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Amides carbon-hydrogen bonds

Amides Carbon, hydrogen, single bonds, and at least one -CONH24 in the molecule (may include double and triple bonds and other structures) H 0 1 II H h-c-c— n 1 H H Ethanamide... [Pg.100]

Oxidative attack on a carbon-hydrogen bond of an alkyl group a to a nitrogen atom is not restricted to saturated aliphatic amines. In fact X in an X-N-CH- structural subunit can be virtually any common atomic grouping that can be found in stable organic molecules. For example, w-carbon hydrogens of Aralkyl-substituted aromatic cyclic amines (119), aryl amines (120), amides (121), amidines (122), A-nitrosodialkylamines (123), etc. are all subject to oxidative attack, carbinolamine formation, and in most cases release of an aldehyde or ketone depending on the substitution pattern (1° or 2°)... [Pg.79]

Like carbene insertions into carbon-hydrogen bonds, metal nitrene insertions occur in both intermolecular and intramolecular reactions.For intermole-cular reactions, a manganese(III) meio-tetrakis(pentafluorophenyl)porphyrm complex gives high product yields and turnovers up to 2600 amidations could be effected directly with amides using PhI(OAc)2 (Eq. 51). The most exciting development in intramolecular C—H reactions thus far has been the oxidative cychzation of sulfamate esters (e.g., Eq. 52), as well as carbamates (to oxazolidin-2-ones), ° and one can expect further developments that are of synthetic... [Pg.585]

Biocatalysts are being applied widely in the industry, including the preparation of carbon-carbon bonds. Stereoselective oxidation with biocatalysts is an area where chemistry will find it hard to compete. A need still exists for new catalysts to replace stoichiometric reagents, as in the reduction of an amide to an amine, amide formation, and substitution of an alcohol (Mitsunobu reaction) (258). In both arenas of catalysis, the overall goal for green chemistry and stereoselectivity must be carbon-hydrogen bond activation. [Pg.2132]

Advantage can be taken of the enhanced polarity of a carbon-silicon bond over that of a carbon-hydrogen bond in the displacement of 2-tri-methylsilyl groups by reaction with a number of carbonyl reagents to give imidazoles substituted at C-2 by secondary alcohol, acyl, aroyl, ester, and amide functions. ... [Pg.299]

Amide (carbon double-bonded to one oxygen, and single-bonded to one nitrogen atom (which in turn has 2 single bonds that link to hydrogen atoms or hydrocarbons) as well)... [Pg.90]

Because the polarity of carbon-hydrogen bond is very small and exhibits very low acidity, very strong bases are required for such reactions. However, C-H bonds adjacent to substituents such as carbonyl or cyano groups are stabiUzed by resonance/induction and are more acidic. Nitrogen bases have been used effectively in these reactions to minimize the nucleophihc addition that can compete with proton removal when an organometallic compound such as n-butyllithium is used as the base. For example, methyl ketones react with Hthium diisopropylamide (LDA) to form the enolate ion (Eq. (3.4)), and even more sterically hindered amides have been used. The enolate anion is a strong base and a good nucleophile ... [Pg.70]

Ammonia and the carbon—hydrogen bonds of the methyl groups of 2-butyne both have values of about 38. Therefore, we can expect reasonable amounts of the carbanion to be produced on reaction with the amide ion. 2-Butyne is much more acidic than the parent hydrocarbon butane because the anion formed from 2-butyne is resonance stabilized, and that from butane is not (Fg. 12.8). [Pg.516]

There has been a summary of computational and experimental studies of the use of palladium complexes with A -heterocyclic carbenes (NHCs) in the asymmetric coupling of -hybridized carbon-hydrogen bonds with aryl halides. It has been shown that the electronic and catalytic properties of NHCs fused to porphyrins may be modified by varying the inner metal in the porphyrin. A DPT study of the use of palladium-NHC complexes in the asymmetric intramolecular a-arylation of 2-bromoaryl amides to give 3,3-disubstituted oxindoles (101) has been reported. The likely pathway involves insertion of the palladium into the arene-bromine bond to form a palladacycle which deprotonates to give an (9-enolate. Conversion into the C-enolate followed by reductive elimination gives the product. The intramolecular reaction of 0 a cyclopropane carbon-hydrogen bond in a 2-bromoanilide derivative has been used to form cyclopropyloxindoles, (102), in a palladium-catalysed, silver-mediated reaction. [Pg.242]

Metal-catalysed biaryl formation continues to be of interest, and there has been a theoretical study of reactivity and regioselectivity in biaryl formation involving the cleavage of carbon-hydrogen bonds by a concerted metalation-deprotonation pathway. Various combinations of metal/ligand/base have been evaluated for the arylation of benzene with aryl bromides at high temperatures and pressures. The combination of cobalt(III) acetylacetonate and lithium bis(trimethylsilyl)amide proved to be effective. ... [Pg.234]

Rotation about the carbon-nitrogen bond is slow in amides The methyl groups of NJ dimethylformamide are nonequivalent because one is cis to oxygen the other cis to hydrogen... [Pg.1236]


See other pages where Amides carbon-hydrogen bonds is mentioned: [Pg.397]    [Pg.78]    [Pg.288]    [Pg.3]    [Pg.449]    [Pg.85]    [Pg.95]    [Pg.322]    [Pg.113]    [Pg.268]    [Pg.37]    [Pg.372]    [Pg.88]    [Pg.380]    [Pg.382]    [Pg.232]    [Pg.240]    [Pg.253]    [Pg.359]    [Pg.1515]    [Pg.525]    [Pg.1144]    [Pg.207]    [Pg.31]    [Pg.783]    [Pg.1144]    [Pg.1145]    [Pg.235]    [Pg.517]    [Pg.164]    [Pg.75]    [Pg.17]    [Pg.172]    [Pg.13]   
See also in sourсe #XX -- [ Pg.2 , Pg.3 , Pg.4 , Pg.5 , Pg.7 ]




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Amide bonds

Amide hydrogen bonds

Amides hydrogenation

Amides: , bonding

Amidic hydrogen bonding

Carbon amide

Carbon-hydrogen bonds

Carbon-hydrogen bonds intermolecular amidation

Carbon-hydrogen bonds intramolecular amidation

Hydrogen bonding amides

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