Formic Acid → (7S,10R)-7,8,9,10-Tetrahydro-2,9,9-trimethoxy-7-methyl-10-phenanthridinol

HRID 963270Notes

Reaction equation

HRID 963270 reaction equation
FC(F)(F)S(O[C:7]1[N:8]=[C:9]2[C:14](=[C:15]3[C:20]=1[C@@H:19]([CH3:21])[CH2:18][C:17]([O:24][CH3:25])([O:22][CH3:23])[C@@H:16]3[OH:26])[CH:13]=[C:12]([O:27][CH3:28])[CH:11]=[CH:10]2)(=O)=O.C(N(CC)CC)C.C(O)=O>O1CCOCC1>[CH3:28][O:27][C:12]1[CH:11]=[CH:10][C:9]2[C:14](=[C:15]3[C:20](=[CH:7][N:8]=2)[C@@H:19]([CH3:21])[CH2:18][C:17]([O:22][CH3:23])([O:24][CH3:25])[C@@H:16]3[OH:26])[CH:13]=1

Participants

5

Reactant 3

HCID 284Formic AcidHCID 8471TriethylamineHCID 57051562(7S)-2,9,9-Trimethoxy-7beta-methyl-7,8,9,10-tetrahydrophenanthridine-6,10alpha-diol 6-(trifluoromethanesulfonate)

Product 1

HCID 11034022(7S,10R)-7,8,9,10-Tetrahydro-2,9,9-trimethoxy-7-methyl-10-phenanthridinolYield 97%

Reagents, catalysts & solvents 1

HCID 312751,4-DioxaneSolvent

Conditions

Temperature
23 °C

Procedure

Tetrakistriphenylphosphine palladium (778 mg, 673 mmol, 0.04 equiv) was added to a deoxygenated solution of (7S,10R)-7,8,9,10-tetrahydro-2,9,9-trimethoxy-7-methyl-6,10-phenanthridinediol 6-(trifluoromethanesulfonate) (13, 7.60 g, 16.8 mmol, 1 equiv) and triethylamine (9.40 mL, 67.3 mmol, 4.00 equiv) in dioxane (300 mL) at 23° C. The resulting solution was deoxygenated by alternately evacuating the reaction vessel and flushing with argon (5×). Formic acid (1.70 mL,. 43.8 mmol, 2.63 equiv) was added slowly over 5 min via syringe and the resulting solution was heated at reflux for 20 min, then was allowed to cool to 23° C. The reaction mixture was partitioned between saturated aqueous sodium chloride solution (300 mL) and ethyl acetate (300 mL). The aqueous layer was separated and further extracted with ethyl acetate (2×300 mL). The combined organic layers were dried over sodium sulfate and were concentrated in vacuo. The residue was purified by flash column chromatography (ether initially, grading to 20% ethyl acetate-ether) to provide (7S,10R)-7,8,9,10-tetrahydro-2,9,9-trimethoxy-7-methyl-10-phenanthridinol (15) as a white foam (mp 135°-136° C., 4.94 g, 97%). ##STR25##

Workup

  1. customThe resulting solution was deoxygenated
  2. customby alternately evacuating the reaction vessel
  3. customflushing with argon (5×)
  4. temperaturethe resulting solution was heated
  5. temperatureat reflux for 20 min
  6. customThe reaction mixture was partitioned between saturated aqueous sodium chloride solution (300 mL) and ethyl acetate (300 mL)
  7. customThe aqueous layer was separated
  8. extractionfurther extracted with ethyl acetate (2×300 mL)
  9. dry with materialThe combined organic layers were dried over sodium sulfate
  10. concentrationwere concentrated in vacuo
  11. customThe residue was purified by flash column chromatography (ether initially

Sources & evidence

ORD record
ord-76a3f19d144a4cde8c417b17f9735fdd
Source dataset
uspto-grants-1998_06
Patent number
US05763451

Reaction notes

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