Trifluoroacetic acid → 2-(Cyclopentyloxy) acetohydrazide

2.60 g of cyclopentyloxyacetic acid (18.03 mmol, 1.0 eq.) are placed in 50 mL of dichloromethane at room temperature with stirring. 2.86 g of tert-butyl hydrazinecarboxylate (21.64 mmol, 1.2 eq.), 2.437 g of hydroxybenzotriazole (18.03 mmol, 1.0 eq.), 4.148 g of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (21.64 mmol, 1.2 eq.) and 4.08 mL of diisopropylethylamine (23.44 mmol, 1.3 eq.) are successively added with stirring. After 18 hours, the reaction medium is diluted with dichloromethane and washed twice with water. The organic phase is dried over sodium sulfate, filtered and evaporated. The residue is dissolved in 60 mL of dichloromethane. 15 mL of trifluoroacetic acid (201.93 mmol, 11.20 eq.) are added. The reaction medium is stirred for 2 hours and concentrated under vacuum. The residue is chromatographed on silica gel, eluting with a dichloromethane/methanol/aqueous ammonia gradient ranging from 99/1/0.1 to 95/5/0.5. 2.7 g of cyclopentyloxyacetic acid hydrazide are obtained.

1. stirringwith stirring
2. washwashed twice with water
3. dry with materialThe organic phase is dried over sodium sulfate
4. filtrationfiltered
5. customevaporated
6. dissolutionThe residue is dissolved in 60 mL of dichloromethane
7. stirringThe reaction medium is stirred for 2 hours
8. concentrationconcentrated under vacuum
9. customThe residue is chromatographed on silica gel
10. washeluting with a dichloromethane/methanol/aqueous ammonia gradient

ORD record

ord-e3e210e6293a478ca2285555c668cd66

Source dataset

uspto-grants-2013_10

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08546391B2