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1.
N. B. Chernysheva A. A. Bogolyubov V. V. Nesterov M. Yu. Antipin V. V. Semenov 《Chemistry of Heterocyclic Compounds》2003,39(7):925-936
The reaction of 5-methyl-5-(4-methyl-3-pentenyl)-4-methylene-1,3-dioxolan-2-one with primary amines gives the corresponding 4-hydroxy-4-methyloxazolidin-2-ones. These undergo an intramolecular amidoalkylation reaction to form 1-oxa-3-azapentalen-2-ones which are potential precursors of cyclopentanyl cis-2-amino alcohols. 相似文献
2.
Ab initio molecular orbital calculations have been performed to explore the reaction potential energy surfaces of silylenoid H2SiLiF with XH
n
hydrides, where XH
n
= CH4, NH3, H2O, HF, SiH4, PH3, H2S, and HCl. We have identified a previously unreported reaction pathway on each reaction surface, H2SiLiF + H-XH
n
−
1
→ H
n
XSiLiF + H2, which involves H2 elimination following the initial formation of an association complex via a four-membered ring transition state to form the substituted three-membered ring silylenoid H
n
XSiLiF and a H2 molecule. This theoretical calculations suggest that (i) for H2 eliminations there is a very clear trend toward lower activation barriers and more exothermic interactions on going from left to right along a given row in periodic table, and (ii) for the second-row hydrides, the H2 elimination reactions are less exothermic than for the first-row hydrides and the reaction barriers are lower for X–S and Cl. Compared to the insertions of H2SiLiF into XH
n
, the H2 elimination pathways should be unfavorable with higher barrier and lower exothermic. 相似文献
3.
The reaction of 2,4-dichloroquinolines with o-aminoacetophenone and o-aminobenzophenone under neat conditions yielded 2′-acetyl and 2′-benzoyl substituted-4-chloro-2-(N-phenylamino)quinolines, respectively, which on treatment with sodium methoxide afforded the 2′-substituted-4-methoxy-2-(N-phenylamino)quinolines. These potential intermediates, on polyphosphoric acid–catalyzed cyclization at two different temperatures, gave the respective 6-methyl and 6-phenyl substituted dibenzo[b,g][1,8]naphthyridin-5-ones. These temperature differences for the formation of the final products were due to the in situ formation of the respective 2′-substituted-2-(N-phenylamino)quinolin-4-ones from the chloro and methoxy intermediates. The naphthyridin-5-ones were subjected to N-methylation, where the methyl group in the 1-position was found to hinder the reaction sterically, consequently increasing the reaction time to more than that of the other derivatives. 相似文献
4.
N,N′‐Diiodo‐N,N′‐1,2‐ethandiylbis(p‐toluene sulfonamide) (NIBTS) is a good and new reagent for synthesis of 2‐arylbenzimidazoles and 2‐arylbenzothiazoles at room temperature under solvent‐free condition with good to high yield. Absence of solvent, short reaction times, non‐corrosive, operational simplicity and environmentally friendliness are the main advantages of this procedure. 相似文献
5.
Gade Srinivas Reddy Kadaboina Rajasekhar Cherukupally Praveen Kaga Mukkanti 《合成通讯》2013,43(22):3884-3893
3,4-Dihydro-1,4,4a,6a-tetraaza-benzo[a]fluoren-2-one, a new tetracyclic heterocyclic framework, is designed through a simple and convenient synthetic sequence. Its 6-aryl derivatives are synthesized starting from 1H-indole-2-carboxylic acid. The reaction of differently substituted phenacyl bromides with 1H-indole-2-carboxylic acid and POCl3-mediated cyclization of the resultant 1H-indole-2-carboxylic acid phenacyl ester provided 2-oxa-4a-aza-fluoren-1-one, and its sequential reaction with hydrazine and 2-chloro-acetamide furnished the desired new heterocyclic compounds 7a–f. 相似文献
6.
Kochetkov K. A. Harutyunyan S. R. Kuz"mina N. A. Savel"eva T. F. Maleev V. I. Peregudov A. S. Vyskočil S. Sagiyan A. S. 《Russian Chemical Bulletin》2001,50(9):1620-1624
Alkali metal salts of substituted (S)-prolines, alkali metal alkoxides of (S)-prolinol, and Na salts of chiral substituted 2-amino-2"-hydroxy-1,1"-binaphthyls can catalyze the asymmetric Michael reaction of diethyl malonate with crotonaldehyde to give adducts in >90% yields with ee up to 40%. The influences of the catalyst structure, the nature of the alkali metal cation, temperature, the solvent, and salt additives on the reaction outcome were studied. 相似文献
7.
