1754-88-7Relevant academic research and scientific papers
Substituted dienes prepared from betulinic acid – Synthesis, cytotoxicity, mechanism of action, and pharmacological parameters
Frydrych, Ivo,Urban, Milan,?arek, Jan,Benická, Sandra,D?ubák, Petr,Gurská, Soňa,Hajdúch, Marián,Kotulová, Jana,Li?ková, Barbora,Olejníková, Denisa,Pokorny, Jan
, (2021/07/28)
A set of new substituted dienes were synthesized from betulinic acid by its oxidation to 30-oxobetulinic acid followed by the Wittig reaction. Cytotoxicity of all compounds was tested in vitro in eight cancer cell lines and two noncancer fibroblasts. Almost all dienes were more cytotoxic than betulinic acid. Compounds 4.22, 4.30, 4.33, 4.39 had IC50 below 5 μmol/L; 4.22 and 4.39 were selected for studies of the mechanism of action. Cell cycle analysis revealed an increase in the number of apoptotic cells at 5 × IC50 concentration, where activation of irreversible changes leading to cell death can be expected. Both 4.22 and 4.39 led to the accumulation of cells in the G0/G1 phase with partial inhibition of DNA/RNA synthesis at 1 × IC50 and almost complete inhibition at 5 × IC50. Interestingly, compound 4.39 at 5 × IC50 caused the accumulation of cells in the S phase. Higher concentrations of tested drugs probably inhibit more off-targets than lower concentrations. Mechanisms disrupting cellular metabolism can induce the accumulation of cells in the S phase. Both compounds 4.22 and 4.39 trigger selective apoptosis in cancer cells via intrinsic pathway, which we have demonstrated by changes in the expression of the crucial apoptosis-related protein. Pharmacological parameters of derivative 4.22 were superior to 4.39, therefore 4.22 was the finally selected candidate for the development of anticancer drug.
Reactivity of a Sterically Unencumbered α-Borylated Phosphorus Ylide towards Small Molecules
Radius, Michael,Sattler, Ewald,Berberich, Helga,Breher, Frank
, p. 12206 - 12213 (2019/08/30)
The influence of substituents on α-borylated phosphorus ylides (α-BCPs) has been investigated in a combined experimental and quantum chemical approach. The synthesis and characterization of Me3PC(H)B(iBu)2 (1), consisting of small Me substituents on phosphorous and iBu residues on boron, is reported. Compound 1 is accessible through a novel synthetic approach, which has been further elucidated through DFT studies. The reactivity of 1 towards various small molecules was probed and compared with that of a previously published derivative, Ph3PC(Me)BEt2 (2). Both α-BCPs react with NH3 to undergo heterolytic N?H bond cleavage. Different di- and trimeric ring structures were observed in the reaction products of 1 with CO and CO2. With PhNCO and PHNCS, the expected insertion products [Me3PC(H)(PhNCO)B(iBu)2] and [Me3PC(H)(PhNCS)B(iBu)2], respectively, were isolated.
Enantioselective palladium-catalyzed addition of malonates to 3,3-difluoropropenes
Drouin, Myriam,Paquin, Jean-Fran?ois
, p. 6023 - 6032 (2018/09/11)
Monofluoroalkenes bearing a malonate unit at the β position can be synthesized by the enantioselective addition of diesters to 3,3-difluoropropenes. The difference in reactivity regarding the geometry and the substituents of the alkene of the 3,3-difluoropropenes, as well as the alkyl groups of the malonates, was studied and limitations were identified. The reaction was also performed with different 3,3-difluoropropenes. Further synthetic transformations of a newly functionalized monofluoroalkene were also accomplished.
