季戊四醇双缩醛的合成

以苯为溶剂，ＴｓＯＨ为催化剂合成了几种长直链的季戊四醇双缩醛。     

季戊四醇双缩醛的合成与表征

本文报道了用１２－钨磷酸作催化剂合成了６种季戊四醇双缩醛，其结构用元素分析ＩＲ及＾１ＨＮＭＲ等进行了表征。     

甲基磺酸催化合成季戊四醇双缩醛(酮)

季戊四醇双缩醛、双缩酮化合物在工业和有机合成中应用广泛。工业上常作为增塑剂、抗氧剂、杀虫剂和表面活性剂的消泡剂,在有机合成中用来合成有生理活性的物质和作为醛、酮的保护基团。季戊四醇双缩醛、酮的合成通常在酸性条件下进行,已报道的催化剂有质子酸:如盐酸[1]、硫酸[     

微波辐射下氨基磺酸催化合成季戊四醇双缩醛(酮)

微波辐射下,以氨基磺酸作催化剂,不用溶剂,合成了8种季戊四醇双缩醛(酮)。     

脱铝超稳Y沸石催化合成季戊四醇双缩醛

脱铝超稳Ｙ沸石催化合成季戊四醇双缩醛＊袁先友张敏王小勇（零陵师范高等专科学校化学系湖南永州４２５０００）关键词脱铝超稳Ｙ催化季戊四醇双缩醛中图分类号Ｏ６２３．４１３，Ｏ６２３．５１１季戊四醇双缩醛可用作杀虫剂，塑料等的抗氧化剂，各种表面活性剂的消泡剂...     

微波辐射条件下季戊四醇双缩醛和双缩酮化合物的合成

微波辐射硫酸锆-硅胶催化季戊四醇与醛、酮缩合反应,高收率制得了双缩醛和双缩酮化合物.该方法操作简便,收率高,催化剂可重复使用,是一种环境友好型催化反应.     

微波促进活性炭负载磷钨酸催化合成短链季戊四醇双缩醛

以活性炭负载磷钨酸为催化剂,用微波辐射法合成了5种短链季戊四醇双缩醛(3a~3 e),其中季戊四醇双缩丙醛(3b)未见文献报道。3的结构经1H NMR,IR和元素分析表征。     

季戊四醇双缩脂肪族醛(酮)螺环化合物的合成

以脂肪族醛(酮)为原料,对甲苯磺酸为催化剂,在环己烷中回流分水反应合成了一系列季戊四醇双缩脂肪族醛(酮)螺环化合物(3a~3l),其中3,9-二甲基-3,9-二丁基-2,4,8,10-四氧杂螺[5.5]十一烷(3i)和3,7,11,15,18,21-六氧杂三螺[5.2.2.512.29.26]二十一烷(3k)为新化合物,其结构经1H NMR,13C NMR和ESI-MS表征。     

双季戊四醇六丙烯酸酯的合成和表征

以双季戊四醇和丙烯酸为原料直接酯化合成了双季戊四醇六丙烯酸酯,考察了原料配比、溶剂用量、催化剂、阻聚剂用量、温度、脱色剂、反应时间等因素对反应的影响,得到了最佳反应条件,当双季戊四醇∶丙烯酸∶甲苯=1∶7.2∶3.77(物质的量之比),催化剂选用对甲苯磺酸,加入量为双季戊四醇质量的4%,采用复合阻聚剂,加入量为丙烯酸质量的4%,反应时间8 h,脱色剂TSJ-1用量为双季戊四醇用量的3%,产率较高可达75.0%,副反应少,产品色度较浅可达30号色.     

微波辐射条件下季戊四醇杂二缩醛(酮)的合成

在微波辐射下, 以活性炭负载磷钨酸为催化剂, N,N-二甲基甲酰胺为溶剂, 将季戊四醇与醛(酮)缩合得到季戊四醇单缩醛(酮), 然后再与另一种醛缩合合成了9种季戊四醇杂二缩醛(酮). 产物经过元素分析, IR和¹H NMR表征.     

1H NMR Investigation of Si-alkylsubstituted 1,3,5-Trisilacyclohexanes

Alkylsubstituted derivatives of 1,3,5-trisilacyclohexane have been prepared and their ¹H NMR spectra recorded and analyzed. For the compound series 1-mono-, cis-1,3-di- and cis-cis-1,3,5-tri-alkylated derivatives (alkyl = Me, Et, i-Pr and t-Bu) it is found that the conformational preference for an equatorial position of the substituents in the chair form is considerably less than for cyclohexane derivatives. In the compound series trans-1,3-di- and cis-trans-1,3,5-tri-alkylated derivatives the t-butyl group is found to behave uniqually by forcing the ring to escape into the twist-boat form. Each kind of substituent is found to have a characteristic effect on the chemical shift values of the ring protons.     

