Sulfuric Acid → 3,5-Dioxo-2,3,4,5-tetrahydro-1,2,4-triazine-6-carboxylic acid

HRID 573426Notes

Reaction equation

FC1C=CC([N:8]2[C:13](=[O:14])[C:12]([C:15]([OH:17])=[O:16])=[N:11][N:10](C(C)C)[C:9]2=[O:21])=CC=1.S(=O)(=O)(O)O.C(OC(C1C(=O)N(C2C=CC(F)=CC=2)C(=O)N(C(C)C)N=1)=O)C.[Na+].[Cl-]>O>[O:21]=[C:9]1[NH:8][C:13](=[O:14])[C:12]([C:15]([OH:17])=[O:16])=[N:11][NH:10]1

Participants

Conditions

Temperature: 40 °C

Procedure

4-(4-Fluorophenyl)-2-isopropyl-3,5-dioxo-2,3,4,5-tetrahydro[1,2,4]triazine-6-carboxylic acid. Sulfuric acid (10 mL, 200 mmol) was carefully added to a mixture of 4-(4-fluorophenyl)-2-isopropyl-3,5-dioxo-2,3,4,5-tetrahydro-1,2,4-triazine-6-carboxylic acid ethyl ester (1100 mg, 3.4 mmol) and water (2 mL). The mixture became homogenous after a few minutes. The reaction mixture was stirred at 40° C. overnight, was cooled to rt and was carefully added to ice. The mixture was saturated with solid NaCl and was extracted repeatedly from EtOAc (3×). The combined EtOAc layer was washed with brine, dried over magnesium sulfate, and concentrated to give the product as foam (100%). LCMS m/z=294 (M+1); 1H NMR (Methanol d4) δ: 7.35-7.31 (2 m, 4H), 4.95 (m, 1H), 4.31 (q, 2H, J=7.0 Hz), 1.41 (d, 6H, J=6.6 Hz).

Workup

waitThe mixture became homogenous after a few minutes
temperaturewas cooled to rt
additionwas carefully added to ice
extractionwas extracted repeatedly from EtOAc (3×)
washThe combined EtOAc layer was washed with brine
dry with materialdried over magnesium sulfate
concentrationconcentrated

Sources & evidence

ORD record: ord-e8acde933ff940a6b79efc6b5eeb1640
Source dataset: uspto-grants-2015_05
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US09029538B2

Reaction notes

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