Reaction of pyran-2-thiones 4 with nitrosoderivatives led surprisingly to type-8 (19) adducts which proved to be isomeric with the initially expected primary Diels-Alder cycloadducts 5. Methyl 2-thioxo-2H-pyran-5-carboxylate (4f), when reacted with nitrosobenzene at -10°, led quantitatively to the thieto-oxazine intermediate 13, which turned out to be the cornerstone of the complex cycloaddition-rearrangement
吡喃-2-硫酮的反应4与导致令人惊奇的亚硝基衍生物型- 8(19被证明是同分异构体与最初的预期主要)加合物狄尔斯-阿尔德cycloadducts 5。当在-10°下与亚硝基苯反应时,2-thioxo-2 H -pyran-5-羧酸甲酯(4f)定量地导致硫代恶嗪中间体13转化为复杂的环加成重排5 的基石。8个反应途径(方案3)。差示扫描量热法,与18a 19a相同转化,被允许证明该多步重排总体上是高温放热过程,最终产物19代表沿着该反应路径的能量吸收器。
Development of Novel <i>N</i>-hydroxypyridone Derivatives as Potential Anti-Ischemic Stroke Agents
Our previous study had identified ciclopirox (CPX) as a promising lead compound for treatment of ischemic stroke. To find better neuroprotective agents, a series of N-hydroxypyridone derivatives based on CPX were designed, synthesized, and evaluated in this study. Among these derivatives, compound 11 exhibits significant neuroprotection against oxygen glucose deprivation and oxidative stress -induced injuries in neuronal cells. Moreover, compound 11 possesses good blood-brain barrier permeability and superior antioxidant capability. In addition, a complex of compound 11 with olamine-11.01a possesses good water solubility, negligible hERG inhibition, and superior metabolic stability. The in vivo experiment demonstrates that 11.01a significantly reduces brain infarction and alleviates neurological deficits in middle cerebral artery occlusion rats. Hence, compound 11.01a is identified in our research as a prospective prototype in the innovation of stroke treatment.
New chemotypes acting as isozyme-selective carbonic anhydrase inhibitors with low affinity for the offtarget cytosolic isoform II
作者:Fabrizio Carta、Daniela Vullo、Alfonso Maresca、Andrea Scozzafava、Claudiu T. Supuran
DOI:10.1016/j.bmcl.2012.01.129
日期:2012.3
Considering phenols and coumarins as lead molecules for obtaining non-sulfonamide inhibitors of carbonic anhydrases (CAs, EC 4.2.1.1), we screened a large number of compounds possessing diverse chemotypes, but structural features which resemble the two chemical classes. Here we report an investigation of such derivatives which do not significantly inhibit CA II, but show interesting inhibition profiles against other isozymes. Pyridine-N-oxide-2-thiophenol, thiobenzoic acid, thimerosal, two oximes derived from a six-membered-ring lactone and from coumarin; 2-hydroxyquinoline and coumaphos, were investigated as inhibitors of CA I-XIV. All these compounds did not inhibit CA II, whereas the two oximes and 2-hydroxyquinoline were low nanomolar inhibitors of CA I, IX, XII, XIII and XIV, showing a very different inhibition profile compared to sulfonamides and sulfamates. Some other compounds showed low micromolar inhibition of other isoforms of interest, such as CA VA/VB, CA VI and VII. This study demonstrates that a rather wide range of structures show low nanomolar-micromolar inhibitory activity against many CA isozymes, without inhibiting significantly the offtarget isoform CA II. (C) 2012 Elsevier Ltd. All rights reserved.
5- and 6-Membered (thio)lactones are prodrug type carbonic anhydrase inhibitors
作者:Fabrizio Carta、Alfonso Maresca、Andrea Scozzafava、Claudiu T. Supuran
DOI:10.1016/j.bmcl.2011.11.018
日期:2012.1
The inhibition of the zinc enzyme carbonic anhydrase (CA, EC 4.2.1.1) with (thio) coumarins has been recently reported (Maresca et al., J. Am. Chem. Soc. 2009, 131, 3057). Here we demonstrate that a series of gamma- and delta-(thio) lactones also act as mechanism based, prodrug type CA inhibitors, similar to the (thio) coumarins. Through the esterase activity of CA, these compounds are hydrolyzed in situ to the corresponding hydroxy/keto/mercapto acids which thereafter act as inhibitors. CA isoforms I and IX were efficiently inhibited by simple such compounds, with KIs in the range of 0.92-19.1 mu M, whereas CA II was not inhibited at all. Isoform-selective CA inhibitors which spare the ubiquitous off-target CA II may have interesting applications for example for selectively inhibiting the tumor-associated CA IX, a validated anticancer target. (C) 2011 Elsevier Ltd. All rights reserved.