Nitric Acid → (4-Methoxy-7-nitro-benzothiazol-2-yl)-carbamic acid methyl ester

HRID 51856

Reaction equation

[CH3:1][O:2][C:3](=[O:16])[NH:4][C:5]1[S:6][C:7]2[CH:13]=[CH:12][CH:11]=[C:10]([O:14][CH3:15])[C:8]=2[N:9]=1.[N+:17]([O-])([OH:19])=[O:18]>C(O)(=O)C>[CH3:1][O:2][C:3](=[O:16])[NH:4][C:5]1[S:6][C:7]2[C:13]([N+:17]([O-:19])=[O:18])=[CH:12][CH:11]=[C:10]([O:14][CH3:15])[C:8]=2[N:9]=1

Participants

Conditions

Temperature: 70 °C

Procedure

To a stirred solution of 13.6 g (57.1 mmol) (4-methoxy-benzothiazol-2-yl)-carbamic acid methyl ester in 300 ml acetic acid at room temperature was added 200 ml 65% nitric acid and the mixture heated at 70° C. for 4 h. The mixture was then poured onto stirred ice-water and the resulting slurry was filtered. The filter-cake was dissolved in THF and 5 N sodium hydroxide solution was added until the pH was 8. This mixture was then stirred for 1 h, filtered, and the filter-cake dried in vacuo to afford 7.61 g (47%) (4-methoxy-7-nitro-benzothiazol-2-yl)-carbamic acid methyl ester as a yellow crystalline solid. Meanwhile, the filtrate was separated into its aqueous and organic phases and the organic phase was dried over sodium sulfate and concentrated in vacuo. The residue was resuspended in 200 ml THF and 200 ml methanol and heated at 70° C. overnight. The mixture was then cooled to room temperature and the resulting crystals were collected by filtration, washed with THF, and dried in vacuo to afford a further 1.50 g (9%) of product as a yellow crystalline solid. ES-MS m/e (%): 306 (M+Na+, 28), 2,S4 (M+H+, 100).

Workup

additionThe mixture was then poured
filtrationthe resulting slurry was filtered
dissolutionThe filter-cake was dissolved in THF
addition5 N sodium hydroxide solution was added until the pH was 8
filtrationfiltered
customthe filter-cake dried in vacuo

Sources & evidence

ORD record: ord-eb53f462705a46c4acdd6b967ffb3632
Source dataset: uspto-grants-2004_03
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US06713499B2

Linked notes

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