(1Z)-1-hydroxyiminopropan-2-one

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Aminomalononitrile p-toluenesulfonate salt (20.0 g, 79 mmol) and pyruvaldehyde 1-oxime (6.88 g, 79 mmol) were combined in a flask. iPrOH (140 mL) was added, and the resulting yellow slurry was allowed to stir at room temperature for 18 h, during which time a yellow precipitate accumulated. The mixture was filtered and the precipitate was washed with iPrOH (2×50 mL) and DI H2O (20 mL), then lyophilized to give 2-amino-3-cyano-5-methypyrazine N-oxide (10.7 g). The mixture was filtered the precipitate was washed with iPrOH (2×50 mL) and DI H2O (20 mL)

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: N-Chlorosuccinimide (7.3 g) was added, portionwise, to a solution of 2-oxopropanal 1-oxime (4.8 g) in dimethylformamide (30 ml). The reaction was heated to 50° and hydrochloric acid gas bubbled through to initiate the reaction. The mixture was then stirred at room temperature for an hour. Poured into water, extracted with ether and the extracts worked up to give crude 1-chloro--oxopropanal 1-oxime. This (1.5 g) in dimethylformamide (25 ml) was then reacted with sodium methanethiolate (0.86 g). After 5 hours at below 5°, the mixture was poured into water and extracted with ether and the extracts worked up to give crude 1-methylthio-oxopropanal 1-oxime. This (1.0 g) was then reacted with 2,6-dichloro-4-trifluoromethylphenylhydrazine (1.84 g), in a similar to that described in Example 1, to give 2-(2,6-dichloro-4-trifluoromethylphenylhydrazono)-methylthiopropanal-1-oxime. This (1.4 g) was then reacted with acetic anhydride, in a similar manner to Example 5, to give 2-(2,6-dichloro-4-trifluoromethyl-phenylhydrazono)-1-methylthiopropanal 1-acetyloxime. This (1.4 g) was then stirred with a mixture of caesium carbonate (1.1 g) and tetrahydrofuran (40 ml) at room temperature for 2 hours. Solvent was removed and the residue worked up to give compound 3. The reaction was heated to 50° hydrochloric acid gas bubbled through the reaction extracted with ether to give crude 1-chloro--oxopropanal 1-oxime extracted with ether to give crude 1-methylthio-oxopropanal 1-oxime

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A solution of 2,6-dichloro-4-trifluoromethylphenylhydrazine (10.2 g) in ether (15 ml) was added with cooling to a solution of `2-oxopropanal 1-oxime (3.62 g) in ether (15 ml) at 0°. The mixture was stirred at room temperature overnight and magnesium sulphate and charcoal added. The mixture was filtered and solvent evaporated under reduced pressure. The residue was purified by column chromatography to give 2-(2,6-dichloro-4-trifluoromethylphenylhydrazono)propanal 1-oxime, m.p, c.108°. The mixture was filtered solvent evaporated under reduced pressure The residue was purified by column chromatography

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: The intermediate 2-amino-5-methylpyrazine is prepared stepwise, starting with 2-oxopropanal 1-oxime. This oxime is allowed to react with aminomalononitrile tosylate [prepared by the method of Ferris et al., J. Am. Chem. Soc. 88, 3829 (1966)], to yield 2-amino-3-cyano-5-methylpyrazine 1-oxide. The pyrazine 1-oxide prepared in this manner is allowed to react with phosphorous trichloride to yield 2-amino-3-cyano-5-methylpyrazine. This 2-amino-3-cyano-5-methylpyrazine is hydrolyzed with aqueous sodium hydroxide to yield 2-amino-3-carboxy-5-methylpyrazine, which, when heated in tetrahydronaphthalene, is decarboxylated to yield the desired 2-amino-5-methylpyrazine. prepared by the method of Ferris et al., J

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Aminomalononitrile p-toluenesulfonate salt (20.0 g, 79 mmol) and pyruvaldehyde 1-oxime (6.88 g, 79 mmol) were combined in a flask. iPrOH (140 mL) was added, and the resulting yellow slurry was allowed to stir at room temperature for 18 h, during which time a yellow precipitate accumulated. The mixture was filtered and the precipitate was washed with iPrOH (2×50 mL) and DI H2O (20 mL), then lyophilized to give 2-amino-3-cyano-5-methypyrazine N-oxide (10.7 g). The mixture was filtered the precipitate was washed with iPrOH (2×50 mL) and DI H2O (20 mL)

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: The intermediate 2-amino-5-methylpyrazine is prepared stepwise, starting with 2-oxopropanal 1-oxime. This oxime is allowed to react with aminomalononitrile tosylate [prepared by the method of Ferris et al., J. Am. Chem. Soc. 88, 3829 (1966)], to yield 2-amino-3-cyano-5-methylpyrazine 1-oxide. The pyrazine 1-oxide prepared in this manner is allowed to react with phosphorous trichloride to yield 2-amino-3-cyano-5-methylpyrazine. This 2-amino-3-cyano-5-methylpyrazine is hydrolyzed with aqueous sodium hydroxide to yield 2-amino-3-carboxy-5-methylpyrazine, which, when heated in tetrahydronaphthalene, is decarboxylated to yield the desired 2-amino-5-methylpyrazine. prepared by the method of Ferris et al., J

