- A new procedure for preparing 3,4-dinitrobenzoic acid
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A new efficient procedure of synthesis of 3,4-dinitrotoluene from 3-nitro-4-aminotoluene was developed. Oxidation of 3,4-dinitrotoluene with an ozone-oxygen mixture to 3,4-dinitrobenzoic acid in the presence of cobalt(II) acetate was studied.
- Andreev,Potapenko,Pogorelova,Krasil'nikov,Band
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- Method for estimating SN1 rate constants: Solvolytic reactivity of benzoates
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Nucleofugalities of pentafluorobenzoate (PFB) and 2,4,6-trifluorobenzoate (TFB) leaving groups have been derived from the solvolysis rate constants of X,Y-substituted benzhydryl PFBs and TFBs measured in a series of aqueous solvents, by applying the LFER equation: log k = sf(Ef + Nf). The heterolysis rate constants of dianisylmethyl PFB and TFB, and those determined for 10 more dianisylmethyl benzoates in aqueous ethanol, constitute a set of reference benzoates whose experimental ΔG ? have been correlated with the ΔH? (calculated by PCM quantum-chemical method) of the model epoxy ring formation. Because of the excellent correlation (r = 0.997), the method for calculating the nucleofugalities of substituted benzoate LGs have been established, ultimately providing a method for determination of the SN1 reactivity for any benzoate in a given solvent. Using the ΔG? vs ΔH? correlation, and taking sf based on similarity, the nucleofugality parameters for about 70 benzoates have been determined in 90%, 80%, and 70% aqueous ethanol. The calculated intrinsic barriers for substituted benzoate leaving groups show that substrates producing more stabilized LGs proceed over lower intrinsic barriers. Substituents on the phenyl ring affect the solvolysis rate of benzhydryl benzoates by both field and inductive effects.
- Matic, Mirela,Denegri, Bernard,Kronja, Olga
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supporting information
p. 8986 - 8998,13
(2012/12/12)
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- A green, reusable and highly efficient solid acid catalyst for the oxidation of aldehydes to the corresponding carboxylic acids using H 2O2 and KMnO4:H5PV 2Mo10O40 (10-molybdo-2-vanadophosphoric heteropolyacid)
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H5PV2Mo10O40-catalyzed oxidation of aromatic aldehydes to the corresponding carboxylic acids using hydrogen peroxide and KMnO4 as oxidants under mild conditions is reported. This system provides an efficient, convenient and practical method for the oxidation of aromatic aldehydes. In this work, differences between Keggin and Well-Dawson type polyoxometalates are addressed in term of relative stability, hardness and acidity.
- Shojaei, Abdollah Fallah,Rezvani, Mohamad Ali,Heravi, Majid
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experimental part
p. 1513 - 1522
(2012/03/08)
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- 6-Lithioquinoxalines and Their Transformations
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6-Bromo-2,3-diphenylquinoxaline reacts with butyllithium to give the 6-lithio derivative in a yield of more than 80%, which reacts with electrophiles such as benzophenone, Michler ketone, methyl ethyl ketone, iodine, selenium, and dimethylformamide to give the corresponding quinoxaline derivatives. 6-Bromo-2,3-dimethylquinoxaline is metallated with butyl- and phenyllithium at the methyl groups and benzene ring. These organolithium compounds react with benzophenone to give the corresponding diphenyl- and triaryl-carbinols, whose yield and ratio were determined by HPLC. These results open prospects for preparing new quinoxaline derivatives substituted at the annelated benzene ring.
- Dobrodei,El'tsov
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p. 620 - 629
(2007/10/03)
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