1.Ethyl 3-(2,4-dioxocyclohexyl)propanoate as a novel precursor for N-substituted 4,4a,5,6-tetrahydroquinoline-2,7(1H,3H)-diones and their corre
Thakur V1,2, Sharma D1, Das P3,4. Mol Divers. 2016 Feb;20(1):29-40. doi: 10.1007/s11030-015-9643-x. Epub 2015 Nov 4.
Ethyl 3-(2,4-dioxocyclohexyl)propanoate has been explored as a precursor for the synthesis of N-substituted 4,4a,5,6-tetrahydroquinoline-2,7(1H,3H)-diones following conventional protecvtion, selective amidation, and deprotective-cyclization approaches. Moreover, a facile process for the selective dehydrogenative aromatization of these diones was developed to afford the corresponding N-substituted 3,4-dihydro-7-hydroxyquinolin-2(1H)-ones and N-substituted 7-hydroxyquinolin-2(1H)-ones under mild conditions.
2.Cytotoxic cochlioquinone derivatives from the endophytic fungus Bipolaris sorokiniana derived from Pogostemon cablin.
Wang M1, Sun ZH2, Chen YC2, Liu HX2, Li HH2, Tan GH2, Li SN2, Guo XL3, Zhang WM2. Fitoterapia. 2016 Apr;110:77-82. doi: 10.1016/j.fitote.2016.02.005. Epub 2016 Feb 11.
Chemical investigation of the liquid culture of the endophytic fungus Bipolaris sorokiniana A606, which was isolated from the medicinal plant Pogostemon cablin resulted in the isolation of four new cytotoxic compounds, named isocochlioquinones D-E (1-2) and cochlioquinones G-H (3-4), along with five known cochlioquinone analogues (5-9). Their structures were determined on the basis of extensive spectroscopic analysis. Isocochlioquinone D (1) possessed a rare benzothiazin-3-one moiety and cochlioquinone G (3) was the first example of cochlioquinones bearing an indole-4,7-dione fragment. All of the isolates (1-9) were evaluated for their cytotoxic activities against MCF-7, NCI-H460, SF-268 and HepG-2 tumor cell lines by the sulforhodamine B (SRB) assay. Compounds 4 and 6-9, featuring a cochlioquinone core, exhibited potent cytotoxicities in vitro against the four tumor cell lines, and a preliminary structure-activity relationship of these compounds was also discussed.
3.Design, synthesis of 6-substituted-pyrido[3,2-d]pyridazine derivatives with anticonvulsant activity.
Dong ZQ, Liu XM, Wei CX1, Quan ZS2. Med Chem. 2015;11(6):595-601.
Aim to find new compounds with stronger anticonvulsant activity and lower neurotoxicity, a novel series of 6-substituted-pyrido[3,2-d]pyridazine derivatives was synthesized using furo[3,4-b]pyridine-5,7-dione as the starting material. We evaluated their anticonvulsant activity and neurotoxicity using by maximal electroshock (MES) and rotarod neurotoxicity (TOX) tests. The results showed that N-m-chlorophenyl-[1,2,4]triazolo- [4,3-b]-pyrido[3,2- d]pyridazin-6-amine (3) was the most potent anticonvulsant, with ED50 value of 13.6 mg/kg and protective index ( PI = TD50/ED50) values of 7.2 in the MES test. Compound N-m-chlorophenyltetriazolo[5,1-b]-pyrido[3,2-d]pyridazin-6-amine (19), exhibited significant anticonvulsant activity in maximal electroshock test with PI value of 13.4, which was safer than marketed drug carbamazepine.
4.Synthesis and Antiplasmodial Evaluation of Analogues Based on the Tricyclic Core of Thiaplakortones A-D.
Schwartz BD1, Coster MJ2, Skinner-Adams TS3, Andrews KT4, White JM5, Davis RA6. Mar Drugs. 2015 Sep 15;13(9):5784-95. doi: 10.3390/md13095784.
Six regioisomers associated with the tricyclic core of thiaplakortones A-D have been synthesized. Reaction of 1H-indole-4,7-dione and 1-tosyl-1H-indole-4,7-dione with 2-aminoethanesulfinic acid afforded a regioisomeric series, which was subsequently deprotected and oxidized to yield the tricyclic core scaffolds present in the thiaplakortones. All compounds were fully characterized using NMR and MS data. A single crystal X-ray structure was obtained on one of the N-tosyl derivatives. All compounds were screened for in vitro antiplasmodial activity against chloroquine-sensitive (3D7) and multidrug-resistant (Dd2) Plasmodium falciparum parasite lines. Several analogues displayed potent inhibition of P. falciparum growth (IC50 < 500 nM) but only moderate selectivity for P. falciparum versus human neonatal foreskin fibroblast cells.