Abstract
A short and efficient synthesis of 1-(3-tert-butyl-1-phenyl-1H-pyrazol-5-yl)-3-(5-(2-morpholinoethoxy)-2H-chromen-8-yl) urea derivatives (1a–c), a novel type of p38 MAPK inhibitors, is described. The Claisen thermal rearrangement of arylpropargyl ethers was employd as a key step to synthesize the chromene core. The solvent effect on the ratio of the resultant two isomers of Claisen thermal rearrangement, namely 2-methylbenzofuran and 2H-chromen, was also investigated.
ACKNOWLEDGMENT
This work was financially supported by the National Natural Science Foundation of China (No. 30873135).