Possible conformations and relative stability of the 7-membered ring in 1α,5β,6,7α(H)-and 1β,5α,6,7α(H)-guai-11(13)-en-6,12-olides

Stereoisomers of 1,5,6,7(H)- and 1,5,6,7(H)-guai-11(13)-en-6,12-olides are calculated using molecular mechanics. The possibility of forming various conformations in the 7-membered ring is examined as a function of the fusion to the 5-membered C-ring. The effect of the methyl orientation on the conformation of the 7-membered ring and the relative stability of the conformers are discussed.Insitute of Phytochemistry, Karaganda, fax (3212)-43-37-73. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 54–56, January–February, 2000.     

微波辐射下无催化剂一锅法合成N-甲基十氢吖啶-1,8-二酮化合物

为了研究从简单易得的原料在无催化剂的条件下一锅法合成N-甲基十氢吖啶-1,8-二酮化合物，我们以各类醛（脂肪醛、芳香醛、二醛）、达咪酮或1,3-环己二酮和甲胺为原料，以乙二醇或水为溶剂，经微波辐射，一步反应得到了一系列N-甲基十氢吖啶-1,8-二酮化合物。反应时间从传统热反应的4-5小时缩短至2-10分钟，产率较高（56-95%），并且不需要使用催化剂。该反应后处理方便，只需要简单洗涤，环境友好，为合成此类化合物提供了一种简便、有效的合成方法。该方法不仅适用于一元脂肪醛、芳香醛，还适用于芳香二醛，因此可以合成含有一个或两个十氢吖啶结构单元的杂环化合物。     

Synthese und Geruch von Tricyclo[6.2.2.02, 7]dodecan-Derivaten

Summary The acetale-ketone9 was synthesized as precursor for the preparation of -santalol derivatives posessing a bicyclo[2.2.2]octane nucleus. After methylenation of the keto-group the subsequent acidic hydrolysis of the acetal leads via a Prins reaction of the liberated aldehyde with the methylene group to tricyclo[6.2.2.0^{2, 7}]dodecane derivatives. Their olfactory properties are described.

     

Synthesis and Antibacterial Activities of 4-Amino-3-(1-aryl-5-methyl-1,2,3-triazol-4-yl)-5-mercapto-1,2,4-triazoles/2-Amino-5-(1-aryl-5-methyl-1,2,3-triazol-4-yl)-1,3,4-thiadiazoles and Their Derivatives

ＩｎｔｒｏｄｕｃｔｉｏｎＳｃｈｉｆｆｂａｓｅｓ ,ａｍｉｄｅｓ ,ｉｍｉｄａｚｏｌｏ[2 ,1 ｂ] 1,3,4 ｔｈｉａｄｉａｚｏｌｅｓ,ａｎｄ 7Ｈ ｓ ｔｒｉａｚｏｌｏ[3,4 ｂ] 1,3,4 ｔｈｉａｄｉ ａｚｉｎｅｓｃｏｎｔａｉｎｉｎｇｈｅｔｅｒｏｃｙｃｌｅｓｈａｖｅｂｅｅｎａｔｔｒａｃｔｉｎｇｍｕｃｈａｔｔｅｎｔｉｏｎａｓｐｏｔｅｎｔｉａｌａｎｔｉｆｕｎｇａｌａｇｅｎｔｓ .1 51,2 ,3 ｔｒｉａ ｚｏｌｅ ,6 7ｍｅｒｃａｐｔｏ 1,2 ,4 ｔｒｉａｚｏｌｅ ,81,3,4 ｔｈｉａｄｉａｚｏｌｅ9 10ａｎｄｔｈｅｉｒｒｅｌａｔｅｄｃｏ…     

铁(Ⅲ)-4,7-二甲基-1,10-邻菲啰啉配合物的光还原研究及应用

实验发现,在散射光中铁(Ⅲ)-4 7-二甲基-1,10-邻菲啰啉配合物能发生显著的光还原反应,在溶液酸度为pH 3.0～5.0范围内,加入EDTA可阻止上述反应的进行。此法用于测铁矿中铁的价态比,结果令人满意。     

