Norchlorcyclizine → Cetirizine ethyl ester

HRID 1871007Notes

Reaction equation

HRID 1871007 reaction equation
[Cl:1][C:2]1[CH:7]=[CH:6][C:5]([CH:8]([C:15]2[CH:20]=[CH:19][CH:18]=[CH:17][CH:16]=2)[N:9]2[CH2:14][CH2:13][NH:12][CH2:11][CH2:10]2)=[CH:4][CH:3]=1.Cl[CH2:22][CH2:23][O:24][CH2:25][C:26]([O:28][CH2:29][CH3:30])=[O:27]>C(N(CC)CC)C>[Cl:1][C:2]1[CH:3]=[CH:4][C:5]([CH:8]([C:15]2[CH:16]=[CH:17][CH:18]=[CH:19][CH:20]=2)[N:9]2[CH2:10][CH2:11][N:12]([CH2:22][CH2:23][O:24][CH2:25][C:26]([O:28][CH2:29][CH3:30])=[O:27])[CH2:13][CH2:14]2)=[CH:6][CH:7]=1

Participants

4

Reactant 2

HCID 9340NorchlorcyclizineHCID 10964894Ethyl 2-(2-chloroethoxy)acetate

Product 1

HCID 9844843Cetirizine ethyl esterYield 89%

Reagents, catalysts & solvents 1

HCID 8471TriethylamineSolvent

Procedure

The present inventors have found that when the reaction is performed in a tertiary amine as both solvent and acid scavenger at elevated temperature, significantly higher yield is obtained. Namely, when 1-[(4-chlorophenyl)phenylmethyl]piperazine is reacted in a pressure vessel with ethyl 2-chloroethoxyacetate in triethylamine at 135° C. for 10 hours, ethyl [2-[4-[(4-chlorophenyl)phenylmethyl]-1-piperazinyl]ethoxy]acetate is obtained in 89% yield. When catalytic amounts of potassium iodide or tetrabutylammonium iodide are present in the reaction, slightly higher yield is obtained. If triisopropylamine or pyridine are used instead of triethylamine and the reaction is carried out at the same temperature at atmospheric pressure, a drop of 30-40% in the reaction yield is observed.

Workup

  1. customacid scavenger at elevated temperature, significantly higher yield
  2. customis obtained

Sources & evidence

ORD record
ord-edd692d347b74356a96619ef7662d27f
Source dataset
uspto-grants-2000_08
Patent number
US06100400

Reaction notes

Loading…