81831-68-7Relevant articles and documents
(2,5)Pyrazinophanes: Synthesis and Molecular Structure
Eiermann, Uwe,Kriegel, Claus,Neugebauer, Franz A.,Staab, Heinz A.
, p. 3655 - 3658 (1988)
The pseudoortho (4a) and the pseudogeminal (2,5)pyrazinophane (4b) have been synthesized via 1,6-Hofmann elimination of trimethylammonium hydroxide (2b) and dimerization of the generated 2,5-dihydro-2,5-bis(methylene)pyrazine (3).The molecular structures of both isomers, 4a and 4b, were determined by X-ray analysis.
N -Hydroxyphthalimide/benzoquinone-catalyzed chlorination of hydrocarbon C-H bond using N -chlorosuccinimide
Li, Zi-Hao,Fiser, Béla,Jiang, Biao-Lin,Li, Jian-Wei,Xu, Bao-Hua,Zhang, Suo-Jiang
supporting information, p. 3403 - 3408 (2019/04/01)
The direct chlorination of C-H bonds has received considerable attention in recent years. In this work, a metal-free protocol for hydrocarbon C-H bond chlorination with commercially available N-chlorosuccinimide (NCS) catalyzed by N-hydroxyphthalimide (NHPI) with 2,3-dicyano-5,6-dichlorobenzoquinone (DDQ) functioning as an external radical initiator is presented. Aliphatic and benzylic substituents and also heteroaromatic ones were found to be well tolerated. Both the experiments and theoretical analysis indicate that the reaction goes through a process wherein NHPI functions as a catalyst rather than as an initiator. On the other hand, the hydrogen abstraction of the C-H bond conducted by a PINO species rather than the highly reactive N-centered radicals rationalizes the high chemoselectivity of the monochlorination obtained by this protocol as the latter is reactive towards the C(sp3)-H bonds of the monochlorides. The present results could hold promise for further development of a nitroxy-radical system for the highly selective functionalization of the aliphatic and benzylic hydrocarbon C-H.
Design, synthesis, and cytotoxic analysis of novel hederagenin–pyrazine derivatives based on partial least squares discriminant analysis
Fang, Kang,Zhang, Xiao-Hua,Han, Yao-Tian,Wu, Gao-Rong,Cai, De-Sheng,Xue, Nan-Nan,Guo, Wen-Bo,Yang, Yu-Qin,Chen, Meng,Zhang, Xin-Yu,Wang, Hui,Ma, Tao,Wang, Peng-Long,Lei, Hai-Min
, (2018/10/20)
Hederagenin (He) is a novel triterpene template for the development of new antitumor compounds. In this study, 26 new He–pyrazine derivatives were synthetized in an attempt to develop potent antitumor agents; they were screened for in vitro cytotoxicity against tumor and non-tumor cell lines. The majority of these derivatives showed much stronger cytotoxic activity than He. Remarkably, the most potent was compound 9 (half maximal inhibitory concentration (IC50) was 3.45 ± 0.59 μM), which exhibited similar antitumor activities against A549 (human non-small-cell lung cancer) as the positive drug cisplatin (DDP; IC50 was 3.85 ± 0.63 μM), while it showed lower cytotoxicity on H9c2 (murine heart myoblast; IC50 was 16.69 ± 0.12 μM) cell lines. Compound 9 could induce the early apoptosis and evoke cell-cycle arrest at the synthesis (S) phase of A549 cells. Impressively, we innovatively introduced the method of cluster analysis modeled as partial least squares discriminant analysis (PLS-DA) into the structure–activity relationship (SAR) evaluation, and SAR confirmed that pyrazine had a profound effect on the antitumor activity of He. The present studies highlight the importance of pyrazine derivatives of He in the discovery and development of novel antitumor agents.
