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3-Methoxycarbonylpyrazine 1-oxide with acetic anhydride

Amino-2prepared from 2-amino-3-cyanopyrazine 1-oxide by reflux with acetic acid-acetic anhydride followed by ready deacetylation by refluxing in methanol (538), and in a similar manner 3-amino-2-ethoxycarbonyl-5-hydroxypyrazine has been prepared from 2-amino-3-ethoxycarbonylpyrazine 1 -oxide through 3-acetamido-2-ethoxycarbonyl-5 ydroxy-pyrazine (538), and 2-amino-3-carbamoyl-6-hydroxy-5-methylpyrazine from 2-amino-3-cyano-5-methylpyrazine 1-oxide (538). The preparation of 24 ydroxy-6-methoxycarbonylpyrazine (10) has been claimed from 3-methoxycarbonylpyrazine 1-oxide with acetic anhydride followed by hydrolysis (1057) [cf. Nov Cek et al. (839), who claim it to be the 5-isomer, and Foks (744)]. [Pg.162]

Hydrolysis of 2,6-diacetoxy-3,5-diphenylpyrazine (9) (from 2-hydroxy-3,5-diphenylpyrazine 1 -oxide by refluxing with acetic acid-acetic anhydride) with potassium hydrogen carbonate in methanol gave 2,6-dihydroxy-3,5-diphenylpyrazine (873), and 2-acetoxy-6-methoxycarbonylpyrazine (from 3-methoxycarbonyl-pyrazine 1-oxide with acetic anhydride) with methanolic hydrogen chloride gave 2-hydroxy-6 -methoxycarbonylpyrazine (838). [Pg.162]

Acetoxylative deoxygenations are as follows. 3-Methoxycarbonylpyrazine 1-oxide refluxed with acetic anhydride for 30 hours gave 2-acetoxy-6-methoxy-carbonylpyrazine (838), but Novdcek et al. (839) claim that the product (prepared with acetic anhydride at 160°) after hydrolysis with water was 2-hydroxy-5( )-methoxycarbonylpyrazine and 2-amino-3-ethoxycarbonylpyrazine 1-oxide refluxed with acetic acid-acetic anhydride gave 3-acetamido-2-ethoxycarbonyl-5-hydroxypyrazine (538). [Pg.304]


See also in sourсe #XX -- [ Pg.162 , Pg.304 ]




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2- -3-methoxycarbonylpyrazine

Acetalization-oxidation

Acetals oxidation

Acetate oxidation

Acetic anhydride with acetals

Acetic oxide

Oxidations acetic anhydride

With acetic anhydride

With anhydrides

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