110524-88-4

Basic information

• Product Name: (Z)-1-Phenyl-2-pyrazin-2-yl-ethenol
• CAS NO: 110524-88-4
• Molecular Weight: 198.224
• Mol File: 110524-88-4.mol
• Article Data: 3

Chemical Properties

• CAS DataBase Reference: (Z)-1-Phenyl-2-pyrazin-2-yl-ethenol(CAS DataBase Reference)
• NIST Chemistry Reference: (Z)-1-Phenyl-2-pyrazin-2-yl-ethenol(110524-88-4)
• EPA Substance Registry System: (Z)-1-Phenyl-2-pyrazin-2-yl-ethenol(110524-88-4)

Safety Data

• Hazardous Substances Data: 110524-88-4(Hazardous Substances Data)

Upstream product

• 40061-45-8 1-phenyl-2-(pyrazin-2-yl)ethanone 
• 109-08-0 2-Methylpyrazine 
• 100-47-0 benzonitrile 

Downstream Products

• 40061-45-8 1-phenyl-2-(pyrazin-2-yl)ethanone 

Relevant articles and documents

Keto-Enol Tautomerism of Phenacylpyrazine: Acid Catalysis with Protonation at Nitrogen

Kinetic and equilibrium measurements for ionisation and enolisation of 2-phenacylpyrazine in aqueous solution at 25 deg C yield a tautomeric constant pKE = 2.05 (where KE = /) and pKas for loss of a methylene proton and for protonation at nitrogen of 11.90 and 0.40, respectively.In contrast to 2-phenacylpyridine the low basicity of the pyrazine nitrogens renders an enaminone tautomer less stable than the enol and a value of pKM = 4.4 (KM = /) is estimated for this equilibrium.Evidence is presented that acid catalysis of keto-enol tautomerism occurs with protonation at the N-1 nitrogen atom rather than carbonyl group (or N-4 nitrogen) despite the proton being bound to oxygen in the enolic product.This preference reflects relative magnitudes of binding constants (1/Ka) and activating factors (PAF) for protonation at the different positions.Broensted and Marcus equations are used to express catalytic efficiency in terms of equilibrium constants for binding the catalyst to the reactant and products of the uncatalysed reaction.The form of catalysis observed, which reflects the influence of proton binding on the activation energy of the reaction, is contrasted with that in intramolecular or enzymatic reactions, which normally derives from approximation of the reactants and is entropic in origin.The significance of optimum binding of the catalyst to the transition state in the two cases is briefly compared.

Cyclisation par amination intramoleculaire dans la serie de la pyrazine.

An original one-pot synthesis of 4,7-diazaindoles is achieved by metalation of methylpyrazines or methylquinoxaline which are then condensed with an aromatic nitrile : an intermediate imine-enamine is formed which leads, by intramolecular cyclization, to diazaindoles.