2-ureido-4-pyrimidone

Meijer et al. reported the self-aggregation behavior of a molecule in chloroform (Fig. 11.8) containing two units of 2-ureido-4-pyrimidone linked through a spacer (which self-associates in the DDAA-AADD pattern strongly with a dimerization constant >106 m ) [36], This compound formed viscous solutions in chloroform, and the viscosity observed was dependent on the concentration and temperature. 

Scheme 1 Hydrogen-bonding motifs discussed in this chapter. Upy 2-ureido-4-pyrimidone, DAN 2,7-diamido-l,8-naphthyridine, DAP diacyldiaminopyridine, HW Hamilton wedge, UG ureidoguanosine, CA cyanuric acid...

FIGURE 5 Quadmpole hydrogen bonding dimer of 2-ureido-4-pyrimidone groups. 

Fig. 4. Supramolecular fullerene polymer constituted by self-complementaiy 2-ureido-4-pyrimidones.

Quadruple hydrogen bond arrays introduced to functionalized fullerenes have been used in the formation of self-assembled Cgo dimers (Figure 2.14) through 2-ureido-4-pyrimidones recognition moieties. " ... 

The monomeric unit used in the studies in shown in Fig. 45.3. It is based on poly(s-caprolactone) with a terpyridine ligand (for metal complexation) at one end and an ureido-pyrimidone group (for hydrogen bonding) on the other end. The polymeric spacer is used to control the solubility in various solvents, in such a way that both hydrogen-bonding and metal-complexation can take place simultaneously. This unit shows a good solubility in chloroform. 

Figure 5.12 Self-associative hydrogen bonded polymer networks based on (a) 2-ureido-4[lH]-pyrimidone (UPy), (b) 1,2,4-triazine, and (c) urazole carboxylic acid.

Figure 5.13 Self-associative polymer network formed via the dimerization of 2-ureido-4[lH]-pyrimidone groups attached to the polymer backbone.

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