These minor differences suggest that the properties emergent from the delocalized N-lone pair and destabilization C = S and C = Se ? bond in thiourea and selenourea will also be similar.
42.
It is proposed that activation occurs via H bonding of both the nitronate and the ester to the thiourea catalyst and explains the interesting selectivity for the " E " ester.
43.
The nitro and cyano groups are sufficiently electronegative to reduce the pK a of the neighboring nitrogens to the same acidity of the thiourea group, hence preserving the activity of the drug in a physiological environment.
44.
Some compounds can considerably increase or decrease the solubility of AgX . Examples of compounds that increase the solubility include : cyanide, thiocyanate, thiosulfate, thiourea, amines, ammonia, sulfite, thioether, crown ether.
45.
The pharmaceuticals thiobarbituric acid and sulfathiazole are prepared using thiourea . 4-Amino-3-hydrazino-5-mercapto-1, 2, 4-triazole is prepared by the reaction of thiourea and hydrazine.
46.
The pharmaceuticals thiobarbituric acid and sulfathiazole are prepared using thiourea . 4-Amino-3-hydrazino-5-mercapto-1, 2, 4-triazole is prepared by the reaction of thiourea and hydrazine.
47.
Thiourea catalysts with pendant chiral backbones have shown to activate systems with tethered nitroalkane and ester motifs to induce asymmetric IMA . The utility of this transformation was demonstrated in the synthesis of cyclic ? amino acid precursors ( figure 1 ).
48.
Most conventionally used accelerators are problematic when CR rubbers are cured and the most important accelerator has been found to be ethylene thiourea ( ETU ) which, although being an excellent and proven accelerator for polychloroprene, has been classified as reprotoxic.
49.
The reaction is accomplished when hydrogen is released by a reducing agent, normally sodium hypophosphite ( Note : the hydrogen leaves as a hydride ion ) or thiourea, and oxidized, thus producing a negative charge on the surface of the part.
50.
To date various organic transformations are organocatalyzed through double hydrogen-bonding " N, N "'- bis [ 3, 5-bis ( trifluoromethyl ) ] phenyl thiourea at low catalyst loadings and in good to excellent product yields.
