Ethyl chloroformate → HCID 86682563, compound

Temperature

-78 °C

4-pentynoic acid (2.01 g) and hexamethylphosphoamide (6.99 mL) were dissolved in 80 mL of THF, and LDA (20.1 mL) was added dropwise over 20 minutes while stirring at −78° C. After this solution was stirred at −78° C. for 1 hour, a solution of ethyl chloroformate (2.18 g) in 20 mL of THF was added dropwise over 15 minutes, and the mixture was stirred at that temperature for 30 minutes. Thereafter, acetic acid (1.15 mL) was added, a temperature was raised to room temperature, a 10% aqueous potassium dihydrogen phosphate solution was added, and extraction operation (THF once, tetrabutyl methyl ether two times) was performed. After the resulting organic layer was dried with magnesium sulfate, the solvent was distilled off under reduced pressure to obtain the crude product. The crude product was purified by silica gel column chromatography (A/B=30%→45%, A=ethyl acetate: acetic acid=30:1, B=n-hexane) to obtain the title compound (641 mg) having the following physical property values.

1. stirringAfter this solution was stirred at −78° C. for 1 hour
2. stirringthe mixture was stirred at that temperature for 30 minutes
3. temperaturea temperature was raised to room temperature
4. extractionextraction operation (THF once
5. dry with materialAfter the resulting organic layer was dried with magnesium sulfate
6. distillationthe solvent was distilled off under reduced pressure
7. customto obtain the crude product
8. customThe crude product was purified by silica gel column chromatography (A/B=30%→45%

ORD record

ord-05714761853542e2be66f28e185e4bcc

Source dataset

uspto-grants-2015_04

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09006246B2