卤代-2-(3-甲基-5-取代-4H-1,2,4-三唑-4-基)-苯甲酸的合成

邻氮基苯甲酸;缩合反应;卤代-2-(3-甲基-5-取代-4H-1;2;4-三唑-4-基)-苯甲酸的合成     

2-氨基-6-氟-9-(4-羟基-3-羟甲基丁基)嘌呤的合成

报道了2-氨基-6-氟-9-(4-羟基-3-羟甲基丁基)嘌呤(1)的合成, 通过对起始原料2-氨基-6-氯-9-(4-乙酰氧基-3-乙酰氧甲基丁基)嘌呤(2)水解脱去乙酰基, 得到2-氨基-6-氯-9-(4-羟基-3-羟甲基丁基)嘌呤(3). 化合物3与三甲胺乙醇溶液在混合溶剂[V(THF)∶V(DMF)＝3∶1]中反应得到相应的氯化铵盐4, 然后与KF在DMF溶剂中反应, 得到化合物1. 产品经UV-vis, IR, ¹H NMR, ¹⁹F NMR和MS表征. 考察了反应温度、氟化试剂等因素对氟化反应的影响, 为6位含氟的嘌呤核苷类化合物的合成提供了一种直接、简易的新方法.     

1,5-二-(3-硝基苯基)-1,4-戊二烯-3-酮的超声合成

1;5-二-(3-硝基苯基)-1;4-戊二烯-3-酮的超声合成;二-（硝基苯基）-戊二烯-酮;合成;超声;催化     

6-亚甲基-17α-乙酰氧基-18-甲基-19-失碳-孕甾-4-烯-3,20-二酮的合成新方法研究

报道了16-亚甲基-17α-乙酰氧基-18-甲基-19-失碳-孕甾-4-烯-3,20-二酮的新合成方法. 以左旋18-甲基炔诺酮为原料, 通过脱水、氧化、环合、热解、环氧化、开环氧环、水解七步反应合成了目标化合物, 总收率20.0%. 其中化合物12, 13, 14, 15, 16尚未见文献报道.     

微波作用下1-苯基-5-[5-(芳胺羰基甲硫基)-4-苯基-1,2,4-三唑-3-甲硫基]四唑的合成及生物活性

采用微波和相转移催化法通过1-苯基-5-(4-苯基-1,2,4-三唑-5-巯基-3-甲硫基)四唑(2)与2-氯乙酰芳胺(3)反应高效、快速地合成了10种尚未见文献报道的1-苯基-5-[5-(芳胺羰基甲硫基)-4-苯基-1,2,4-三唑-3-甲硫基]四唑. 其结构经 IR, ¹H NMR, ¹³C NMR 和元素分析表征. 生物活性实验结果表明, 该类化合物在较低浓度下部分化合物对小麦芽有很好的促进作用.     

无催化剂条件下2-氨基-3-氰基-4-芳基-7,7-二甲基-5-氧代-5,6,7,8-四氢-4H-苯并吡喃的合成

芳亚苄基丙二腈;二甲基环己二酮;无催化剂条件下2-氨基-3-氰基-4-芳基-7;7-二甲基-5-氧代-5;6;7;8-四氢-4H-苯并吡喃的合成     

2-氨基-5-(2-氯吡啶-4-基)-1,3,4-噻二唑衍生物的合成及生物活性

酰胺;2-氨基-5-(2-氯吡啶-4-基)-1;3;4-噻二唑衍生物的合成及生物活性     

2-乙氧羰基-3-溴-4-甲基-5-甲酰基-吡咯的合成

2-乙氧羰基-3-溴-4-甲基-5-甲酰基-吡咯的合成;乙氧羰基二甲基吡咯;乙氧羰基溴二甲基吡咯;乙氧羰基溴甲基甲酰基吡咯     

3-巯基-5-芳香基-4-芳基亚甲胺基-4H-1,2,4-三唑的合成及波谱研究

5-取代-4-氨基-3-巯基-1,2,4-三唑与芳香醛在弱酸性乙醇溶液中反应, 合成了一系列3-巯基-5-芳香基-4-芳基亚甲胺基-4H-1,2,4-三唑(3a～3d)及水溶性的3-巯基-5-(D-葡萄糖-1-基)-4-(4-氯代苯基)亚甲胺基-4H-1,2,4-三唑(3e)新化合物. 以元素分析, IR, NMR, MS实验技术对其结构进行了表征, 并研究其NMR波谱特征.     

