end of the reaction (after the complete consumption of H2O2), the released tungstate species are re-captured by the support. The W/Zn-SnO2 catalyst can be reused at least nine times for the oxidative cleavage of 1-methyl-1-cyclohexene without loss of catalytic performance and can be applied to the oxidation of various other substrate molecules.
Rapid chemoselective deprotection of benzyl esters by nickel boride
Khurana, Jitender M.,Arora, Reema
experimental part, p. 1127 - 1130 (2009/12/03)
Benzyl esters of a variety of acids can be chemoselectively cleaved on treatment with nickel boride in methanol at ambient temperature to give the parent carboxylic acids in high yields. Other protecting functionalities such as methyl, ethyl, tert-butyl, and trityl esters as well as benzyl ethers, tert-butyl ethers, and Nbenzylamides are unaffected under these conditions. Georg Thieme Verlag Stuttgart.