L 696229 → 3-[2-(1,3-benzoxazol-2-yl)ethyl]-5-ethyl-6-methyl-1H-pyridine-2-thione

HRID 1033016Notes

Reaction equation

HRID 1033016 reaction equation
[O:1]1[C:5]2[CH:6]=[CH:7][CH:8]=[CH:9][C:4]=2[N:3]=[C:2]1[CH2:10][CH2:11][C:12]1[C:13](=O)[NH:14][C:15]([CH3:20])=[C:16]([CH2:18][CH3:19])[CH:17]=1.COC1C=CC(P2(=S)SP(=S)(C3C=CC(OC)=CC=3)[S:31]2)=CC=1>C1(C)C=CC=CC=1>[O:1]1[C:5]2[CH:6]=[CH:7][CH:8]=[CH:9][C:4]=2[N:3]=[C:2]1[CH2:10][CH2:11][C:12]1[C:13](=[S:31])[NH:14][C:15]([CH3:20])=[C:16]([CH2:18][CH3:19])[CH:17]=1

Participants

4

Reactant 2

HCID 72352L 696229HCID 87949Lawesson's reagent

Product 1

HCID 30004373-[2-(1,3-benzoxazol-2-yl)ethyl]-5-ethyl-6-methyl-1H-pyridine-2-thioneYield 24.7%

Reagents, catalysts & solvents 1

HCID 1140TolueneSolvent

Procedure

A mixture of 3-[2-(benzoxazol-2-yl)-ethyl]-5-ethyl-6-methyl pyridin-2(1H)-one (150 mg, 0.53 mmol) and 2,4-bis(4-methoxyphenyl)-1,3-dithia-2,4-diphosphetane-2,4-disulfide (Lawesson's Reagent) (485 mg, 1.2 mmol) in dry toluene (4 mL) was refluxed for 6-10 hours. The solvent was evaporated and the reaction residue was flash chromatographed on silica gel eluting with 0.5% methanol/chloroform. The appropriate fractions were combined and crystallized from ethyl acetate to yield 80 mg of slightly impure product. This material was re-chromatographed on silica gel eluting with chloroform. The appropriate fractions were combined, the solvent evaporated, and the residue recrystallized from boiling diethyl ether, after addition of sufficient methylene chloride to effect complete dissolution, to yield 39 mg (24%) of pure product, m.p. 199°-201° C.

Workup

  1. temperaturewas refluxed for 6-10 hours
  2. customThe solvent was evaporated
  3. customchromatographed on silica gel eluting with 0.5% methanol/chloroform
  4. customcrystallized from ethyl acetate
  5. customto yield 80 mg of slightly impure product
  6. customThis material was re-chromatographed on silica gel eluting with chloroform
  7. customthe solvent evaporated
  8. customthe residue recrystallized
  9. additionafter addition of sufficient methylene chloride
  10. dissolutiondissolution

Sources & evidence

ORD record
ord-4eb1d4fc8a94409f95b7338acb1aa19b
Source dataset
uspto-grants-1994_05
Patent number
US05308854

Reaction notes

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