TY - JOUR

T1 - Unusual Formation of 1,2,4-Oxadiazine Core in Reaction of Amidoximes with Maleic or Fumaric Esters

AU - Presnukhina, Sofia I.

AU - Tarasenko, Marina V.

AU - Geyl , Kirill K.

AU - Baykova, Svetlana O.

AU - Baykov, Sergey V.

AU - Shetnev, Anton A.

AU - Boyarskiy, Vadim P.

N1 - Presnukhina, S.I.; Tarasenko, M.V.; Geyl, K.K.; Baykova, S.O.; Baykov, S.V.; Shetnev, A.A.; Boyarskiy, V.P. Unusual Formation of 1,2,4-Oxadiazine Core in Reaction of Amidoximes with Maleic or Fumaric Esters. Molecules 2022, 27, 7508. https://doi.org/10.3390/molecules27217508

PY - 2022/11/3

Y1 - 2022/11/3

N2 - We have developed a simple and convenient method for the synthesis of 3-aryl- and 3-hetaryl-1,2,4-oxadiazin-5-ones bearing an easily functionalizable (methoxycarbonyl)methyl group at position 6 via the reaction of aryl or hetaryl amidoximes with maleates or fumarates. The conditions for this reaction were optimized. Different products can be synthesized selectively in good yields depending on the base used and the ratio of reactants: substituted (1,2,4-oxadiazin-6-yl)acetic acids, corresponding methyl esters, or hybrid 3-(aryl)-6-((3-(aryl)-1,2,4-oxadiazol-5-yl)methyl)-4H-1,2,4-oxadiazin-5(6H)-ones. The reaction is tolerant to substituents’ electronic and steric effects in amidoximes. As a result, a series of 2-(5-oxo-3-(p-tolyl)-5,6-dihydro-4H-1,2,4-oxadiazin-6-yl)acetic acids, their methyl esters, and 1,2,4-oxadiazoles based on them were prepared and characterized by HRMS, 1H, and 13C NMR spectroscopy. The structures of three of them were elucidated with X-ray diffraction.

AB - We have developed a simple and convenient method for the synthesis of 3-aryl- and 3-hetaryl-1,2,4-oxadiazin-5-ones bearing an easily functionalizable (methoxycarbonyl)methyl group at position 6 via the reaction of aryl or hetaryl amidoximes with maleates or fumarates. The conditions for this reaction were optimized. Different products can be synthesized selectively in good yields depending on the base used and the ratio of reactants: substituted (1,2,4-oxadiazin-6-yl)acetic acids, corresponding methyl esters, or hybrid 3-(aryl)-6-((3-(aryl)-1,2,4-oxadiazol-5-yl)methyl)-4H-1,2,4-oxadiazin-5(6H)-ones. The reaction is tolerant to substituents’ electronic and steric effects in amidoximes. As a result, a series of 2-(5-oxo-3-(p-tolyl)-5,6-dihydro-4H-1,2,4-oxadiazin-6-yl)acetic acids, their methyl esters, and 1,2,4-oxadiazoles based on them were prepared and characterized by HRMS, 1H, and 13C NMR spectroscopy. The structures of three of them were elucidated with X-ray diffraction.

KW - amidoximes

KW - heterocycles

KW - Esters

KW - nucleophilic addition

KW - cyclization

KW - basic medium

UR - https://www.mdpi.com/1420-3049/27/21/7508

M3 - Article

VL - 27

JO - Molecules

JF - Molecules

SN - 1420-3049

IS - 21

M1 - 7508

ER -