Pyrazinecarbaldehydes oxidation

Although most pyrazinecarbaldehydes are reasonably stable toward aerial oxidation, they are often stored or characterized only as their acetals, oximes, hydra-... 

Reactions of pyrazinecarbaldehydes already discussed include reduction to hydroxyalkylpyrazines (Section 5.2.1) and oxidation to pyrazinecarboxylic acids (Section 8.1.1) no Cannizzaro disproportionations appear to have been reported recently. 

Pyrazinecarbonitrile Oxides are unstable but they can be generated from pyrazinecarbaldehyde oximes with TV-chlorosuccinimide and then trapped immediately by appropriate dipolarophiles to afford cyclic adducts, as illustrated in the following examples ... 

Amino-5-phenyl-2-pyrazinecarbaldehyde 3-Amino-5-phenyl-2-pyrazinecarbonitrile 3-Amino-6-phenyl-2-pyrazinecarbonitrile 3-Amino-6-phenyl-2-pyrazinecarbonitrile 4-oxide 3-Amino-A-phenyl-2-pyrazinecarboxamide 3-Amino-5-phenyl-2-pyrazinecarboxamide 3-Amino-6-phenyl-2-pyrazinecarboxamide 3-Amino-6-phenyl-2-pyrazinecarboxamide 4-oxide... 

Chloro-3,6-diisobutyl-2(17/)-pyrazinone 2-Chloro-3,6-diisopropyl-5-methylaminopyrazine 2-Chloro-3,6-diisopropylpyrazine 5-Chloro-3,6-diisopropyl-2-pyrazinecarbaldehyde 1-oxide 2-Chloro-3,6- diisopropylpyrazine 1 - oxide 2-Chloro-3,6-diisopropylpyrazine 4-oxide... 

Phenylpteridine (117) gave 3-ethyliminomethyl-6-phenyl-2-pyrazinamine (119) (neat EtNH2, 20°C, 4 h 78% via the adduct (118)] or a separable mixture of 4-ethylamino-7-phenylpteridine (120) and 3-amino-5-phenyl-2-pyrazinecarbaldehyde (121) [neat EtNH, KMnO4 (1 mol), 17°C, 5 h 26 and 38%, respectively, after separation the second, presumably via the Schiff base (119)] the aldehyde (121) was oxidized further to 3-ainino-5-phenyl-2-pyrazinecarboxylic acid (122) (KMnO4, H,O, 20°C, 1 h 28%). ... 

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