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1.
由具有2位氢的3-氨基-2-烯丙亚胺与N-氯或N-溴琥珀酰亚胺以甲苯作溶剂在常温下反应,制备了-些未见文献报道的2-氯和2-溴-3-氨基-2-烯丙亚胺,化合物结构均经元素分析,^1H NMR,^13C NMR和MS确证。  相似文献   

2.
1-(4-乙酰氨基苯基)-α-溴代-1-丙酮(I)是合成强心药物匹莫苯(Pirnobendan)和新型抗抑郁类药物氨基酮的主要中间体,它可以1-(4-乙酰氨基苯基)丙酮(Ⅱ)为原料,通过α位溴代得到。主要方法有:(1)以冰醋酸作溶剂,滴加溴的醋酸溶液反应后,经氯仿萃取,硅胶G柱层析分离得产品。  相似文献   

3.
吴小云  尹晓刚  龚维  陈治明  陈卓 《化学通报》2016,79(12):1156-1160
以氰基查尔酮类化合物及丙二腈为原料,醋酸锌为催化剂,经串联反应合成2-氨基-4H-吡喃类衍生物。考察催化剂、溶剂、反应时间及温度、原料摩尔比对产率的影响。最优条件为:氰基查尔酮类化合物与丙二腈物质的量比为1.0:1.0,醋酸锌(10mol%)作催化剂,二氯甲烷作溶剂,反应温度为30℃,产率最高为99.5%。  相似文献   

4.
以碳酸钾作碱,DMF作溶剂,5%Pd/C催化1,3-二羰基化合物在室温下与氧气反应,直接得到α-羟基化合物,其结构经NMR和MS表征.  相似文献   

5.
以2-萘酚和三氯甲苯为起始原料,异丙醇水溶液作溶剂,非催化条件下合成了1-苯甲酰基-2-萘酚。考察了三氯甲苯用量、醇、水和异丙醇的体积比、溶剂用量及回流反应时间对产率的影响。确定较佳工艺条件为:2-萘酚50 mmol,三氯甲苯60 mmol,异丙醇水溶液18 mL(V水∶V异丙醇=1∶5),回流反应时间2 h,1-苯甲酰基-2-萘酚收率达74%。异丙醇经回收后可重复利用。产品结构经IR,1H NMR,13C NMR及元素分析进行了表征。  相似文献   

6.
吴君  谢永美 《合成化学》2018,26(11):827-832
以六氟异丙醇作溶剂,α-溴代酰胺在三乙胺作用下脱去一分子溴化氢,原位生成氮杂氧杂烯丙基离子中间体,再与硝酮发生[3+3]环加成反应,高收率合成了一系列1,2,4-噁二嗪-5-酮类化合物,其结构经1H NMR, 13C NMR, HR-MS(ESI)和X-射线单晶衍射确证。  相似文献   

7.
刘倩  赵利飞  李文红  李媛 《有机化学》2012,32(11):2122-2128
以取代苯、丁烯二酸酐、邻氨基(对氯邻氨基)苯酚为原料,合成了一系列2-酯基-1,5-苯并氧氮杂衍生物,其结构通过IR,1H NMR,MS(HRMS)及元素分析进行表征.同时,确定了一个主要副产物2-苯甲酰甲基-2H-1,4-苯并噁嗪-3(4H)-酮(6h’)的结构,提出了其可能的生成机理.研究还表明,中间体4-芳基-4-氧代-2-丁烯酸酯(4)在对甲基苯磺酸为催化剂、DMF作溶剂、回流温度下反应时主要生成目标产物2-酯基-1,5-苯并氧氮杂6,而在冰醋酸为催化剂、甲醇作溶剂、回流温度下反应时则主要生成副产物6h’.  相似文献   

8.
以芳醛、氰乙酸酯和4-羟基喹啉-2-酮为原料,乙醇为溶剂,在KF—Al2O3催化下80℃,一步合成了2-氨基-4-芳基-5,6-二氢化-4H-吡喃[3,2-c]喹啉-5-酮-3-羧酸酯衍生物,和其它方法相比,具有反应条件温和,容易操作和产率高等优点,产物4a的结构通过X单晶衍射分析确证.  相似文献   

9.
以芳醛、6-甲基-4-羟基-2-吡喃酮为原料,醋酸酐为溶剂合成了一系列3,6-二甲基-9-芳基-1,8-二氧代-2,7,10-三氧杂蒽,产物的结构经红外、核磁、元素分析及X射线衍射法表征;并对反应过程提出了可能的机理.  相似文献   

10.
(1S,3S)-1,3-二苯基-1,3-丙二胺的合成   总被引:1,自引:1,他引:0  
以二氯甲烷作溶剂,N-Boc保护的二氢吡唑在六甲基磷酰胺存在下与苯基格氏试剂反应,比较大量地制备了对应的四氢吡唑(4);再由4合成消旋的1,3-二苯基-1,3-丙二胺(1,总收率35%);1经L-二苯甲酰酒石酸盐拆分制得光学纯的(1S,3S)-1,3-二苯基-1,3-丙二胺,其结构经1HNMR确证。  相似文献   

