反应详情

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.

1. customA dye of the invention is prepared
2. customequipped with a mechanical stirrer
3. customa Dean & Stark adapter or glass trap to collect
4. distillationdistilled off solvent, and a condenser
5. additionAbout 600 parts of triethyl orthoacetate are added to the flask
6. temperaturewhile refluxing
7. temperaturemaintained at 120°-140° C
8. customThe ethanol formed
9. distillationis distilled off
10. customare removed
11. additionare added
12. customto precipitate the product
13. filtrationFiltering