Hydrochloric Acid → Pentoxazone

HRID 2289013Notes

Reaction equation

HRID 2289013 reaction equation
[Cl:1][C:2]1[C:7]([O:8][CH:9]2[CH2:13][CH2:12][CH2:11][CH2:10]2)=[CH:6][C:5]([NH:14][C:15](=[O:19])[O:16][CH2:17][CH3:18])=[C:4]([F:20])[CH:3]=1.O[CH:22]([C:28](C)=C)[C:23](OCC)=O.Cl.C[OH:33]>C(N(CCCC)CCCC)CCC>[Cl:1][C:2]1[C:7]([O:8][CH:9]2[CH2:10][CH2:11][CH2:12][CH2:13]2)=[CH:6][C:5]([N:14]2[C:18](=[O:33])[C:17](=[C:22]([CH3:28])[CH3:23])[O:16][C:15]2=[O:19])=[C:4]([F:20])[CH:3]=1

Participants

6

Reactant 4

HCID 313Hydrochloric AcidHCID 887MethanolHCID 108555893-Butenoic acid, 2-hydroxy-3-methyl-, ethyl esterHCID 11033971N-[4-Chloro-5-(cyclopentyloxy)-2-fluorophenyl]carbamic acid ethyl ester

Product 1

HCID 11714234PentoxazoneYield 67.4%

Reagents, catalysts & solvents 1

HCID 7622TributylamineCatalyst

Conditions

Temperature
200 °C

Procedure

Ethyl N-(4-chloro-5-cyclopentyloxy-2-fluorophenyl)carbamate (6.02 g, 20 mmol), ferric chloride (53.5 mg, 0.33 mmol) and tributylamine (185 mg, 1.00 -mmol) were introduced into a two-necked flask (50 cc) equipped with a distillation unit and heated to 200° C. Ethyl 2-hydroxy-3-methyl-3-butenoate (4.33 g, 30 mmol) was added dropwise to the mixed solution over 30 minutes, and after the addition, the solution was stirred at 200° C. for 3.5 hours. After completion of the reaction, the reaction solution was allowed to cool to 70 to 80° C., and a mixed solution consisting of methanol (10 mL) and 6N hydrochloric acid (0.5 mL) was added thereto and mixed homogeneously. Then, the reaction solution was left to stand at room temperature. The precipitated solid was collected by filtration, washed with a mixed solution consisting of methanol (20 mL) and 6N hydrochloric acid (1 mL) and then water (20 mL) and dried completely under reduced pressure to obtain 3-(4-chloro-5-cyclopentyloxy-2-fluorophenyl)-5-isopropylidene-1,3-oxazolidine-2,4-dione (4.77 g, yield 67.4%).

Workup

  1. customequipped with a distillation unit
  2. additionafter the addition
  3. customAfter completion of the reaction
  4. temperatureto cool to 70 to 80° C.
  5. additionwas added
  6. additionmixed homogeneously
  7. waitThen, the reaction solution was left
  8. customto stand at room temperature
  9. filtrationThe precipitated solid was collected by filtration
  10. washwashed with a mixed solution
  11. dry with materialwater (20 mL) and dried completely under reduced pressure

Sources & evidence

ORD record
ord-4fec8aff4b59401382fd0f7e77ef75ea
Source dataset
uspto-grants-2000_07
Patent number
US06090946

Reaction notes

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