A Facile One Pot Synthesis of New Tricyclic Coumarins from Single Synthon [1]

作者：Kalkhambkar Rajesh G; Kulkarni Geeta M; Kulkarni Manohar V^*

来源：Journal of Heterocyclic Chemistry, 2013, 50(5): 1014-1020.

DOI：10.1002/jhet.1032

A high yielding method for the synthesis of new tricyclic coumarins is reported herein using 8-formyl-7-hydroxy-4-methyl coumarin as a single synthon. Different strategies were employed to synthesize tricyclic coumarins fused with isoxazole and pyran at C7-C8 position in the coumarin skeleton. Functional group modifications during the construction of pyrazolyl coumarin has resulted in novel oxidative ipso nitration. The O-tosylate was subjected to conditions of pressure in a sealed tube experiment, since it was not possible to replace the 7-hydroxy group of coumarin by regular methods. All the compounds synthesized during the present investigation were characterized by IR, 1H-NMR, 13C-NMR, ESI-MS, and elemental analysis. The X-ray diffraction data of some of the intermediate hydrazones are also reported herein.

• 出版日期2013-9