- Reversed electron apportionment in mesolytic cleavage: The reduction of benzyl halides by SmI2
-
The paradigm that the cleavage of the radical anion of benzyl halides occurs in such a way that the negative charge ends up on the departing halide leaving behind a benzyl radical is well rooted in chemistry. By studying the kinetics of the reaction of substituted benzylbromides and chlorides with SmI2 in THF it was found that substrates para-substituted with electron-withdrawing groups (CN and CO2Me), which are capable of forming hydrogen bonds with a proton donor and coordinating to samarium cation, react in a reversed electron apportionment mode. Namely, the halide departs as a radical. This conclusion is based on the found convex Hammett plots, element effects, proton donor effects, and the effect of tosylate (OTs) as a leaving group. The latter does not tend to tolerate radical character on the oxygen atom. In the presence of a proton donor, the tolyl derivatives were the sole product, whereas in its absence, the coupling dimer was obtained by a SN2 reaction of the benzyl anion on the neutral substrate. The data also suggest that for the para-CN and CO2Me derivatives in the presence of a proton donor, the first electron transfer is coupled with the proton transfer. Reverse breakup: In the mesolytic cleavage of the radical anions of benzyl halides that are para-substituted by CN or CO2Me groups, the halogen departs, counterintuitively, as a radical and the benzyl system carries the negative charge (see figure).
- Yitzhaki, Offir,Hoz, Shmaryahu
-
p. 9242 - 9248
(2015/06/16)
-
- Design, synthesis and anticancer activities of novel otobain derivatives
-
A series of novel racemic otobain derivatives was designed and synthesised using 2-piperonyl-1,3-dithianes in the conjugate addition-alkylation to 5H-furan-2-one, followed by cationic cyclisation. All the synthesised compounds were consequently evaluated for their anticancer activity against several human cancers in vitro. The efficacy of the most active compound 27g was comparable with etoposide, with IC50 values ranging from 1.06 μM to 4.16 μM in different cancer cell lines. Notably, compound 27g strongly induced cell cycle arrest and increased the expression of mitosis-specific markers MPM-2 and phosphorylated histone H3, but it did not trigger cell apoptosis. Further a colony formation assay showed that compound 27g effectively inhibited the anchor growth of lung cancer cells in a dose-dependent manner. More importantly, compound 27g at 40 mg kg-1 significantly suppressed tumour volume (P 0.01) and tumour weight (P 0.05) in a human lung cancer cell xenograft mouse model without causing systematic toxicity in mice. Our findings indicated that compound 27g has significant potential for further drug development.
- Li, Zhongzhou,Su, Hui,Yu, Weiwei,Li, Xinjun,Cheng, Hao,Liu, Mingyao,Pang, Xiufeng,Zou, Xinzhuo
-
p. 277 - 287
(2015/12/30)
-
- A direct transformation of Aryl Aldehydes to Benzyl Iodides Via reductive iodination
-
A facile transformation of aryl aldehydes to benzyl iodides through one-pot reductive iodination is reported. This protocol displays remarkable functional group tolerance and the title compound was obtained in good to excellent yield.
- Ruso, Jayaraman Sembian,Rajendiran, Nagappan,Kumaran, Rajendran Senthil
-
-
- NOVEL ANTIVIRAL PYRROLOPYRIDINE DERIVATIVES AND METHOD FOR PREPARING THE SAME
-
The present invention relates to a pyrrolopyridine derivative represented by the Chemical Formula I, and a racemate or a stereoisomer thereof, or a pharmaceutically acceptable salt thereof, and relates to an antiviral composition including the same as an active ingredient. The compound of the Chemical Formula I has excellent antiviral activity and selectivity for wild type and resistant HIV-1, and thereby is useful as a therapeutic agent for acquired immune deficiency syndrome (AIDS).
- -
-
Paragraph 0439; 0440; 0441
(2014/09/16)
-
- NOVEL ANTIVIRAL PYRROLOPYRIDINE DERIVATIVE AND A PRODUCTION METHOD FOR SAME
-
The present invention relates to a pyrrolopyridine derivative represented by the Chemical Formula I, and a racemate or a stereoisomer thereof, or a pharmaceutically acceptable salt thereof, and relates to an antiviral composition including the same as an active ingredient. The compound of the Chemical Formula I has excellent antiviral activity and selectivity for wild type and resistant HIV-1, and thereby is useful as a therapeutic agent for acquired immune deficiency syndrome (AIDS).
- -
-
Paragraph 0420; 0421; 0422
(2014/12/09)
-
- Antitumor agents. 120. New 4-substituted benzylamine and benzyl ether derivatives of 4'-O-demethylepipodophyollotoxin as potent inhibitors of human DNA topoisomerase II
-
A number of new 4'-O-demethylepipodophyllotoxin derivatives possessing various 4β-N- or 4β-O-benzyl groups have been synthesized and evaluated for their inhibitory activity against the human DNA topoisomerase II as well as for their activity in causing cellular protein-linked DNA breakage. The 4β-N-benzyl derivatives 9-22 are, in general, as active or more active than etoposide (1). The most active compounds are 14, 16, and 17, which are more than 2-fold more potent than 1. The results indicated that a basic unsubstituted 4β-benzylamino moiety is structurally required for the enhanced activity. Replacement of the benzyl nitrogen with oxygen gave compounds (23 and 24) which are inactive. The ability of these compounds to inhibit human DNA topoisomerase II and to cause protein-linked DNA breakage appears to have no direct correlation with cytotoxicity in KB cells.
- Zhou,Wang,Chang,Chen,Cheng,Lee
-
p. 3346 - 3350
(2007/10/02)
-