Synthesis of 1,2,3-triazoles containing an allomaltol moiety from substituted pyrano[2,3-d]isoxazolones via base-promoted Boulton–Katritzky rearrangement

• Constantine V. Milyutin,
• Andrey N. Komogortsev and
• Boris V. Lichitsky

Beilstein J. Org. Chem. 2024, 20, 1334–1340, doi:10.3762/bjoc.20.117

• ]isoxazolone derivatives with various hydrazines was studied. It was shown that the considered process includes formation of corresponding hydrazones followed by Boulton–Katritzky rearrangement. As a result, the general method for the synthesis of substituted 1,2,3-triazoles bearing an allomaltol fragment was

• types of aforementioned structures were proved by X-ray analysis. Keywords: allomaltol; Boulton–Katritzky rearrangement; hydrazones; pyrano[2,3-d]isoxazolones; recyclization; 1,2,3-triazoles; Introduction The Boulton–Katritzky rearrangement (BKR) also known as mononuclear heterocyclic rearrangement is

• to Boulton–Katritzky rearrangement are furazanes and furoxanes. In the case of furazanes the recyclization leads to 1,2,3-triazoles with an oxime moiety in the side chain [13][14]. At the same time 1,2,3-triazole N-oxides are formed from similar furoxanes [15]. Furthermore, special attention is paid

Mild and efficient synthesis and base-promoted rearrangement of novel isoxazolo[4,5-b]pyridines

• Vladislav V. Nikol’skiy,
• Mikhail E. Minyaev,
• Maxim A. Bastrakov and
• Alexey M. Starosotnikov

Beilstein J. Org. Chem. 2024, 20, 1069–1075, doi:10.3762/bjoc.20.94

• the basis of readily available 2-chloro-3-nitropyridines via the intramolecular nucleophilic substitution of the nitro group as a key step. The previously unknown base-promoted Boulton–Katritzky rearrangement of isoxazolo[4,5-b]pyridine-3-carbaldehyde arylhydrazones into 3-hydroxy-2-(2-aryl[1,2,3

• ]triazol-4-yl)pyridines was observed. Keywords: aromatic nitro compounds; Boulton–Katritzky rearrangement; isoxazolo[4,5-b]pyridines; nucleophilic substitution; 1,2,3-triazoles; Introduction Nitrogen heterocycles represent a very important class of organic compounds that has found application in various

• isoxazolo[4,5-b]pyridines 12 were obtained in pure form, however, cyclization of hydrazone 11a provided an inseparable mixture of two compounds which could be attributed to the target isoxazolo[4,5-b]pyridine 12a and triazole 13a formed as a result of Boulton–Katritzky rearrangement (Scheme 5). When this