The preparation of ester heterocycles mostly uses heteroatoms as nucleophilic sites, which are achieved by intramolecular substitution or addition reactions. Compound: 3,5-Dimethyl-4-nitropyridine 1-oxide( cas:14248-66-9 ) is researched.Category: isoxazole.Kaneko, Chikara; Yokoe, Ichiro; Yamada, Sachiko published the article 《N-Oxides of 11-deficient N-heteroaromatics. VIII. Photochemical rearrangement of pyridine and quinoline 1-oxides having sterically hindered 4-nitro group》 about this compound( cas:14248-66-9 ) in Tetrahedron Letters. Keywords: PYRIDINES PHOTO REARRANGEMENT; QUINOLINE PHOTO REARRANGEMENT; PHOTO REARRANGEMENT QUINOLINE; REARRANGEMENT PHOTO QUINOLINE. Let’s learn more about this compound (cas:14248-66-9).
EtOH (550 ml.) containing 1 g. 3,5,4-Me2(O2N)C5H2NO irradiated (N atm.) 1.5 hrs. by a Hanovia 450 w. high-pressure Hg-arc lamp placed inside a watercooled pyrex immersion well, the solvent evaporated, and the residue recrystallized from 1:10 MeOH-Me2CO yielded 30% 3,5,4-Me2(HO)C5H2NO, m. 184°, (Hertog and Combe, CA 47, 5938c). A mechanistic pathway involving nitro-nitrite rearrangement as a key step was tentatively suggested. Steric hindrance by the 2 ortho Me groups may prevent abstraction of H from the solvents by the excited species and thus inhibit formation of the 4-hydroxyamino compound Under the above conditions photolysis of 4-nitroquinoline 1-oxide gave only 7% 2,4-dihydroxyquinoline, m. 300°, whereas 3-methyl-4-nitroquinoline 1-oxide gave 30% 3-methyl-2,4-dihydroxyquinoline, m. 264-5°; monoacetate, m. 241-3°. Contrary to the photolysis of 4-nitro derivatives of pyridine, 2-picoline, 3-picoline, and 2,6-lutidine 1-oxides, the presence of O did not affect the formative of these products but the yields of the corresponding 4-hydroxy derivatives were somewhat lower.
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Reference:
Isoxazole – Wikipedia,
Isoxazole | C3H3NO – PubChem