Water → Indole

Temperature

-70 °C

The synthesis was carried out with reference to the disclosure of Reference Article 11. There was dissolved aniline (34) (16.8 mmol) in methylene chloride, the resulting solution was cooled to −70° C., a solution (8 ml) of separately synthesized BuOCl (16.8 mmol) in methylene chloride was dropwise added to the cooled solution and then the mixture was stirred at −70° C. for 15 minutes. To the reaction solution, there was dropwise added a solution (8 ml) of separately synthesized MeSCH2CO2Et (16.8 mmol) in methylene chloride over not less than one hour and the mixture was further stirred for 2 hours. To the resulting reaction solution, there was dropwise added a solution (8 ml) of TEA (16.8 mmol) in methylene chloride over not less than 30 minutes, the mixture was stirred for 15 minutes at that temperature and then the temperature thereof was raised up to room temperature. To the mixture, there was added 10 ml of water, the mixture was then stirred for 15 minutes, followed by concentration, addition of ether (20 ml) and a 2M HCl (13 ml), extraction with ether, drying of the extract and the subsequent concentration thereof. The resulting compound (4.25 mmol) was dissolved in HMPA (5 ml) and an LR reagent (2.1 mmol) was added in an argon atmosphere. After the post-treatment, Ra—Ni (4-spoonful) and MeOH (60 ml) were added to the mixture and the latter was refluxed with heating for one hour. The Raney-Ni catalyst was removed from the reaction system through decantation, the solution was concentrated, followed by drying of the concentrate and purification by column chromatography (3 cm) to thus give indole (35) in a yield of 3.76 mmol (88%).

1. stirringthe mixture was further stirred for 2 hours
2. customTo the resulting reaction solution, there
3. stirringthe mixture was stirred for 15 minutes at that temperature
4. temperaturethe temperature thereof was raised up to room temperature
5. stirringthe mixture was then stirred for 15 minutes
6. concentrationfollowed by concentration, addition of ether (20 ml)
7. extractiona 2M HCl (13 ml), extraction with ether
8. customdrying of the
9. extractionextract
10. concentrationthe subsequent concentration
11. temperaturethe latter was refluxed
12. temperaturewith heating for one hour
13. customThe Raney-Ni catalyst was removed from the reaction system through decantation
14. concentrationthe solution was concentrated
15. customby drying of the
16. concentrationconcentrate
17. custompurification by column chromatography (3 cm) to thus give indole (35) in a yield of 3.76 mmol (88%)

ORD record

ord-6ae07c6f1a8b444bb02030464f805fe6

Source dataset

uspto-grants-2013_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08440169B2