Pyridine → 2-Methyl-5-nitrobenzoxazole
Reaction equation
[NH2:1][C:2]1[CH:7]=[C:6]([N+:8]([O-:10])=[O:9])[CH:5]=[CH:4][C:3]=1[OH:11].N1C=CC=[CH:14][CH:13]=1>>[N+:8]([C:6]1[CH:5]=[CH:4][C:3]2[O:11][C:13]([CH3:14])=[N:1][C:2]=2[CH:7]=1)([O-:10])=[O:9]Participants
3
Procedure
A dye of the invention is prepared by dissolving about 369 parts of 2-amino-4-nitrophenol in about 600 ml of warm pyridine in a 2 liter three-necked flask equipped with a mechanical stirrer, a Dean & Stark adapter or glass trap to collect distilled off solvent, and a condenser. About 600 parts of triethyl orthoacetate are added to the flask while refluxing using an oil bath maintained at 120°-140° C. The ethanol formed is distilled off followed by the pyridine until about 500 ml of total solvent are removed. The reaction mixture is stirred overnight at room temperature after which about 1500 ml of ethanol are added to precipitate the product. Filtering provided 5-nitro-2-methylbenzoxazole (1) as a tannish-brown solid which is washed with ethanol, ethyl acetate, and then ligroin, and dried under vacuum.
Workup
- customA dye of the invention is prepared