Isothiocyanates 2 molecules

The cycloaddition of two isothiocyanate molecules, prepared by condensation of 6-methoxy-3-pyridinamine and thiophosgene, produces a new type... 

Greenhill and coworkers have shown that the reaction of cyclic enaminones with isothiocyanates can be controlled regioselectively to attack the nitrogen or the / -carbon according to the reaction conditions8. Surprisingly, a heterocyclic spiro-product formed by reaction with two isothiocyanate molecules is observed in one case (equation 4). (equation 4). 

Rather similar results are obtained by comparing the bond angles in the silyl and methyl ethers (Fig. 18.5) and isothiocyanates (Fig. 18.6). In dimethyl ether the oxygen is hybridized approximately sp with two lone pairs on the oxygen atom as compared to an approximate sp hybrid in disiloxane with ir bonding. In the same way the methyl isothiocyanate molecule, CHjN=C=S, has a lone pair localized on the nitrogen atom, hence is bent (N sp ), but the delocalization of this lone pair into a ir orbital on the silicon atom of H3SiN=C=S leads to a linear structure for this molecule. 

The use of UV adsorption enhancers as reagents that introduce a UV chromaphore into a molecule that is transparent in the UV wavelength range has already been briefly discussed. The two most common reagents are the phenyl and methyl isothiocyanates. These reagents react with amino acids to form thiodantoins. 

Flamers R. J., Coulter S. K., Ellison M. D., Flovis J. S., Padowitz D. F., Schwartz M. P., Greenlief C. M., Russell J. N. Jr Cycloaddition Chemistry of Organic Molecules With Semiconductor Surfaces Acc. Chem. Res. 2000 33 617 624 Keywords carbonyi group, semiconductor materiais, surface reaction, aikenes, aromatic compounds, azo compounds, cycioaikadienes, isothiocyanates, unsaturated compounds... 

D. Pseudohalogeno-derivatives.—Little work has been carried out in this area. Isocyanates of cyclic phosphazenes, previously unknown, are thought to be formed in the reaction of NgPaBrg with AgOCN in nitro-methane. They were detected by i.r. spectroscopy, and underwent ready polymerization, which precluded their isolation. On the other hand, isothiocyanates, [NP(NCS)2] (n = 3 or 4), are well known and a detailed study of their spectra has been reported. The azide, N3Pa(N3)8, has been the subject of an i.r. study which suggests that the molecule has Z)3A symmetry. 

Note that carbon monoxide inserts into the Zr-H bond of 1 (2 equiv.) to afford an T -formaldehydo-type complex [(Cp2ZrCl)]2(g-CH20) [200-202]. Iminoacyl zir-conocene complexes are formed after addition of 1 to isonitriles [203]. Carbon dioxide [183, 202] is reduced to formaldehyde with 1 (2 equiv.). C02-like molecules such as isocyanates RNCO [204], isothiocyanates RNCS [205], and carbodiimides RNCNR [204] are readily converted to the corresponding bidentate form-amido ligands. 

The nondestructive introduction of a fluorescent label would provide the molecule with a nonradioactive fluorophore, yet would preserve the option for direct radiolabelling of the fluorescent moiety with 125Iodine. This approach was pioneered by Nagasawa et al. (5) who reacted native or /V-desulfated heparins with a fluorescein isothiocyanate (FITC). The resulting degree of labelling was low... 

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