共查询到20条相似文献,搜索用时 534 毫秒
1.
改进了邻溴苯基-2-(口恶)唑啉的合成方法,使得N-(β-羟乙基)-2-(口恶)溴苯甲酰胺在氯化亚砜作用下缩合成唑啉的收率从40%左右提高到84%,并避免了使用NaH试剂,为芳基-2-(口恶)唑啉的合成提供一条方便、经济的路线.实验结果表明,反应温度对唑啉的收率的影响显著,随着反应温度的升高收率明显降低,室温下几乎得不到目标产物.根据实验结果推测其反应过程是经过互变异构酰亚胺中间物Ⅰ进行的. 相似文献
2.
Cordonier CE Satake K Atarashi M Kawamoto Y Okamoto H Kimura M 《The Journal of organic chemistry》2005,70(9):3425-3436
[reaction: see text] The reaction of 2-methoxy-3H-azepines, in the presence or absence of a nucleophile, with N-bromosuccinimide (NBS) gave a regioselective 1,4-adduct from which the corresponding 2H-azepine derivatives were formed via base-promoted hydrogen bromide elimination, generally in moderate to quantitative yield. Competitive formation of 4-bromo-2-methoxy-3H-azepine by electrophilic substitutuion or 3H-azepin-2-yl 2H-azepin-2-yl ether by transetherification was minimized at lower reaction temperatures. Quantitative substitution of 2-(2',4',6'-trichlorophenoxy)-2H-azepine derivatives, formed in moderate yield from the respective 3H-azepine and NBS in the presence of 2,4,6-trichlorophenol (TCP), by various nucleophiles gave the corresponding 2-substituted 2H-azepine. Among these nucleophiles were alkanethiol and alkylamine that are not tolerated in the reaction of 3H-azepine and NBS. 相似文献
3.
The elementary reaction of CH2Cl+O2 in gas phase was investigated by time-resolved FTIR emission spectroscopy. Vibrationally excited products CO (v·4), and CO2 (o3, v·7) were observed. The yield ratio of CO/CO2(o3) was 72.2§7. The reaction pathways were studied theoretically at QCISD//UB3LYP/6-311++G(d,p) level. In the beginning of the reaction, CH2Cl radical associated with O2 to form CH2ClOO, followed by removal of the Cl atom to yield another intermediate dioxirane CH2OO. Subsequently, a series of isomerization and decomposition of the CH2OO took place, yielding the ˉnal products of CO and CO2. The calculated result was in consistent with the experimental observation. 相似文献
4.
2-Bromo-3,4-dicyanopyridine 2 was obtained in moderate yield by reacting 1,1,2,2-tetracyano-3-trimethylsiloxycyclobutane 1 with phosphorus tribromide. Similarly, reaction of 1 with chlorinating reagents such as thionyl chloride and oxalyl chloride led to the corresponding 2-chloro-3,4-dicyanopyridine 3 in 40% yield. A reaction mechanism is suggested. 相似文献
5.
[STRUCTURE: SEE TEXT] A neutral rhodium(I)/BINAP complex effectively catalyzed a [2+2+2] cycloaddition of 1,6-diynes with isothiocyanates to give bicyclic thiopyranimines in 59-98% isolated yield. The reaction with carbon disulfide also proceeded to give bicyclic dithiopyrones in 74-85% isolated yield. 相似文献
6.
一种新的催化剂,SnCl2·2H2O,已用于2,3-二甲基-2-丁烯与乙酐的酰化反应来制备高产率的3,3,4-三甲基-4-戊烯-2-酮
(TMP). 发现SnCl2·2H2O是室温下2,3-二甲基-2-丁烯与乙酐进行酰化反应的有效催化剂.
考察了催化剂用量、乙酐用量、反应时间和溶剂的加入等因素对该酰化反应的影响.
发现当催化剂/2,3-二甲基-2-丁烯摩尔比在0.30/1和 0.60/1之间、反应时间为2
h时,所得酰化产品的产率最高.
该酰化反应进行到完全所需的时间取决于催化剂用量和乙酐用量.
在需要加入溶剂的情况下,二氯甲烷或氯仿是一种合适的溶剂. 相似文献
7.
