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A Facile One Pot Synthesis of New Tricyclic Coumarins from Single Synthon [1
Author(s) -
Kalkhambkar Rajesh G.,
Kulkarni Geeta M.,
Kulkarni Manohar V.
Publication year - 2013
Publication title -
journal of heterocyclic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.321
H-Index - 59
eISSN - 1943-5193
pISSN - 0022-152X
DOI - 10.1002/jhet.1032
Subject(s) - chemistry , synthon , coumarin , tricyclic , isoxazole , nitration , proton nmr , carbon 13 nmr , annulation , stereochemistry , organic chemistry , combinatorial chemistry , catalysis
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, 1 H‐NMR, 13 C‐NMR, ESI‐MS, and elemental analysis. The X‐ray diffraction data of some of the intermediate hydrazones are also reported herein.