Synthesis and Tautomerism of Substituted
Pyrazolo[4,3-c]pyrazoles

J 2013

Synthesis and Tautomerism of Substituted Pyrazolo[4,3-c]pyrazoles

KADAM, Shivaji Sambhaji; Lukáš MAIER; Ioannis KOSTAKIS; Nicole POULI; Jaromír TOUŠEK et. al.

Základní údaje

Originální název

Synthesis and Tautomerism of Substituted Pyrazolo[4,3-c]pyrazoles

Autoři

KADAM, Shivaji Sambhaji (356 Indie, domácí); Lukáš MAIER (203 Česká republika, domácí); Ioannis KOSTAKIS (300 Řecko); Nicole POULI (300 Řecko); Jaromír TOUŠEK (203 Česká republika, domácí); Marek NEČAS (203 Česká republika, domácí); Panagiotis MARAKOS (300 Řecko) a Radek MAREK (203 Česká republika, garant, domácí)

Vydání

European Journal of Organic Chemistry, Weinheim, WILEY-VCH, 2013, 1434-193X

Další údaje

Jazyk

angličtina

Typ výsledku

Článek v odborném periodiku

Obor

10401 Organic chemistry

Stát vydavatele

Německo

Utajení

není předmětem státního či obchodního tajemství

Odkazy

DOI: 10.1002/ejoc.201300606

Impakt faktor

Impact factor: 3.154

Kód RIV

RIV/00216224:14740/13:00066252

Organizační jednotka

Středoevropský technologický institut

DOI

http://dx.doi.org/10.1002/ejoc.201300606

UT WoS

000328739500009

Klíčová slova anglicky

NMR chemical shift; synthesis of pyrazolo[4.3-c]pyrazoles; stability of tautomers; regioisomers; low-temperature NMR; X-ray diffraction; DFT calculations

Štítky

rivok

Příznaky

Mezinárodní význam, Recenzováno

Změněno: 13. 3. 2018 10:11, doc. Mgr. Marek Nečas, Ph.D.

Anotace

V originále

Fused five-membered nitrogen heterocycles comprise a very important group of compounds frequently utilized in pharmaceutical applications. In this study, we report the first systematic synthesis of substituted pyrazolo[4,3-c]pyrazoles and three regio-isomers of their N-methyl derivatives. All compounds were fully characterized by using NMR spectroscopy in solution and selected compounds also by X-ray diffraction in the solid state. 1H, 13C, and 15N NMR data for all isomers were interpreted by DFT calculations of nuclear shielding constants and indirect spin-spin coupling constants. The N-methyl isomers were used in the following steps as model compounds to investigate a potential N1-H/N4-H, N2-H/N4-H, and N1-H/N5-H tautomerism of 3,6-substituted pyrazolo[4,3-c]pyrazoles by using low-temperature NMR spectroscopy. All bases were shown to occur predominantly in the N1-H/N4-H tautomeric form and the structure of minor form was governed by the substituents at positions 3 and 6. Stabilities of individual tautomeric forms are calculated by DFT methods and discussed. A relationship between the tautomeric populations and the ratios among N-methyl isomers obtained upon methylation of selected base in solution is investigated.

Návaznosti

ED1.1.00/02.0068, projekt VaV

Název: CEITEC - central european institute of technology

GAP206/12/0539, projekt VaV

Název: Struktura a dynamika komplexů přechodných kovů a jejich interakce s kavitandy (Akronym: METALIN)

Investor: Grantová agentura ČR, Struktura a dynamika komplexů přechodných kovů a jejich interakce s kavitandy

Přiložené soubory

EJOC13_2013_6811.pdf

Požádat o autorskou verzi souboru

Citovat

KADAM, Shivaji Sambhaji; Lukáš MAIER; Ioannis KOSTAKIS; Nicole POULI; Jaromír TOUŠEK; Marek NEČAS; Panagiotis MARAKOS a Radek MAREK. Synthesis and Tautomerism of Substituted Pyrazolo[4,3-c]pyrazoles. European Journal of Organic Chemistry. Weinheim: WILEY-VCH, 2013, roč. 2013, č. 30, s. 6811-6822. ISSN 1434-193X. Dostupné z: https://dx.doi.org/10.1002/ejoc.201300606.

