Phosphoric Acid → HCID 68470346, compound

HRID 505828Notes

Reaction equation

HRID 505828 reaction equation
[C:1]1([C:7]2[NH:11][C:10]3[S:12][C:13]([C:15]([O:17][CH2:18][CH3:19])=[O:16])=[CH:14][C:9]=3[C:8]=2[C:20](OC(C)(C)C)=O)[CH:6]=[CH:5][CH:4]=[CH:3][CH:2]=1.C(OC(=O)C)(=O)C.[C:34]1(=O)[CH2:39][CH2:38]C[CH2:36][CH2:35]1.P(=O)(O)(O)O.C([SiH](CC)CC)C>C(O)(=O)C>[CH:20]1([C:8]2[C:9]3[CH:14]=[C:13]([C:15]([O:17][CH2:18][CH3:19])=[O:16])[S:12][C:10]=3[NH:11][C:7]=2[C:1]2[CH:6]=[CH:5][CH:4]=[CH:3][CH:2]=2)[CH2:38][CH2:39][CH2:34][CH2:35][CH2:36]1

Participants

7

Reactant 5

HCID 1004Phosphoric AcidHCID 7918Acetic AnhydrideHCID 7967CyclohexanoneHCID 12052TriethylsilaneHCID 68471083HCID 68471083, compound

Product 1

HCID 68470346HCID 68470346, compoundYield 58%

Reagents, catalysts & solvents 1

HCID 176Acetic AcidSolvent

Conditions

Temperature
80 °C

Procedure

A solution (0.2 M) of 4-tert-butyl 2-ethyl 5-phenyl-6H-thieno[2,3-b]pyrrole-2,4-dicarboxylate in acetic acid was treated with acetic anhydride (2.5 eq.), cyclohexanone (10 eq.) and 85% phosphoric acid (2.3 eq.). The mixture was heated at 80° C. overnight, then it was poured into ice cold ammonium hydroxide. The product was extracted with AcOEt and the combined organic layers were washed sequentially with aqueous HCl (1 N), aqueous NaHCO3 (saturated solution) and brine then dried and concentrated. The crude was dissolved in TFA and cooled to 0° C. The resulting solution (0.1 M) was treated with triethylsilane (2 eq.) and stirred at 0° C. for 1 h then solvent was evaporated to give a residue that was purified by flash chromatography on silica gel (1:9 AcOEt/petroleum ether) to afford the title compound (58%) as a solid.

Workup

  1. additionit was poured into ice cold ammonium hydroxide
  2. extractionThe product was extracted with AcOEt
  3. washthe combined organic layers were washed sequentially with aqueous HCl (1 N), aqueous NaHCO3 (saturated solution) and brine
  4. customthen dried
  5. concentrationconcentrated
  6. dissolutionThe crude was dissolved in TFA
  7. temperaturecooled to 0° C
  8. customsolvent was evaporated
  9. customto give a residue that
  10. customwas purified by flash chromatography on silica gel (1:9 AcOEt/petroleum ether)

Sources & evidence

ORD record
ord-7862af3e97cd432693dde08efb4615bd
Source dataset
uspto-grants-2010_08
Patent number
US07781431B2

Reaction notes

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