Abstract
The crystal structure determination of tautomeric products produced by the alkylation of 1-(2-pyridinyl)-3-phenyl-4-propyl-1H-5-hydroxypyrazole 2 was investigated. Treatment of 2 with isopropyloxycarbonyloxymethyl iodide and potassium carbonate under phase-transfer conditions affords two major products out of three possible O-, N-, and C-alkylated tautomers. The tautomeric structures of O-alkylated 3a and N-alkylated 3c were elucidated by means of NMR spectroscopic investigations and confirmed by single crystal X-ray analysis. The single crystal structures of alkylated compounds provide clear difference between the tautomeric pyrazole and pyrazolone ring systems in terms of bond lengths and torsional angles, moreover, conformational changes between two tautomers.
Original language | English |
---|---|
Article number | 128272 |
Journal | Journal of Molecular Structure |
Volume | 1215 |
DOIs | |
State | Published - 5 Sep 2020 |
Bibliographical note
Funding Information:This work was supported by the Institutional Research Program ( SI-1911-20 ) of Korea Research Institute of Chemical Technology , Aging project ( 2017M3A9D8062955 to YSB) and Stem Cell grant ( 2017M3A9B3061850 to YSB) funded by Ministry of Science and ICT.
Funding Information:
This work was supported by the Institutional Research Program (SI-1911-20) of Korea Research Institute of Chemical Technology, Aging project (2017M3A9D8062955 to YSB) and Stem Cell grant (2017M3A9B3061850 to YSB) funded by Ministry of Science and ICT.
Publisher Copyright:
© 2020
Keywords
- C NMR
- 1-(2-Pyridinyl)-5-hydroxypyrazole
- Crystal structure
- N-Alkylation
- O-Alkylation
- Tautomerism