RuCl2(PPh3)3-Catalyzed Facile One-Pot Synthesis of 1,2-Dihydro-1-arylnaphtho1,2-e 1,3oxazine-3-ones and 1,2-Dihydro-1-arylnaphtho1,2-e1,3oxazine-3-thiones

摘要

Benzoxazinones and benzthioxazinones have received considerable attention because of the attractive pharmacological properties associated with their heterocyclic scaffold. Molecules bearing these skeletons have been reported to exhibit a variety of biological properties, including antiinflammatory, antiulcer, antipyretic, antihypertensive, and antifungal activities. Some of these compounds also exhibit several important biological activities such as DP receptor antagonism, integrin antagonism, platelet fibrinogen receptor antagonism, calmodulin antagonism, and inhibition of the transforming growth factor β (TGF-β) signaling pathway, soybean lipoxygenase, and other protein kinase. Because of the importance of these compounds, several synthetic methods for 1,2-dihydro-1-arylnaphtho1,2-e1,3oxazine-3-ones and 1,2-dihydro-1-arylnaphtho1,2-e1,3oxazine-3-thiones have been developed. The reported methods mainly include one-pot three-component reactions of 2-naphthol, aromatic aldehydes, and urea or thiourea (Scheme 1). These reactions for the synthesis of 2-dihydro-1-aryl-naphtho1,2-e1,3oxazine-3-ones have been studied with the use of several catalysts and reagents such as Cu-nano-particles/PEG-400, TMSCl, HClO4/SiO2 H3Mo_(12)O_(40)P, montmorillonite K10 clay, and iodine. Interestingly, several synthetic approaches for the synthesis of 2-dihydro-1-arylnaphtho1,2-e1,3oxazine-3-ones have been described, but only one example for the synthesis of 1,2-dihydro-1-arylnaphtho1,2-e1,3oxazine-3-thiones has been reported through multi-component reaction. The method also involves montmorillonite K10 clay-catalyzed reaction of 2-naphthol, aryl aldehydes, and thiourea.