N amides

The reactions of pyridinium N-alkoxides (158-161) orpyridinium N-amides (162) with cyanide demonstrate a useful substitution reaction for pyridines. 

Example Optically active aldehyde (10) was needed for a synthesis of biotin. The compound has a 1,1-dlX disconnection (10a) clearly available and a C-N (amide) disconnection leaving (11) which has the same skeleton as the amino acid cysteine (12). 

Detailed kinetic study on the reaction further revealed that the isomerization reaction occurs intramolecularly and proceeds via the initial dissociative bond cleavage of either Pt-N(amidate) or Pt-O(amidate) (53) (see Fig 12). In addition, it was suggested that the... 

The D2 receptor types, besides being subdivided into D3 and D4 types, are further divided into the D2 long and D2 short forms. D2 antagonists, in addition to virtually all therapeutically active neuroleptics, also include such novel drugs as raclopride, eticlopride and sniperone while quinpirole is an example of a specific D2 receptor agonist. The latter drugs are not available for therapeutic use. A malfunction of the D2 receptors has been associated with psychosis, extrap)n amidal side effects and hyperprolactinaemia. 

Os (Tp)(NHPh)(Cl)2] exhibits low acidity and low basicity it is less acidic and less basic than aniline. It was suggested that this is a result of both Os— N(amide) tt bonding and the inductive effect of the oxidizing Os(IV) center. Reaction of [Os (Tp)(NHPh)(Cl)2] with MeOTf at 80 °C for 6T produces [Os (Tp)(NHPh)(OTf)2] and CH3CI. The X-ray structure of [Os (Tp)(NH-Ph)(OTf)2] shows a distorted octahedral structure Os— N(amido) = 1.939A and... 

Various five-coordinate compounds are known for the configuration d of the oxovanadium(IV) and titanium(III). The complexes of the oxo-vanadium can have structures (more or less distorted) referable to the trigonal bip5n amid or more commonly to the square p n amid. 

In the organozinc amide complex (180) (Figure 89), the zinc atom has a distorted tetrahedral coordination geometry as the result of the coordination by the nitrogen atoms of a TMEDA molecule. The Zn—N bond distances [2.182(3) and 2.252(3) A] of the coordinating TMEDA molecule are considerably longer than the Zn—N amide a-bond [1.904(3) A]. 

Other monomeric silylamido complexes have also been obtained by the addition of tmeda (A, A, A A"-tetramethylethylenediamine) or pmdeta (N,N,N ,N" - pentamethyl-diethylenetriamine) to afford [(tmeda)LiN(SiMe3)2] which has three coordinate lithium Li—N(amide)= 1.893(3) A and [(pmdeta)LiN(SiMe3)2 with 4-coordinate Li and Li—N (amide = 1.988(6) A. The use of very large substituents at the amido ligand can also afford monomeric structures. Examples include [Li(thf)3N(SiMe2Ph)2], [Li(thf)2N(SiPh3)2l/ [Li(th )2N(SiBu 2F)2] [Li(thf)2N (C6F5)(SiBu 2F) ] and [Li(thf)3 NMes (SiPr 2X) ]... 

The terminal and bridging Al-N(amide) bond lengths are in the range 1.821(6)-1.844... 

Synthesis of Peptides Containing C/N Amide Bond Replacements... 

Wrasidlo 79) fabricated semipermeable poly(N-amide)imide (26) membrane from 3,3, 4,4 -benzophenonetetracarboxylic dianhydride (27) and isophthalic dihydrazide (28). The membrane with 28 i thickness had a water flux of 11401/m2 day-2000 A and salt rejection of 99.95%, while a 39.8% acetylated cellulose acetate membrane with 16 ji thickness had values of 118 1/m2 day and 99.35%. 

Bis(pyrrole-2-aldiminato)nickel(II) complexes (125) are diamagnetic in the solid state when R = H, Pr, Pr and Et, and paramagnetic pseudotetrahedral when R = Bu. 1001-1003 In solution there exists an equilibrium between square planar and tetrahedral species when R = Pr1, Bus and Bu Such equilibria were also investigated for complexes of the type (126) obtained from the condensation reaction in basic media of o-aminobenzaldehyde and a number of diamines in the presence of nickel(II).1004-1007 Square planar complexes (127)1008,1009 and (128)1010 were obtained with deprotonated pyridinecarboxamide ligands. In these complexes the Ni—N (amide) bond distance (184-187 pm) is shorter than the Ni—N (pyridine) distance (192-195 pm). 

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