Jordanka Petrova Marko Kirilov Snejana Momchilova 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1):29-35
Abstract The reaction of lithium derivatives of N,N,N',N'-tetramethyldiamides of arylmethanephosphonic acids (1-Li) with aldehydes 2 is studied. It is found that under certain reaction conditions (THF, 5 hrs at -70°C and then allowing to warm to room temperature) the aldol stage of the reaction is highly stereoselective, only erythro adducts (2-hydroxyphosphonamides) 3, 4 being formed in 47–75% yields. By heating of 3 and 4 in neutral medium the corresponding (Z)-olefins 5, 6 are obtained (yields 64–74%). It is established that an acid catalyzed olefination of 2-hydroxyphosphonamides is also possible, but the reaction is not stereospecific. 相似文献
8.
The three-component condensation of aromatic aldehydes, methylurea, and α-nitroacetophenone affords both N(1)-and N(3)-methyl-substituted 4,6-diaryl-5-nitro-3,4-dihydropyrimidin-2(1H)-ones depending on the structure of aldehyde. Intermediate 4,6-diaryl-4-hydroxy-3-methyl-5-nitrohexahydropyrimidin-2-ones
and trisubstituted urea, which is the transformation product of the 4-hydroxy-3-methyl derivative in an acidic medium (retro-Henry
reaction), were identified in the reaction mixtures.
Dedicated to the memory of Academician N. N. Vorozhtsov on the 100th anniversary of his birth.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1141–1145, June, 2007. 相似文献
9.
Marwan Batiha Ala'a H. Al‐Muhtaseb Mohammednoor Altarawneh 《International journal of quantum chemistry》2012,112(3):848-857
Unlike the chemistry underlying the self‐coupling of phenoxy (C6H5O) radicals, there are very limited kinetics data at elevated temperatures for the reaction of the phenoxy radical with other species. In this study, we investigate the addition reactions of O2, OH, and NO2 to the phenoxy radical. The formation of a phenoxy‐peroxy is found to be very slow with a rate constant fitted to k = 1.31 × 10?20T2.49 exp (?9300/T) cm3/mol/s in the temperature range of (298–2,000 K) where the addition occurs predominantly at the ortho site. Our rate constant is in line with the consensus of opinions in the literature pointing to the observation of no discernible reaction between the oxygen molecule and the resonance‐stabilized phenoxy radical. Addition of OH at the ortho and para sites of the phenoxy radical is found to afford adducts with sizable well depths of 59.8 and 56.0 kcal/mol, respectively. The phenoxy‐NO2 bonds are found to be among the weakest known phenoxy‐radical bonds (1.7–8.7 kcal/mol). OH‐ and O2‐initiated mechanisms for the degradation of atmospheric phenoxy appear to be negligible and the fate of atmospheric phenoxy is found to be controlled by its reaction with NO2. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2011 相似文献
10.
Li-Lin Jiang Sen-Jie Hu Dr. Qing Xu Dr. Hongxing Zheng Dr. Wen-Ting Wei 《化学:亚洲杂志》2021,16(20):3068-3081
2-Pyrrolidones have aroused enormous interest as a useful structural moiety in drug discovery; however, not only does their syntheses suffer from low selectivity and yield, but also it requires high catalyst loadings. The radical cyclization of 1,n-enynes and 1,n-dienes has demonstrated to be an attractive method for the synthesis of 2-pyrrolidones due to its mild reaction conditions, fewer steps, higher atom economy, excellent functional group compatibility, and high regioselectivity. Furthermore, radical receptors with unsaturated bonds (i. e. 1,n-enynes and 1,n-dienes) play a crucial role in realizing radical cyclization because of the ability to selectively introduce one or more radical sources. In this review, we discuss representative examples of methods involving the radical cyclization of 1,n-enynes and 1,n-dienes published in the last five years and discuss each prominent reaction design and mechanism, providing favorable tools for the synthesis of valuable 2-pyrrolidone for a variety of applications. 相似文献
11.
12.
T. V. Mikhalina S. V. Rubashko E. P. Fokin I. Yu. Bagryanskaya Yu. V. Gatilov 《Russian Chemical Bulletin》1995,44(12):2346-2349
It was shown that the reaction of 2-chloro-3-(4-N,N-dimethylaminoanilino)-1,4-naphthoquinone with piperidine in the absence of a solvent gives not only a product of replacement of the chlorine atom by a piperidino group, 3-(4-N,N-dimethylaminoanilino)-2-piperidino-1,4-naphthoquinone, but also 2-(4-N,N-dimethylaminoanilino)-1,4-naphthoquinone and 2-(4-N,N-dimethylaminoanilino-2-piperidino)-1,4-naphthoquinone. The latter compounds are the only reaction products formed in dimethyl sulfoxide. The reaction with morpholine occurs in a similar way, whereas that with pyrrolidine gives only a product of replacement of the chlorine atom by hydrogen.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2451–2454, December, 1995. 相似文献
13.
