19060-10-7Relevant academic research and scientific papers
Pd(II)-catalyzed acetalization of terminal olefins with electron-withdrawing groups in supercritical carbon dioxide: selective control and mechanism
Wang, Zhao-Yang,Jiang, Huan-Feng,Ouyang, Xiao-Yue,Qi, Chao-Rong,Yang, Shao-Rong
, p. 9846 - 9854 (2007/10/03)
Pd(II)-catalyzed acetalization of terminal olefins with electron-withdrawing groups was carried out smoothly in supercritical carbon dioxide under oxygen atmosphere when polystyrene-supported benzoquinone (PS-BQ) or CuII (CuI) chloride was employed as cocatalyst. The higher selectivity was achieved, without any chlorinated by-product detected, when using PS-BQ instead of CuII (or CuI) chloride. PS-BQ could be recycled with excellent catalytic activity remaining after each simple filtration. Chlorine ion was demonstrated to be a promoter. The different acetalization mechanisms were revealed by the subtle relationship of chlorine ion and benzoquinone (BQ) to the catalytic activity of PdCl2/PS-BQ, PdII-CuCl2 or Pd(OAc)2/PS-BQ.
Synthesis and cytotoxicity studies of new analogues of polyamines
Badolo, Lassina,Gelbcke,Dubois,Hanocq
, p. 15 - 19 (2007/10/03)
In order to regulate simultaneously the biosynthesis and the transport of natural polyamines, the synthesis of a series of N-methylated analogues of N,N'-Bis(benzyl)-alkanediamines (propanediamine and butanediamine) was achieved and the cytotoxicity of these compounds on the P388D1 cell line was determined. Experiments were conducted in a growth culture medium 20 μM of 2-mercaptoethanol or 0.1 mM of aminoguanidine. Their cytotoxic effects were compared to those obtained under the same conditions with natural polyamines known as toxic compounds at high concentrations. The IC50 of each compound was found very similar for all experimental conditions (IC50 ~150 μM) at the opposite of spermidine and spermine which were less toxic (IC50 >500 μM) when cells were grown in the presence of aminoguanidine (a specific inhibitor of fetal calf serum's PAO). THe DL-difluoromethylornithine (DEMO) and MDL 72527DA, two well known inhibitors of ornithine decarboxylase (ODC) and Polyamine Oxidase (PAO) respectively, had no toxicity on the P388D1 cells compared to our compounds. Our most toxic compound was N1,N4-Bis(benzyl)-N1,N4-bis(methyl)-1,4-butanediamine (6) with an IC50 of 127 ± 3 μM (in culture medium alone). The synthesis of the β-aminothioether derivative of N-benzylputrescine (11) and the β-aminothiol derivative of N-benzylspermidine (13) were also related. The Compound 11 was tested against the P388D1 cells, and did not show any cytotoxic effect. The N-methyl derivatives should give the advantage to be used at low concentrations than those used to test the DFMO.
Difunctional and Hetercyclic Prducts from the Ozonolysis of Conjugated C5-C8 Cyclodienes
Griesbaum, Karl,Jung, In Chang,Mertens, Henri
, p. 6024 - 6027 (2007/10/02)
Ozonolyses of the conjugated C5-C8 cyclodienes 1a-d in methanol, followed by reduction with DMS, have been examined.Monoozonolyses gave the corresponding unsaturated dialdehydes 2e as the primary products.In subsequent reactions, the dialdehydes 2e derived from the monoozonolyses of 1a, 1b, and 1c gave in high yields the heterocyclic compounds 7, 8k, and 9k, respectively.Diozonolyses of 1a-d gave the corresponding dialdehydes 3e as the primary products.In subsequent reactions, the dialdehydes 3e derived from 1b and 1c gave the heterocyclic compounds 8l and 9l, respectively.In addition, aldehydes 2e and 3e undervent partial acetalization reactions with methanol.
Synthesis and Diels-Alder reactions of (E)-6,6-dimethoxy-3-hexen-2-one
Yates, Peter,Douglas, Stephen Paul
, p. 2760 - 2765 (2007/10/02)
Treatment of 3,3-dimethoxypropanal (2) with (acetylmethylene)triphenylphosphorane (4) gives (E)-6,6-dimethoxy-3-hexen-2-one (5).Reaction of 5 with cyclopentadiene, 1,3-cyclohexadiene, anthracene, and 1,3-diphenylisobenzofuran gives Diels-Alder adducts, which on hydrolysis are converted to the corresponding keto aldehydes.Attempts to effect intramolecular aldol condensation of the latter were unsuccessful.Hydrolysis of the exo-acetyl adduct from 1,3-diphenylisobenzofuran with aqueous formic acid gives 4-acetyl-2,3,3a,4,5,9b-hexahydro-5,9b-diphenylnaphthofuran-2,5-diol, via aldehyde formation and hydrolytic cleavage of the ether bridge.The adduct from cyclopentadiene under anhydrous acid conditions give 3-acetyl-9-methoxy-tetracyclo2,4.03,7>nonane (27).
