Synthesis and intramolecular transformations of 8-substituted 11-nitro-2-phenyl-5,6-dihydro-2H-2,6-methanobenzo[g][1,3,5]oxadiazocin-4(3H)-one diastereomers
- Authors: Sedova V.F.1, Krivopalov V.P.1, Shkurko O.P.1
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Affiliations:
- N. N. Vorozhtsov Novosibirsk Institute of Organic Chemistry, Siberian Branch of the Russian Academy of Sciences
- Issue: Vol 65, No 1 (2016)
- Pages: 215-222
- Section: Full Articles
- URL: https://journals.rcsi.science/1066-5285/article/view/236913
- DOI: https://doi.org/10.1007/s11172-016-1287-1
- ID: 236913
Cite item
Abstract
The Biginelli reaction between 5-R-salicylic aldehyde (R = H, Me, and Br), α-nitroacetophenone, and urea affords 8-R-11-nitro-2-phenyl-5,6-dihydro-2H-2,6-methanobenzo-[g][1,3,5]oxadiazocin-4(3Н)-ones as mixtures of two diastereomers. The ratio of diastereomers depends on the catalyst (HCl) concentration in the reaction medium. In DMSO and DMF, the resulting compounds undergo oxadiazocine ring opening with establishment of a three-component equilibrium between 4-(2-hydroxy-5-R-phenyl)-5-nitro-6-phenyl-3,4-dihydropyrimidin-2(1Н)-one as the major component and diastereomeric methanobenzoxadiazocines as two minor components. Dilution of these solutions with water favors the oxa-Michael reaction resulting in the reverse transformation of dihydropyrimidinones into the corresponding starting diastereomers.
About the authors
V. F. Sedova
N. N. Vorozhtsov Novosibirsk Institute of Organic Chemistry, Siberian Branch of the Russian Academy of Sciences
Email: oshk@nioch.nsc.ru
Russian Federation, 9 prosp. Akad. Lavrentéva, Novosibirsk, 630090
V. P. Krivopalov
N. N. Vorozhtsov Novosibirsk Institute of Organic Chemistry, Siberian Branch of the Russian Academy of Sciences
Email: oshk@nioch.nsc.ru
Russian Federation, 9 prosp. Akad. Lavrentéva, Novosibirsk, 630090
O. P. Shkurko
N. N. Vorozhtsov Novosibirsk Institute of Organic Chemistry, Siberian Branch of the Russian Academy of Sciences
Author for correspondence.
Email: oshk@nioch.nsc.ru
Russian Federation, 9 prosp. Akad. Lavrentéva, Novosibirsk, 630090