B环对位取代异黄酮化合物的核磁共振研究

对14个合成的B环对位取代异黄酮化合物核磁共振氢谱进行了研究.利用超导核磁共振归属了B环无取代异黄酮质子的化学位移,根据取代基化学位移的变化影响规律考察了取代基对分子的影响方式.研究结果表明,2'(6'),3'(5')位质子共振迁移分别与取代基参数σ_p和S_o线性相关,说明4'位取代基主要通过电子效应影响其间位质子,其磁各向异性仅影响邻位质子,该取代基对A环质子影响不大,而对C环尤其是对2-H影响较明显.     

NMR Studies on Hydrolysis and Condensation Reactions of Alkoxysilanes Containing Si—H Bonds

Hydrolysis and condensation reactions of four organically modified alkoxides, used for the preparation of silicon oxycarbide gel precursors, have been followed by 29Si NMR. Triethoxysilane (HSi(OEt)3) and methyldiethoxysilane (MeHSi(OEt)2) react extremely fast compared to methyltriethoxysilane (MeSi(OEt)3) and tetraethoxysilane (Si(OEt)4). Co-hydrolysis reactions between different pairs of precursors—MeSi(OEt)3/Si(OEt)4; MeSi(OEt)3/HSi(OEt)3; MeHSi(OEt)2/Si(OEt)4; and MeHSi(OEt)2/HSi(OEt)3—were investigated by solution state 29Si and 17O NMR. Despite significantly different reactivities between precursors, evidence for co-condensation reactions has been found for each system. Finally, two-dimensional 29Si-1H heteronuclear correlation MAS-NMR spectroscopy was used to probe the local environments of the various Si sites in the product hybrid networks.     

Complete 1H and 13C NMR assignment for aryl diisoprenes

The characterization of four aryl diisoprenes was carried out by 1D‐ and 2D‐NMR methods, which permitted the assignment of the signals of all protons and all carbon atoms. Copyright © 2003 John Wiley & Sons, Ltd.     

Assignment of the 1H and 13C NMR signals of some hydroxyphenylcoumarins

The complete 1H and 13C NMR assignments of six hydroxyphenylcoumarins have been made using 1D and 2D NMR techniques, including COSY, HMQC and HMBC experiments.     

Assignment of the 1H and 13C NMR signals of some benzofurocoumarins

The complete 1H and 13C NMR assignment of four 6,7-benzo-fused furocoumarins (1-4) and three 3,4-benzo-fused furocoumarins (5-7) has been performed using 1D and 2D NMR techniques, including COSY, HMQC and HMBC experiments.     

Application of 1H NMR in the flow surveillance of oil wells

Test‐separator units, as traditional methods of well surveillance, mainly suffer from their inherent constraints including the expensive instrumental, mechanical, electrical, piping and safety devices along with technical and protective inspections, repair and operation services, facilities and infrastructures. Other problems are time and cost consuming, uncertainty of well isolation in test separator and need to close the co‐line wells, which are diminished using multivariate thermal well testing. A novel approach was proposed and tested to classify the oil samples taken from individual wells by source and type. The novelties of this work were the use of the applied aspects of ¹H NMR spectroscopy in petroleum upstream engineering, the replacement of traditional test methods, the improvement of the confidence of tests and the recognition of multisource streams. The weighed sum method was used to correlate the spectra information, taken from the samples of Iranian offshore oil wells. The experimental results and the field data revealed that the present approach was appropriate for precocious, quick and reliable surveillance of individual oil wells located in an oil field. The model was supported by field experiments and has predicted the accurate productivity of oil wells with respect to the current expensive techniques since 2010. Copyright © 2012 John Wiley & Sons, Ltd.     

Complete assignment of 1H and 13C NMR data of some flavonol derivatives

Nine flavonol derivatives were studied. Previously reported NMR data of three of these derivatives were corrected. We report complete assignments of the NMR data for six flavonol derivatives not previously studied.     

1H, 13C and 15N NMR spectra of ciprofloxacin

1H NMR assignment, including the values of delta(H) and J(H,H) for the cyclopropane moiety, and 13C NMR and 15N NMR spectral data for ciprofloxacin are presented.     

1H and 13C NMR studies of the protonation of isomeric methoxysulmazole analogues

The major protonation sites of six cardiotonic isomeric 2-aryl-n-methoxy-1H-imidazo[4,5-b]- and -[4,5-c]-pyridines (n = 4–7) were determined by ¹H and ¹³C NMR methods. All the 1H-imidazo[4,5-c]pyridines and the 7-methoxy derivative of sulmazole were found to protonate at the pyridyl nitrogen. Protonation occurred at the imidazo nitrogen, however, for the 5- and 6-methoxy derivatives of sulmazole.