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3,3′‐diaryl‐5‐morpholino‐4,5,4′,5′‐tetrahydro‐4,5′‐spirobi[isoxazoles]. Synthesis by cycloaddition reactions and substituent effect on the cycloaddition kinetics
Author(s) -
Beltrame Paolo,
Gelli Gioanna
Publication year - 1986
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.5570230557
Subject(s) - chemistry , cycloaddition , nitrile , substituent , aryl , methylene , medicinal chemistry , oxide , organic chemistry , catalysis , alkyl
3‐Aryl‐4‐methylene‐5‐morpholino‐4,5‐dihydroisoxazoles 1a‐e were synthesized; fifteen different 3,3′‐diaryl‐5‐morpholino‐4,5,4′,5′‐tetrahydro‐4,5′‐spirobi[isoxazoles] 3 were obtained by their reaction with some stable aryl nitrile oxides. The spiro‐derivatives were characterized by their nmr spectra. Kinetic measurements showed that substituents on the nitrile oxide have a weak effect on the cycloaddition rate (Hammett ' p = ca 0.3), while substituents on the dipolarophile have no effect at all.