Hydrochloric Acid → 2-Chloro-3-methylbenzaldehyde

A suspension of 2-chloro-m-xylene (15 ml), N-bromosuccinimide (23.3 g) and benzoyl peroxide (200 mg) in carbon tetrachloride (150 ml) was heated under reflux for 6 hours. The insoluble material was filtered off and the filtrate was concentrated under reduced pressure. The obtained residue was purified by silica gel column chromatography (eluent:hexane) to give 2-bromomethyl-1-chloro-6-methylbenzene (16.0 g) as a colorless oil. 2-Bromomethyl-1-chloro-6-methylbenzene (25.4 g) and hexamethylenetetramine (32.4 g) were dissolved in acetic acid-water (1:1, 10 ml) and the mixture was heated under reflux for 5 hours. To the reaction mixture was added concentrated hydrochloric acid (40 ml) and the mixture was heated under reflux for 1 hour. The reaction mixture was extracted with ethyl acetate. The extract was washed with an aqueous sodium hydrogencarbonate solution and a saturated aqueous sodium chloride solution, and dried over anhydrous magnesium sulfate. The solvent was evaporated to give 2-chloro-3-methylbenzaldehyde (19.4 g) as a yellow oil. Subsequently, the title compound was prepared from 2-chloro-3-methylbenzaldehyde, 3-aminopyrazole and ethyl 3-ketohexanoate in the same manner as in Example 25.

1. temperaturethe mixture was heated
2. temperatureunder reflux for 5 hours
3. temperaturethe mixture was heated
4. temperatureunder reflux for 1 hour
5. extractionThe reaction mixture was extracted with ethyl acetate
6. washThe extract was washed with an aqueous sodium hydrogencarbonate solution
7. dry with materiala saturated aqueous sodium chloride solution, and dried over anhydrous magnesium sulfate
8. customThe solvent was evaporated

ORD record

ord-1173a5c410ae449982073854eb8529fa

Source dataset

uspto-grants-2005_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06977262B2