A new transition-metal-free 9-azabicyclo[3.3.1]nonan-N-oxyl (ABNO) catalyzed aerobic oxidative synthesis of 2-substituted 4H-3,1-benzoxazines and quinazolines has been developed through cascade reaction of aldehydes with 2-aminobenzyl alcohols and 2-aminobenzylamines, respectively. Under the optimal reaction conditions, the two kinds of heterocycles were obtained in 72–97 % isolated yield.
Highly Efficient One-Pot Synthesis of 2-Substituted Quinazolines and 4<i>H</i>-Benzo[<i>d</i>][1,3]oxazines<i>via</i>Cross Dehydrogenative Coupling using Sodium Hypochlorite
describes a catalyst-free synthesis of 2-substitutedquinazolines and 4H-benzo[d][1,3]oxazines using commericially available sodiumhypochlorite as oxidant. Operational simplicity, mild reaction conditions and the ability to construct structurally diverse 2-quinazolines and 2-substituted4H-benzo[d][1,3]oxazines by this method render it to be a practical alternative for the synthesis of these heterocycles
该通报描述了使用市售的次氯酸钠作为氧化剂的无催化剂合成2-取代的喹唑啉和4 H-苯并[ d ] [1,3]恶嗪。操作简便,反应条件温和以及通过该方法构造结构上不同的2-喹唑啉和2-取代的4 H-苯并[ d ] [1,3]恶嗪的能力使其成为合成这些杂环的实用选择。
Synthesis of 3H-Quinazolin-4-ones and 4H-3,1-Benzoxazin-4-ones via Benzylic Oxidation and Oxidative Dehydrogenation using Potassium Iodide-tert-Butyl Hydroperoxide
作者:R. Arun Kumar、C. Uma Maheswari、Satheesh Ghantasala、C. Jyothi、K. Rajender Reddy
DOI:10.1002/adsc.201000580
日期:2011.2.11
and elegant method for benzylic activation was demonstrated employing the potassium iodide/tert-butyl hydrogen peroxide catalytic system. This methodology was further extended for the synthesis of biologically important heterocycles namely, 3H-quinazolin-4-ones and 4H-3,1-benzoxazin-4-ones including mecloqualone and etaqualone which are important quinazolinone-based drugs used for the treatment of insomnia
用碘化钾/叔丁基过氧化氢催化体系证明了一种简单而优雅的苄基活化方法。该方法被进一步扩展为合成重要的杂环化合物,即3 H-喹唑啉-4-酮和4 H -3,1-苯并恶嗪-4-酮,包括甲氯喹酮和依他马酮,这是用于治疗的基于喹唑啉酮的重要药物失眠的好收成。