Trifluoroacetic acid → 4-Phenanthrenol, 3-methyl-

In a 500 ml 3-neck flask equipped with magnetic stirrer and reflux condenser with nitrogen inlet, 66 ml of trifluoroacetic acid and 88 ml of trifluoroacetic anhydride were mixed together cautiously. The mixture was stirred under nitrogen and 54.6 g (0.21 mole) of 97% triphenylmethanol was added in increments over a 30 minute period giving an intense yellow-green solution. Heat was liberated. The reaction mixture was refluxed for one hour, cooled and 22.0 g (0.105 mole) of 3-methyl-1,2,3,4-tetrahydrophenanthrone as prepared above was added all at once, followed by refluxing under nitrogen for 21 hours. The amber mixture was cooled in an ice water bath and filtered to remove the solids. The filtrate was poured on crushed ice and the light tan precipitate was collected, washed with water and air-dried overnight. The solids were extracted with several portions of hexanes at room temperature to take up the 4-phenanthrol trifluoroacetate. The hexanes were concentrated to 400 ml, cooled in a freezer, then filtered. The filtrate was concentrated under vacuum to an oil. 40 ml of degassed 10% aqueous sodium hydroxide (containing a trace amount of sodium hydrosulfite) was added to the oil, followed by 110 ml of methanol. Nitrogen was passed through the mixture with stirring for one hour at room temperature. The mixture was filtered, and while cooling in an ice water bath, the filtrate was acidified with dilute hydrochloric acid to give a light tan precipitate. The precipitate was collected by filtration, washed with water and dried under vacuum to give 17.9 g (79.13% by weight) of 3-methyl-4-phenanthrol as a tan solid. M/e 208; M.P. 88°-92° C.; λmax 275 (16,200) methanol.

1. customIn a 500 ml 3-neck flask equipped with magnetic stirrer
2. temperaturereflux condenser with nitrogen inlet
3. customgiving an intense yellow-green solution
4. temperatureHeat
5. temperatureThe reaction mixture was refluxed for one hour
6. temperaturecooled
7. additionabove was added all at once,
8. temperatureby refluxing under nitrogen for 21 hours
9. temperatureThe amber mixture was cooled in an ice water bath
10. filtrationfiltered
11. customto remove the solids
12. additionThe filtrate was poured
13. customon crushed ice
14. customthe light tan precipitate was collected
15. washwashed with water
16. customair-dried overnight
17. extractionThe solids were extracted with several portions of hexanes at room temperature
18. concentrationThe hexanes were concentrated to 400 ml
19. temperaturecooled in a freezer
20. filtrationfiltered
21. concentrationThe filtrate was concentrated under vacuum to an oil
22. addition40 ml of degassed 10% aqueous sodium hydroxide (containing a trace amount of sodium hydrosulfite)
23. additionwas added to the oil
24. stirringwith stirring for one hour at room temperature
25. filtrationThe mixture was filtered
26. temperaturewhile cooling in an ice water bath
27. customto give a light tan precipitate
28. filtrationThe precipitate was collected by filtration
29. washwashed with water
30. customdried under vacuum

ORD record

ord-2741bd5cf4df4277aae87776585e1acd

Source dataset

uspto-grants-1990_01

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04891298