Hydrochloric Acid → 5-nitro-3-pyridin-2-yl-3,4-dihydro-2H-1,4-benzoxazine-3-carboxylic acid

HRID 589064Notes

Reaction equation

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

Participants

Conditions

Temperature: 100 °C

Procedure

5-Nitro-3-pyridin-2-yl-3,4-dihydro-2H-1,4-benzoxazine-3-carbonitrile (80 mg, 0.3 mmol) was dissolved in concentrated hydrochloric acid (3 mL, 100 mmol) and heated to 100° C. for 2 h. The reaction was allowed to cool to room temperature, diluted with water, and the pH was adjusted to pH 7 with sodium bicarbonate. The neutralized solution was then extracted with ethyl acetate. The combined organic layers were washed with brine, dried over magnesium sulfate, and concentrated to give crude 5-nitro-3-pyridin-2-yl-3,4-dihydro-2H-1,4-benzoxazine-3-carboxylic acid as a solid (0.025 g. 30%). LCMS calculated for C14H12N3O5 (M+H)+: m/z=302.1. found: 301.9.

Workup

temperatureto cool to room temperature
extractionThe neutralized solution was then extracted with ethyl acetate
washThe combined organic layers were washed with brine
dry with materialdried over magnesium sulfate
concentrationconcentrated

Sources & evidence

ORD record: ord-50db896168114558b0c356817440040e
Source dataset: uspto-grants-2016_01
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US09227985B2

Reaction notes

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