(E)-Selective Wittig Reactions between a Nonstabilized Phosphonium Ylide Bearing a Phosphastibatriptycene Skeleton and Benzaldehydes
Uchiyama, Yosuke,Ohtsuki, Takemaru,Murakami, Rikiya,Shibata, Munenori,Sugimoto, Jun
, p. 159 - 174 (2017/01/14)
Wittig reactions between benzaldehyde derivatives and a nonstabilized phosphonium ylide bearing a phosphastibatriptycene skeleton, regarded as a tridentate aryl ligand, gave (E)-alkenes with high selectivity in the presence of both lithium and sodium salts. As previously reported, reactions between a triphenylphosphonium ylide and benzaldehyde derivatives under the same conditions afforded mainly (Z)-alkenes. Variable-temperature (VT)31P{1H} NMR spectra showed two signals, assigned to cis- and trans-1,2-oxaphosphetanes, which were observed at different temperatures (–80 °C and –40 °C, respectively) in the Wittig reaction between benzaldehyde and the nonstabilized phosphonium ylide bearing the phosphastibatriptycene skeleton, in the presence of both lithium and sodium salts, and showed the existence of equilibrium between these products at –40 °C. On the other hand, this equilibrium was not clearly observed in the reaction between the triphenylphosphonium ylide and benzaldehyde, for which only one signal was detected. The observed intermediates were confirmed to be 1,2-oxaphosphetanes by deprotonation of the isolated β-hydroxyalkylphosphonium salts bearing a phosphastibatriptycene skeleton and a triphenylphosphine moiety, respectively. Crossover reactions were conducted in the deprotonations of β-hydroxyalkylphosphonium salts with TMS2NNa in the presence of p-chlorobenzaldehyde, resulting in the observation of signals corresponding to 1,2-oxaphosphetanes containing phenyl and p-chlorophenyl groups at the 4-positions, indicating the exchange process between benzaldehyde and p-chlorobenzaldehyde at –40 °C for the phosphastibatriptycene system and at 0 °C for triphenyl derivatives. These results clearly indicated that stereochemical drift occurred at those temperatures, even in reactions using nonstabilized phosphonium ylides. The stereochemical drift in the phosphastibatriptycene system occurred at a lower temperature than in the case of the triphenyl derivative, thus explaining the (E)-selective Wittig reactions between the benzaldehyde derivatives and the nonstabilized phosphastibatriptycene-based phosphonium ylide in the presence of lithium and sodium salts.
Nucleophilic 1,1-Difluoroethylation with Fluorinated Phosphonium Salt
Deng, Zuyong,Liu, Can,Zeng, Xian-Liang,Lin, Jin-Hong,Xiao, Ji-Chang
, p. 12084 - 12090 (2016/12/23)
The fluorinated phosphonium salt (Ph3P+CF2CH3 BF4-) was shown to act as a nucleophilic 1,1-difluoroethylation agent to enable difluoroethylation of aldehydes and imines.
A transition-metal-free Heck-type reaction between alkenes and alkyl iodides enabled by light in water
Liu, Wenbo,Li, Lu,Chen, Zhengwang,Li, Chao-Jun
, p. 6170 - 6174 (2015/06/08)
A transition-metal-free coupling protocol between various alkenes and non-activated alkyl iodides has been developed by using photoenergy in water for the first time. Under UV irradiation and basic aqueous conditions, various alkenes efficiently couple with a wide range of non-activated alkyl iodides. A tentative mechanism, which involves an atom transfer radical addition process, for the coupling is proposed.
Comparative study of the phospha- and arsa-Wittig reaction using 1H, 75As and 17O NMR spectroscopy
Raeck, Christian,Berger, Stefan
, p. 4934 - 4937 (2007/10/03)
The existence of oxaarsetanes during an arsa-Wittig reaction has been proved by 1H and 17O NMR spectroscopy. 75As NMR spectra were obtained from the corresponding arsonium salts and arsane oxides. The dynamic 1H NMR spectra of phospha- and arsaylides were compared. Wiley-VCH Verlag GmbH & Co. KGaA, 2006.
Ester compounds
-
, (2008/06/13)
Ester compounds shown by the formula: wherein R1represents a hydrogen atom, halogen atom, C1-C3alkyl group optionally substituted by halogen atom(s), C2-C3alkenyl group optionally substituted by halogen atom(s), C1-C3alkoxy group optionally substituted by halogen atom(s), C1-C3alkylthio group optionally substituted by halogen atom(s) or (C1-C3alkoxy)methyl group optionally substituted by halogen atom(s), n represents an integer of 1 to 4 and X represents a hydrogen atom or C1-C3alkyl group, have excellent pesticidal activity.
Reactions of aldehydes with polymer-supported selenoalkylidenetriphenylphosphoranes. A facile method for the synthesis of carbonyl compounds
Huang, Xian,Sheng, Shou-Ri
, p. 9035 - 9037 (2007/10/03)
The transylidation reactions of polymer-bound selenium bromide with alkylidenetriphenylphosphoranes 1 gave resin 2, which is sufficiently reactive to undergo Wittig-type reactions to afford the vinylic selenide resins 3. Cleavage gave ketones and aldehydes under different conditions.
Base-Induced and -Directed Rearrangements of 4-Monotosylated Perhydronaphthalene-1,4-diols. Synthesis of (+/-)-5-epi-Nardol
Wijnberg, Joannes B. P. A.,Jenniskens, Louis H. D.,Brunekreef, Gerd A.,Groot, Aede de
, p. 941 - 948 (2007/10/02)
The utility of perhydronaphthalene precursors for the synthesis of sesquiterpenes which possess a cis-fused perhydroazulene skeleton with an exocyclic methylene unit has been examined.For this purpose the tosylates 3, 4, 28, and 29 were prepared, and thei
