3-Ethyl-1 pyrazinone

An interesting parallel was found while the microwave-enhanced Heck reaction was explored on the C-3 position of the pyrazinone system [29]. The additional problem here was caused by the capability of the alkene to undergo Diels-Alder reaction with the 2-azadiene system of the pyrazinone. An interesting competition between the Heck reaction and the Diels-Alder reaction has been noticed, while the outcome solely depended on the substrates and the catalyst system. Microwave irradiation of a mixture of pyrazinone (Re = H), ethyl acrylate (Y = COOEt) and Pd(dppf)Cl2 resulted in the formation of a mixture of the starting material together with the cycloaddition product in a 3 1 ratio (Scheme 15). On the contrary, when Pd(OAc)2 was used in combination with the bulky phosphine ligand 2-(di-t-butylphosphino)biphenyl [41-44], the Heck reaction product was obtained as the sole product. When a mixture of the pyrazinone (Re = Ar) with ethyl acrylate or styrene and Pd(dppf)Cl2 was irradiated at 150 °C for 15 min, both catalytic systems favored the Heck reaction product with no trace of Diels-Alder adduct. [Pg.278]

Conversion of pyrazinones into bromopyrazines is known (82MI2), as is side-chain bromination, particularly when NBS is used under conditions conducive to radical formation. Thus, 2-ethyl-3-methylpyrazine was converted into the l -bromoethyl derivative (72JOC511). [Pg.319]

Amino-2-phenylacetamide (192) and ethyl benzoylformate (193) gave 5-hy-droxy-3,6-diphenyl-2(l //)-pyrazinone (194) (EtONa, EtOH, reflux, 5 h 19%).1386 ... [Pg.28]

Amino-3-methyl-2-butanone (270) and ethyl glycinate (271) gave 5,6, 6-trimcthyl-3,6-dihydro-2( I //(-pyrazinone (272) (Et3N, PhH, reflux, 5 days ... [Pg.36]

Ethyl 2,3-dichloro-6-methylfuro[2,3-b]pyrazinc-7-carboxylate (89) gave 5,6-dichloro-3-ethoxycarbonylmethyl-2(l//)-pyrazinone (90) (NH4OH, NH4C1, EtOH—THF, 50°C, 12 h 29%).1308... [Pg.61]

I -Benzyl-3,6-dichloro-2( l//)-pyrazinonc (127, R = Cl) gave l-benzyl-5-chloro-3-methyl-2(17/)-pyrazinone (127, R = Me) [Me4Sn, Pd(PPh3)4, PhMe, reflux, <5 days residue from evaporation, KF, AcOEt, 20°C, 12 h 81%) or its 3-ethyl ho-mologues (127, R = Et) (Et4Sn, likewise 95%) 391 analogues similarly.391... [Pg.98]

Hydroxy-5,6-diisopropyl-2(l//)-pyrazinone (264, R = H) gave 1-benzoyloxy-5,6-diisopropyl-2(l//)-pyrazinonc (264, R = Bz) (BzCl, pyridine, CH2C12, 5 20°C, 12 h 64%) 1515 several analogues like 5-chloro-1 -(p-chloroben-zoyloxy)-6-ethyl-2(l//)-pyrazinone (265), were made similarly.1011515... [Pg.234]

Aminopentanoyl)ethyl]-l-benzyloxy-5,6-dimethyl-2(l//)-pyrazinone (311) and a coligand afforded a gallium complex that showed promise for extraction of primary ammonium ions.179... [Pg.240]

Amperozide, 4-[4,4-bis(p-fluorophenyl)butyl]-A, -ethyl-1 -piperazinecarboxamide, analgesic and tranquilizer [75558-90-6],1711 Arglecin (H 7), 6-(3-guanidinopropyl)-3-isobutyl-2(l//)-pyrazinone, a Strepto-myces sp metabolite [34098-41-4].295... [Pg.241]

Benzyl-5-ethoxy-6-methyl-2 (I //)-pyrazinono 6-Benzyl-3-ethyl-l-hydroxy-2n //)-pyraz,inone 6-Benzyl-3-ethyl-5-methyl-2(l//)-pyrazinone... [Pg.371]

Benzyloxy-6-hydroxymethyl-3-isobutylpyrazine 4-oxide 2-Benzyloxy-6-iodomethyl-3-isobutyl-5-methoxypyrazine 4-oxide 2-Benzyloxy-3-isobutyl-6-mesyloxy-methyl-5-methoxypyrazine-4-oxide 1 - Benzyloxy-3 - (2-methoxycarbonyl-ethyl)-5,6-dimethyl-2(l/7)-pyrazinone... [Pg.373]

Ethyl-5,6-diphenyl-2(177)-pyrazinone 6-Ethyl-3,5-diphenyl-2(177)-pyrazinone Ethyl 6-ethoxy-2-pyrazinecarboximidate Ethyl 6-ethoxy-2-pyrazinecarboxylate TV-Ethyl-3-ethylamino-5-methylamino-... [Pg.421]

Ethyl-5-hydroxy-6-methyl-2(177)-pyrazinone 2-(l-Ethyl-l-hydroxypropyl)pyrazine... [Pg.421]

Ethyl-6-isobutyl-5-methyl-2(177)-pyrazinone Ethyl 5-isopropyl-6-methyl-3-oxo-3,... [Pg.421]

Ethyl-3-methyl-5-phenyl-2(177)-pyrazinone 5-Ethyl-3-methyl-2-pyrazinamine 1-oxide 2-Ethyl-3-methylpyrazine... [Pg.422]

Amino-iV-(l-chloroacetyl-3-metliylbutyl)butyrainide (25, R = H), prepared in situ as hydrochloride by treatment of its A-tert-butoxycarbonyl derivative (25, R = CO2BU ) in HCl-dioxane, gave 3-ethyl-6-isobutyl-5-methyl-2(l7/)-pyrazinone (26) (MeOH, reflux, 2 h 90%) many analogues were made similarly. - "- -1 ... [Pg.6]

Ethyl-2(l//)-pyrazinone gave only 3-ethyl-l-(pyridm-2-ylniethyl)-2(l//)-pyrazi-none (54) (NaH, McjNlH IO, 25°C, 2 h then 2-chloromethylpyridine J, 25°C, 18h 62%) 2... [Pg.199]

Diphenyl-2(l//)-pyrazinone (56, R = H) gave l-ethyl-5,6-diphenyl-2(l//)-pyrazinone (56, R = Et) and a separable trace of the ethoxy isomer (Et2SO4, MeONa, MeOH, 20°C reflux, 1 h %) homologues likewise. ... [Pg.199]

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