2- -5-isobutylpyrazine 1-oxide

Chloro-3-isobutylpyrazine 4-oxide gave 3-isobutyl-2( I // )-pyrazinone 4-oxide (111, R = Hu ) (5 M NaOH, reflux, 2 h 39%) 86 2-chloro-3-phenylpyrazine 4-oxide gave 3-phenyl-2( I //(-pyrazinone 4-oxide (111, R = Ph) (KOH, H20—EtOH, reflux, 1 h 30%) 1290 also analogues likewise.1290... 

Benzyloxy-5-chloro-6-hydroxymethyl-3-isobutylpyrazine 4-oxide gave 2-benzyloxy-5-chloro-3-isobutyl-6-[(tetrahydropyran-2-yloxy)methyl]pyrazine 4-oxide (150) (3,4-dihydro-2//-pyran, TsOH.H20, CH2C12, 20°C, 1 h 95%).848... 

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... 

Chloro-3-isobutyl-6-methylpyrazine 1-oxide 2-Chloro-6-isobutyl-3-methylpyrazine 1-oxide 2-Chloro-6-isobutyl-3-methylpyrazine 4-oxide 2-Chloro-3-isobutyl-5-phenylpyrazine 2-Chloro-3-isobutylpyrazine... 

Chloro-5-isobutylpyrazine 6-Chloro-5-isobutyl-2-pyrazinecarbothioamide 6-Chloro-5-isobutyl-2-pyrazinecarboxamide 2-Chloro-3-isobutylpyrazine 4-oxide 2-Chloro-5-isopentyl-3,6-dimethylpyrazine 2-Chloro-3-isopropenyl-6-isopropyl-5-methoxypyrazine 5-Chloro-6-isopropenyl-3-isopropyl-l-methyl-2(177)-pyrazinone... 

Dimethylamino-7V-hydroxy-2-pyrazinecarboxamide 6-Dimethylamino-7V-hydroxy-2-pyrazinecarboxamidine 2-Dimethylamino-5-iodopyrazine 2-Dimethylamino-6-iodopyrazine 2-Dimethylamino-5-iodopyrazine 4-oxide 2-Dimethylamino-3-isobutylpyrazine 2-Dimethylamino-6-isobutylpyrazine 2-Dimethylamino-5-methoxy-3,6-dimethylpyrazine 2-Dimethylaminomethyl-3,6-bismethylthiopyrazine 2-Dimethylamino-6-methyl-5-phenylpyrazine 4-oxide 2-Dimethylamino-3-methylpyrazine 2-Dimethylamino-6-methylpyrazine 2-Dimethylamino-3-methylpyrazine 4-oxide Dimethyl 5-amino-6-oxo-1,6-dihydro-2,3-pyrazinedicarboxylate 2-Dimethylamino-5-phenylpyrazine 2-(3-Dimethylaminopropyl)-6-methylpyrazine... 

Chloro-2,5 diisobuty Ipyrazine 1 -oxide 2-(l -Acetoxy-2 -methylpropyl)-3- chloro-5-isobutylpyrazine 760a... 

Chloro-3,6-diisobutylpyrazine 1-oxide 5-(l -Acetoxy-2 -methyl)propyl-3-chloro-2-isobutylpyrazine 113b... 

TS-Butyl-3-hydrazino-5-isobutylpyrazine 1-oxide was prepared from the chloro analogue and hydrazine hydrate at 130 (313) and 2-(l -acetoxy-2 -methylpropyl)-... 

Diazomethane methylation of 3-hydroxy-2,5-diisobutylpyrazine 1,4-dioxide has been shown to give the 4-methoxypyrazine 1-oxide, 2,5-diisobutyl4-methoxy-3-0X0-3,4-dihydropyrazine 1-oxide (96) (843, 980) [and some 3-methoxy-2,5-diisobutylpyrazine 1,4-dioxide (4 l)(980)] 5-s-butyl-3-hydroxy-2-isobutylpyrazine... 

When 2-hydroxy-3,5-diphenylpyrazine 1-oxide was heated under reflux with an excess of acetic anhydride, a crystalline triacetoxy compound was obtained which was thought to have an open chain structure [AcO-CH=CPh-N=CPh-C(OAc)=N-OAc], but when the 2-hydroxypyrazine-l-oxide was boiled with a mixture of acetic anhydride and acetic acid, 2,6-diacetoxy-3,5-diphenylpyrazine was obtained (873) which was hydrolyzed by potassium hydrogen carbonate in methanol to 2,6-dihydroxy-3,5-diphenylpyrazine (873). 2-Hydroxy-5-methyl-3-phenylpyrazine 1-oxide behaved differently and when refluxed with acetic anhydride gave 5-acetoxymethyl-2-hydroxy-3-phenylpyrazine (100) and 2-hydroxy-3-methyl-5-phenylpyrazine 1-oxide similarly gave 3-acetoxymethyl-2-hydroxy-5-phenylpyrazine (873). When 2- l-hydroxy-2 -methylpropyl)-5-isobutylpyrazine 1-oxide was heated with a mixture of acetic anhydride and sodium acetate on a water bath 2-(l -acetoxy-2 -methylpropyl)-5-isobutylpyrazine 1 oxide was obtained (760a). 

Hydroxy-5-(1 -hydroxy-2 -methylpropyl)-2-isobutylpyrazine 1,4-dioxide was deoxygenated by titanium trichloride in dry tetrahydrofuran under nitrogen at room temperature to give 2-hydroxy-6-(r-hydroxy-2 -methylpropyl)-3-isobutyl-pyrazine 1 oxide (DL-neohydroxyaspergillic acid) (760a). 

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