Hydrochloric Acid → Methyl 6-chloro-2-thioxo-2,3-dihydrobenzoxazole-4-carboxylate

HRID 249825Notes

Reaction equation

HRID 249825 reaction equation
[NH2:1][C:2]1[C:11]([OH:12])=[CH:10][C:9]([Cl:13])=[CH:8][C:3]=1[C:4]([O:6][CH3:7])=[O:5].[K].C(O[C:18]([S-])=[S:19])C.Cl>N1C=CC=CC=1>[Cl:13][C:9]1[CH:10]=[C:11]2[O:12][C:18](=[S:19])[NH:1][C:2]2=[C:3]([C:4]([O:6][CH3:7])=[O:5])[CH:8]=1

Participants

5

Reactant 3

HCID 313Hydrochloric AcidHCID 58085785Methyl 2-amino-5-chloro-3-hydroxybenzoateHCID 86623717potassium O-ethylxanthate

Product 1

HCID 58085840Methyl 6-chloro-2-thioxo-2,3-dihydrobenzoxazole-4-carboxylateYield 99.3%

Reagents, catalysts & solvents 1

HCID 1049PyridineSolvent

Conditions

Temperature
125 °C

Procedure

To a mixture of methyl 2-amino-5-chloro-3-hydroxybenzoate (4.00 g, 19.84 mmol) in anhydrous pyridine (30 mL) was added potassium-O-ethylxanthate (3.50 g, 21.82 mmol), and the reaction mixture heated to 125° C. for 3 h under nitrogen atmosphere. The warm solution was poured into a mixture of concentrated HCl (12 mL) and ice (120 mL), the resulting precipitate filtered, and dried under vacuum to provide methyl 6-chloro-2-thioxo-2,3-dihydrobenzoxazole-4-carboxylate (4.80 g, 99%) as a yellow solid: 1H NMR (300 MHz, CDCl3) δ 8.10 (s, 1H), 7.81 (d, J=1.9 Hz, 1H), 7.48 (d, J=1.9 Hz, 1H), 4.01 (s, 3H); MS (ESI+) m/z 244 (M+H).

Workup

  1. filtrationthe resulting precipitate filtered
  2. customdried under vacuum

Sources & evidence

ORD record
ord-964137f1f1de484a8cbd7fa5407f5ff2
Source dataset
uspto-grants-2011_01
Patent number
US07863271B2

Reaction notes

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