Zinc chloride catalyzed multicomponent synthesis of pyrazolopyridocoumarin scaffolds was written by Shamala, Devadas;Shivashankar, Kalegowda;Chandra;Mahendra, Madegowda. And the article was included in Journal of Chemical Sciences (Berlin, Germany) in 2019.COA of Formula: C5H9N3 This article mentions the following:
An efficient synthesis of a series of pyrazolopyridocoumarins I (R1 = Ph, 4-bromophenyl, 2,3-dimethoxyphenyl, etc.; R2 = Et, Me) is reported by condensation of 4-hydroxycoumarin, benzaldehydes R1CHO and 1-alkyl-5-amino-pyrazoles II in the presence of 10 mol% zinc chloride in ethanol under reflux conditions through one-pot reaction. The significant attraction of this protocol is being a simple procedure, mild reaction condition, and excellent yield. The mol. structure of the compound I (R1 = 2,3-dimethoxyphenyl; R2 = Et) is established by single crystal X-ray structure determination In the experiment, the researchers used many compounds, for example, 1-Ethyl-1H-pyrazol-5-amine (cas: 3528-58-3COA of Formula: C5H9N3).
1-Ethyl-1H-pyrazol-5-amine (cas: 3528-58-3) belongs to pyrazole derivatives. Pyrazole and its derivatives are considered a pharmacologically important active scaffold that possesses almost all types of pharmacological activities. Protonation of pyrazole in strong acid leads to pyrazolium cations, which undergo electrophilic substitution preferentially at C3 rather than C4. The pyrazole anion is not reactive toward nucleophiles but is mostly reactive to electrophiles.COA of Formula: C5H9N3
Referemce:
Pyrazole – Wikipedia,
Pyrazoles – an overview | ScienceDirect Topics