NR function

Sulfur imides with a single NR functionality, S5NR (6.12), SeNR (6.13) (R = Oct), " SgNH (6.14), ° and S9NH (6.15) ° are obtained by a methodology similar to that which has been used for the preparation of unstable sulfur allotropes, e.g., S9 and Sio. Eor example, the metathesis reaction between the bis(cyclopentadienyl)titanium complexes 6.8-6.10 and the appropriate dichlorosulfane yields 6.14 and 6.15 (Eq. 6.4). °... 

Imine (Section 19.8) A compound with the R2C=NR functional group. 

Syntheses of Amides and Analogous Compounds with CO-NR Functions... 

Imido selenium compounds Se(NR)2, where R = Bu or Ts, were first noted to give allylic amination of alkenes and alkynes.232 Formally the NR function is inserted into the allylic C—H bond yielding the C—NHR moiety. Related reactivity was also found for the sulfur imides, S(NR)2.233 Reactions between 1,3-dienes and Se(NTs)2 give [4 + 2] adducts which, in the presence of TsNH2, react to generate 1,2-disulfonamides.234... 

Nuclear receptors (NR) function as ligand-activated transcription factors that regulate expression of a host of genes, including those coding for key drug-metabolizing enzymes and transporters. It is now known that the induction... 

Unlike the steroid receptors, most of which function as homodimers, a second class of NRs function as heterodimers with the retinoid X receptor (RXR). Importantly, these receptors serve as sensors for metabolites such as fatty acids, oxysterols, and bile acids. Key elements of ligand recognition and receptor activation have been elucidated following structure-function analyses of several receptors in this family including the PPARs, liver X receptors (LXRs), and FXR. 

The chemistry of organoimido compounds is currently of interest in studies of transition-metal multiple bonds. As a result of the robust M NR function, it has been possible to prepare imido complexes of a diversity of metals. For synthetic work with earlier transition metal complexes in high valence states, organoimido compounds are less likely to polymerize than species containing the terminal oxo group. An added advantage is that any polymeric compounds formed are likely to be soluble in organic solvents. 

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