Tetrafluoroboric acid → HCID 12799964, compound

2-(n-Pentadecyl)indole-6-carboxylic acid (16.0 g) was dissolved in a mixture of tetrahydrofuran (400 ml) and ethanol (100 ml), containing aqueous fluoroboric acid (100 ml, of strength 40% w/v). The stirred mixture was hydrogenated over platinum oxide (2.0 g) at room temperature and atmospheric pressure. After 6 hours the mixture was filtered, the residue was washed with diethyl ether (100 ml) and the combined filtrates were concentrated in vacuo until a solid separated. The mixture was adjusted to pH 7 by treatment with an aqueous solution of sodium hydroxide (strength 50% w/v) and was then adjusted to pH 4-5 with glacial acetic acid. The mixture was extracted with diethyl ether (3×100 ml), and the ether solution was dried over magnesium sulphate and, on evaporation in vacuo, gave a solid. The solid was recrystallised from a mixture of toluene and hexane (equal parts by volume) to give (RS)-2-(n-pentadecyl)-indoline-6-carboxylic acid (7.3 g), in the form of a colourless solid, m.p. 119°-122° C.

1. filtrationAfter 6 hours the mixture was filtered
2. washthe residue was washed with diethyl ether (100 ml)
3. concentrationthe combined filtrates were concentrated in vacuo until a solid
4. customseparated
5. extractionThe mixture was extracted with diethyl ether (3×100 ml)
6. dry with materialthe ether solution was dried over magnesium sulphate and, on evaporation in vacuo
7. customgave a solid
8. customThe solid was recrystallised from a mixture of toluene and hexane (equal parts by volume)

ORD record

ord-6a0158bbec014d7a8b04b7d67aa89549

Source dataset

uspto-grants-1985_01

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04493843