5H-Cyclopenta[h]quinazoline, 6,6a,7,8,9,9a-hexahydro-7,7,8,9,9-pentamethyl-

Hydrolysis

Description of key information

The substance is hydrolytically stable in an OECD TG 111 study at pH 4, 7 and 9 at 25°C (DT50> 1 year).

Key value for chemical safety assessment

Half-life for hydrolysis:

1 yr

at the temperature of:

25 °C

Additional information

Hydrolysis of the substance as a function of pH was examined in a study according to OECD TG 111 and in compliance with GLP (Envigo, 2016). Sample solutions were prepared in stoppered glass flasks by adding defined nominal concentrations to sterile buffer solutions with pH4, 7, and 9 and maintained at 50°C for a period of up to 240 hours. A co-solvent of acetonitrile was used to aid solubility. The solutions were shielded from light. In addition, a direct test at pH4, 7, and 9 was performed at 25°C for the duration of 30 days under otherwise the same conditions. Sample solutions were taken at various times, the concentration of each sample solution determined by HPLC (done for 2 components), and hydrolysis rates calculated. In the tests at 50°C data indicated the absence of any significant hydrolysis, i.e. less than 10% over a time period exceeding 120 hours at 50 °C. In the direct test at 25°C component 1 showed no evidence of any ongoing hydrolysis at pH4, 7 and 9. Component 2 also showed no evidence of any ongoing hydrolysis at pH7 and 9, but at pH4 the decrease in concentration versus time yielded a hydrolysis rate of 5.83E-04 h-1 which relates to a half-life of 49.5 days. Altogether, based on the results, the whole substance was considered to be hydrolytically stable.