Anilides metallation

Transition-Metal Catalyzed Cyclizations. o-Halogenated anilines and anilides can serve as indole precursors in a group of reactions which are typically cataly2ed by transition metals. Several catalysts have been developed which convert o-haloanilines or anilides to indoles by reaction with acetylenes. An early procedure involved coupling to a copper acetyUde with o-iodoaniline. A more versatile procedure involves palladium catalysis of the reaction of an o-bromo- or o-trifluoromethylsulfonyloxyanihde with a triaLkylstaimylalkyne. The reaction is conducted in two stages, first with a Pd(0) and then a Pd(II) catalyst (29). 

Aromatic amines form addition compounds and complexes with many inorganic substances, such as ziac chloride, copper chloride, uranium tetrachloride, or boron trifluoride. Various metals react with the amino group to form metal anilides and hydrochloric, sulfuric, or phosphoric acid salts of aniline are important intermediates in the dye industry. 

Salicyl-u-toluide has been prepared only by the action of phosphorus oxychloride upon a mixture of salicylic acid and o-toluidine. The useful methods of preparation of salicylanilide are by the interaction of salicylic acid and aniline in the presence of phosphorus trichloride, by heating phenyl salicylate and aniline, and from o-hydroxybenzamide and bromobenzene in the presence of small amounts of sodium acetate and metallic copper. A number of these and other anilides have been described. ... 

Chemical/Physical. Alkali or alkaline earth metals dissolve in aniline with hydrogen evolution and the formation of anilides (Windholz et ah, 1983). Laha and Luthy (1990) investigated the redox reaction between aniline and a synthetic manganese dioxide in aqueous suspensions at the pH range 3.7-6.5. They postulated that aniline undergoes oxidation by loss of one electron forming cation radicals. These radicals may undergo head-to-tail, tail-to-tail, and head-to-head... 

Dissolved metals and metal-containing surfaces play an important role in the transformation of organic contaminants in the subsurface environment. Metal ions can catalyze hydrolysis in a way similar to acid catalysis. Organic hydrolyzable compounds susceptible to metal ion catalysis include carboxylic acids, esters, amides, anilides, and phosphate-containing esters. Metal ions and protons... 

BuLi—KOBu-f metallates ortho to powerfully electron-withdrawing and acidifying fluoro even if much stronger directors (by the usual considerations) are present, such as methoxy (619, 620) or anilide (621) groups (Scheme 242). ... 

Amides with electron-withdrawing substituents can be sufficiently labile towards nucleophilic attack to enable their use as protective groups. This is the case, for example, with trifluoro- [102,290] and trichloroacetamides [163], which are readily hydrolyzed under mild conditions (Figure 10.13). Suitable nucleophiles are hydrazine [291], aliphatic amines, and hydroxide, but if a hydrophobic support has been chosen, it must be borne in mind that the reactivity of alkali metal hydroxides will be reduced because of poor diffusion into the support. Amides of electron-poor amines (e.g. anilides) can also be readily cleaved by nucleophiles [292],... 

Processes include the Fischer indole synthesis from arylhydrazones and related sigmatropic syntheses, reductive evclizations of nitni compounds, the Madelung synthesis from anilides and related base-cululyxed condensations. and transition-metal catalyzed cyclizations,... 

Even more striking is the effect on chemical reactions in the films, particularly various photo-chemical reactions. The reactions of stearic anilide, a-hydroxystearic acid, and proteins, all appear to be affected by traces of metallic ions too small to be always identifiable. As yet, the results are preliminary, but they show promise of being well worth further investigation, particularly as traces of heavy metallic ions occasionally have a remarkable biological effect (the oligodynamic action). 

One-step partial oxidation of propane to acrylic acid (an essential chemical widely used for the production of esters, polyesters, amides, anilides, etc.) has been investigated so far on three types of catalysts, namely, vanadium phosphorus oxides, heteropolycompounds and, more successfully, on mixed metal oxides. The active catalysts generally consist of Mo and V elements, which are also found in catalysts used for the oxidation of propene to acrolein and that of acrolein to acrylic acid. 

Although boron is more accurately described as a metalloid rather than a metal, this section is concluded by two papers that describe the structures and bonding in several organoboron/organophosphorus compounds that display ylidic character. The X-ray structure of 9-borylanthracene (88) shows that only one of the diisopropylphosphine moieties is bonded to the boron in the solid state. However, H NMR evidence shows that an intramolecular bond-switching process takes place very rapidly in solution. The structures of a series of borabenzene adducts of phosphorus ylides, iminophosphoranes and tertiary phosphines have also been determined. Treatment of l-chloro-3,5-dimethyl-2-(trimethylsilyl)-l,2-dihydroborinine (89) with methylenetriphenylphosphorane (90) produces (triphenylphosphonio)methanide-3,5-dimethylborabenzene (91). However, if the reaction sequence is reversed and (90) is treated with (89), then (trimethylsilyl)(triphenylphosphonio)methanide-3,5-dimethylborabenzene (92) is obtained (Scheme 26). Treatment of an isomeric mixture of l-chloro(trimethyl-silyl)dihydroborinines (93) with N-(triphenylphosphoranylidene)aniline (94) produces iV-(triphenylphosphonio)anilide-borabenzene (95) (Scheme 27). Crystal structures of (91), (92) and (95) show that the P-C or P-N bonds are... 

Soonafterward, Buchwald and coworkers reported an efficient Pd-catalyzed oxidative cross-coupling of A-acetanilides with simple arenes in a similar manner [70]. In the presence of 5-10 mol% Pd(OAc)2 and 10-20 mol% DMSO, the cross-coupling reaction took place smoothly between anilides and 4—11 equiv. of simple arenes in TFA under an oxygen atmosphere (Scheme 23). The reaction conditions could tolerate a wide range of substrates. The metal-free oxidant represents a great advantage of the current catalytic system. 

Analogously, the steric hindrance around the metal center caused by the three bulky anilide ligands in the nitrile adducts of the molybdenum trisanilide complex discussed previously, RCN-Mo(N[ t-Bu] Ar)3, prevents the reaction at the metal. In fact, the nitrile... 

A key intermediate for the synthesis of several derivatives is 2-lithiotellurophene, obtained by metallation of tellurophene with 2-butyllithium in ethereal solution. Treatment of 2-lithiotellurophene with dimethyl sulfate, -methyl form anilide, acetaldehyde, carbon dioxide, hexachloroethane, hexabromoethane, and dimethyl sulfide gives, respectively, 2-methyltellurophene (10), tellurophene-2-carboxaldehyde (9), l(2-tellurienyl)ethanol (11), 2-tellurophenecarboxylic acid (12), 2-chloro-(13), 2-bromo- (14), and 2-methylthiotellurophene (15). 

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