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1.
P. F. Vlad A. Chokyrlan M. D’Ambrosio M. N. Koltsa A. N. Barba K. Edu A. Byryyak A. Nikolescu A. Mari K. Deleanu 《Chemistry of Natural Compounds》2011,47(3):397-403
A new synthesis of 13E-ent-crotonadiol and its 13Z-isomer from 6a-acetoxy-14,15-bis-norlabd-8(17)-en13-one is described. A
mixture of methyl esters of 13E- and 13Z-6a-acetoxylabd-8(17),13-dien-15-oic and 13E- and 13Z-6a-hydroxylabd-8(17),13-dien-15-oic
acids was formed by its reaction with trimethylphosphonoacetate. Mixtures of 13E- and 13Z-6a-hydroxylabd-8(17),13-dien-15-oic
acids were formed by hydrolysis of this mixture. These were separated, methylated, and reduced by LiAlH4 to give the pure 13E- and 13Z-crotonadiols in 64 and 16% yields, respectively. The two known syntheses of crotonadiol from
(+)-larixol were reproduced. It was shown that they produced only 13E-crotonadiol. 相似文献
2.
The stereoselective synthesis of Z-β-siloxyacrylonitriles via base-induced ring cleavage of isoxazole precursors is described. Z-β-siloxyacrylonitriles react with organolithium compounds to give high yields of β-enaminoketones 1. 相似文献
3.
1,3-Dipolar cycloaddition of E-2-arylidene-1-indanones 1a-h and Z-aurones 3a-c with diazomethane provided trans-spiro-1-pyrazolines 2a-h and 4a-c , respectively, as sole products. However, the same cycloaddition of Z-1-thioaurones 5a-f afforded a mixture of Z-α-methyl-1-thioaurones 6a-f and trans-cyclopropane derivatives 7a-f as a result of the spontaneous denitrogenation of the initially formed 1-pyrazolines. Similar reaction of Z-2-arylidene-2,3-dihydro-1H-indol-3-ones 8a,b and diazomethane yielded trans-cyclopropanes 9a,b . Structure and stereochemistry of the compounds synthesized have been elucidated by nmr spectroscopic measurements. 相似文献
4.
Conclusions A simple method was proposed for the synthesis of 8Z-1-dodecenyl acetate and 9Z-1-tetradecenal from 1,1,9-trichloro-1-nonene.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 9, pp. 2131–2132, September, 1981. 相似文献
5.
Robert B. Bates Laurent M. Duguay Robert E. Klenck George R. Kriek Michael S. Tempesta Arthur D. Brewer 《Journal of heterocyclic chemistry》1982,19(4):927-928
2-Ethyl-1,4-benzothiazin-3(4H)-one and bromine react smoothly to give Z-2-(1-bromoethylidine)-2(H)-1,4-benzothiazin-3(4H)-one, which results from a complex bromination-oxidation sequence. The structure of this product was determined by an X-ray study. 相似文献
6.
The arene-olefin meta-photocycloaddition is shown to provide the basis for an effective and general approach to polyquinane natural products as demonstrated by the synthesis of (±)-isocomene (5) in five steps based on Z-2-bromo-2-butene and 2-bromotoluene. 相似文献
7.
G. A. Tolstikov V. N. Odinokov R. I. Galeeva R. S. Bakeeva V. R. Akhunova 《Chemistry of Natural Compounds》1982,18(2):219-224
A new synthesis of 1-acetoxyalk-Z-enes (sex pheromones of insects of the orderLepidoptera) has been developed which is based on the selective ozonolysis of 1-methylcycloocta-1Z-5Z-diene — a cooligomer of isoprene and butadiene. 相似文献
8.
Julia S. Lock Bruce L. May Philip Clements Stephen F. Lincoln Christopher J. Easton 《Journal of inclusion phenomena and macrocyclic chemistry》2004,50(1-2):13-18
E-4-(2-(4- tert - butylphenyl) ethen-1- yl)benzoate, E-1–, photoisomerizes to the Z-1– isomer and vice versa in the free state and in the binary complexes 2·E-1–, 2·Z-1–, 3·E-1– and 3·Z-1– where 2 is the urea-linked cyclodextrin N-(6
A
-deoxy--cyclodextrin-6
A
- yl)-N-(6
A
-deoxy--cyclodextrin-6
A
- yl)urea and 3 is N,N- bis(6
A
-deoxy--cyclodextrin-6
A
- yl)urea. In 2·E-1–and 3·E-1– the stilbene occupies both cyclodextrin (CD) components of 2 and 3, whereas in 2·Z-1– and 3·Z-1– it only occupies one CD component while the other CD component is unoccupied. 4- tert - Butylphenolate, 4–, and its carboxylate, 5–, and sulfonate, 6–, analogues form the ternary complex 2·Z-1–·4– and its analogues and also 3·Z-1–·4– and its analogues. These photoisomerize to 2·E-1–and 3·E-1– and either free 4–, 57– or 6– and thereby function as molecular devices. 相似文献
9.
