Crystal structure determination of N- and O-alkylated tautomers of 1-(2-pyridinyl)-5-hydroxypyrazole

Venkata S. Sadu; Yoon Mi Choi; Koteswara R. Kamma; Chong Hyeak Kim; Yun Soo Bae; Kee In Lee

doi:10.1016/j.molstruc.2020.128272

Crystal structure determination of N- and O-alkylated tautomers of 1-(2-pyridinyl)-5-hydroxypyrazole

Venkata S. Sadu, Yoon Mi Choi, Koteswara R. Kamma, Chong Hyeak Kim, Yun Soo Bae, Kee In Lee

Life Sciences

Research output: Contribution to journal › Article › peer-review

2 Scopus citations

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	https://doi.org/10.1016/j.molstruc.2020.128272
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

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10.1016/j.molstruc.2020.128272

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title = "Crystal structure determination of N- and O-alkylated tautomers of 1-(2-pyridinyl)-5-hydroxypyrazole",

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.",

keywords = "C NMR, 1-(2-Pyridinyl)-5-hydroxypyrazole, Crystal structure, N-Alkylation, O-Alkylation, Tautomerism",

author = "Sadu, {Venkata S.} and Choi, {Yoon Mi} and Kamma, {Koteswara R.} and Kim, {Chong Hyeak} and Bae, {Yun Soo} and Lee, {Kee In}",

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: {\textcopyright} 2020",

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doi = "10.1016/j.molstruc.2020.128272",

language = "English",

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T1 - Crystal structure determination of N- and O-alkylated tautomers of 1-(2-pyridinyl)-5-hydroxypyrazole

AU - Sadu, Venkata S.

AU - Choi, Yoon Mi

AU - Kamma, Koteswara R.

AU - Kim, Chong Hyeak

AU - Bae, Yun Soo

AU - Lee, Kee In

N1 - 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

PY - 2020/9/5

Y1 - 2020/9/5

N2 - 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.

AB - 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.

KW - C NMR

KW - 1-(2-Pyridinyl)-5-hydroxypyrazole

KW - Crystal structure

KW - N-Alkylation

KW - O-Alkylation

KW - Tautomerism

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Crystal structure determination of N- and O-alkylated tautomers of 1-(2-pyridinyl)-5-hydroxypyrazole

Abstract

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Keywords

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