603-12-3Relevant academic research and scientific papers
Mapping the Relationship between Glycosyl Acceptor Reactivity and Glycosylation Stereoselectivity
van der Vorm, Stefan,van Hengst, Jacob M. A.,Bakker, Marloes,Overkleeft, Herman S.,van der Marel, Gijsbert A.,Codée, Jeroen D. C.
supporting information, p. 8240 - 8244 (2018/05/03)
The reactivity of both coupling partners—the glycosyl donor and acceptor—is decisive for the outcome of a glycosylation reaction, in terms of both yield and stereoselectivity. Where the reactivity of glycosyl donors is well understood and can be controlled through manipulation of the functional/protecting-group pattern, the reactivity of glycosyl acceptor alcohols is poorly understood. We here present an operationally simple system to gauge glycosyl acceptor reactivity, which employs two conformationally locked donors with stereoselectivity that critically depends on the reactivity of the nucleophile. A wide array of acceptors was screened and their structure–reactivity/stereoselectivity relationships established. By systematically varying the protecting groups, the reactivity of glycosyl acceptors can be adjusted to attain stereoselective cis-glucosylations.
F-18 RADIOLABELED COMPOUNDS FOR DIAGNOSING AND MONITORING KIDNEY FUNCTION
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Page/Page column, (2014/04/03)
The invention relates to 18F-labeled compounds of formula (I), hydrates, isomers, or pharmaceutically acceptable salts thereof, process for their preparation and pharmaceutical compositions. The invention relates to the methods of diagnosing kidney function in humans by PET imaging.
Method for estimating SN1 rate constants: Solvolytic reactivity of benzoates
Matic, Mirela,Denegri, Bernard,Kronja, Olga
supporting information, p. 8986 - 8998,13 (2012/12/12)
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.
Vicarious nucleophilic substitution: A dramatically shortened synthesis of 2-amino-6-nitrobenzoic acid labelled with carbon-14
Kelly, Terence P.,Filer, Crist N.,Wright, Christopher
scheme or table, p. 345 - 351 (2012/02/01)
Literature preparations of 2-amino-6-nitrobenzoic acid are usually based on phthalic anhydride. In order to make [benzene-14C(U)]-2-amino-6- nitrobenzoic acid, [benzene-14C(U)]-phthalic anhydride has to be prepared in multiple steps from [14C(U)]-benzene, resulting in an unacceptably lengthy 14-step synthesis. We have been able to develop a completely different method of synthesis, producing [benzene- 14C(U)]-2-amino-6-nitrobenzoic acid from [14C(U)]-benzene in just four steps with an overall radiochemical yield of 32%.
PROCESS FOR PREPARING SUBSTITUTED AROMATIC CARBOXYLIC ACIDS
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Page/Page column 2, (2010/09/17)
A process for preparing an aromatic carboxylic acid having a heteroatom containing substituent is provided that includes reaction in a vessel of an aromatic precursor having an aromatic core with at least one heteroatom containing substituent and at least one hydrogen extending from the core, with a haloacetonitrile under reaction conditions to form an aromatic acetonitrile with an acetonitrile moiety. The aromatic acetonitrile is exposed to an oxidizing agent under conditions to convert the acetonitrile moiety to a carboxylic acid group to prepare the aromatic carboxylic acid having the heteroatom containing substituent.
Synthesis of reference substances for highly polar metabolites of nitroaromatic compounds
Schmidt, Torsten C.,Steinbach, Klaus,Buetehorn, Ulf,Heck, Kerstin,Volkwein, Ute,Stork, Gottfried
, p. 3119 - 3130 (2007/10/03)
Transformation processes of nitroaromatic compounds (NAC) lead to polar and highly hydrophilic metabolites. For the unequivocal identification of proposed metabolites reference substances are needed. Since most of them are not commercially available, their synthesis was done in our group. In many cases no satisfying synthesis schemes were found in the literature. In this communication, we therefore describe the preparation, structural elucidation and separation of 17 compounds. Many of the newly synthesized analytes were found in various water samples from a former ammunition plant.
Electrophilic Aromatic Substitution. Part 37. Products of Aromatic Nitrations of some Chloronitrobenzenes and Substituted Benzoic Acids in Solutions of Dinitrogen Pentaoxide and of Nitronium Salts in Nitric Acid
Moodie, Roy B.,Sanderson, Andrew J.,Willmer, Richard
, p. 645 - 650 (2007/10/02)
Yields of aromatic products of nitration in nitric acid solutions containing dinitrogen pentaoxide or nitronium salt have been determined.Evidence for the intrusion of a mechanism other than the normal nitronium ion one comes from comparison of products in the two media and from the observation of 15N NMR CIDPN effects.The additional mechanism operative with some substrates in concentrated solutions of dinitrogen pentaoxide is postulated to be one in which reversible addition of the NO3 radical is followed by combination with NO2.Dienes produced in this way can give aromatic nitroproducts by elimination of nitric acid.Nitrodecarboxylation of substituted benzoic acids occurs by a radical process.
Preparation of Some Acetylated, Reduced and Oxidized Derivatives of 2,4-Diaminotoluene and 2,6-Dinitrotoluene
Mori, Masa-aki,Inoue, Masami,Nunozawa, Tetsuji,Miyahara, Tatsuro,Kozuka, Hiroshi
, p. 4859 - 4861 (2007/10/02)
4-Acetylamino-2-hydroxylaminotoluene (4AA2HAT) and 2-hydroxylamino-6-nitrotoluene (2HA6NT) were prepared from 4-acetylamino-2-nitrotoluene (4AA2NT) and 2,6-dinitrotoluene (2,6-DNT), respectively, by reduction with zinc dust and NH4Cl. 2,6-Dinitrobenzylalcohol (2,6-DNB) and 2,6-dinitrobenzoic acid (2,6-DNBA) were prepared from 2,6-dinitrobenzaldehyde (2,6-DNBAl) by reduction with NaBH4 and by oxidation with KMnO4, respectively. 2-Acetylamino-4-aminobenzoic acid (2AA4ABA) was prepared from 4-nitroanthranilic acid (4NAA) by acetylation followed by reduction with NaBH4 and Pd-C. 2,4-Diacetylaminobenzoic acid (2,4-DAABA) was prepared from 4NAA by reduction with NaBH4 and Pd-C followed by acetylation. 4-Acetylamino-2-aminobenzoic acid (4AA2ABA) was prepared from 4NAA by reduction and acetylation followed by chelation with Cu(AcO)2.Keywords- 4-acetylamino-2-hydroxylaminotoluene; 2-hydroxylamino-6-nitrotoluene; 2,6-dinitrobenzylalcohol; 2,6-dinitrobenzoic acid; 2-acetylamino-4-aminobenzoic acid; 4-acetylamino-2-aminobenzoic acid; 2,4-diacetylaminobenzoic acid; carcinogenicity; mutagenicity; preparation
