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Thermolysis of η2-benzoyl(phenyl)zirconocene yields the η2-benzophenonzirconocene complex 2, isolated as a dimer. 2 exhibits an ambivalent reactivity pattern. The formation of five-membered metallacycles from 2 and olefinic hydrocarbons possibly proceeds analogous to reactions of “normal” metalolefin π-complexes. However, both reactions with the electron-deficient olefins dimethylfumarate and -maleate and the behavior towards electrophilic and protic reagents as well as aromatic hydrocarbons might be interpreted in terms of a metallaoxirane-character of 2. 相似文献
4.
Reaction of (η-C5H4CH3)2TiCl2 with CH3OCH2MgCl yielded (η-C5H4-CH3)2Ti(Cl)CH2OCH3 (2a). Complex 2a crystallizes in space group P21/n with cell constants a 8.162(1), b 11.004(2), c 15.297(2) Å, β 96.40(1)°. In contrast to the three-membered metallacyclic zirconium compound of analogous composition (η-C5H5)2Zr(Cl)CH2OCH3 (1), the titanocenyl-substituted ether 2a has an open-chain (η1-O“-outside”) type structure. 相似文献
5.
Summary. GABA-receptor-ligands are still very interesting in drug-development. Usually benzodiazepines are used in the treatment but they
have serious side-effects. Thus, a recently synthesized quioxaline derivative which showed reduced side-effects in an animal
model was used as a model-substance. The cyclus was modified to optimize the pharmacological profile. Accordingly, a series
of imidazo-thieno-thiazines was synthesized starting from 5-acetyl-2-chloro-3-nitrothiophene to yield 6-ethyl-2,3-dihydro-1H-thieno[2,3-b][1,4]thiazine-2-one. Reaction with potassium tert-butoxide and diethylchlorophosphate gave an intermediate, which resulted in the desired ring system after adding the corresponding
isocyanides and potassium tert-butoxide.
Corresponding author. E-mail: thomas.erker@univie.ac.at
Received August 6, 2002; accepted August 13, 2002 相似文献
6.
Hill M Erker G Kehr G Fröhlich R Kataeva O 《Journal of the American Chemical Society》2004,126(35):11046-11057
The dimethylsilanediyl-bridged ansa-zirconocene dichloride 1, that contains a pendent allyl substituent at a Cp-ring, adds HB(C(6)F(5))(2) to the vinyl group to yield the bifunctional zirconocene/borane complex 2. Substituted benzimidazoles were added to the strongly electrophilic borane moiety as protective groups, which allowed subsequent chloride versus -CH(2)SiMe(3) exchange at zirconium to take place by treatment with the respective alkyllithium reagent. Alternatively, the introduction of active sigma-ligands at zirconium is carried out first, followed by the hydroboration reaction. This route was followed for the synthesis of the diphenyl-ansa-zirconocene/borane complex 12. Complex 12 reacts slowly in solution by intramolecular electrophilic attack of the borane at its adjacent Cp-ring, followed by deprotonation using a [Zr]-Ph group to yield the zwitterionic complex 14 featuring a borata-tetrahydroindenyl moiety as part of the ansa-metallocene framework. Complex 14 was characterized by X-ray diffraction. It adds PMe(3) at zirconium to yield 15. Thermolysis of 12 with excess PMe(3) leads to the formation of the (aryne)zirconocene complex 18, which is stabilized by PMe(3) coordination to zirconium and PMe(3) addition to boron. N-Methylbenzimidazole adds to the -B(C(6)F(5))(2) unit of 12 to give the 1:1 adduct 19. Thermolysis of 19 at 80 degrees C in benzene solution in the presence of one additional equivalent of N-methylbenzimidazole results in deprotonation of the substrate to yield the sigma-N-methylbenzimidazolyl zirconium complex 20 (as a mixture of two diastereoisomers). An additional N-methylbenzimidazole ligand is bonded to the B(C(6)F(5))(2) unit in this product. 相似文献
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Thomas Erker 《Journal of heterocyclic chemistry》1993,30(3):807-809
Thieno-anellated compounds analogous to Clobazam (1) [2] and the nootropic drugs 2 and 3 [3] were synthesized. Thus, nucleophilic substitution on halogenated nitrothiophene derivatives with aniline and reaction with ethyl malonyl chloride gave after cyclisation the thieno[2,3-b]diazepinedione derivatives 7 and 14 . These compounds were methylated to give the thieno-anellated heterocycles 8 and 9 . 相似文献