128102-81-8

Upstream product

• 617-35-6 2-oxo-propionic acid ethyl ester 
• 452-58-4 2,3-Diaminopyridine 
• 1825-45-2 2,2-dihydroxypropanoic acid 
• 406946-75-6 3-phenacylidene-3,4-dihydro-1H-pyrido<2,3-b>pyrazin-2-one 

Downstream Products

• 1426833-03-5 1-(3-chloro-phenyl)-4-methyl-2,3,5,6,9b-pentaaza-cyclopenta[a]naphthalene 
• 1426833-04-6 1-(2-chloro-6-methyl-phenyl)-4-methyl-2,3,5,6,9b-pentaazacyclopenta[a]naphthalene 
• 1426833-31-9 C₁₆H₁₄ClN₅O 
• 1426833-05-7 1-(2,6-dichloro-phenyl)-4-methyl-2,3,5,6,9b-pentaazacyclopenta[a]naphthalene 
• 1426833-32-0 C₁₅H₁₁Cl₂N₅O 
• 1426833-06-8 1-(2,6-dimethyl-phenyl)-4-methyl-2,3,5,6,9b-pentaazacyclopenta[a]naphthalene 
• 1426833-33-1 C₁₇H₁₇N₅O 

Relevant academic research and scientific papers

Pyrido[4,3- e ][1,2,4]triazolo[4,3- a ]pyrazines as selective, brain penetrant phosphodiesterase 2 (PDE2) inhibitors

A novel series of pyrido[4,3-e][1,2,4]triazolo[4,3-a]pyrazines is reported as potent PDE2/PDE10 inhibitors with drug-like properties. Selectivity for PDE2 was obtained by introducing a linear, lipophilic moiety on the meta-position of the phenyl ring pending from the triazole. The SAR and protein flexibility were explored with free energy perturbation calculations. Rat pharmacokinetic data and in vivo receptor occupancy data are given for two representative compounds 6 and 12.

Unambiguously Confirmed Structure of 2-Phenacylidene-1,2-dihydro-4H-pyridopyrazin-3-one and 3-Phenacylidene-3,4-dihydro-1H-pyridopyrazin-2-one

To determine the structures of two isomeric products, 2-phenacylidene-1,2-dihydro-4H-pyridopyrazin-3-one (2) and 3-phenacylidene-3,4-dihydro-1H-pyridopyrazin-2-one (3) obtained by condensation of 2,3-diaminopyridine (1) with ethyl benzoylpyruvate , these compounds were hydrolyzed to give 2-methyl-4H-pyridopyrazin-3-one (4) and 3-methyl-1H-pyridopyrazin-2-one (5), respectively .Both hydrolysates 4 and 5 were hydrogenated to afford 2-methyl-1,2-dihydro-4H-pyridopyrazin-3-one (6) and 3-methyl-3,4-dihydro-1H-pyridopyrazin-2-one (7).The latter compound was identical with an unequivocally synthesized compound providing proof for the structures of all these compounds.

Comparative Kinetic Studies on the Synthesis of Quinoxalinone Derivatives and Pyridopyrazinone Derivatives by the Hinsberg Reaction

Kinetic studies on the anelation of quinoxalinone derivatives 3a-c and pyridopyrazinone derivatives 5a-c and 6a-c synthesized by the Hinsberg reaction is reported. o-Phenylenediamine or 2,3-diaminopyridine were treated with bifunctional carbonyl compounds such as glyoxylic, pyruvic and benzoylformic acids under different experimental conditions.When pyridopyrazine derivatives were synthesized both position isomers were achieved applying regioselective reactions.Mixture were avoided by looking for special experimental conditions that led unambigously to only one of the components of the classic "Hinsberg mixture".Quinoxalinone derivatives 3a-c were obtained at room temperature in good yields (>90percent) using anhydrous methanol or ethanol as solvents.On the other hand, only pyridopyrazin-3(4H)-one (5a) was regioselectively attained in aqueous buffer of pH 7 while 3-methylpyridopyrazinone derivatives were regioselectively separated using anhydrous methanol for one isomer, 5b, and anhydrous chloroform for the other isomer, 6b, at room temperature.Yields were higher than 80percent.Reactions with benzoylformic acid did not give good yields and only 2-phenylpyridopyrazin-3(4H)-one (5c) could be obtained using anhydrous chloroform (yield pyrazin-3(4H)-one (5c) in good yields applying this technique.The other isomer, 3-phenylpyrazin-2(1H)-one (6c) was always formed together with the former isomer and could not be isolated from the mixture, when other solvents than chloroform were used as the reaction media.