Isocyanides, 4-nitrophenyl

Both 2-azido [184] and 2-nitrophenyl isocyanides [185] are suitable synthons for the generation of the freely unstable 2-aminophenyl isocyanide and they have been used (Fig. 23) in the template-controlled preparation of NH,NH-stabilized benzim-idazolin-2-ylidene hgands. Both phenyl isocyanides coordinate readily to transition metal centers. The isocyanide ligand in complex 65 reacts with PPhs and the... 

Complex 61 is also accessible from the 2-nitrophenyl isocyanide complex 68 by reduction of the nitro group with Sn/HCl. Incomplete reduction of the nitro group in 68 with Raney-Nickel/hydrazine yields, after intramolecular cyclization, the complex 70 with the NH,NOH-stabilized benzimidazolin-2-ylidene ligand. Complex 69 with the 2-hydoxylamin-substituted phenyl isocyanide ligand presumably occurs as an intermediate in this reaction. The alkylation of both the NH,NH- and the NH, NOH-stabilized NHC ligands in 67 and 70, respectively, proceeds readily (Fig. 23) [184, 185]. 

Gilley CB, Kobayashi Y (2008) 2-nitrophenyl isocyanide as a versatile convertible isocyanide rapid access to a fused y-lactam (3-lactone bicycle. J Org Chem 73 4198 204 Chen JJ, Golebiowski A, Klopfenstein SR, West L (2002) The universal Rink-isonitrile resin applications in Ugi reactions. Tetrahedron Lett 43 4083 085 Hulme C, Peng J, Morton G, Salvino JM, Herpin T, Labaudiniere R (1998) Novel safety-catch linker and its application with a Ugi/De-BOC/Cyclization (UDC) strategy to access carboxylic acids, 1, 4-benzodiazepines, diketopiperazines, ketopiperazines and dihydroqui-noxalinones. Tetrahedron Lett 39 7227-7230... 

In general, the hydrolysis of amides requires conditions that are not compatible with the survival of several functional groups [10]. If the amide nitrogen is linked to an electron-withdrawing moiety, alkaline hydrolysis of the amide group is easier. Following this observation Martens and co-workers used 4-methoxy-2-nitrophenyl isocyanide 14 (or 2-methoxy-4-nitrophenyl isocyanide) as a convertible isocyanide for the preparation of Peptide Nucleic Acid (PNA) monomers [8a] (for another example, see Ref. [11]). The Ugi-4CR between isocyanide 14, carboxymethyl nucleo-... 

Complex 67 is also accessible from the 2-nitrophenyl isocyanide complex 68 by reduction of the nitro group with Sn/HCl. Incomplete reduction of the nitro group in... 

While the template-stabilized 2-aminoethyl isocyanide ligand in 48 was observed more or less by accident, the directed stabilization of /3-amino functionalized isocyanides is possible at electron-rich metal templates. Isocyanides 35, 41 and 2-nitrophenyl isocyanide form the electron-rich complexes of types 50 and 51. Reduction of the 2-azido or 2-nitro functions leads to the 2-amino-substituted isocyanides in complexes 52 and 53 that are stabilized by M CsNR backbonding and thus undergo no cyclization to the NH,NH-NHC ligands (Scheme 9.16) [64]. 

An alternative method for the synthesis of [(NHC)M] complexes is to bind ligands to a transition metal that can subsequently be converted into an NHC ligand. Using 2-azidophenyl isocyanide" " or 2-nitrophenyl isocyanide" as synthons for the unstable 2-amino isocyanide, diprotic benzannulated NHC-metal complexes were obtained, and easily alkylated to give A,A -disubstituted benzimidazolylidenes. This methodology was also applied to ruthenium-based catalysts (Scheme 3.6)." ... 

Methoxy-2-nitrophenyl Isocyanide Martens and coworkers [61] have utilized 3-methoxy-2-nitrophenyl isocyanide (MNPIC) (ly) to synthesize fully protected PNA monomers [62] 220. The anilide can be hydrolyzed by methanolic KOH to obtain the corresponding acid 221 (Scheme 7.73). Structurally, the PNAs are quite similar to the backbone of DNA or RNA. The oligomers of PNAs have become quite a useful tool in biomedical discoveries. 

Irradiation of diphenyl N(p-nitrophenyl) cyclopropenone imine (268) gave, in a clear-cut photoreaction, the phenanthreno indenone imine 275170) resulting from two units of 268 by loss of two hydrogens and p-nitrophenyl isocyanide the mechanism of this transformation has not yet been elucidated. 

SYNS BENZENE, 1-ISOCYANO-4-NITRO- p-NITROPHENYL ISOCYANIDE 4-NITROPHENYL ISOCYANIDE p-NITROPHENYL ISONITRILE PHENYL ISOCYANIDE, p-NITRO-... 

NITRO-l,4-PHENYLENEDIAMINE see ALL750 4-NITRO-l,2-PHENYLENEDIAMINE see ALL500 o-NITRO-p-PHENYLENEDIAMINE (MAK) see ALL750 4-NITROPHENYL ISOCYANIDE see IKH780 p-NITROPHENYL ISOCYANIDE see IKH780 p-NITROPHENYL ISONITRILE see IKH780... 

The reaction of 1-diethylaminoprop-l-yne with 4-nitrophenyl isocyanide at 25 °C for 12 days produced 2-dimethylamino-3-methyl-AT-(4-nitrophenyl)cyclopropenimine (2) in 34% yield. 

C5 sHfl 6MoN602P2S , Tetraphenylphosphonium nitrosyl(N,N)dimethylcarb-amido)tetrakis(thiocyanato-N)-molybdate(VI), 45B, 907 C56H32Cl2F8N8Rh2 2 H2O, Tetrakis(p-fluorophenyl isocyanide)rhodi-um(l) chloride dimer d-ihydrate, 45B, 908 C56H32CI2N1gOieRh2, Tetrakis(p-nitrophenyl isocyanide)rhodium(I) chloride dimer, 45B, 908... 

Nitrophenyl Isocyanide Although o-nhrophenyl isocyanide (ONPIC, Iz) was known for quite a while, Hahn and coworkers have recently reported the first synthesis of ONPIC [88] as a ligand in metal complexation. It can be readily synthesized from commercially available o-nitroaniline 6x via formamide 81 formation followed by dehydration (Scheme 7.75). 

This procedure illustrates the best way to prepare aryl isocyanides. It is quite general, having been used by Ugi and Meyr e to make the following isocyanides from the corresponding form-amides phenyl (56%), />-tolyl (66%), 2,6-dimethylphenyl (88%), mesityl (80%), o-chlorophenyl (43%), -chlorophenyl (54%), 2-chloro-6-methylphenyl (87%), -methoxyphenyl (64%), p-di-ethylaminophenyl (75%), -nitrophenyl (41%), and 2-naphthyl (50%). Aliphatic isonitriles are generally best prepared by a simpler procedure involving the action of phosphorus oxychloride on an N-alkylformamide in the presence of pyridine.7... 

PEPTIDES Bis(o- or p-nitrophenyl)phenyl-phosphonate. f-Butyl isocyanide. N-Hydroxysuccinimide. 

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