- Facile and efficient synthesis of hydroxyalkyl esters from cyclic acetals through aerobic photo-oxidation using anthraquinone-2-carboxylic acid
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Abstract A convenient metal-free oxidation protocol of various cyclic acetals with molecular oxygen and anthraquinone-2-carboxylic acid under visible light irradiation by a fluorescent lamp afforded their corresponding hydroxyalkyl esters.
- Yamaguchi, Tomoaki,Kudo, Yasuhisa,Hirashima, Shin-ichi,Yamaguchi, Eiji,Tada, Norihiro,Miura, Tsuyoshi,Itoh, Akichika
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p. 1973 - 1975
(2015/03/18)
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- A facile access to polyfunctional oxygen-containing heterocycles via intramolecularly formed protic oxonium ylide trapping processes
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Based on the assumption that intramolecularly formed protic oxonium ylides could be trapped by electrophiles, transition-metal-catalyzed reactions of diazoesters bearing a primary hydroxy group with electron-deficient aldehydes and isatins were examined.
- Guo, Xin,Liu, Wei,Hu, Wenhao
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supporting information
p. 117 - 120
(2014/01/06)
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- Iodine-catalyzed tandem synthesis of terminal acetals and glycol mono esters from olefins
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A new metal-free protocol is described for the synthesis of terminal acetals by tandem oxidative rearrangement of olefins using oxone as an oxidant in the presence of iodine. Moreover, a one-pot procedure for the preparation of glycol mono esters from olefins is also presented for the first time using the same reagent system. The Royal Society of Chemistry 2013.
- Kumar, Macharla Arun,Swamy, Peraka,Naresh, Mameda,Reddy, Marri Mahender,Rohitha, Chozhiyath Nappunni,Prabhakar, Sripadi,Sarma, Akella Venkata Subrahmanya,Kumar, Joseph Richard Prem,Narender, Nama
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p. 1711 - 1713
(2013/03/14)
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- Facile oxidative hydrolysis of acetals to esters using hypervalent iodine(III)/LiBr combination in water
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The combination of (diacetoxy)iodobenzene (PhI(OAc)2, DIB) and lithium bromide (LiBr) efficiently oxidized cyclic and acyclic acetals to the corresponding hydroxyalkyl carboxylic esters and simple esters in good to excellent yields. The merits of this reaction are that it employs commercially available and non-explosive hypervalent iodine(III) reagent, water as the solvent, a short reaction time, and mild reaction conditions.
- Panchan, Waraporn,Chiampanichayakul, Supanimit,Snyder, Deanna L.,Yodbuntung, Siriporn,Pohmakotr, Manat,Reutrakul, Vichai,Jaipetch, Thaworn,Kuhakarn, Chutima
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experimental part
p. 2732 - 2735
(2010/05/17)
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- 2-Iodoxybenzoic acid/tetraethylammonium bromide/water: An efficient combination for oxidative cleavage of acetals
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A simple and efficient procedure has been developed for the oxidation of cyclic and acyclic acetals to the corresponding hydroxyalkyl carboxylic esters and simple esters, respectively. 2-Iodoxybenzoic acid (IBX) in the presence of tetraethylammonium bromide was employed for the reaction in aqueous media. The salient features of the protocol include short reaction time, environmentally benign reagents and solvent, and moderate to high yields. Georg Thieme Verlag Stuttgart.
- Kuhakarn, Chutima,Panchan, Waraporn,Chiampanichayakul, Supanimit,Samakkanad, Natthapol,Pohmakotr, Manat,Reutrakul, Vichai,Jaipetch, Thaworn
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experimental part
p. 929 - 934
(2009/10/14)
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- A diazonium ion cascade from the nitrosation of tolazoline, an imidazoline-containing drug
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Tolazoline (1-benzylimidazoline), a representative imidazoline-containing drug, reacts readily with nitrite in acetic acid to produce a complex product mixture. Fourteen compounds have been identified as products of this transformation when an 8-fold excess of HNO2 is used. The products, which include N-nitrosoamides, esters, alcohols, and phenylacetic acid, are rationalized as arising from a cascade of reactive diazonium ions. N-Nitrosotolazoline can be isolated from the nitrosation reaction in good yield when the mixture is extracted with CH2Cl2 as the transformation progresses. It nitrosates much more rapidly (50x) than tolazoline to give, among other products, the oxime [1-(N-nitroso-2-imidazolinyl) benzylidene]hydroxylamine, which can also be produced in good yield from the reaction of tolazoline with isopropyl nitrite. At low substrate and nitrite concentrations, the main reaction products are N-nitrosotolazoline, its decomposition product N-2-hydroxyethylphenylacetamide, the above-mentioned oxime, phenyl acetic acid, and 2-hydroxyethyl phenylacetate. The tolazoline nitrosation rate in three buffer systems has been determined at pH 3.4 and 37°C (kobs = 6.25 × 10-5 s-1 in 0.5 M acetate buffer with a 10 * [NO2-] = 250 mM). Because N-nitrosotolazoline exhibits the chemical properties of a direct-acting mutagen and carcinogen, we have used the rate data to estimate its level of formation at nitrite concentrations 3 mM. Cursory examination of the nitrosation chemistry of oxymetazoline, a related drug, is primarily focused at its electron-rich aromatic ring.
- Loeppky, Richard N.,Shi, Jianzheng,Barnes, Charles L.,Geddam, Sailaja
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p. 295 - 307
(2008/12/22)
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- Al2O3/MeSO3H (AMA) as a new reagent with high selective ability for monoesterification of diols
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A new facile method for monoesterification of diols has been developed. A variety of diols, in particular oligoethylene glycols, were selectively monoesterified in excellent yields by reaction with aromatic and aliphatic acids in the presence of Al2O3/MeSO3H as a new reagent without use of any solvents.
- Sharghi, Hashem,Sarvari, Mona Hosseini
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p. 3627 - 3633
(2007/10/03)
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- Oxidative ring cleavage of cyclic acetals with hypervalent tert-butylperoxy-λ3-iodanes
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(matrix presented) Exposure of cyclic acetals to 1-tert-butylperoxy-1,2-benziodoxol-3(1H)-one in the presence of tert-butyl hydroperoxide and potassium carbonate in benzene at room temperature results in oxidative ring cleavage to glycol monoesters via intermediate tert-butylperoxy ortho esters.
- Sueda, Takuya,Fukuda, Sonoko,Ochiai, Masahito
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p. 2387 - 2390
(2007/10/03)
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- Cobalt(II) catalyzed oxidation of 2-substituted 1,3-dioxolanes with molecular oxygen
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Cobalt(II) chloride catalyzed oxidation of 2-substituted 1,3-dioxolanes in 1,2-dimethoxyethane afforded formate esters and acids in high yields.Is was found that the presence of catalytic amounts of ZnCl2 increased the rate of oxidation.A free-radical mechanism is proposed, involving participation of superoxocobalt, and the esterification of the alcohol and acid.
- Li, Pei,Alper, Howard
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- Rhutenium-Catalyzed Oxidation of Cyclic Acetals with tert-Butyl Hydroperoxide. A Facile Synthesis of Glycol Monoesters
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The ruthenium-catalyzed oxidation of cyclic acetals with tert-butyl hydroperoxide under mild conditions gives the corresponding glycol monoesters efficiently.The present oxidation reaction provides a useful method for the synthesis of glycol monoesters from 1-alkenes by combination with palladium-catalyzed acetalization of 1-alkenes.
- Murahashi, Shun-Ichi,Oda, Yoshiaki,Naota, Takeshi
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p. 2237 - 2240
(2007/10/02)
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