Reaction #7739

Reaction equation

2-[2-(4-fluorophenyl)acetyl]-4-oxo-pyrazolidine-1-carboxylic acid benzyl ester

morpholine

Na(OAc)3BH

HOAc

HCl

HCl

→

desired product

Yield 60.0%

2-[2-(4-fluorophenyl)acetyl]-4-morpholin-4-yl-pyrazolidine-1-carboxylic acid benzyl ester

Yield 60.0%

Solvents

THF

Conditions

Workup

1. 1
   Otherthen partitioned between diethyl ether and NaHCO3
2. 2
   ExtractionThe aqueous layer was extracted several times with ether
3. 3
   Otherdried
4. 4
   Concentrationconcentrated in vacuo to a clear oil which
5. 5
   workup.DISSOLUTIONwas re-dissolved in ether
6. 6
   FiltrationThe solid is collected by filtration

Procedure

To a solution of 2-[2-(4-fluorophenyl)acetyl]-4-oxo-pyrazolidine-1-carboxylic acid benzyl ester, 11, (0.14 g, 0.4 mmol) and morpholine (0.038 mL, 0.43 mmol) in THF at room temperature is added Na(OAc)3BH (0.125 g, 0.6 mmol) and HOAc (0.022 mL, 0.4 mmol). The solution is stirred 12 hours then partitioned between diethyl ether and NaHCO3. The aqueous layer was extracted several times with ether and the organic layers combined, dried, and concentrated in vacuo to a clear oil which was re-dissolved in ether and one equivalent of ethereal HCl is added and a white solid forms. The solid is collected by filtration and 100 mg (60% yield) of the desired product is isolated as the HCl salt.

Source