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1.
采用图论方法对单一种取代基取代的金刚烷和烷基取代的金刚烷构型、手性构型和非手性构型数进行了计算,结果分别以母函数形式和表格形式给出。 相似文献
2.
Calculation of the rotational barriers for the trans- and cis-forms of 2-(p-methoxy)-1-acetyl-pyrroline are presented in this paper. It is found that thetrans-isomer is slightly more favourable energetically, while the rotations of the cis-form are highly impeded. Hence the relevant rotations are in thetrans-form which stabilizes its energy by forming a weak inner proton bond between the carbonyl oxygen and the pyrroline ring. The acetyl rotational barrier is of the order of 8 kcal, which is well in accord with experimental data reported in the literature for other acetyl-amide derivatives.[/p]Work supported in part by Instituto Mexicano del Petróleo. 相似文献
3.
Ricardo Castanedo 《Tetrahedron letters》2006,47(6):973-976
The Birch reduction-dialkylation reaction has been studied with different aromatic carboxylic acids and primary and secondary bromides. From these results it can be concluded that it is a reasonably general reaction. However, we found important exceptions with the primary bromides: allyl bromide, β-phenethyl bromide, and 5-bromo-2-methyl-2-pentene. The unusual behavior of allyl bromide is briefly discussed. 相似文献
4.
提出了一种动力学李代数方法来研究取代苯体系的非线性光学性质. 对于给定的PPP模型(Pariser-Parr-Pople)哈密顿量, 生成了一个动力学李代数. 依据这些代数元构造出演化算子作为群参数的函数, 通过求解一组非线性微分方程能够得到这些群参数. 再按照统计力学中的密度算子公式给出取代苯分子体系偶极矩的统计平均值. 于是导出二阶极化率的表达式. 与其他量子力学计算结果比较, 表明这种动力学李代数方法在预言有机共轭分子的非线性光学性质上同样有用. 相似文献
5.
Marijan Kočevar Branko Stanovnik Miha Tišler 《Monatshefte für Chemie / Chemical Monthly》1988,119(5):597-603
Pyrido[2,3:3,4]pyrazolo[5,1-c][1,2,4]benzotriazin-4(1H)ones were transformed via their oximes in aSemmler-Wolff aromatization process in the tetracyclic heteroaromatic amines4 or bySchmidt reaction into a mixture of the same amine4 and a ring enlarged lactam3. Syntheses of some halo pyrazolo[3,4-b]pyridines and a photochemical transformation of 3-azidopyrazolo[3,4-b]pyridine are also described.
Über dieSemmler-Wolff- undSchmidt-Reaktion einiger Pyrido[2,3:3,4]pyrazolo[5,1-c][1,2,4]benzotriazine
Zusammenfassung Pyrido[23:3,4]pyrazolo[5,1-c][1,2,4]benzotriazin-4(1H)one werden über Oxime in einerSemmler-Wolff-Reaktion in die tetracyklischen aromatischen Amine4 umgewandelt. In einerSchmidt-Reaktion wurden dieselben Ketone in ein Gemisch aus Amin4 und Lactam3 übergeführt. Synthesen von halogensubstituierten Pyrazolo[3,4-b]pyridinen und photochemische Umwandlung von 3-Azidopyrazolo[3,4-b]pyridin werden beschrieben.相似文献
6.
Taterao M. Potewar 《Tetrahedron letters》2007,48(10):1721-1724
An efficient synthesis leading directly to 1-substituted-1H-1,2,3,4-tetrazoles from easily available amines and sodium azide in stoichiometric proportions using a room-temperature ionic liquid, namely, 1-n-butylimidazolium tetrafluoroborate in excellent yields is described. The inherent Brønsted acidity and high polarity of the IL results in a significant enhancement in the reaction rate. 相似文献
7.
Summary Two new cyclodextrin (CD) derivatives, heptakis{2,6-di-O-pentyl-3-O-[3′-(2″-chloro-4″,5″-dioxylmethene)-phenyl-5′-iso-oxazolylmethyl]}-β-CD
(CD I) and heptakis{2,6-di-O-methyl-3-O-[3′-(2″-chloro)-phenyl-5′-iso-oxazolylmethyl]}-β-CD (CD II) were synthesized and coated
on fused-silica capillary columns. Their chromatographic characteristics, including column efficiency, polarity, selectivity
and phase transition were studied and compared with similar β-CD stationary phases. It was found that the heterocycle group
has a significant effect on the selectivity of the CD stationary phases. Both stationary phases can be successfully used to
separate many di- and trisubstituted benzene positional isomers and show stronger separation ability in separating low-polarity
benzene positional isomers than other β-CD stationary phases. 相似文献
8.
Yusuf M. Al-Hiari Ali M. Qaisi Mustafa M. El-Abadelah Wolfgang Voelter 《Monatshefte für Chemie / Chemical Monthly》2006,137(2):243-248
Summary. A synthesis of 3-(4-methoxycarbonyl-2,6-dinitrophenyl)indole, its 2,6-diamino analog, and 3-(2-amino-4-trifluoromethyl-6-nitrophenyl)indole
is described. 4-(Trifluoromethyl)phenyl derivatives exhibit higher antibacterial potency than the former 4-(methoxycarbonyl)phenyl
homologs, while 3-(4-trifluoromethyl-2-nitrophenyl)indole was the most active agent in the series, with MIC ≈ 7 μg/cm3 against E. coli and S. aureus. 相似文献
9.
A facile seven-step sequence was developed from 4′-bromopropiophenone, utilizing a Suzuki-type coupling with an alkene, to give several novel 5-substituted pyrazole derivatives in overall yields of 11-31%. They are potent CB1 antagonists and have binding affinities similar to SR 141716A. Like SR 141716A, they may prove to be clinically useful for the treatment of obesity. 相似文献
10.
Three new thiosemicarbazides (1 a-c ) were prepared from N-[4-phenyl-5-(2-thienyl)-1,2,4-triazol-3-yl]mercaptoacetohydrazide. Reaction of (1 a-c) with the appropriate phenacyl bromide afforded thiazoline derivatives (2 a-i) whereas their reaction with chloroacetic acid or maleic anhydride gave the corresponding thiazolidine derivatives (3 a,b) and (4 a,b) . Cyclodesulfurization of (1 a-c) with DCCD in toluene yielded 5-substituted-amino-1,3,4-oxadiazoles (5 a,b) , while their dehydration with PPA gave the corresponding 5-substituted-amino-1,3,4-thiadiazoles (6 a-c) . Six representative compounds were tested for their in-vitro antimicrobial activity against some pathogenic microorganisms, some of them were proved to be active. 相似文献