An efficient synthesis of 3-(3-methyl-1-aryl-1H-pyrazol-5-yl)-2H-2-chromen-2-one derivatives by the reaction of salicylaldehydes, 4-hydroxy-6-methyl-2H-pyran-2-one, and arylhydrazine in acetonitrile under reflux condition and in the presence of piperidine is reported. This three-component reaction has some advantages such as ease of handling, good yields, and easy purification. All structures were confirmed by infrared, mass, 1H NMR, and 13C NMR spectroscopy. 相似文献
14.
Vakiti Srinivas 《合成通讯》2013,43(3):388-393
One-pot synthesis of 14-aryl-14H-7-oxa-benzo[a]naphthacene-8,13-diones was developed by the reaction of 2-hydroxynaphthalene-1,4-dione, aromatic aldehydes, and 2-naphthol in the presence of acetic acid. The structures of these compounds were identified by elemental analyses, infrared, 1H NMR, and mass. 相似文献
15.
Andrzej Piasecki 《Monatshefte für Chemie / Chemical Monthly》1986,117(11):1287-1293
2-(2-Alkoxyethyl)-1,3-dioxanes (1) were prepared by ap-toluenesulfonic acid-catalyzed, one-step reaction of propenal with a mixture of aliphatic alcohol and trimethylene glycol in good yields. The transacetalization reaction of 1,1,3-trialkoxypropanes (3) with ethylene glycol or propylene-(1,2)glycol afforded good yields of pure 2-(2-alkoxyethyl)-1,3-dioxolanes (5 or6), respectively. This reaction proceeds through an intermediate 1,3-dialkoxy-1-(2-hydroxyalkoxy)-propane.
Ein- oder Zweistufensynthese von 2-(2-Alkoxyethyl)-1,3-dioxacyclanen
Zusammenfassung In der durchp-Toluolsulfonsäure — katalysierten, direkten Reaktion von Propenal mit einem Gemisch von aliphatischem Alkohol und Trimethylenglykol wurden die entsprechenden 2-(2-Alkoxyethyl)-1,3-dioxane (1) in guten Ausbeuten erhalten. Die Umacetalisierung von 1,1,3-Trialkoxypropanen (3) mit Ethylenglykol oder 1,2-Propylenglykol lieferte 2-(2-Alkoxyethyl)-1,3-dioxolane (5 oder6) in guten Ausbeuten. Die Umacetalisierungsreaktion von 1,1,3-Trialkoxypropanen verläuft über 1,3-Dialkoxy-1-(2-hydroxyalkoxy)-propane als Zwischenprodukte.相似文献
16.
17.
Thirupathi Rapolu Pavan Kumar K. V. P. Korupolu Raghu Babu Satheesh Kumar Dende Rajashekar Reddy Nimmareddy 《合成通讯》2019,49(10):1308-1315
A rapid and efficient one-pot method for the synthesis of 2-ethylamino benzimidazole, benzoxazole, and benzothiazole derivatives has been described. The reaction of o-phenylenediamines or o-aminophenols or 2-mercaptoanilines with EDC.HCl under microwave irradiation afforded the corresponding 2-ethylamino benzimidazole, benzoxazole and benzothiazole derivatives in excellent yields. 相似文献
18.
The reaction of various organic and inorganic acids (HX) with iodonium ylides2 leads to nucleophilic substitution of the iodobenzene substituent by the anionX
– to yield the heterocycles5. Some of them are hydrolyzed to the hydroxy compounds3 or reduced to the starting compounds1 under the reaction conditions. Reaction of the iodonium ylide2b with monomethyl sulfate gives the salt9, which with bases undergoes nucleophilic substitution to compounds8 and10–12, respectively, or is converted to2b again. 相似文献
19.
M. Bakavoli M. Nikpour M. Rahimizadeh 《Phosphorus, sulfur, and silicon and the related elements》2013,188(10):2265-2268
The synthesis of some new 3-(alkylthio)-1-phenyl-1H-[1, 3, 4]thiadiazino[5, 6-b]quinoxalines 4 have been achieved by cyclocondensation reaction of the alkyl-2-phenylhydrazinecarbodithioates 1 with 2,3-dichloroquinoxaline 2 in basic N,N-dimethylformamide. 相似文献
20.
Yu. G. Gololobov O. A. Linchenko Yu. G. Trishin P. V. Petrovskii S. A. Starikova 《Russian Chemical Bulletin》2004,53(4):889-896
The reaction of C,N-diphenylnitrilimine with a P-zwitterion derived from Pri
3P and H2C=C(CN)CO2Et afforded the first representative of 2-pyrazolines containing the phosphonium group and products of the addition of nitrilimine to Pri
3P and H2C=C(CN)CO2Et. The reaction of the P-zwitterion with C-4-nitrophenyl-N-phenylnitrilimine gave rise to a condensation product of one Pri
3P molecule and two nitrilimine molecules. The three-dimensional structures of the compounds synthesized were established by X-ray diffraction analysis. 相似文献