The regioselectivity of the formation of 2-pyrazolylthiazoles and their precursors from the reaction of 2-hydrazinothiazoles with 4,4,4-trifluoro-1-hetaryl-1,3-butanediones

Reaction of 2-hydrazinothiazoles 1 with 1-thienyl- and 1-furyl-1,3-butanediones 2a,b in methanol in the presence of hydrochloric acid mainly leads to a mixture of pyrazoles 3 and pyrazolines 4 or pyrazoles 3 and 5 in strong acidic conditions. Isomeric hydrazones 6 and pyrazolines 4 were formed and isolated in these reactions in the absence of hydrochloric acid. It has been shown that the regioselectivity in the reaction of diketones 2 with hydrazine 1 is governed by both the concentration of acid and the nature of substituents in the 1,3-diketones 2. Cyclization of hydrazones 6 is shown to occur under milder conditions than dehydration for pyrazolines 4. The new heterocyclic compounds were prepared and fully characterized by NMR spectra and by X-ray analysis for 3c.     

双环[3.3.0]-3,7-辛二烯-2,6-二酮晶体的分子结构

利用 Enraf-Nonius CAD4四圆单晶衍射仪测定了双环[3.3.0]-3,7-辛二烯-2,6-二酮(2)的单晶结构,晶体属三斜晶系,空间群为 PI,晶胞参数为:a=6.596(2)(?),b=7.414(1)(?),c=7.359(1)(?),α=106.64(1)°,β=100.17(1)°,γ=98.44(1)°,ν=331.9((?)~3),Ζ=2。用直接法得到分子的粗结构。对1013个可观察反射点用全矩阵最小二乘法修正,最后得R=0.060,结构测定的结果证实:两个五员环自成一个平面,两平面间夹角为117.3°。     

钇与2-(4′-氯-2′-膦酰基一苯偶氮)-7-(2′,6′-二溴-4′-氯-一苯偶氮)-1,8-二羟基-3,6-萘二磺酸配位反应动力学研究和机理探讨

用停流分光光度法获得反应的经验速率方程为R=k[y(H_2O~n)~(3+)]·[H_6R]·[H~+]~(-1)。参考Eigen-Tamm机理和测得的动力学参数,拟出了反应的可能机理。     

Structural and photocatalytic properties of the new solid photocatalyst In2BiTaO7

In₂BiTaO₇ was synthesized using the solid-state reaction method and its photocatalytic properties were investigated. The results of powder X-ray diffraction (XRD) indicated that the compound crystallizes in the pyrochlore-type structure, cubic system with space group Fd-3m. The lattice parameter is 10.6972(1) ?. In addition, the compound shows strong optical absorption in the visible region (λ > 420 nm) and the band gap of In₂BiTaO₇ was estimated to be about 2.47 eV. For the photocatalytic reaction, H₂ or O₂ evolution was observed from CH₃OH/H₂O or AgNO₃ solution respectively with In₂BiTaO₇ as the photocatalyst under visible light irradiation, indicating that In₂BiTaO₇ is responsive to visible light for splitting water. Furthermore, the catalyst remained photoactive in the wavelength range up to 510 nm. Photocatalytic degradation of methylene blue (MB) dye over the compound was further investigated under visible light irradiation. The results showed that complete removal of aqueous MB could be achieved after irradiation for 135 min over In₂BiTaO₇. Furthermore, under visible light irradiation In₂BiTaO₇ showed markedly higher catalytic activity compared to P-25 for MB photocatalytic degradation.     

光学纯7,7′-二取代联二萘酚催化乙基锌对醛的对映选择性加成

合成了一类光学纯的7,7′-二取代联二萘酚, 并将其用在乙基锌对醛的对映选择性加成, 以54%～88%的产率和最高88%的对映选择性得到了光学活性的1-苯基-1-丙醇.