Z-6-Heneicosen-11-one (1) and Z-1,6-Heneicosen-11-one (2) are the sex pheromones of the Douglas-Fir Tussock moth, ‘Orgyia Pseudo Sugata’, isolated1,2 in 1975 and 1978 respectively. In contrast with other lepidopterous pheromones, which are unsaturated C12-C14 primary alcohols or acetates, these were found to be C21 ketones. The Douglas-Fir Tussock moth is a severe defoliator of the Fir forest; consequently, considerable interest attends the synthesis of these two pheromones. A number of syntheses of these two pheromones have been reported3 amongst which is one of our synthesis using N,N-dimethyl acetone 4 hydrazone as key intermediate. 相似文献
10.
Ali Ramazani Ali Morsali Bijan Ganjeie Ali Reza Kazemizadeh Ebrahim Ahmadi 《Phosphorus, sulfur, and silicon and the related elements》2013,188(11):2439-2442
Abstract Selenourea reacts with dialkyl acetylenedicarboxylates in acetone to form 1:1 adducts, which undergo a cyclization reaction to produce alkyl Z-2-(2-amino-4-oxo-1,3-selenazol-5(4H)-yliden) acetates in fairly good yields. The reaction is completely stereoselective. 相似文献
11.
Heimei Yuki Yoshio Okamoto Yuichi Doi 《Journal of polymer science. Part A, Polymer chemistry》1979,17(7):1911-1921
α-Isobutyl-L -aspartate oligomers, Z-(α-i-Bu-Asp)2n–OEt (n = 1–5), where Z = benzyloxycarbonyl and OEt = ethyl ester, were prepared stepwise, and their conformation in solution was investigated by optical rotation, circular dichroism (CD), and NMR spectroscopy. The oligomers up to hexamer existed only in a disordered form. An ordered structure began to appear at octamer and decamer in chloroform and 2,2,2-trifluoroethanol. The ordered structure was more favorable for N-unprotected oligomers, H-(α-i-Bu-Asp)2n–OEt, in comparison with the corresponding Z-(α-i-Bu-Asp)2n–OEt. The effects of oligomer concentration and temperature on the structure were slightly observed. The most likely ordered structure was a β form caused by intramolecular association. 相似文献
12.
An enantioselective synthesis of E/Z-13,14-dinor-inter-p-phenylene carbacyclin (E/Z-2d) by a new strategy has been realized that holds the prospect of serving as a general route for carba-prostacyclin analogues. The key intermediate in this synthesis is the bicyclic azoene Ts-9, and the key step is the regio- and stereoselective conjugate addition of the chiral arylcopper compound Cu-8d/P-n-Bu3 to the azoene with formation of hydrazone 7d. Enantioselective synthesis of azoene Ts-9 of 95% ee from ketone 4 was accomplished in four and five steps, respectively. Thus, enantioselective deprotonation of bicyclic ketone 4 with chiral base Li-10 and trapping of lithium enolate 11 with ClSiMe3 gave enol ether 12, which was chlorinated with N-chlorosuccinimide (NCS) to afford chloro ketone 13. Alternatively, chloro ketone 13 was also prepared upon chlorination of 11 with NCS. Chloro ketone 13 was converted to chloro hydrazone 14, which upon treatment with a mild base furnished azoene Ts-9. Arylcopper compound 8d of 98% ee was obtained in two steps from alcohol 16, which was prepared by enantioselective reduction of ketone 17 with (-)-diisopinocampheylchloroborane. Carbacyclin derivative E/Z-2d was found to be essentially inactive as an inhibitor of ADP induced human platelet aggregation, having an IC50 of >10 micromol/L. 相似文献
13.
I. A. Aitov V. N. Nesterov Yu. A. Sharanin Yu. T. Strachkov 《Russian Chemical Bulletin》1996,45(2):417-419
The reaction of (4-R-benzoyl)(2-bromopyridinitim) methylides with ethoxyrnethylene-rnalononitrile is stereoselective and affords Z-1-[1-(4-R-benzoyl)-2-ethoxyvinyl]-2-dicyationietliylene-1,2-dihydropyridines. The structure of 1-[1-(4-chlorobenzoyl)-2 ethoxyvinyll-2-dicyanomethylene-1,2-dihydropyridine has been established by X-ray structural study.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 434–436, February, 1996. 相似文献
14.