11.
Spectral-luminescent properties of the newly synthesized 2-(3-coumarinyl)-5-(2′-(R-amino)-phenyl)-1,3,4-oxadiazoles has been investigated in solvents of various polarity and hydrogen-bonding ability. It has been found that for all the studied compounds no excited state intramolecular proton transfer occurs despite the presence of coumarinyl fragment - electron acceptor effect of the coumarinyl fragment is not sufficient to increase the excited state acidity of the amino group. It has been found that the absorption spectra of the studied compounds shift to higher energy with increase in solvent polarity, whereas corresponding fluorescence spectra shift to lower energy with solvent polarity increase. It has been suggested that long-wavelength shifts of the fluorescence spectra of the studied compounds with increase in solvent polarity is caused by the solvent relaxation. The observed solvent relaxation effect allow us to propose some of the studied compounds as potential probes to monitor changes in solvent relaxation in low-polar media and as potential probes for rigidochromic effect.  相似文献   

12.
The photophysical properties of 3-[2-(4-diphenylaminophenyl)benzoxazol-5-yl]alanine methyl ester (1b) and its Boc derivative (1a) were studied in a series of solvents. Its UV-Vis absorption spectra are less sensitive to the solvent polarity than the corresponding fluorescence spectra which show pronounced solvatochromic effect leading to large Stokes shifts. Using an efficient solvatochromic method, based on the molecular-microscopic empirical solvent polarity parameter E(T)(N), a large change of the dipole moment on excitation has been found. From an analysis of the solvatochromic behaviour of the UV-Vis absorption and fluorescence spectra in terms of bulk solvent polarity functions, f(epsilon(r),n) and g(n), a large excited-state dipole moment (mu(e) = 11D), almost perpendicular to the smaller ground-state dipole moment, was observed. This demonstrates the formation of an intramolecular charge-transfer excited state. Large changes of the fluorescence quantum yields as well as the fluorescence lifetimes with an increase of a solvent polarity cause that the new non-proteinogenic amino acid, 3-[2-(4-diphenylaminophenyl)benzoxazol-5-yl]-alanine methyl ester, is a new useful fluorescence probe for biophysical studies of peptides and proteins.  相似文献   

13.
The molar transition energy (E(T)) polarity values for the dye 4-[4-(dimethylamino)styryl]-1-methylpyridinium iodide were collected in binary mixtures comprising a hydrogen-bond accepting (HBA) solvent (acetone, acetonitrile, dimethyl sulfoxide (DMSO), and N,N-dimethylformamide (DMF)) and a hydrogen-bond donating (HBD) solvent (water, methanol, ethanol, propan-2-ol, and butan-1-ol). Data referring to mixtures of water with alcohols were also analyzed. These data were used in the study of the preferential solvation of the probe, in terms of both solute-solvent and solvent-solvent interactions. These latter interactions are of importance in explaining the synergistic behavior observed for many mixed solvent systems. All data were successfully fitted to a model based on solvent-exchange equilibria. The E(T) values of the dye dissolved in the solvents show that the position of the solvatochromic absorption band of the dye is dependent on the medium polarity. The solvation of the dye in HBA solvents occurs with a very important contribution from ion-dipole interactions. In HBD solvents, the hydrogen bonding between the dimethylamino group in the dye and the OH group in the solvent plays an important role in the solvation of the dye. The interaction of the hydroxylic solvent with the other component in the mixture can lead to the formation of hydrogen-bonded complexes, which solvate the dye using a lower polar moiety, i.e. alkyl groups in the solvents. The dye has a hydrophobic nature and a dimethylamino group with a minor capability for hydrogen bonding with the medium in comparison with the phenolate group present in Reichardt's pyridiniophenolate. Thus, the probe is able to detect solvent-solvent interactions, which are implicit to the observed synergistic behavior.  相似文献   

14.
Electronic structure calculations, steady-state electronic spectroscopy, and femtosecond time-resolved emission spectroscopy are used to examine the photophysics of trans-4-(dimethylamino)-4'-cyanostilbene (DCS) and its solvent dependence. Semiempirical AM1/CI calculations suggest that an anilino TICT state is a potential candidate for the emissive state of DCS in polar solvents. But observation of large and solvent-independent absorption and emission transition moments in a number of solvents (M(abs) = 6.7 +/- 0.4 D and M(em) = 7.6 +/- 0.8 D) rule out the involvement of any such state, which would have a vanishingly small transition moment. The absorption and steady-state emission spectra of DCS evolve in a systematic manner with solvent polarity, approximately as would be expected for a single, highly polar excited state. Attempts to fit the solvatochromism of DCS using standard dielectric continuum models are only partially successful when values of the solute dipole moments suggested by independent measurements are assumed. The shapes of the absorption and emission spectra of DCS change systematically with solvent polarity in a manner that is semiquantitatively reproduced using a coupled-state model of the spectroscopy. Kerr-gate emission measurements show that the emission dynamics of DCS down to subpicosecond times reflect only solvent relaxation, rather than any more complicated electronic state kinetics. The spectral response functions measured with DCS are well correlated to those previously reported for the solvation probe coumarin 153, indicating DCS to be a useful alternative probe of solvation dynamics.  相似文献   

