Hydrochloric Acid → 3-Ethyl-1-methylcyclobutane-1-carboxylic acid

A solution of 19.9 ml (140 mmol) of dry diisopropylamine in 100 ml of dry tetrahydrofuran was stirred in under an argon atmosphere and 63.6 ml (140 mmol) of a solution of n-butyllithium (2.2 M) in hexane was added dropwise thereto while maintaining the temperature below about 5° C. The resultant mixture was then stirred for 15 min with ice-bath cooling. A solution of 8.2 g (64 mmol) of 3-ethylcyclobutanecarboxlic acid (prepared in Example 1E) in 15 ml of dry tetrahydrofuran was added dropwise to the reaction mixture and stirred with cooling for 15 min. Methyl iodide (4.36 ml, 70 mmol) was added to the reaction mixture dropwise and the resultant mixture was stirred without cooling for 2 hr. The mixture was then stirred with ice-methanol bath cooling as 10% hydrochloric acid was added dropwise until the resultant aqueous phase was acidic (about 25 ml was used). The aqueous phase was separated and extracted twice with ether. The combined ether extract was dried over anhydrous magnesium sulfate and the solvent removed in vacuo to yield 10 g of the title compound having the following physical characteristics:

1. additionwas added dropwise
2. temperaturewhile maintaining the temperature below about 5° C
3. temperaturecooling
4. temperaturewith cooling for 15 min
5. temperaturewithout cooling for 2 hr
6. stirringThe mixture was then stirred with ice-methanol bath
7. additionwas added dropwise until the resultant aqueous phase
8. customThe aqueous phase was separated
9. extractionextracted twice with ether
10. extractionThe combined ether extract
11. dry with materialwas dried over anhydrous magnesium sulfate
12. customthe solvent removed in vacuo

ORD-Eintrag

ord-0ac1b8437f414919bc2f11d7d52ae2d1

Quelldatensatz

uspto-grants-1980_09

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US04220795