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51.
Iodobenzene diacetate, a relatively benign nonmetallic oxidant, has been utilized efficiently for the oxidation of N-substituted hydrazones of chalcones to afford 1,3,5-trisubstituted pyrazoles under mild reaction conditions. 相似文献
52.
53.
54.
B. S. Fedorov 《Russian Chemical Bulletin》1996,45(3):722-723
A novel scission reaction of nitraminodiol diacetates of the formula AcO[CH2N(NO2)
x
CH2OAc (x = 1–4) in concentrated sulfuric acid to form formaldehyde, nitramide, and 2-nitro-2-azapropane-1,3-diol disulfate was found.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya. No. 3, pp 761–762, March, 1996. 相似文献
55.
Ogibin Yu. N. Terent"ev A. O. Ananikov V. P. Nikishin G. I. 《Russian Chemical Bulletin》2001,50(11):2149-2155
Hydroperoxidation of C=C-bridged 2-oxabicycloalkenes in which the five- or six-membered oxacycle is fused with the five-, six-, or twelve-membered hydrocarbon ring was studied. The Cu(OAc)2-catalyzed decomposition of the resulting hydroperoxides afforded nine-, ten-, or fifteen-membered trans-alkenolides, respectively. The latter compounds were obtained as pairs of regioisomers, with the isomers in which the double bond is more remote from the ether oxygen atom predominating. 相似文献
56.
Triphenylantimony and triphenylbismuth diacetates, Ph3M(OAc)2 (M = Sb, Bi), were obtained in 50–94 % yields by the reaction of triphenylantimony and triphenylbismuth withtert-butyl peracetate in the presence of acetic acid or acetic anhydride (molar ratio 1 1 1) in toluene.tert-Butyl peracetate oxidizes Ph3M into alkoxides, Ph3M(OAc)OBut, which at the instant of formation are acylated with acetic acid or acetic anhydride to give the corresponding derivatives, Ph3M(OAc)2.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 964–967, May, 1995.This study was financially supported by the Russian Foundation for Basic Research (Grant 94-03-08846). 相似文献
57.
Various ketones were converted to the corresponding α-tosyloxyketones with mCPBA and p-toluenesulfonic acid in the presence of a catalytic amount of iodobenzene. Moreover, secondary alcohols were directly converted to the corresponding α-tosyloxyketones using mCPBA and catalytic amounts of iodobenzene and potassium bromide, followed by treatment with p-toluenesulfonic acid in a one-pot manner. Poly(4-iodostyrene) could be also used as a recyclable catalyst for the same α-tosyloxylation of ketone 相似文献
58.
Cellulose diacetate (CDA) with degree of substitution (DS) of 2.4 was dissolved in dimethylsulfoxide and reacted with octadecenyl
succinic anhydrides (OSAs) using 1-methylimidazole as a promoter. FT-IR and 1H-NMR analysis of the reaction products revealed that half-esterification occurred on residual hydroxyl groups of CDA by OSA,
providing CDA/octadecenyl succinic acid (OSAcid) half esters at yields of more than 90%. The effects of reaction time and
temperature on DS of CDA/OSAcid esters were studied in detail. The higher the reaction temperature, the higher the esterification
rate to form CDA/OSAcid half esters. The maximum DS values were 0.41 and 0.33 for CDA/n-OSAcid and CDA/i-OSAcid esters, respectively.
The original X-ray diffraction pattern of CDA changed with the introduction of OSAcid substituents into CDA, and CDA/OSAcid
esters seemed to have thermoplasticity, depending on DS and the chemical structure of the OSAcids. A soil-embedding test of
films of CDA and CDA/OSAcid esters indicated that the CDA/OSAcid esters that were prepared maintained the biodegradability
of the original CDA. 相似文献
59.
Hidemitsu Uno Seiya Murakami Akiko Fujimoto Youtarou Yamaoka 《Tetrahedron letters》2005,46(23):3997-4000
The first total synthesis of bhimamycin B, a novel member of naphtho[2,3-c]furan quinone antibiotics, was achieved by oxidative skeletal rearrangement of 4-acetylnaphtho[1,2-b]furan-5-ol. 相似文献
60.
T.P. Shakhtshneider S.A. Kuznetsova A.S. Zamay T.N. Zamay E.A. Spivak M.A. Mikhailenko 《Natural product research》2016,30(12):1382-1387
Betulin and its esters are the natural compounds with high in vitro cytotoxicity toward many cancer cells. However, the poor water solubility of these compounds has limited their applications. We prepared new composites of betulin esters using two methods, namely ball-milling of the mixtures of betulin esters with arabinogalactan and preparation of thin films of these mixtures by evaporating the aqueous solutions. These composites revealed higher water solubility as compared with the initial substances without losing the structural integrity and functionality. As a result, the new composites have shown much higher inhibitory effects against different cancer cell lines such as Ehrlich ascites carcinoma cells and lung carcinoma cells (A549) in comparison with the initial substances. The cell viability studies based on Annexin V and Propidium iodide probes have confirmed the high proapoptotic effect of betulin ester derivatives against cancer cells. 相似文献