15.
Dynamic NMR measurements of 8-(dimethylamino)-1-acetonaphthone 1 in neutral solutions reveal a solvent dependency of the barrier to NMe group interchange similar to that reported for N,N-dimethylacetamide. Titrating 1 with TFA in solvents of varying donicities gives rise to equilibrium mixtures of N-protonated aminoketone 2 and the O-protonated transannular addition product 3, the interconversion rate of which is slow on the NMR time scale at ambient temperature. The preference for O- or N-protonation is medium-dependent, the amount of N-protonated 2 increasing with a decrease in the nucleophilicity of the solvent. The set of equilibria which govern the interconversion of 2 and 3 in the titration mixtures are identified and their equilibrium constants evaluated from the NMR data. X-ray analysis of the crystalline trifluoroacetate salt of O-protonated 3 indicates that the transannular N.CO bond of 3 is formed to an extent of only 80%. The equilibrium distribution of 2 and 3, paired with the tetrafluoroborate anion, depends on both the nucleophilicity and the polarity of the solvent. In PhNO(2) the enthalpy change 3 --> 2 amounts to 2.6 kcal/mol.  相似文献   

16.
《Analytical letters》2012,45(9):483-488
Abstract

Pmr is used to evaluate solvent selectivity and to furnish an indication of water structure in binary aqueous solvent - ion exchange resin systems. The hydrogen form of Dowex 50W-X8 equilibrated with binary aqueous solvents exhibits pmr peaks for internal water which are shifted downfield relative to the water - ion exchanger system. The greater the mole fraction of organic solvent in the system, the greater the downfield shift.  相似文献   

17.
The photophysical properties of N-Boc-3-[2-(9-anthryl)benzoxazol-5-yl]-l-alanine methyl ester (BoxAnt) and N-Boc-3-[2-[4-(9′-(10′-butyl)anthryl)phenyl]benzoxazol-5-yl]-l-alanine methyl ester (BoxPhAnt) were studied in a series of solvents. Their absorption spectra are less sensitive to the solvent polarity than the corresponding fluorescence spectra which show a pronounced solvatochromic effect leading to large Stokes shifts. Using an efficient solvatochromic method, based on the empirical solvent polarity parameter , a large change of the dipole moment on excitation for BoxPhAnt has been found. From an analysis of the solvatochromic behaviour of the absorption and fluorescence spectra in terms of bulk solvent polarity functions, f(r, n) and g(n), a larger excited-state dipole moment (about 8 D, ψ = 56) was obtained for BoxPhAnt than for BoxAnt (about 3 D, ψ = 0). Both applied methods gave similar values of the excited-state dipole moments for both compounds studied.  相似文献   

18.
The optical rotation of (S)-(-)-alpha-methylbenzylamine at 589 nm has been measured in 39 different solvents at five different concentrations: 0.25, 0.50, 1.00, 2.00, and 3.00 M. A correlation of the intrinsic rotations (i.e., extrapolation of specific rotations to zero concentration) with Kamlet's and Taft's solvent parameters (alpha, beta, and pi) is established. The polarity/polarizability, pi, and solvent acidity, alpha, terms are found to have a greater effect upon the optical rotation than the basicity of the solvent, beta. The specific rotation for (S)-(-)-alpha-methylbenzylamine has been calculated with Gaussian03 using a PCM model (B3LYP aug-cc-pVDZ) for all 39 solvated systems. Comparisons between the experimental and calculated values show the importance of hydrogen bonding on specific rotation.  相似文献   

19.
Optical resolution of racemic 2-(3-chloro-phenyl)-3.4a. 5.6.7.7a-hexahydrocyclopentapyrimidin-4-one with O.O′-dibenzoyl-2R,3R-tartaric acid in an unusual solvent combination, in water-chloroform two phase solvent system was accomplished. During enantiomeric enrichment of the resulted raw base the optically active base can be recovered from the ethanolic mother liquor.  相似文献   

20.
<正>The acidity constants of TAR in different water-organic solvent binary mixtures at 25℃have been determined spectrophotometrically. DATa ANalysis(DATAN) program was used for calculations of the acidity constants and pure spectra of all formed species and their concentration distribution diagram in applied pH interval.Results show that there are a fairly inverse relationship between acidity constants and the mole fraction of the organic solvent in the binary mixtures.Effects of solvent composition on the pK_as and pure spectrum of each component are also discussed.  相似文献   

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