@article{1116127,
   author = {Kadam, Shivaji Sambhaji and Maier, Lukáš and Kostakis, Ioannis and Pouli, Nicole and Toušek, Jaromír and Nečas, Marek and Marakos, Panagiotis and Marek, Radek},
   article_location = {Weinheim},
   article_number = {30},
   doi = {http://dx.doi.org/10.1002/ejoc.201300606},
   keywords = {NMR chemical shift; synthesis of pyrazolo[4.3-c]pyrazoles; stability of tautomers; regioisomers; low-temperature NMR; X-ray diffraction; DFT calculations},
   language = {eng},
   issn = {1434-193X},
   journal = {European Journal of Organic Chemistry},
   title = {Synthesis and Tautomerism of Substituted Pyrazolo[4,3-c]pyrazoles},
   url = {http://dx.doi.org/10.1002/ejoc.201300606},
   volume = {2013},
   year = {2013}
}

TY  - JOUR
ID  - 1116127
AU  - Kadam, Shivaji Sambhaji - Maier, Lukáš - Kostakis, Ioannis - Pouli, Nicole - Toušek, Jaromír - Nečas, Marek - Marakos, Panagiotis - Marek, Radek
PY  - 2013
TI  - Synthesis and Tautomerism of Substituted Pyrazolo[4,3-c]pyrazoles
JF  - European Journal of Organic Chemistry
VL  - 2013
IS  - 30
SP  - 6811-6822
EP  - 6811-6822
PB  - WILEY-VCH
SN  - 1434193X
KW  - NMR chemical shift
KW  - synthesis of pyrazolo[4.3-c]pyrazoles
KW  - stability of tautomers
KW  - regioisomers
KW  - low-temperature NMR
KW  - X-ray diffraction
KW  - DFT calculations
UR  - http://dx.doi.org/10.1002/ejoc.201300606
L2  - http://dx.doi.org/10.1002/ejoc.201300606
N2  - Fused five-membered nitrogen heterocycles comprise a very important group of compounds frequently utilized in pharmaceutical applications. In this study, we report the first systematic synthesis of substituted pyrazolo[4,3-c]pyrazoles and three regio-isomers of their N-methyl derivatives. All compounds were fully characterized by using NMR spectroscopy in solution and selected compounds also by X-ray diffraction in the solid state. 1H, 13C, and 15N NMR data for all isomers were interpreted by DFT calculations of nuclear shielding constants and indirect spin-spin coupling constants. The N-methyl isomers were used in the following steps as model compounds to investigate a potential N1-H/N4-H, N2-H/N4-H, and N1-H/N5-H tautomerism of 3,6-substituted pyrazolo[4,3-c]pyrazoles by using low-temperature NMR spectroscopy. All bases were shown to occur predominantly in the N1-H/N4-H tautomeric form and the structure of minor form was governed by the substituents at positions 3 and 6. Stabilities of individual tautomeric forms are calculated by DFT methods and discussed. A relationship between the tautomeric populations and the ratios among N-methyl isomers obtained upon methylation of selected base in solution is investigated.
ER  -

KADAM, Shivaji Sambhaji; Lukáš MAIER; Ioannis KOSTAKIS; Nicole POULI; Jaromír TOUŠEK; Marek NEČAS; Panagiotis MARAKOS a Radek MAREK. Synthesis and Tautomerism of Substituted Pyrazolo[4,3-c]pyrazoles. \textit{European Journal of Organic Chemistry}. Weinheim: WILEY-VCH, 2013, roč.~2013, č.~30, s.~6811-6822. ISSN~1434-193X. Dostupné z: https://dx.doi.org/10.1002/ejoc.201300606.

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