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1.
采用溶胶-凝胶法制备了二氧化硅负载硅钨钼酸催化剂。以二氧化硅负载硅钨钼酸为催化剂,环己酮和1,2-丙二醇为原料合成了环己酮1,2-丙二醇缩酮,用正交实验法研究了反应物料配比、催化剂用量、带水剂用量、反应时间等因素对反应的影响。结果表明,在n(环己酮)∶n(1,2-丙二醇)=1∶1.4,催化剂用量为反应物料总质量的0.8%,带水剂环己烷12 mL,反应时间45 min的优化条件下,环己酮1,2-丙二醇缩酮的收率可达84.93%。  相似文献   

2.
本文探讨了钨硅酸的制备方法,以合成环己酮1,2-内二醇缩酮为例验证钨硅酸的催化活性,并探讨了合成其它缩酮(醛)的适宜条件,得到的收率分别为:环己酮1,2-丙二醇缩酮85.5%、环己酮乙二醇缩酮89.6%、丁酮乙二醇缩酮79.5%、丁醛乙二醇缩醛89.1%、丁醛1,2丙二醇缩醛81.5%。  相似文献   

3.
采用气相转移法(VPT)合成了杂原子Mn取代的MnSAPO-34(CHA结构)分子筛.采用X射线衍射(XRD)、傅立叶变换红外光谱(FT-IR)等手段对其进行了表征.结果表明,Mn2+进入到分子筛的骨架中.将该催化剂用于环己酮和1,2-丙二醇的缩酮反应,n(环己酮)∶n(1,2-丙二醇)=1∶1.1,分水剂环己烷用量为...  相似文献   

4.
吕宝兰  杨水金 《合成化学》2005,13(6):624-626
以丁酮和1,2-丙二醇为原料,活性炭负载硅钨酸(H4SiW12O40/C)为催化剂,催化合成了丁酮1,2-丙二醇缩酮。正交试验筛选出最佳反应条件为:丁酮200mmol,n(丁酮):n(1,2-丙二醇)=1.0:1.4,ω(催化剂)=1.2%(以反应物质量计),反应时间1h。在此最佳反应条件下,丁酮1,2-丙二醇缩酮的收率可达71.13%。  相似文献   

5.
碘催化合成环己酮1,2-丙二醇缩醛   总被引:14,自引:1,他引:13  
研究了单质碘催化环已酮与1,2-丙二醇的缩醛化反应,考察了反应时间、醇酮摩尔比、催化剂用量、带水剂用量等因素对环已酮乙二醇缩醛收率的影响。结果表明,在回流条件下,醇酮摩尔比为1.3,催化剂用量为52mg(约占反应体系总摩尔数的0.007%),带水剂环己烷用量为8mL,反应40min后缩醛收率可达79.2%。  相似文献   

6.
硫酸镓催化法合成环己酮乙二醇缩酮   总被引:3,自引:0,他引:3  
以环己酮和乙二醇为原料,硫酸镓为催化剂,在微波辐射和无溶剂条件下,合成了环己酮乙二醇缩酮.探讨了酮醇物质的量比、催化剂用量、微波功率和辐射时间对产品收率的影响.结果表明,环己酮乙二醇缩酮的最佳合成条件为:n(环己酮):n(乙二醇)=1:3,催化剂用量为反应物总质量的2.0%,微波功率为375W,辐射时间为20min.在此条件下,缩酮收率可达96.3%,说明硫酸镓是一种合成环己酮乙二醇缩酮的优良催化剂.  相似文献   

7.
磷钨酸镧催化合成缩醛(酮)的研究   总被引:2,自引:0,他引:2  
以磷钨酸镧为催化剂催化合成了苯甲醛乙二醇缩醛、苯甲醛1,2-丙二醇缩醛及环己酮乙二醇缩酮.较系统研究了反应物料配比、催化剂用量、反应时间、催化剂重复使用性能等因素对反应的影响.结果表明:在醛(酮)/二元醇(乙二醇、1,2-丙二醇)=1.0:1.5(mol/mol),催化剂用量为反应物料总质量的1.0%,环己烷为带水剂,在反应温度86~96℃条件下,反应时间2.0h,苯甲醛乙二醇缩醛收率为78.5%,苯甲醛1,2-丙二醇缩醛收率为76.1%,环己酮乙二醇缩酮收率为79.5%.  相似文献   

8.
漆酚缩甲醛钕聚合物催化合成环己酮乙二醇缩酮   总被引:2,自引:0,他引:2  
以环己酮和乙二醇为原料,漆酚缩甲醛钕聚合物为催化剂合成了环己酮乙二醇缩酮。实验结果表明:在环己酮100mmol,n(环己酮):n(乙二醇)=1:1,漆酚缩甲醛钕聚合物3.0g,环己烷7.5mL,回流反应1.0h,目标化合物的收率达74%。  相似文献   

9.
钛基固体超强酸对环己酮乙二醇缩酮催化反应的特性   总被引:2,自引:1,他引:1  
合成S042-/TiO2、SO42-/TiO2-Ce(Ⅳ)、SO42-/TiO2-ZrO2三种不同的固体超强酸,以环己酮乙二醇缩酮为探针反应,发现550℃下焙烧的SO4 2-/TiO2-Ce(Ⅳ)催化活性最好.并以SO42-/TiO2-Ce(Ⅳ)为催化剂,考察反应温度、催化剂用量、反应时间、反应物配比和带水剂对缩酮化反应转化率和选择性的影响.结果表明,反应温度为110~125℃、催化剂用量占反应物料总质量的0.5%、环己酮和乙二醇物质的量比为1:1.5、反应时间为1 h、环己烷为带水剂时,环己酮的转化率达95.2%,环己酮乙二醇缩酮的选择性98.7%,催化剂的重复使用效果好.  相似文献   

10.
以溴化铜或氯化铜为卤化剂,6-甲基氧基-2-丙酰基萘经羰基α-卤化,1,2-丙二醇缩酮化,醋酸锌或氧化锌催化重排和水解等反应合成外消旋体萘生,总收率为85%-90.4%,(以6-甲氧基-2-丙酰基萘计),一锅法重排合成外消旋体萘普生,不需分离中间体,操作简便,收率高,以氯化铜为卤化剂,氯化锌为催化剂的重排合成工艺较佳。  相似文献   

11.
Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.  相似文献   

12.
A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.  相似文献   

13.
The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp3)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp2)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp2)?H and aliphatic 1,5- and 1,6-C(sp3)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp3)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp2)?H insertion.  相似文献   

14.
The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.  相似文献   

15.
N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).  相似文献   

16.
In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.  相似文献   

17.
An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y1 and Y2. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.  相似文献   

18.
A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL.  相似文献   

19.
In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.  相似文献   

20.
An efficient approach to the synthesis of highly congested di, penta and hexacyclic pyrazoles as well as imidazole fragment containing novel heterocyclic molecule has been developed through a carbanion induced transformation of suitably functionalized 2H-pyran-2-ones, benzo[h]chromene and thiochromeno[4,3-b]pyrans. Due to the presence of fluorescence, we report their prime application metal sensor as off/on switching in ferric ions.  相似文献   

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