2-Methyl-3-nitrobenzoic acid → N-methoxy-N,2-dimethyl-3-nitrobenzamide

Carbonyl diimidazole (9.8 g, 60.7 mmol) was added to a solution of 2-methyl-3-nitrobenzoic acid (10 g, 55 mmol) in CH2Cl2 (200 mL) at 0° C. and stirred for 30 min. The reaction mixture was warmed to room temperature, stirred for 2 h, and cooled to 0 C. N,O-dimethylhydroxylamine hydrochloride was added to the reaction mixture at 0 C, stirred for 30 min., and heated to 45 C for 1 h. The reaction mixture was cooled to room temperature, stirred for 12 h, and quenched with aqueous K2CO3 (10%, 200 mL). The reaction mixture was extracted with CH2Cl2 (3×200 mL) and the combined extracts were dried (MgSO4), filtered, and concentrated in vacuo. Purification by flash column chromatography (silica, 6:4 hexanes:EtOAc) provided the title compound a white solid (2.6 g, 21%). MS: 225 (MH+); HPLC Rf: 3.96 min. (HPLC method 4); HPLC purity: 98%.

1. stirringstirred for 2 h
2. temperaturecooled to 0 C
3. stirringstirred for 30 min.
4. temperatureheated to 45 C for 1 h
5. temperatureThe reaction mixture was cooled to room temperature
6. stirringstirred for 12 h
7. customquenched with aqueous K2CO3 (10%, 200 mL)
8. extractionThe reaction mixture was extracted with CH2Cl2 (3×200 mL)
9. dry with materialthe combined extracts were dried (MgSO4)
10. filtrationfiltered
11. concentrationconcentrated in vacuo
12. customPurification by flash column chromatography (silica, 6:4 hexanes:EtOAc)

ORD record

ord-8a2f085a59964a529adc5d32ba78f5bd

Source dataset

uspto-grants-2007_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07271262B2