922-68-9Relevant articles and documents
Indium-mediated diastereoselective allylation of N-tert-butanesulfinyl imines derived from α-ketoesters
Maciá, Edgar,Foubelo, Francisco,Yus, Miguel
, p. 6001 - 6010 (2016)
The indium-mediated allylation of α-aldimino and -ketimino esters 3 with allylic bromides proceeds with high diastereoselectivity to yield homoallylic α-amino ester derivatives 5, in both THF and water as solvents. The reactions are diastereospecific, the stereochemical outcome depending on the configuration of both the sulfur atom of the sulfinyl group and the C[dbnd]N double bond. Of particular interest are the reaction products using ethyl bromomethylacrylate as allylating reagent because amino diesters are obtained, which can be easily transformed into enantiomerically pure α-methylidene-γ-butyrolactams 6 with an alkoxycarbonyl group on the ring bearing the nitrogen atom.
A metal-free strategy for the cross-dehydrogenative coupling of 1,3-dicarbonyl compounds with 2-methoxyethanol
Chang, Yu-Lun,Huang, Sheng-Hua,Kudale, Vishal Suresh,Wang, Jeh-Jeng,Zheng, Sheng
, p. 1226 - 1230 (2022/02/21)
Here, we report a metal-free approach for the construction of methylene-bridged bis-1,3-dicarbonyl compounds via cross-dehydrogenative coupling of 1,3-dicarbonyl compounds with 2-methoxyethanol. In addition, we have extended this methodology to synthesize tetra-substituted pyridine derivatives using 1,3-dicarbonyl, 2-methoxyethanol and NH4OAc in one step. The key advantages include accepting a wide range of substrates, utilizing O2 as the sole oxidant, and synthesizing biologically active compounds such as 1,4-dihydropyridine and pyrazole. This journal is
An Economical Route to Lamivudine Featuring a Novel Strategy for Stereospecific Assembly
Abdiaj, Irini,Ahmad, Saeed,Burns, Justina M.,Gopalsamuthiram, Vijayagopal,Gupton, B. Frank,Krack, Rudy,McQuade, D. Tyler,Nelson, Ryan C.,Snead, David R.,Stringham, Rodger W.
supporting information, p. 1194 - 1198 (2020/07/15)
An economical synthesis of lamivudine was developed by employing a new method to establish the stereochemistry about the heterocyclic oxathiolane ring. Toward this end, an inexpensive and readily accessible lactic acid derivative served the dual purpose of activating the carbohydrate's anomeric center for N-glycosylation and transferring stereochemical information to the substrate simultaneously. Both enantiomers of the lactic acid derivative are available, and either β-enantiomer in this challenging class of 2′-deoxynucleoside active pharmaceutical ingredients can be formed.
Introduction of fluorine atoms to vitamin D3 side-chain and synthesis of 24,24-difluoro-25-hydroxyvitamin D3
Kawagoe, Fumihiro,Mototani, Sayuri,Yasuda, Kaori,Nagasawa, Kazuo,Uesugi, Motonari,Sakaki, Toshiyuki,Kittaka, Atsushi
, (2019/10/02)
During our ongoing studies of vitamin D, we focused on the vitamin D3 side-chain 24-position, which is the major metabolic site of human CYP24A1. In order to inhibit the metabolism of vitamin D3, 24,24-difluorovitamin D3analogues are important candidates. In this paper, we report the practical introduction of the difluoro-unit to the 24-position to synthesize 24,24-difluoro-CD ring (1) and 24,24-difluoro-25-hydroxyvitamin D3 (2).
Method for producing glyoxylate through oxidation of glycollate
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Paragraph 0080; 0081; 0082; 0083; 0084; 0085; 0086-0131, (2017/12/30)
The invention relates to a method for producing glyoxylate through oxidation of glycollate. The invention mainly aims to overcome the problem of low yield of glyoxylate in the prior art. The method provided by the invention comprises a reaction step of contacting a nitrogen oxide and oxygen-containing gas with glycollate to produce glyoxylate. A catalyst used in the invention comprises the following components by weight: a) 0.5 to 30 parts of at least one active component selected from a group consisting of iron and iron oxides; b) 0 to 10 parts of an auxiliary agent which is at least one metal selected from a group consisting of group IA or group IIA elements or oxides thereof; and c) 70 to 99 parts of a carrier. With such a technical scheme, the above problem is overcome, and the method is applicable to industrial production of glyoxylate through oxidation of glycollate.
POLYGLYOXYLATES, MANUFACTURE AND USE THEREOF
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Page/Page column 24, (2015/11/27)
Self-immolative polymers degrade by an end-to-end depolymerisation mechanism in response to the cleavage of a stabilizing end-cap from the polymer terminus. Examples include homopolymers, mixed polymers including block copolymers, suitable for a variety of applications. A polyglyoxylate can be end-capped or capped with a linker as in a block copolymer.
