Methanol → HCID 19782180, compound

Temperature

-78 °C

50 g (0.23 mol) of the compound from Example 13 are initially introduced in 780 ml of absolute CH2Cl2 at -78° C. 114 ml (1.2 mol) of boron tribromide in 360 ml of absolute CH2Cl2 are then added dropwise and the mixture is stirred at -78° C. for 30 minutes. It is then stirred at 0° C. for 2.5 h, subsequently cooled to -78° C. again and 690 ml of absolute MeOH are added cautiously. After 15 minutes, the mixture is evaporated, the residue is dissolved in 818 ml of MeOH, 272 ml of 2N NaOH solution are added and the mixture is stirred at 20° C. for 2 h. The methanol is evaporated in vacuo, the aqueous phase is washed with 200 ml of ethyl acetate and then acidified to pH 1-2 using concentrated hydrochloric acid with ice cooling. The aqueous phase is shaken twice with 100 ml of ethyl acetate each time, and the combined ethyl acetate phases are dried over Na2SO4 and evaporated. The residue is recrystallized from toluene.

1. stirringIt is then stirred at 0° C. for 2.5 h
2. temperaturesubsequently cooled to -78° C. again
3. waitAfter 15 minutes
4. customthe mixture is evaporated
5. dissolutionthe residue is dissolved in 818 ml of MeOH
6. addition272 ml of 2N NaOH solution are added
7. stirringthe mixture is stirred at 20° C. for 2 h
8. customThe methanol is evaporated in vacuo
9. washthe aqueous phase is washed with 200 ml of ethyl acetate
10. stirringThe aqueous phase is shaken twice with 100 ml of ethyl acetate each time
11. dry with materialthe combined ethyl acetate phases are dried over Na2SO4
12. customevaporated
13. customThe residue is recrystallized from toluene

ORD record

ord-68825f880fd04cd790dfe961dfa6650f

Source dataset

uspto-grants-1993_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05191092