4-甲基-苯磺酸-2-氧-2-[3-(5-芳基-[1,3,4]噁二唑-2-基)-硫脲]-乙基酯的合成及生物活性研究

合成了12个未见文献报道的4-甲基-苯磺酸2-氧-2-[3-(5-芳基-[1,3,4]噁二唑-2-基)-硫脲]-乙基酯, 其结构经元素分析、¹H NMR和IR确证. 初步活性测试结果表明: 部分化合物有较好的杀菌活性.     

Investigation of the sorption of water vapor on cation-substituted vermiculite. 2. Thermodynamic description of sorption equilibria

The changes in the thermodynamic functions of the sorbents were calculated for the first time from measurements of the deformations of vermiculite during the sorption of water vapor and adsorption-calorimetric data.Institute of Physical Chemistry, Russian Academy of Sciences, 117915 Moscow. Institute of Colloid Chemistry and the Chemistry of Water, Academy of Sciences of the Ukraine, 252180 Kiev. Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 6, pp. 1270–1275, June, 1992.     

Thermodynamics of ionization of water over wide ranges of temperature and pressure

We have summarized results of many experimental investigations of the thermodynamics of ionization of H₂O(liq.) from 0–300°C and from 1.0 atm to nearly 8000 atm. Results of these investigations (equilibrium constants, enthalpies of ionization, heat capacities, partial molal volumes, and compressibilities) have been used for a number of thermodynamic calculations. It is particularly noteworthy that it is possible to use thermal data from 0–145°C with an equilibrium constant for 25°C in calculating reasonably accurate equilibrium constants for temperatures as high as 300°C. Similarly, it is possible to use volumetric data that refer to 1.0 atm in calculating useful equilibrium constants that apply for pressures as high as 2000 atm.Much of the work reported here was done while the author was on leave at the University of Lethbridge.     

Thermochemical study of aliphatic and phenyl-substituted geminal diacetates

The standard enthalpies of combustion _c H ^o of aliphatic diacetates1 and aromatic diacetates2 were measured calorimetrically. The enthalpies of vaporization _vap H ^o or sublimation _sub H ^o of1 and2 were obtained from the temperature function of the vapor pressure measured in a flow system. From _f H ^o(g) of1 and2 new values of group increments for the estimation of standard enthalpies of formation of these classes of compounds were derived. The geminal interaction energy between the geminal acyloxy groups shows no anomeric stabilization.Geminal Substituent Effects, Part 12, for part 11 see Ref. 7.     

Thermochemistry of aqueous solutions of alkylated nucleic acid bases. VIII. Enthalpies of hydration of 6-alkyluracils

Enthalpies of solution in water H _sol ^o and enthalpies of sublimation H _sub ^o were determined for a number of crystalline derivatives of uracil: 1,6-dimethyluracil (m ₂ ^1,6 Ura), 1,3,6-trimethyluracil (m ₃ ^1,3,6 Ura), 6-ethyl-1,3-dimethyluracil (e⁶m ₂ ^1,3 Ura), 6-propyl-1,3-dimethyluracil (pr⁶m ₂ ^1,3 Ura) and 6-butyl-1,3-dimethyluracil (but⁶m ₂ ^1,3 Ura). Standard enthalpies of hydration H _hydr ^o and standard enthalpies of interaction H _int ^o of the solutes with their hydration shells were calculated. The data obtained show that dependence of H _int ^o on the number of-CH₂- groups of n-alkyl chain added upon substitution of diketopyrimidine ring is nonlinear. This finding is discussed in connection with results of X-ray diffraction structure determinations for the crystalline compounds.     

