A facile and expedient route for the synthesis of 2‐ethoxy‐ and 2‐(ethylcarboxylate)‐(4H)‐3,1‐benzoxazine‐4‐ones is described using guanidinium chloride as a safe and convenient dehydrocyclizationagent. High yields of the products obtain under mild reaction conditions without need to use of any catalyst and with easy work‐up of the reaction mixture.
A convenient synthesis of anthranilic acids by Pd-catalyzed direct intermolecular ortho-C–H amidation of benzoic acids
作者:Ka-Ho Ng、Fo-Ning Ng、Wing-Yiu Yu
DOI:10.1039/c2cc36502b
日期:——
An efficient method for synthesis of anthranilic acids by Pd-catalyzed ortho-CâH amidation of benzoic acids is disclosed. The amidation is proposed to proceed by carboxylate-assisted ortho-CâH palladation to form an arylpalladium(II) complex, followed by nitrene insertion to the PdâC bond.
A simple and practical route is described for the synthesis of 2-ethoxy-(4H)-3,1-benzoxazine-4-ones using the coupling reaction of anthranilic acid derivatives with diethyl dicarbonate following with fast cyclization of the carbamate adduct with a dehydrocyclization agent such as cyanuric chloride and N,N′-dicyclohexylcarbodiimide in PEG at room temperature. High yields of the products obtained under