Stability Constants of Dihydrodiazepines and Hydrolysis Equilibria

The marked chemical stability of dihydrodiazepines and their ready formation in aqueous solution are reflected in the stability constants for their formation. These were measured12 for a range of methyl-substituted diazepines and referred to the equilibrium of Eq. (4). 

The equilibrium constants for 25°C, ignoring the water formed, are tabulated in approximate order of stability in Table I. 

The parent compound (I) is very difficult to prepare by the standard method from malondialdehyde and ethylenediamine,12 although it is one 

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