STUDIES ON THE REACTIVITY PATTERNS OF HETEROCYCLICS IN AQUEOUS DMSO‐INTERACTION BETWEEN POSITIVE END OF SULFOXIDE DIPOLE AND LONE PAIR ON RING NITROGEN IN PYRIDINE DERIVATIVES

Abstract

The signals for the α, β, and γ protons of pyridine exhibit a downfield shift in DMSO-d₆, compared to CCl₄ as solvent, the order being γ > β > α. This is attributed to an interaction between the positive end of the DMSO dipole and the lone pair of electrons on the ring nitrogen. This effect is also reflected in the faster rate of alkaline hydrolysis of ethyl isonicotinate over ethyl nicotinate and ethyl picolinate in aqueous DMSO relative to aqueous ethanol. Similar solvent effects are also observed in the pmr spectrum of pyrazine.     

Protonation of leucoemeraldine in the solid state and in solution

The protonation of leucoemeraldine in power form and in N-methylpyrrolidinone (NMP) solution by HCIO₄ and HBF₄ has been studied by x-ray photoelectron spectroscopy (XPS), infrared (IR), and ultraviolet (UV)-visible absorption spectroscopy. In powder form, less than 25% of the amine nitrogens can be protonated in the absence of oxygen. The effects of oxygen on the degree of protonation and the distribution of amine and imine units upon deprotonation of the salt are investigated. The degree of protonation in leuccemeraldine can be increased to about 50% with 3 M HCIO₄, similar to that achievable with emeraldine base in powder form. In NMP solution, leucoemeraldine is easily oxidized by dissolved oxygen. Protonation of both leucoemeraldine and emeraldine base in NMP solutions results in metastable species which gradually undergo deprotonation. The resulting products are affected by the O₂ content of the solutions. © 1993 John Wiley & Sons, Inc.     

Thermodynamics of lonization of aqueous lodic acid,an “almost-strong” electrolyte

We have made calorimetric measurements of enthalpies of dilution of aqueous iodic acid and have used these results for evaluation of the standard enthalpy of ionization of HIO₃(aq.). We have also made calorimetric measurements of enthalpies of addition of perchloric acid solution to aqueous solutions of KIO₃, KNO₃, NaIO₃, and NaNO₃ and have used these results to obtain further values for the standard enthalpy of ionization of HIO₃(aq.). On the basis of all these results, we have selected H^o=–660±125 cal-mole^–1 as the best available standard enthalpy of ionization of HIO₃(aq.) at 298.15°K, compared to the previously accepted –2400 cal-mole^–1. Using the best available K=0.157 for ionization, we also obtain G^o=1097 cal-mole^–1 and S^o=–5.9 cal-^oK^–1-mole^–1 for ionization of HIO₃(aq) at 298.15°K.On study leave from Department of Inorganic and Analytical Chemistry, LaTrobe University, Bundoora, Victoria, 3083, Australia, to University of Lethbridge.On study leave from Department of Chemistry, University of Wollongong, Wollongong, N.S.W. 2500, Australia, to University of Lethbridge.     

Relation between characteristic adsorption energy and internal pressure in the theory of volume filling of micropores

An equation for the internal pressure acting on an adsorbate in micropores was obtained on the basis of the assumption that the chemical potential of an adsorbate in micropores is equal to that in an equilibrium gas phase and using the Dubinin-Radushkevich equation. The empirical relation between the characteristic adsorption energy and the half width of pores was expressed in terms of internal pressure and diameter of adsorbate molecules. The two-dimensional pressure was calculated for micropores with plane-parallel walls, where the width of a micropore coincides with the diameter of an adsorbate molecule. The results obtained were compared with the two-dimensional pressure of a monolayer on a free planar surface for an adsorbate and adsorbent of the same nature.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1928–1930, October, 1995.     

钾明矾溶液水解度计算公式

根据盐类水解关系式和水的离子积计算公式,建立了计算盐类水解度和水解产物离解常数的完全方程式。计算值同实验值比较,钾明矾溶液水解度平均偏差为0.6％,离解常数pK_b=11.6±0.1,水的离子积pK_w平均偏差小于0.06,从而改进了苏联的计算公式。     

计量数比规则与等物质的量规则的比较

指出了计量数比规则存在的缺陷:不利于贯彻有关物质的量及其单位摩尔的SI规定,不能继承当量定律的数据资料,不能表示反应的性质,不能正确表达水硬度、碱度、树脂交换容量及电解定律,缺乏科学的导出过程及计量关系表达式,计算过程繁杂。而等物质的量规则继承和发展了当量定律,使整个滴定分析计算简单规范。