Polyglyoxylates: A versatile class of triggerable self-immolative polymers from readily accessible monomers
Fan, Bo,Trant, John F.,Wong, Andrew D.,Gillies, Elizabeth R.
supporting information, p. 10116 - 10123 (2014/08/05)
Self-immolative polymers, which degrade by an end-to-end depolymerization mechanism in response to the cleavage of a stabilizing end-cap from the polymer terminus, are of increasing interest for a wide variety of applications ranging from sensors to controlled release. However, the preparation of these materials often requires expensive, multistep monomer syntheses, and the degradation products such as quinone methides or phthalaldehydes are potentially toxic to humans and the environment. We demonstrate here that polyglyxoylates can serve as a new and versatile class of self-immolative polymers. Polymerization of the commercially available monomer ethyl glyoxylate, followed by end-capping with a 6-nitroveratryl carbonate, provides a poly(ethyl glyoxylate) that depolymerizes selectively upon irradiation with UV light, ultimately generating ethanol and the metabolic intermediate glyoxylic acid hydrate. To access polyglyoxylates with different properties, the polymerization and end-capping approach can also be extended to other glyoxylate monomers including methyl glyoxylate, n-butyl glyoxylate, and benzyl glyoxylate, which can be easily prepared from their corresponding fumaric or maleic acid derivatives. Random copolymers of these monomers with ethyl glyoxylate can also be prepared. Furthermore, using a multifunctional end-cap that is UV-responsive and also enables the conjugation of another polymer block via an azide-alkyne "click" cycloaddition, amphiphilic self-immolative block copolymers are also prepared. These block copolymers self-assemble into micelles in aqueous solution, and their poly(ethyl glyoxylate) blocks rapidly depolymerize upon UV irradiation. Overall, these strategies are expected to greatly expand the utility of self-immolative polymers by providing access for the first time to self-immolative polymers with tunable properties that can be readily obtained from simple monomers and can be designed to depolymerize into nontoxic products.
Determination of absolute configuration of the phosphonic acid moiety of fosfazinomycins
Schiessl, Katharina,Roller, Alexander,Hammerschmidt, Friedrich
, p. 7420 - 7426 (2013/10/22)
Fosfazinomycins A and B produced by Streptomyces lavendofoliae share the same phosphonate moiety with one chiral centre of unknown configuration which was determined by synthesising both enantiomers of 2-hydroxy-2-phosphonoacetic acid methyl ester. A chiral cyclic phosphite was reacted with methyl glyoxylate in a Pudovik reaction to give a pair of diastereomeric α- hydroxyphosphonates, which were separated by HPLC. The configurations at C-2 were assigned on the basis of single crystal X-ray structure analysis. Deprotection of these diastereomers furnished the enantiomeric α-hydroxyphosphonic acids, of which the (S)-configured had the same sign of optical rotation as the phosphonic acid moiety of the two fosfazinomycins.
Fe(II) complexes that mimic the active site structure of acetylacetone dioxygenase: O2 and NO reactivity
Park, Heaweon,Bittner, Michael M.,Baus, Jacob S.,Lindeman, Sergey V.,Fiedler, Adam T.
, p. 10279 - 10289 (2013/01/15)
Acetylacetone dioxygenase (Dke1) is a bacterial enzyme that catalyzes the dioxygen-dependent degradation of β-dicarbonyl compounds. The Dke1 active site contains a nonheme monoiron(II) center facially ligated by three histidine residues (the 3His triad); coordination of the substrate in a bidentate manner provides a five-coordinate site for O2 binding. Recently, we published the synthesis and characterization of a series of ferrous β-diketonato complexes that faithfully mimic the enzyme-substrate intermediate of Dke1 (Park, H.; Baus, J.S.; Lindeman, S.V.; Fiedler, A.T. Inorg. Chem. 2011, 50, 11978-11989). The 3His triad was modeled with three different facially coordinating N3 supporting ligands, and substituted β-diketonates (acacX) with varying steric and electronic properties were employed. Here, we describe the reactivity of our Dke1 models toward O2 and its surrogate nitric oxide (NO), and report the synthesis of three new Fe(II) complexes featuring the anions of dialkyl malonates. Exposure of [Fe( Me2Tp) (acacX)] complexes (where R2Tp = hydrotris(pyrazol-1-yl)borate with R-groups at the 3- and 5-positions of the pyrazole rings) to O2 at -70 °C in toluene results in irreversible formation of green chromophores (λmax ～750 nm) that decay at temperatures above -60 °C. Spectroscopic and computational analyses suggest that these intermediates contain a diiron(III) unit bridged by a trans μ-1,2-peroxo ligand. The green chromophore is not observed with analogous complexes featuring Ph2Tp and PhTIP ligands (where PhTIP = tris(2-phenylimidazoly-4-yl)phosphine), since the steric bulk of the phenyl substituents prevents formation of dinuclear species. While these complexes are largely inert toward O2, Ph2Tp-based complexes with dialkyl malonate anions exhibit dioxygenase activity and thus serve as functional Dke1 models. The Fe/acac X complexes all react readily with NO to yield highspin (S = 3/2) {FeNO}7 adducts that were characterized with crystallographic, spectroscopic, and computational methods. Collectively, the results presented here enhance our understanding of the chemical factors involved in the oxidation of aliphatic substrates by nonheme iron dioxygenases.
