52420-88-9

1,3-Dimethyl-2-methylamino-1,3,2-diazaphospholidine-2,4,5-trione (1b) has been synthesized, and its solvolytic behaviour and X-ray crystal structure determined.Methanolysis of (1b) gives products of the cleavage of both imide P-N bonds, indicating that the ring opening in (1b) is much slower than the second P-N cleavage in the ring-opened intermediate.The low reactivity of (1b) is correlated with the small size (92.3 deg) of the endocyclic N-P-N angle, which suggests that not much energy is released upon the formation of the PV trigonal bipyramidal adduct.The molecular structure of (1b) reveals a high degree of coplanarity of the phospholidine ring with both imide N-methyl groups and both carbonyl oxygen atoms.The geometry indicates that the endocyclic nitrogen atoms in (1b) are involved in the resonance interactions not only with the adjacent carbonyl groups, but also with the phosphoryl centre. 1,3-Dimethyl-2-phenoxy-1,3,2-diazaphospholidine-2,4,5-trione (1a) has been found to react with p-anisidine or ammonia exclusively at the phosphorus atom.In the reaction with p-anisidine both P-O bond cleavage (displacement of phenol) and ring P-N bond cleavage products were obtained; this is interpreted in terms of pseudorotation of the initially formed PV intermediate.Ammonia reacts with (1a) giving exclusively the ring-retained, P-OPh bond cleavage products.Our aminolysis results for (1a) contrast with those reported in the literature.

Mixed phosphoric-carboxylic imides were shown to react with Grignard reagents exclusively at the carbonyl centre.

The neutral and acid-catalyzed solvolysis (hydrolysis and alcoholysis) of mixed phosphoric-carboxylic imides (1), X2P(O)-NR-C(O)R'(X = EtO, MeO, CH2O, Et; R = H, Me; R'= Me, Ph) has been studied and compared with the solvolytic behavior of parent phosphoric and carboxylic amides and symmetrical imides.The neutral cleavage of the P-N bond is believed to involve an oxyphosphorane intermediate.The ionization of 1 follows the amide acidity function, with half-protonation at the carbonyl oxygen atom occuring at ca. 70percent D2SO4.The remarkable stability of the P-N bond in acidic solutions, together with the susceptibility of the N-C(O)solvolysis toward acid catalysis, is consistent with the exclusion of the N-protonation of 1 and is in accordance with carbonyl oxygen protonation and the significant electron-withdrawing effect of the N-phosphinyl substituent.The hydration parameter treatment was applied to the acid-catalyzed N-C(O) hydrolysis of 1d (1, X = EtO; R = R'= Me), and the results are compared with those obtained for the acid-catalyzed hydrolysis of N-methylacetamide.The acidic solvolysis of 1, with respect to both the P(O)-N and N-C(O) cleavage, lies between the extremes characterized by the respective parent amides and symmetrical imides.

Influence of substituent on the reaction rate of the alkali-catalyzed solvolysis of the studied compounds set has been followed.The activation entropy has also been determined.The reaction products have been identified, and their concentration ratio has been determined.The reaction selectivity is mostly influenced by sterical effects in the substrate molecule.The results obtained agree with the SN2 mechanism.