5-bromo-2-fluoro-3-pyridylboronic acid (3) was prepared in high yield by ortho-lithiation of 5-bromo-2-fluoropyridine (1), followed by reaction with trimethylborate. Suzuki reaction of 3 with a range of aryl iodides gave 3-monosubstituted 5-bromo-2-fluoropyridines 4 in excellent yields. A second Suzuki reaction utilizing the bromo constituent of 4 with aryl and heteroaryl boronic acids provided 3,5-disubstituted 2-fluoropyridines 5, which in turn could be converted to the corresponding 2-pyridones 6. 相似文献
8.
Boris Trofimov Boris Timokhin Nina Gusarova Marina Kazantseva Alexander Golubin 《Phosphorus, sulfur, and silicon and the related elements》2013,188(10):2385-2390
Oxidative phosphorylation of alkanols with white phosphorus in the presence of catalytic amounts of CuCl 2 has been effected. The reaction proceeds in the aqueous H 2 O 2 --HCl system exothermically to form dialkylphosphites and trialkylphosphates in a total yield of up to 35%. Conditions for selective synthesis of dialkylphosphites in moderate yield have been found. 相似文献
9.
John J. D'Amico Lydia Suba Peter G. Ruminski 《Journal of heterocyclic chemistry》1985,22(6):1479-1482
Attempts to thermally rearrange 2-benzothiazolylthioacetonitrile ( 1) to the titled compound 8 failed. The reaction of 3-chloromethyl-2-benzothiazolinethione with potassium cyanide in dimethylformamide (DMF) or dimethylsulfoxide (DMSO) at 25-30° afforded 8 in 98% yield. Whereas replacing the DMF or DMSO solvent with acetone furnished the unexpected sulfide 9 in 92% yield. Substituting 3-chloromethyl-2-benzoxazoline-thione as the electrophile in the same reaction gave the sulfide 10 in 95% yield. Possible mechanisms and supporting nmr data are discussed. 相似文献
10.
A new catalytic system for enantioselective [2+2]-cycloaddition reaction of 2-methoxycarbonyl-2-cyclopenten-1-one with thioacetylene derivatives is described. The use of a catalytic amount (20-30 mol%) of copper(II) salt with chiral bis-pyridine ligand was found to be effective in promoting the [2+2]-cycloaddition reaction, furnishing the corresponding bicyclic compound in good yield and good enantioselectivity. 相似文献
11.
12.
Weena Phongsawat Benjamas Netivorruksa Kongkiat Suriye Siraprapha Dokjampa Piyasan Praserthdam Joongjai Panpranot 《天然气化学杂志》2012,(1):83-90
An unconventional metathesis of ethylene and 2-pentene over Re2O7/SiO2-Al2O3 catalysts has been studied as an alternative route for the production of propylene. Complete conversion of 2-pentene and propylene yield as high as 88 wt% were obtained under mild reaction conditions at 35°C and atmospheric pressure. Unlike the conventional metathesis of ethylene and 2-butenes in which isomerization is a competing side reaction, the isomerization of 1-butene product from the unconventional metathesis of ethylene and 2-pentene to 2-butenes can further react with excess ethylene in the feed, resulting in additional increase in propylene yield. The secondary metathesis reaction was found to be favored under ethylene/2-pentene (E/2P) molar ratio 3 and gas hourly space velocity (GHSV) 1000 h-1 at the reaction temperature of 35°C. No catalyst deactivation was observed during the 455 min time-on-stream under the selected reaction conditions. 相似文献
13.
Duane A. Heyman 《Journal of heterocyclic chemistry》1978,15(4):573-576
A method for the synthesis of 2-henzimidazolone ( 1 ) has been devised which does not depend on 1,2-diaminobenzene ( 2 ) as a starting material. This method produces 1 in good yield by the reaction of hypohalite with 2′-carbamoylphthalanilic acid ( 7 ), a compound readily prepared by the reaction of 2-aminobenzamide ( 3 ) and phthalic anhydride. Contrary to prior indications 1 can be hydrolyzed in the presence of acid at temperatures greater than 200 giving excellent yields of 2. 相似文献
14.
Arturo ArduiniAndrea Pochini Andrea SecchiFranco Ugozzoli 《Tetrahedron letters》2003,44(30):5755-5757
Chlorosulfonation of thenoyltrifluoroacetone with neat chlorosulfuric acid was found to give a 25:75 mixture of 3- and 2-chlorosulfonated thenoyltrifluoroacetone isomers in 33% overall yield. The use of dichloromethane as solvent for the chlorosulfonation reaction gave only the 2-chlorosulfonated isomer in 45% yield. On the contrary, the reaction of 2-acetylthiophene with neat chlorosulfuric acid gave only the 3-chlorosulfonated-5-acetylthiophene in 35% yield. The identity of these chlorosulfonated compounds was unambiguously established by NMR techniques and confirmed by the crystal structure determination of the 2-chlorosulfonated isomer. 相似文献
15.
