Utility of Suzuki-Miyaura Cross-Coupling Reaction in Synthesis of Benzo[a]phenothiazine and Benzo[a]phenoxazine Derivatives and their Antimicrobial Screening
作者:Jude I. Ayogu、Benjamin E. Ezema、Chidimma G. Ezema
DOI:10.14233/ajchem.2015.19182
日期:——
Palladium-catalyzed Suzuki-Miyaura cross-coupling reactions of 6-chloro-5H-benzo[a]phenothiazin-5-one (1), 11-amino-6-chloro-9-thio-5H-naphtho[2,1-b]pyrimido[5,4-e][1,4]oxazin-5-one (2) and 6-chloro-5H-naphtho[2,1-b]pyrido[2,3-e][1,4]oxazin-5-one (3) with phenylboronic acid and 3-nitrophenylboronic acid were thoroughly investigated. The above intermediates were prepared by the reactions of 2-aminothiophenol, 4,5-diamino-6-hydroxylpyrimidine-2-thiol and 2-aminopyridin-3-ol each with 2,3-dichloronaphthalene-1,4-dione in a basic medium using benzene/DMF as the solvent. Thereafter, each was subjected to the Suzuki-Miyaura coupling reaction with phenylboronic acid and 3-nitrophenyl boronic acid, refluxing for 7-8 h at 110 °C using tris(dibenzylideneacetone)palladium(0), dicyclohexyl-phosphino-2,6-dimethoxybiphenyl (SPhos), potassium phosphate and toluene as the catalyst, ligand, base and solvent correspondingly to yield the derivatives (1a-b), (2a-b) and (3a-b), respectively. Structures of the compounds were characterized using UV/visible spectrophotometry, FT-IR, 1H NMR and 13C NMR spectroscopy and elemental analysis. The compounds were screened against six micro-organisms, viz: Bacillus subtitis, Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Candida albicans and Aspergillus niger and were shown to have significant activity against some Gram-positive micro-organisms.
在催化的铃木-宫浦交叉偶联反应中,研究了6-氯-5H-苯并[a]噻嗪-5-酮(1)、11-氨基-6-氯-9-硫-5H-萘[2,1-b]嘧啶[5,4-e][1,4]氧杂啉-5-酮(2)以及6-氯-5H-萘[2,1-b]嘧啶[2,3-e][1,4]氧杂啉-5-酮(3)与苯硼酸和3-硝基苯硼酸的交联反应。这些中间体通过将2-氨基硫酚、4,5-二氨基-6-羟基嘧啶-2-硫醇和2-氨基吡啶-3-醇分别与2,3-二氯萘-1,4-二酮在基础介质中使用苯/DMF作为溶剂反应准备而成。随后,将每种化合物与苯硼酸和3-硝基苯硼酸进行铃木-宫浦耦合反应,在110 °C下回流7-8小时,使用三(双苯乙烯)丙烯镍(0)、二环己基磷烷-2,6-二甲氧基联苯(SPhos)、磷酸钾和甲苯作为催化剂、配体、碱和溶剂,最终得到了衍生物(1a-b)、(2a-b)和(3a-b)。使用紫外/可见光分光光度法、FT-IR、1H NMR和13C NMR光谱法以及元素分析对化合物的结构进行表征。这些化合物在六种微生物(如:杜氏芽孢杆菌、金黄色葡萄球菌、绿脓杆菌、大肠杆菌、白色念珠菌和黑曲霉)中进行了筛选,显示出对一些革兰阳性微生物具有显著的活性。