Hydrochloric Acid → Pentoxazone

HRID 2289015Notes

Reaction equation

HRID 2289015 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)[O:16]CC)=[C:4]([F:20])[CH:3]=1.[OH:21][CH:22]([C:27]([CH3:29])=[CH2:28])[C:23]([O:25]C)=O.Cl>C(N(CCCC)CCCC)CCC.C1(C)C=CC=CC=1>[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:23](=[O:25])[C:22](=[C:27]([CH3:29])[CH3:28])[O:21][C:15]2=[O:16])=[C:4]([F:20])[CH:3]=1

Participants

6

Reactant 3

HCID 313Hydrochloric AcidHCID 11033971N-[4-Chloro-5-(cyclopentyloxy)-2-fluorophenyl]carbamic acid ethyl esterHCID 13461762Methyl 2-hydroxy-3-methylbut-3-enoate

Product 1

HCID 11714234PentoxazoneYield 66.8%

Reagents, catalysts & solvents 2

HCID 7622TributylamineCatalystHCID 1140TolueneSolvent

Procedure

Ethyl N-(4-chloro-5-cyclopentyloxy-2-fluorophenyl)carbamate (3.01 g, 10 mmol), methyl 2-hydroxy-3-methyl-3-butenoate (3.09 g, 30 mmol), ferric chloride (162 mg, 1.0 mmol) and tributylamine (92.7 mg, 0.5 mmol) were introduced into a flask (25 cc) equipped with a distillation unit, and the reaction was conducted at 200° C. for 3 hours. After the reaction solution was cooled to room temperature, toluene (30 mL) was added, and then the reaction solution was washed with 1N sodium hydroxide (20 mL×2) and 1N hydrochloric acid (20 mL×2). The organic layer was dried over magnesium sulfate. After the drying agent was filtered off, the filtrate was concentrated under reduced pressure. To the resulting oily crude product, acidic methanol (5.0 mL) was added to form a homogeneous solution. Then, 6N hydrochloric acid (0.25 mL) was further added, and the solution was left to stand at room temperature. The precipitated crystals were collected by filtration, washed with a 20:1 mixed solvent consisting of methanol and 6N hydrochloric acid and dried to obtain 3-(4-chloro-5-cyclopentyloxy-2-fluorophenyl)-5-isopropylidene-1,3-oxazolidine-2,4-dione (2.36 g, yield 66.8%).

Workup

  1. customequipped with a distillation unit
  2. washthe reaction solution was washed with 1N sodium hydroxide (20 mL×2) and 1N hydrochloric acid (20 mL×2)
  3. dry with materialThe organic layer was dried over magnesium sulfate
  4. filtrationAfter the drying agent was filtered off
  5. concentrationthe filtrate was concentrated under reduced pressure
  6. additionTo the resulting oily crude product, acidic methanol (5.0 mL) was added
  7. customto form a homogeneous solution
  8. waitthe solution was left
  9. customto stand at room temperature
  10. filtrationThe precipitated crystals were collected by filtration
  11. washwashed with a 20:1 mixed solvent
  12. customdried

Sources & evidence

ORD record
ord-eaab0ac3d9b14ce79153260a45d10c4d
Source dataset
uspto-grants-2000_07
Patent number
US06090946

Reaction notes

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