Transition-Metal-Free Synthesis of 2-Substituted Benzothiazoles from Nitrobenzenes, Methylheteroaryl Compounds, and Elemental Sulfur, Based on Nitro-Methyl Redox-Neutral Cyclization
has been shown to promote the efficient synthesis of 2-substituted benzothiazoles from easily available nitrobenzenes, methyl-heteroaryl compounds, and elemental sulfur in the absence of transition-metal catalysts. The 2-substituted benzothiazoles were obtained in reasonable yields through the sulfuration of electron-deficient C–H bonds with elemental sulfur. This synthetic methodology also affords
PdCl(dppb)(C3H5) as a catalyst, a range of heteroaryl derivatives undergoes coupling via C–Hbondactivation/functionalization reaction with chloropyridines or chloroquinolines in low to high yields. This air-stable catalyst can be used with a wide variety of substrates. The position of the chloro substituent on pyridines has a minor influence on the yields. On the other hand, the nature on the heteroaryl derivative
芳基氯化物与杂芳烃的直接偶联将具有可持续发展的巨大优势,因为它们的成本更低,质量更轻,可用化合物的多样性更大,并且还因为仅形成了与副产物碱有关的HCl和减少制备这些化合物的步骤数。我们观察到通过使用PdCl(dppb)(C 3 H 5)作为催化剂,一系列杂芳基衍生物通过C–H键活化/官能化反应与氯吡啶或氯喹啉进行低至高收率的偶联。这种空气稳定的催化剂可与多种基材一起使用。吡啶上氯取代基的位置对收率影响很小。另一方面,杂芳基衍生物的性质具有很大的影响。使用苯并恶唑,噻吩或噻唑衍生物可获得最高的收率。氯吡啶与呋喃的偶联也得到了预期的产物,但是产率低至中等。
A robust one-pot synthesis of benzothiazoles from carboxylic acids including examples with hydroxyl and amino substituents
作者:Soraia Meghdadi、Mehdi Amirnasr、Peter C. Ford
DOI:10.1016/j.tetlet.2012.10.035
日期:2012.12
The cyclocondensation of 2-aminothiophenol and carboxylic acids to give benzothiazoles has been carried out under mild conditions using tetrabutylammonium bromide (TBAB) as the reaction medium and triphenyl phosphite as the catalyst. Shorter reaction times, rapid isolation of the products, and excellent yields are advantages of this method. The reaction is found to be general and quite tolerant to
Functionalisation of quinoline N-oxide was investigated using phophazene base as a catalyst; alkynylation and heteroarylation at 2-position were successfully achieved via nucleophilic addition–elimination process.
Quinoline Functionalized Schiff Base Silver (I) Complexes: Interactions with Biomolecules and In Vitro Cytotoxicity, Antioxidant and Antimicrobial Activities
作者:Adesola A. Adeleke、Sizwe J. Zamisa、Md. Shahidul Islam、Kolawole Olofinsan、Veronica F. Salau、Chunderika Mocktar、Bernard Omondi
DOI:10.3390/molecules26051205
日期:——
against Gram-positive and Gram-negative bacteria revealed the influence of structure and anion on the complexes′ moderate to excellent antibacterial activity. In vitro antioxidant activities of the complexes showed their good radical scavenging activity in ferric reducing antioxidant power (FRAP). Complexes with the fluorine substituent or the thiophene or benzothiazole moieties are more potent with IC50