Boñaga LV Zhang HC Moretto AF Ye H Gauthier DA Li J Leo GC Maryanoff BE 《Journal of the American Chemical Society》2005,127(10):3473-3485
We investigated the formation of macrocycles from alpha,omega-diynes in cobalt-mediated co-cyclotrimerization reactions. Long-chain alpha,omega-diynes underwent metal-mediated [2 + 2 + 2] cycloadditions with nitriles, cyanamides, or isocyanates in the presence of CpCo(CO)2 (Cp = cyclopentadienide) to yield pyridine-containing macrocycles, i.e., meta- and para-pyridinophanes, such as 5m/5p, 35m/35p, and 41m/41p. The regioselectivity of these reactions was affected by the length and type of linker unit between the alkyne groups, as well as by certain stereoelectronic factors. An analogous alpha,omega-cyano-alkyne, 28, combined with an alkyne to yield two isomeric meta-pyridinophanes, such as 5m and 29m, and an ortho cycloadduct (benzannulation product), such as 29o. We developed a reaction protocol for these cobalt-based [2 + 2 + 2] cycloadditions that involves markedly improved conditions such that this process offers a convenient, flexible synthetic approach to macrocyclic pyridine-containing compounds. For example, diyne 6 reacted with p-tolunitrile in 1,4-dioxane to give 7p and 7m (7:1 ratio) in 87% yield at a moderate temperature of ca. 100 degrees C in 24 h without photoirradiation or syringe-pump addition. Isocyanates were also effective reactants, as exemplified by the formation of 44p almost exclusively (44p:44m > 50:1) in 64% yield from diyne 8 and 2-phenylethylisocyanate. By using this improved protocol we were able to co-cyclotrimerize long-chain alpha,omega-diynes with alkynes in certain cases to demonstrate a successful macrocyclic variant of the Vollhardt reaction. For instance, diyne 6 reacted with dipropylacetylene to give paracyclophane 57p and benzannulene 57o (2:1 ratio) in 29% yield. 相似文献
16.
F. G. Weber K. Brosche Ch. Seedorf A. Rinow 《Monatshefte für Chemie / Chemical Monthly》1969,100(6):1924-1927
2-Iodo-3-chloro-1,3-diphenyl-1-propanones react with phenylhydrazine to yield the 1,3,5-Triaryl-Δ2-pyrazoline. The reaction proceeds with elimination of ICl to the chalcones and their reaction with an excess of phenylhydrazine. 相似文献
17.
以商品TiO2-P25为原料,通过浸渍法负载一定量过渡金属Cu,得到一系列不同含量的CuOx/TiO2光催化剂。利用X射线衍射(XRD),X-射线光电子能谱(XPS),BET,高分辨率透射镜(HRTEM),X射线荧光光谱(XRF)和光致发光光谱(PL)等方法对催化剂进行了详细表征,在自建的光催化反应器中评价了气态水光催化还原CO2反应的活性和CH4收率。结果表明负载CuOx后的TiO2纳米材料光催化性能显著提高,其中1%CuOx/TiO2样品紫外光照72 h后,CH4生成量达到了24.86 µmol•gTi-1。同时,CuOx负载量、反应温度、反应时间等因素对CH4收率均有显著影响。 相似文献
18.
19.
20.
以廉价的2-溴苯甲醚制取了格氏试剂,通过Kumada偶联反应得到2-噻吩基苯甲醚,再通过吡啶盐酸盐脱甲基得到2-噻吩基苯酚。从催化剂、配体、溶剂等方面对Kumada偶联反应进行了筛选和优化,结果表明Kumada偶联反应时,72℃以Pd(dppf)Cl2(0.001 mol)为催化剂(dppf,二茂铁),三苯基膦(PPh3)和1,1’-双(二苯基膦)二茂铁(dppf)作为配体,四氢呋喃和乙二醇二甲醚为混合溶剂,反应16 h,得到2-噻吩基苯甲醚,纯度95%,产率65%。再通过吡啶盐酸盐脱甲基得到2-噻吩基苯酚,纯度大于98%,产率65%。该方法原料便宜,后处理简单,收率较高。 相似文献