Triethylamine → Pentoxazone

HRID 1684328Notes

Reaction equation

HRID 1684328 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]([N:14]=[C:15]=[O:16])=[C:4]([F:17])[CH:3]=1.[OH:18][CH:19]([C:24]([CH3:26])=[CH2:25])[C:20]([O:22]C)=O.C(N(CC)CC)C.C(=O)([O-])[O-].[K+].[K+]>C1(C)C=CC=CC=1.CO>[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:20](=[O:22])[C:19](=[C:24]([CH3:26])[CH3:25])[O:18][C:15]2=[O:16])=[C:4]([F:17])[CH:3]=1

Participants

7

Reactant 4

HCID 8471TriethylamineHCID 11430Potassium CarbonateHCID 13461762Methyl 2-hydroxy-3-methylbut-3-enoateHCID 544415444-Chloro-5-cyclopentyloxy-2-fluorophenylisocyanate

Product 1

HCID 11714234PentoxazoneYield 75.7%

Reagents, catalysts & solvents 2

HCID 887MethanolSolventHCID 1140TolueneSolvent

Conditions

Temperature
100 °C

Procedure

A 20-L stainless steel vessel equipped with a mechanical stirrer and a dropping funnel was charged with a solution of 4-chloro-5-cyclopentyloxy-2-fluorophenylisocyanate (4.00 kg, 15.6 mol) and methyl 2-hydroxy-3-methyl-3-butenoate (2.40 kg; purity=ca. 90%; 18.4 mol) in toluene (10 L). To the solution being cooled in an ice water bath, triethylamine (40 mL) was added dropwise slowly enough to ensure against the increase in the temperature of the solution. The solution was stirred at the same temperature for 3 h until TLC confirmed that the starting materials had disappeared. Subsequently, potassium carbonate (200 g) was added and, with the resulting methanol being removed with a fitted distillator, the mixture was stirred under heating in a water bath (100° C.) for 5 h. After completion of the reaction, the reaction mixture was washed with 1N HCl (10 L), 1N sodium hydroxide (10 L) and again with 1N HCl (10 L). The toluene layer was dried with anhydrous magnesium sulfate and the solvent was distilled off under vacuum; thereafter, hexane was added in an amount about one half of the resulting oil and the mixture was left to stand at room temperature, thereby producing 3N-(4-chloro-5-cyclopentyloxy-2-fluorophenyl)-5-isopropyliden-2,4-oxazolidinedione as whitish yellow solids (4.19 kg, 11.8 mol; yield=75.7%; primary crystal). MP: 104.5°-105.0° C. 1H-NMR(CDCl3,TMS,ppm): δ1.49-1.97(8H,m), 2.03(3H,s), 2.31(3H,s), 4.73(1H,m), 6.88(1H,d,JHF =6.6Hz), 7.33(1H,d,JHF =8.5Hz). IR (KBr disk, cm-1): 2970, 1815, 1740, 1500, 1200.

Workup

  1. temperatureTo the solution being cooled in an ice water bath
  2. temperatureincrease in the temperature of the solution
  3. customremoved with a fitted distillator
  4. stirringthe mixture was stirred
  5. customAfter completion of the reaction
  6. washthe reaction mixture was washed with 1N HCl (10 L), 1N sodium hydroxide (10 L) and again with 1N HCl (10 L)
  7. dry with materialThe toluene layer was dried with anhydrous magnesium sulfate
  8. distillationthe solvent was distilled off under vacuum
  9. additionthereafter, hexane was added in an amount about one half of the resulting oil
  10. waitthe mixture was left
  11. customto stand at room temperature

Sources & evidence

ORD record
ord-92c860782b4e44c9a34234840d449eac
Source dataset
uspto-grants-1997_06
Patent number
US05639915

Reaction notes

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