N.D. Zelinsky Institute of Organic Chemistry RAS; Leninsky prosp. 47, 119991 Moscow, Russia.
Chemistry Department, Lomonosov Moscow State University, Leninskie gory, 1/3, 119991 Moscow, Russia.
Molecules. 2020 May 8;25(9):2194. doi: 10.3390/molecules25092194.
A number of novel 6-R-isoxazolo[4,3-]pyridines were synthesized and their reactions with neutral C-nucleophiles (1,3-dicarbonyl compounds, π-excessive (het)arenes, dienes) were studied. The reaction rate was found to be dependent on the nature of the substituent 6-R. The most reactive 6-nitroisoxazolo[4,3-]pyridines are able to add C-nucleophiles in the absence of a base under mild conditions. In addition, these compounds readily undergo [4+2]-cycloaddition reactions on aromatic bonds C=C(NO) of the pyridine ring, thus indicating the superelectrophilic nature of 6-NO-isoxazolo[4,3-]pyridines.
许多新型 6-R-异恶唑并[4,3-b]吡啶被合成，并研究了它们与中性 C-亲核试剂（1,3-二羰基化合物、π-过剩（杂）芳烃、二烯）的反应。反应速率被发现取决于 6-R 取代基的性质。最活泼的 6-硝基异恶唑并[4,3-b]吡啶在温和条件下无需碱即可与 C-亲核试剂加成。此外，这些化合物容易在吡啶环的芳香键 C=C(NO)上发生[4+2]-环加成反应，从而表明 6-NO-异恶唑并[4,3-b]吡啶具有超亲电性。
