Thiourea groups

One group which could have utility in this context is the thiourea group (Fig. 17). Unfortunately, repeated attempts to generate the dianion via directed lithiation of A(,-dimethyl-Ar-phenylthiourea were unsuccessful. Again, bromo compounds came to the rescue. The 2-bromo derivative could be deprotonated (N-... 

Figure 6.55 Uncharged tris-thiourea 190 without guanidinium moiety and charged guanidinium structure 191 without a thiourea group appeared catalytically inactive in the Henry reaction of cyclohexane carboxaldehyde with nitromethane, while guanidine-thiourea 183 gave 99% yield and 95% ee under identical (optimized) conditions.

Receptors with two urea or thiourea groups clearly bind H2PO4 more strongly than receptors with one of those groups only, as can be seen from the increases in the AT, value from 19 (28 M" ) to 13 (110 M ) or from 20 (120 M" ) to 14 (820 M ). Considerable downfield shifts induced in the H NMR chemical shifts of the... 

Post reaction of these polymers with aniline leads to polymers end capped with a thiourea group. Aziridines of these types that have been polymerized include p-tolyl and p-nitrophenyloxythiocarbonyls and p-tolyl, p-chlorophenyl and p-methoxyphenyldithiocarbonyls. Molecular weights in all cases were low, being in the neighborhood of 1500-3000. 

The preparation and structural investigation of silver(I) thiourea complexes have been the subject of numerous reports.340 In solution, the formation of stable, mononuclear complexes containing up to four thiourea groups has been proposed and the associated thermodynamic data are collected in Table 47. -342... 

Attempts have been made to deprotonate the coordinated thiourea group. Upon contact of Ag(tu)3N03 with ammonia, the initially white complex became grey and turned black following complete removal of the solvent. The products obtained (ammonium nitrate, silver sulfide, thiourea and cyanamide)were rationalized by equations (22) and (23).347... 

What kinds of adsorptives were examined in which environments Besides the well known affinity of thiophilic elements like mercury, and, to a lesser extent copper, towards thiol or thiourea groups, adsorption experiments were reported for ... 

Replacing the thiourea group by a cyanoguanidine group gives a compound equipotent with cimetidine, but it has poor crystallinity for pharmaceutical development ... 

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