Poly amidines

It has been found that DTBP cross-linking substantially increased the salt stability of the complexes. The salt stabilization is reversed upon the addition of DTT, which cleaves the bifunctional reagent, indicating that it is not due to the conversion of the amines to amidines and is dependent upon the cross-linking. Similar results were achieved with other polycations, including poly(allylamine), and histone HI. 

The readiness of amidine formation in reactions of lactim ethers with amines has been used in the synthesis of 8,9-poly methylene-purines.97 Attempts to condense 2 (R = Me) with uramil and l,3-dimethyl-4,5-diaminouracil failed.97 Lactim ethers were also found not to react with derivatives of 5-aminouracil, probably due to the low basicity of the latter.97... 

S2.7nm) with sulfete-groups on the surfoce the cationic latex was also polys ene (diameter 43.4 nm) with surface amidine groups. It can be seen from Fig. 24 that the system becomes completely unstable when the ratio N / N+ + W ) reaches 0.25. 

A valuable route to chloro- and dichloro-l,3,5-triazines involves the reaction of poly-chloroimides with amidines. These eyclizations are also carried out under Schotten- Baumann conditions,408 with the dichlorotriazines being prepared in a two-phase system consisting of water/dichloromethane. 

In Chart 2 are depicted various poly-valent donor building blocks such as thiols, secondary amines, phosphotyl imines and ylids which serve both the purposes of diversification and cleavage as well as of construction of the central core stmctures. Bidentate nucleophiles such as thioamides, thioureas, ureas, isothioureas, amidines, guanidines, 1,2-dihydroxybenzenes, 2-aminothiophenols and others (see Chart 2) were exclusively employed for the synthesis of the cores as exemplified in Chapter 3 and 4 (the indicated references refer to these examples)... 

More dinltrlle is then added to the amldlne to give a linear poly(lmldoyl amidine). Ring closure to trlazlne can be accomplished with an acid fluoride or an anhydride. For example, a low-molecular weight, linear poly(imldoyl amldlne) derived from 8-EDAF dinltrlle was prepared and converted to the polytrlazlne by (CFjC0)20 treatment. 

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