Hydrochloric Acid → 3-(4-Methoxyphenyl)pyrazin-2(1H)-one
Reaction equation
CO[C:3]1[CH:8]=[CH:7][C:6]([NH:9][CH2:10][C:11]([NH2:13])=O)=[CH:5]C=1.[CH:14]([CH:16]=O)=O.[OH-:18].[Na+].Cl.[C:21](=O)(O)[O-].[Na+].[CH3:26][OH:27]>>[OH:18][C:5]1[C:6]([C:7]2[CH:8]=[CH:3][C:26]([O:27][CH3:21])=[CH:16][CH:14]=2)=[N:9][CH:10]=[CH:11][N:13]=1Participants
Procedure
p-Methoxyphenyl glycinamide (0.10 mole) in 125 ml. methanol cooled to -30°C is treated with a solution of 19.3 g. (0.10 ml.) of 30% glyoxal in 25 ml. methanol also precooled to -30°C. The mixture is stirred and added dropwise during 15-30 minutes to 10 ml (0.125 mole) of 12.5N aqueous sodium hydroxide, the temperature of the reaction mixture being held at -20° to 15°C during this addition. The mixture is refrigerated 1-2 hours at -10°C, then 1 hour at -2° to 3°C, whereupon there is added 12N HCl followed by 5 g. solid sodium bicarbonate to neutralize any excess acid. The solution then is evaporated to dryness and the residue extracted with chloroform. The extracts are evaporated and the product crystallized from a suitable solvent mixture, i.e. chloroform-methanol to give 2-hydroxy-3-p-methoxyphenylpyrazine.
Workup
- additionis treated with a solution of 19.3 g
- customalso precooled to -30°C
- additionthe temperature of the reaction mixture being held at -20° to 15°C during this addition
- customThe solution then is evaporated to dryness
- extractionthe residue extracted with chloroform
- customThe extracts are evaporated
- customthe product crystallized from a suitable solvent mixture, i.e. chloroform-methanol
Sources & evidence
- ORD record
- ord-fed06eb616a54de6afcc0b5766335e97
- Source dataset
- uspto-grants-1976_03
- Patent number
- US03946009
Reaction notes
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