Yield:25387-67-1 100%

Reaction Conditions:

with sodium hydroxide;water at 50; for 1 h;

Steps:

2

1.045g CPT lactone was weighted in a sterile round bottom flask (250ml). 20% of the needed volume water, to reach a final CPT concentration of 25mM, was added and 3.34g 1 N NaOH was added to the inhomogeneous mixture. The amount of NaOH is selected to reach a molar ratio of CPT/NaOH of 1:1.05. The mixture is intensively stirred and heated to a temperature of 50°C. It takes about 1 hour until a homogeneous solution is formed, which means that CPT lactone has been quantitatively converted into its water-soluble carboxylate form. Further studies has proofed that increasing the temperature up to 90°C accelerates the conversion into the CPT carboxylate form. Stirring for at least 4-6 hours has been proofed to be not critical for the chemical stability of CPT. The solution is cooled down to room temperature and can be stored light-protected and at 4°C for at least 24hours. (Long time storage stability of the final CPT-Na stock solution is discussed later) The pH of the final solution is between 10 and 11.5.

References:

EP1547582,2005,A1 Location in patent:Page/Page column 10