Di-tert-butyl dicarbonate → 17beta-Carbomethoxy-6-t-butylcarboxy-6-azaandrost-4-en-3-one

HRID 1077588Notes

Reaction equation

HRID 1077588 reaction equation
[C:1]([C@H:5]1[CH2:10][CH2:9][C@H:8]2[C@H:11]3[C@H:21]([CH2:22][CH2:23][C@:6]12[CH3:7])[C@:19]1([CH3:20])[C:14]([CH2:15][C@@H:16]([O:24][Si](C(C)C)(C(C)C)C(C)C)[CH2:17][CH2:18]1)=[N:13][CH2:12]3)([O:3][CH3:4])=[O:2].C([O:39][C:40](OC(OC(C)(C)C)=O)=[O:41])(C)(C)C.[F-].C([N+](C[CH2:65][CH2:66][CH3:67])(CCCC)CCCC)CCC.[Cr](O[Cr]([O-])(=O)=O)([O-])(=O)=O.[NH+]1C=CC=C[CH:78]=1.[NH+]1C=CC=CC=1>N1C=CC=CC=1.O1CCCC1.O>[C:1]([C@H:5]1[CH2:10][CH2:9][C@H:8]2[C@H:11]3[C@H:21]([CH2:22][CH2:23][C@:6]12[CH2:7][C:40]([OH:41])=[O:39])[C@:19]1([CH3:20])[C:18](=[CH:17][C:16](=[O:24])[CH2:15][CH2:14]1)[N:13]([C:66]([CH3:65])([CH3:67])[CH3:78])[CH2:12]3)([O:3][CH3:4])=[O:2]

Participants

8

Reactant 4

HCID 90495Di-tert-butyl dicarbonateHCID 2724130Cornforth reagentHCID 2724141Tetrabutylammonium FluorideHCID 1045826517beta-Carbomethoxy-3beta-triisopropylsilyloxy-6-azaandrost-5-ene

Product 1

HCID 8674903517beta-Carbomethoxy-6-t-butylcarboxy-6-azaandrost-4-en-3-one

Reagents, catalysts & solvents 3

HCID 962WaterSolventHCID 1049PyridineSolvent2×HCID 8028TetrahydrofuranSolvent

Procedure

Crude 17β-carbomethoxy-3β-triisopropylsilyloxy-6-azaandrost-5-ene (66 g, 0.135 mol)is dissolved in pyridine (500 mL), treated with di-t-butyldicarbonate (150 g, 0.69 mol) and allowed to stir overnight. The pyridine is removed by rotary evaporation and tetrabutylammonium fluoride (500 mL, 1M, 0.5 mol) in tetrahydrofuran (THF) added carefully and the reaction heated to reflux for 5 min. The THF is removed by rotary evaporation, the residue dissolved in ethyl acetate (500 mL), washed cautiously with water, saturated aqueous NaCl, dried with MgSO4 and concentrated. This material is dissolved in DMF (500 mL), is treated with pyridinium dichromate (153 g, 0.41 mol) and allowed to stir overnight. The reaction is poured into water (700 mL) and extracted with ethyl acetate (2×500 mL). The combined extracts are washed with water, 5% aqueous CuSO4, saturated aqueous NaCl, dried over MgSO4, concentrated and flash chromatographed (0-60%, diethyl ether/hexanes) to give 17β-carbomethoxy-6-t-butylcarboxy-6-azaandrost-4-en-3-one as an off-white foam; yield: 37.5 g (64%); FAB mass spec. MH+ 432.

Workup

  1. additionadded carefully
  2. temperaturethe reaction heated
  3. temperatureto reflux for 5 min
  4. customThe THF is removed by rotary evaporation
  5. dissolutionthe residue dissolved in ethyl acetate (500 mL)
  6. washwashed cautiously with water, saturated aqueous NaCl
  7. dry with materialdried with MgSO4
  8. concentrationconcentrated
  9. dissolutionThis material is dissolved in DMF (500 mL)
  10. stirringto stir overnight
  11. extractionextracted with ethyl acetate (2×500 mL)
  12. washThe combined extracts are washed with water, 5% aqueous CuSO4, saturated aqueous NaCl
  13. dry with materialdried over MgSO4
  14. concentrationconcentrated
  15. customflash chromatographed (0-60%, diethyl ether/hexanes)

Sources & evidence

ORD record
ord-e5de452256254dc2afa3e59d8969ae4a
Source dataset
uspto-grants-1996_08
Patent number
US05543406

Reaction notes

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