Reaktion #61310

Reaktionsgleichung

tBuOK

(4Benzyl-6-ethoxycarbonylmethyl-1-methylpiperazin-2-yl)acetic acid ethyl ester

TFA

→

piperazine

9-Methyl-7-oxo-3,9-diazabicyclo[3.3.1]nonane-3-carboxylic acid tert-butyl ester

Lösungsmittel

toluene

MeOH

Reaktionsbedingungen

Aufarbeitung

1. 1
   Sonstigethe flask was purged with nitrogen
2. 2
   workup.ADDITIONPd/C (10%, 50% moisture, 3.6 g) was added
3. 3
   SonstigeThe flask was closed
4. 4
   Sonstigepurged with hydrogen (3×)
5. 5
   Filtrationthe mixture was filtered through celite
6. 6
   Waschenwashed with MeOH
7. 7
   SonstigeThe solvent was removed under reduced pressure
8. 8
   Trocknenthe foamy residue (92.7 g) was dried under high vacuum

Vorschrift

(4Benzyl-6-ethoxycarbonylmethyl-1-methylpiperazin-2-yl)acetic acid ethyl ester (Patent WO 92/05174) (71.0 g, 0.196 mol) was dissolved in MeOH (400 mL). TFA (77.8 mL, 1.02 mol) was added and the flask was purged with nitrogen. Pd/C (10%, 50% moisture, 3.6 g) was added. The flask was closed and purged with hydrogen (3×). After 1 day, the mixture was filtered through celite and washed with MeOH. The solvent was removed under reduced pressure and the foamy residue (92.7 g) was dried under high vacuum. A sol. of tBuOK (117.2 g, 1.04 mol) in toluene (3.07 L) was heated to reflux. A sol. of the crude piperazine formerly obtained, dissolved in THF (300 mL), was added dropwise over 50 min.

Quelle