Sodium Hydroxide → 4-(5-Chloro-2-methoxy-benzenesulfonyl)-3,4-dihydro-2H-benzo[1,4]oxazine-6-carboxylic acid

HRID 1360231Notes

Reaction equation

C[O:2][C:3]([C:5]1[CH:6]=[CH:7][C:8]2[O:13][CH2:12][CH2:11][N:10]([S:14]([C:17]3[CH:22]=[C:21]([Cl:23])[CH:20]=[CH:19][C:18]=3[O:24][CH3:25])(=[O:16])=[O:15])[C:9]=2[CH:26]=1)=[O:4].[OH-].[Na+]>O1CCCC1.CO>[Cl:23][C:21]1[CH:20]=[CH:19][C:18]([O:24][CH3:25])=[C:17]([S:14]([N:10]2[C:9]3[CH:26]=[C:5]([C:3]([OH:4])=[O:2])[CH:6]=[CH:7][C:8]=3[O:13][CH2:12][CH2:11]2)(=[O:15])=[O:16])[CH:22]=1

Participants

Conditions

Temperature: 45 °C

Procedure

A solution of 4-(5-chloro-2-methoxy-benzenesulfonyl)-3,4-dihydro-2H-benzo[1,4]oxazine-6-carboxylic acid methyl ester (7.1 g, 17.8 mmol) in tetrahydrofuran (100 mL) and methanol (50 mL) was treated with 3N NaOH (25 mL, 75 mmol, 4.2 equiv.). The mixture was stirred at 45° C. for 1.5 hours. The organic solvents were then removed and the residue acidified with HCl 3N (25 mL). The white precipitate which formed was filtered, washing with water, and dried under high vacuum. 4-(5-Chloro-2-methoxy-benzenesulfonyl)-3,4-dihydro-2H-benzo[1,4]oxazine-6-carboxylic acid was obtained as a white solid, 6.79 g (99%), MS (ISP): m/e=382.0 (M−H), which was used crude in the following reaction.

Workup

customThe organic solvents were then removed
customThe white precipitate which formed
filtrationwas filtered
washwashing with water
customdried under high vacuum

Sources & evidence

ORD record: ord-94fa7dd39ea64d34a17ec4dbf039b042
Source dataset: uspto-grants-2011_02
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US07879845B2

Reaction notes

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