Nitric Acid → 5-Chloro-2-methyl-6-nitro-1,3-benzoxazole

HRID 1068540

Reaction equation

[Cl:1][C:2]1[CH:3]=[CH:4][C:5]2[O:9][C:8]([CH3:10])=[N:7][C:6]=2[CH:11]=1.[N+:12]([O-])([OH:14])=[O:13].O1C2C=CC=CC=2N=C1>S(=O)(=O)(O)O>[Cl:1][C:2]1[C:3]([N+:12]([O-:14])=[O:13])=[CH:4][C:5]2[O:9][C:8]([CH3:10])=[N:7][C:6]=2[CH:11]=1

Participants

Conditions

Temperature: 20 °C

Procedure

Concentrated sulfuric acid (150 mL) was stirred mechanically and cooled in an ice/water bath. To this was gradually added 5-chloro-2-methylbenzoxazole (1), (75 g, 0.45 Moles), at such a rate that the temperature stayed at 30° C., over a 15-20 minute period. A solution of concentrated sulfuric acid (40 mL), and concentrated nitric acid (32 mL), was prepared and added drop by drop to the benzoxazole solution at such a rate that the temperature was maintained at approximately 20° C. When this acid solution had been added the cooling bath was removed and the mixture allowed to stir at room temperature for 1 hour. At the end of this period the solution was carefully poured onto ice with good stirring. Sufficient water was then added to get good mixing. The solid was filtered off, washed well with water followed by methanol and finally air dried. Yield 90.6 g

Workup

temperaturecooled in an ice/water bath
additionWhen this acid solution had been added the cooling bath
customwas removed
additionAt the end of this period the solution was carefully poured onto ice with good stirring
additionSufficient water was then added
customto get good mixing
filtrationThe solid was filtered off
washwashed well with water
customdried

Sources & evidence

ORD record: ord-809f8d48942c4e64b6132b9c3aaf5797
Source dataset: uspto-grants-2001_06
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US06251575B1

Linked notes

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