Reaction #81338

ord-468ef4c572d441718aaea53408d681ed

Reaction equation

O=C(O)C(F)(F)F
trifluoroacetic acid
CCC(=O)O[C@]1(C(=O)C(O)OC(=O)[C@@H](NC(=O)OC(C)(C)C)C(C)C)CC[C@H]2[C@@H]3C[C@H](C)C4=CC(=O)C=C[C@]4(C)[C@H]3[C@@H](O)C[C@@]21C
N-(1,1-dimethylethoxycarbonyl)valine [11β,21-dihydroxy-3,20-dioxo-6α-methyl-17-propionyloxy-pregna-1,4-dien-21-yl] ester
→
CCC(=O)O[C@]1(C(=O)C(O)OC(=O)[C@@H](N)C(C)C)CC[C@H]2[C@@H]3C[C@H](C)C4=CC(=O)C=C[C@]4(C)[C@H]3[C@@H](O)C[C@@]21C.O=C(O)C(F)(F)F
valine [11β,21-dihydroxy-3,20-dioxo-6α-methyl-17-propionyloxy -pregna-1,4-dien-21-yl] ester trifluoroacetate
Yield 80.0%

Reactants

O=C(O)C(F)(F)F
trifluoroacetic acid
CCC(=O)O[C@]1(C(=O)C(O)OC(=O)[C@@H](NC(=O)OC(C)(C)C)C(C)C)CC[C@H]2[C@@H]3C[C@H](C)C4=CC(=O)C=C[C@]4(C)[C@H]3[C@@H](O)C[C@@]21C
N-(1,1-dimethylethoxycarbonyl)valine [11β,21-dihydroxy-3,20-dioxo-6α-methyl-17-propionyloxy-pregna-1,4-dien-21-yl] ester

Reagents

None

Conditions

Detailed conditions
See reaction.notes.procedure_details.

Workup

  1. 1
    TemperatureUnder initial cooling
  2. 2
    OtherThen, the trifluoroacetic acid is evaporated in a vacuum
  3. 3
    workup.ADDITIONis added
  4. 4
    Otherevaporated to dryness in a vacuum
  5. 5
    OtherThe residue is crystallized

Procedure

Under initial cooling, 5 ml of trifluoroacetic acid is poured over 896 mg (1.42 mmol) of N-(1,1-dimethylethoxycarbonyl)valine [11β,21-dihydroxy-3,20-dioxo-6α-methyl-17-propionyloxy-pregna-1,4-dien-21-yl] ester, and it is stirred for 1-2 hours at room temperature. Then, the trifluoroacetic acid is evaporated in a vacuum. The residue is taken up in a little dichloromethane, 5 ml of toluene is added and then evaporated to dryness in a vacuum. The residue is crystallized. 728 mg (80%) of valine [11β,21-dihydroxy-3,20-dioxo-6α-methyl-17-propionyloxy -pregna-1,4-dien-21-yl] ester trifluoroacetate is obtained. Melting point 148° C.

Source

DOI: 10.6084/m9.figshare.5104873.v1Patent: US05616573uspto-grants-1997_04