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: The intermediate 2-amino-5-methylpyrazine is prepared stepwise, starting with 2-oxopropanal 1-oxime. This oxime is allowed to react with aminomalononitrile tosylate [prepared by the method of Ferris et al., J. Am. Chem. Soc. 88, 3829 (1966)], to yield 2-amino-3-cyano-5-methylpyrazine 1-oxide. The pyrazine 1-oxide prepared in this manner is allowed to react with phosphorous trichloride to yield 2-amino-3-cyano-5-methylpyrazine. This 2-amino-3-cyano-5-methylpyrazine is hydrolyzed with aqueous sodium hydroxide to yield 2-amino-3-carboxy-5-methylpyrazine, which, when heated in tetrahydronaphthalene, is decarboxylated to yield the desired 2-amino-5-methylpyrazine. prepared by the method of Ferris et al., J

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: The intermediate 2-amino-5-methylpyrazine is prepared stepwise, starting with 2-oxopropanal 1-oxime. This oxime is allowed to react with aminomalononitrile tosylate [prepared by the method of Ferris et al., J. Am. Chem. Soc. 88, 3829 (1966)], to yield 2-amino-3-cyano-5-methylpyrazine 1-oxide. The pyrazine 1-oxide prepared in this manner is allowed to react with phosphorous trichloride to yield 2-amino-3-cyano-5-methylpyrazine. This 2-amino-3-cyano-5-methylpyrazine is hydrolyzed with aqueous sodium hydroxide to yield 2-amino-3-carboxy-5-methylpyrazine, which, when heated in tetrahydronaphthalene, is decarboxylated to yield the desired 2-amino-5-methylpyrazine. prepared by the method of Ferris et al., J

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: The intermediate 2-amino-5-methylpyrazine is prepared stepwise, starting with 2-oxopropanal 1-oxime. This oxime is allowed to react with aminomalononitrile tosylate [prepared by the method of Ferris et al., J. Am. Chem. Soc. 88, 3829 (1966)], to yield 2-amino-3-cyano-5-methylpyrazine 1-oxide. The pyrazine 1-oxide prepared in this manner is allowed to react with phosphorous trichloride to yield 2-amino-3-cyano-5-methylpyrazine. This 2-amino-3-cyano-5-methylpyrazine is hydrolyzed with aqueous sodium hydroxide to yield 2-amino-3-carboxy-5-methylpyrazine, which, when heated in tetrahydronaphthalene, is decarboxylated to yield the desired 2-amino-5-methylpyrazine. prepared by the method of Ferris et al., J

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: N-Chlorosuccinimide (7.3 g) was added, portionwise, to a solution of 2-oxopropanal 1-oxime (4.8 g) in dimethylformamide (30 ml). The reaction was heated to 50° and hydrochloric acid gas bubbled through to initiate the reaction. The mixture was then stirred at room temperature for an hour. Poured into water, extracted with ether and the extracts worked up to give crude 1-chloro--oxopropanal 1-oxime. This (1.5 g) in dimethylformamide (25 ml) was then reacted with sodium methanethiolate (0.86 g). After 5 hours at below 5°, the mixture was poured into water and extracted with ether and the extracts worked up to give crude 1-methylthio-oxopropanal 1-oxime. This (1.0 g) was then reacted with 2,6-dichloro-4-trifluoromethylphenylhydrazine (1.84 g), in a similar to that described in Example 1, to give 2-(2,6-dichloro-4-trifluoromethylphenylhydrazono)-methylthiopropanal-1-oxime. This (1.4 g) was then reacted with acetic anhydride, in a similar manner to Example 5, to give 2-(2,6-dichloro-4-trifluoromethyl-phenylhydrazono)-1-methylthiopropanal 1-acetyloxime. This (1.4 g) was then stirred with a mixture of caesium carbonate (1.1 g) and tetrahydrofuran (40 ml) at room temperature for 2 hours. Solvent was removed and the residue worked up to give compound 3. The reaction was heated to 50° hydrochloric acid gas bubbled through the reaction extracted with ether to give crude 1-chloro--oxopropanal 1-oxime extracted with ether to give crude 1-methylthio-oxopropanal 1-oxime

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A solution of 2,6-dichloro-4-trifluoromethylphenylhydrazine (10.2 g) in ether (15 ml) was added with cooling to a solution of `2-oxopropanal 1-oxime (3.62 g) in ether (15 ml) at 0°. The mixture was stirred at room temperature overnight and magnesium sulphate and charcoal added. The mixture was filtered and solvent evaporated under reduced pressure. The residue was purified by column chromatography to give 2-(2,6-dichloro-4-trifluoromethylphenylhydrazono)propanal 1-oxime, m.p, c.108°. The mixture was filtered solvent evaporated under reduced pressure The residue was purified by column chromatography

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: The intermediate 2-amino-5-methylpyrazine is prepared stepwise, starting with 2-oxopropanal 1-oxime. This oxime is allowed to react with aminomalononitrile tosylate [prepared by the method of Ferris et al., J. Am. Chem. Soc. 88, 3829 (1966)], to yield 2-amino-3-cyano-5-methylpyrazine 1-oxide. The pyrazine 1-oxide prepared in this manner is allowed to react with phosphorous trichloride to yield 2-amino-3-cyano-5-methylpyrazine. This 2-amino-3-cyano-5-methylpyrazine is hydrolyzed with aqueous sodium hydroxide to yield 2-amino-3-carboxy-5-methylpyrazine, which, when heated in tetrahydronaphthalene, is decarboxylated to yield the desired 2-amino-5-methylpyrazine. prepared by the method of Ferris et al., J