326598-35-0Relevant academic research and scientific papers
Efficient stereoselective synthesis of benzoxazines via copper-catalyzed three-component coupling reactions
Xu, Xiaobing,Liang, Linfeng,Liu, Jun,Yang, Jingyu,Mai, Lugen,Li, Yanzhong
body text, p. 57 - 59 (2009/04/11)
A convenient one-pot synthesis of 1,4-benzoxazines via three-component coupling and subsequent O-cyclization is reported. The present reaction provides an efficient protocol to functionalized 1,4-benzoxazine derivatives in good to high yields from aldehyd
Palladium-catalyzed heteroannulation leading to heterocyclic structures with two heteroatoms: A highly regio- and stereoselective synthesis of (Z)-4-alkyl-2-alkyl(aryl)idene-3,4-dihydro-2H-1,4,-benzoxazines and (Z)-3-alkyl(aryl)idene-4-tosyl-3,4-dihydro-2H-1,4-benzoxazines
Kundu,Chaudhuri,Upadhyay
, p. 20 - 29 (2007/10/03)
A highly convenient method has been developed for the synthesis of (Z)-4-alkyl-2-alkyl(aryl)idene-3,4-dihydro-2H-1,4-benzoxazines 9 and (Z)-3-alkyl(aryl)idene-4-tosyl-3,4-dihydro-2H-1,4-benzoxazines 34-38 through palladium - copper-catalyzed reactions. Aryl halides 7 reacted with 2-[Nalkyl(benzyl)-N-prop-2′-ynyl]aminophenyl tosylate 6 in the presence of (PPh3)2PdCl2 (3 mol %), CuI(5 mol %) in triethylamine at room temperature to yield 2-[N-alkyl(benzyl)-N-(3-aryl-prop-2′-ynyl)]aminophenyl tosylates 8 in extremely good yields (72-96%). The latter could then be cyclized with KOH in ethanol - water to Z-9 in a highly regio- and stereoselective manner. Similarly, palladium copper-catalyzed reaction of 2-(prop-2′-ynyloxy)aniline (21) with aryl iodides 7 led to 22-26 which after tosylation and cyclization with cuprous iodide in CH3CN in the presence of K2CO3 and Bu4-NBr led to the (Z)-3-alkyl(aryl)idene-4-tosyl 3,4-dihydro-2H-1,4-benzoxazines 34-38 in good overall yields. The Z-stereochemistry of the products was established from 1H NMR spectra, 3JCH values (between vinylic proton and methylenic carbon of the heterocyclic ring), NOE experiments, and X-ray analysis· The method was also found to be suitable for the synthesis of bis(benzoxazinylated) derivatives 17, 39, and 2-alkyl-3,4-dihydro-2H-1,4-benzoxazines 18. Our method for the synthesis of 3,4-dihydro-2H-1,4-benzoxazines is highly efficacious, using easily available starting materials under very mild conditions. Also the synthesis of some novel 5-substituted uracil derivatives 40 and 41 containing the benzoxazinyl moiety and of potential biological interest is being reported.
A highly stereoselective synthesis of (Z)-N-Aryl(alkyl)-2-arylidine-2,3-dihydro-1,4-benzoxazines through palladium catalyzed reactions
Chaudhuri, Gopeswar,Chowdhury, Chinmay,Kundu, Nitya G.
, p. 1273 - 1275 (2007/10/03)
A highly efficient and stereoselective synthesis of (Z)-N-Aryl(alkyl)-2-arylidine-2,3-dihydro-1,4-benzoxazines is described where palladium-catalyzed reactions play a significant role.
