21663-61-6Relevant articles and documents
Studies on some mono- and di-substitution reactions with cyclopentadienyliron complexes of o-, m- and p-dichlorobenzenes
Lee, C. C.,Zhang, C. H.,Abd-El-Aziz, A. S.,Piorko, A.,Sutherland, R. G.
, p. 217 - 230 (1989)
Reaction of the cyclopentadienyliron (CpFe) complex of o-, m- or p-dichlorobenzene (Ia, Ib or Ic, respectively) with an excess of n-butylamine gave only monosubstitution of one of the two chloro groups, while a similar reaction carried out in the presence of some added HOAc resulted in disubstitution of both chloro groups.On the other hand, in the reaction of Ia, Ib or Ic with one equivalent or with an excess of pyrrolidine, respectively, mono- or disubstitution took place.These observations support the previous suggestion that, under the basic conditions of the reaction, deprotonation of the monosubstitution product from a reaction with a primary amine would render the second chloro group incapable of undergoing another nucleophilic substitution, while for a reaction with a secondary amine, there could be no deprotonation with the monosubstitution product, thus allowing disubstitution to occur.When Ia, Ib or Ic are reported with an excess of NaCN in DMF for up to 4 days, only monosubstitution was observed, a pure product being obtained with Ia, while with Ib or Ic, the product was contaminated with a large amount of starting material.When the same reaction of Ia, Ib or Ic with NaCN was carried out for 30 min and then worked up without any added aqueous NH4PF6, cyclohexadienyl complexes from the nucleophilic addition of a cyanide ion were obtained.Under similar reaction conditions but with the reaction time extended for 2 days, Ia could also give rise to products derived from monosubstitution and cyanide addition.Mechanistic implications of these results are discussed.
Synthesis of aryl dihydrothiazol acyl shikonin ester derivatives as anticancer agents through microtubule stabilization
Lin, Hong-Yan,Li, Zi-Kang,Bai, Li-Fei,Baloch, Shahla Karim,Wang, Fang,Qiu, Han-Yue,Wang, Xue,Qi, Jin-Liang,Yang, Raong-Wu,Wang, Xiao-Ming,Yang, Yong-Hua
, p. 93 - 106 (2015/06/16)
The high incidence of cancer and the side effects of traditional anticancer drugs motivate the search for new and more effective anticancer drugs. In this study, we synthesized 17 kinds of aryl dihydrothiazol acyl shikonin ester derivatives and evaluated their anticancer activity through MTT assay. Among them, C13 showed better antiproliferation activity with IC50 = 3.14 ± 0.21 μM against HeLa cells than shikonin (IC50 = 5.75 ± 0.47 μM). We then performed PI staining assay, cell cycle distribution, and cell apoptosis analysis for C13 and found that it can cause cell arrest in G2/M phase, which leads to cell apoptosis. This derivative can also reduce the adhesive ability of HeLa cells. Docking simulation and confocal microscopy assay results further indicated that C13 could bind well to the tubulin at paclitaxel binding site, leading to tubulin polymerization and mitotic disruption.
Ammoxidation of 2,6-dichloro toluene - From first trials to pilot plant studies
Martin,Kalevaru,Smejkal
scheme or table, p. 275 - 279 (2011/01/04)
The scaling-up of the gas phase catalytic ammoxidation of 2,6-dichloro toluene (DCT) to 2,6-dichloro benzonitrile (DCBN) over a promoted vanadium phosphate (VPO) catalyst from first lab-scale experiments to pilot plant runs is reported. First experiments in a row of conversions of isomeric dichloro toluenes using simple, non-promoted VPO catalysts only show poor yield and selectivity. In particular, DCT ammoxidation is hindered due to bulky chlorine substituents probably preventing a sufficient interaction of the methyl group and lattice oxygen and/or N-containing surface species. Improved synthesis of VPO catalyst with the addition of promoters and γ-alumina or titania leads to significant increase in DCT conversion and DCBN yield. A Cr containing vanadyl pyrophosphate catalyst admixed with titania (anatase) showed conversion up to 97% with DCBN yields of ca. 80%. The same catalyst was also used for pilot plant runs, usually in the form of 5 mm × 3.5 mm shaped tablets that were prepared from a larger batch of solid synthesis. The scaling-up of the process using 100 ml of catalyst was investigated both by catalytic experiments and reactor simulations. The results showed that the temperature control will be crucial in scaling-up. Validation of simulation results with that of experimental results was also checked and a good agreement between measured and simulated results is observed.