Photochromic properties of 2-indolylfulgides, namely, Z-3-[1-(1,3-dimethyl-1H-indol-2-yl)ethylidene]-4-isopropylidenetetrahydrofuran-2,5-dione andE-3-isopropylidene-4-(1-methyl-1H-indol-2-ylmethylidene)tetrahydrofuran-2,5-dione, were studied. The quantum yields of their photochemical isomerizations in
toluene and the rate constant of the dark ring-opening in ethanol were determined. The fluorescence spectra of the open and
cyclic forms of 2-indolylfulgides were measured. It was assumed that the excited-stateZ-isomer can be transformed into a cyclic isomer without intermediacy of anE-isomer in the ground state.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1026–1029, June, 2000. 相似文献
15.
天然昆虫性信息素常是一定比例的两个或几个顺、反异构体的混合物。合成顺式烯烃已有许多有效的方法,如用Lindlar或P-2Ni催化剂氢化炔键,这些方法不仅产率高而且产物的纯度也高。本文报道应用HNO_3-NaN_2异构化双键的方法,使易得的顺式烯烃转化为顺、反异构体的混合物,并研究了温度对反应产物顺、反比例的影响。我们选用顺-3-辛烯醇-1(la)及其乙酸酯(lb),顺-9-十四烯醇-1-乙酸酯(2)和顺-11-十四烯醇-1-乙酸酯(3)进行实验。它们在各种温度下用HNO_3-NaNO_2转化可得不同比例的顺、反混合物(表1)。 相似文献
16.
The question concerning the synthesis of the 1,4-dihydro-3(2H)cinnolinone was solved and some new tetracyclic derivatives are described. The structure and the synthesis of the two isomers 2-(2-carbomethoxymethylphenyl)phthalazine-1(2H),4(3H)dione and 1-(2-carbomethoxybenzoyl)-1,2-dihydrocinnolin-3(4H)one are discussed. 相似文献
17.
The synthesis of 3-(1H-imidazol-1-yl)-4H-1-benzopyran-4-ones 2 and of 2-(1H-imidazol-1-yl)-4H-1-benzopyr-an-4-ones 11 are described. The former proceeds through chroman ring closure from 2-(1H-imidazol-1-yl)-2′-hydroxyacetophenones, the latter occurs reacting 3-bromo-4H-1-benzopyran-4-ones with imidazole and represents an example of a new synthesis of 2-heteroarylchromones. Compounds 2 can be easily reduced to the corresponding chromanones and chromanols previously described in Part 1. 相似文献
18.
等摩尔的甲硼烷甲硫醚(H3B·SMe2)与四溴化碳在60℃下反应20h,定量得到一溴硼烷甲硫醚。从链端烯烃、一卤硼烷甲硫醚和2-[7-辛炔-1-氧基]四氢吡喃及其8-溴代衍生物出发,经硼氢化反应和Zweifel的顺-,反-烯烃合成法,立体选择地合成了鳞翅目昆虫性信息素:(Z)-7-十四烯-1-醇乙酸酯9a、(Z)-7-十六烯-1-醇乙酸酯9b、(E)-7-十四烯-1-醇乙酸酯12及其相应的醇13。产物经GC分析和MS、1H及13C NMR数据证实了它们的纯度和几何构型。 相似文献
19.
The triethylamine-promoted self-condensation of several 2-(2-chloro-2-nitroethenyl)phenols gives the so far unknown Z-11-Nitromethylene-11H-benzofuro[3,2-b][1]benzopyrans. 相似文献
20.
Jeongbin Yim Sujeong Kim Gunter Walcher Wolfgang Pfleiderer 《Helvetica chimica acta》1993,76(5):1970-1979
The nonenzymatic synthesis of aurodrosopterin ( 5 ) from 6-acetyl-2-amino-3, 7, 8, 9-tetrahydro-4H-pyrimido-[4,5-b][1,4]diazepin-4-one ( 3 ) and 7,8-dihydrolumazine ( 4 ) at pH 3 (HCl) was performed. The identity of the synthesized compound with the natural eye pigment isolated from drosophila heads was confirmed by thin-layer chromatography on cellulose and by comparisons of the 1H-NMR and UV/VIS spectra. The nonenzymatic synthesis of a neodrosopterin-like red pigment from 3 and 2,4-diamino-7,8-dihydropteridine was also carried out, but its identity could not be established. This pigment, called aminodrosopterin, has an absorption peak at 489 nm, which is very close to that of neodrosopterin. 相似文献