Amides phenyl-substituted, formation

Carlson, R.L. and Drago, R.S. (1963) Thermodynamic data for the formation of molecular complexes between phenyl-substituted amides and iodine. J. Am. Chem. Soc., 85,505-508. 

When the two groups of the ketone are para-substituted phenyls, the product of the Schmidt reaction is usually a nearly equimolecular mixture of the two isomeric amides.806 This result, obtained instead of a preferential migration of the more electron-releasing group, is consistent with a mechanism in which the formation of the intermediate rather than its rearrangement is rate determining. 

Two transformations should be discussed in more detail (1) presence of the amino group in 275 was utilized for the synthesis of the fused isoquinolinium salt 276 bearing the bicyclic heterocycle as an A-substituent <2003JHC1041> (2) selective nucleophilic substitution of 277 with pyrrolidine was reported <2001ZOR604> to yield only substitution on the phenyl substituent without formation of an amide from the ester group 278. 

It has been suggested that the preferential formation of ( )-alkene on Wittig reaction of amide-substituted phenyl 3-pyridyl ketones with non-stabilized phosphorus ylides which contain a carboxyl terminus is a consequence of either hydrogen bonding or salt... 

These substrates show restricted rotation about the amide bond With no ortho-substituent present, the svn-form predominates with adjacent phenyl rings. Ortho-substitution increases the proportion at equlibrium of the rotamer with anft -phenyl rings. Reduction of the anti-mUmm can lead only to replacement of halogen by hydrogen. For the chlorobcnzanilides, the formation of a product with the chlorine... 

A similar type of reaction, with bond formation between a chlorine substituted thiophene moiety and a phenyl ring connected to the thiophene via an amide bond, was used in the synthesis of 12-carbomethoxy-2-chloronaphtho[2",r, 2,3,-/ ]thieno[4,5, 2,3]-... 

The use of pyrimidines as precursors for pyrrolo[3,4-rf]pyrimidines is the most common synthetic approach. 6-Phenyl-7-(substituted)amino-pyrrolo[3,4-ii]pyrimidine-2,4(l//,3//)-diones (164) are readily obtained from the reaction of 5-formylpyrimidines (163) with arylamines (Equation (54)) <89BCJ3043>. Formation of the Schiff base, followed by cyclization, is the proposed pathway. A more traditional approach is found in the conversion of the cyanoester (165), via the amide, to the corresponding pyrrolopyrimidine (166) (Equation (55)) (88LA643). 

An unusual reaction leading to formation l-substituted-4-thioxopyrazolo[3,4-phenyl isothiocyanate in DMF saturated with hydrogen chloride gives derivatives (317) (Scheme 27). A proposed reaction sequence involves initial electrophilic addition of phenyl isothiocyanate to the protonated o-amino-nitrile to give an o-aminothioamide. This is followed by condensation with DMF-HC1 to yield this amide (316) which then cyclizes to the product (317) [Pg.465]

The formation of activated iminium intermediates derived from nitrogen heterocycles has been reported by Comins and co-workers.163,163a The activation of pyridine derivative with phenyl chloroformate provides pyridinium salt, which smoothly reacts with the zinc homoenolate (Equation (94)).163 163a 164 The reaction of unsaturated amide with Ph jC 1 BI 4 produces iV-acyliminium ions, which react with PhaZn in CH2CI2 producing the desired a--substituted amine (Equation (95)).165... 

The hydrolysis of amides in this series has encountered some difficulties, such as slowing of the reaction by formation of an insoluble sodium salt (a switch to potassium hydroxide often helped). Alkaline conditions favor the Dimroth rearrangement, although this is possible only when the 3 position is substituted (Section III,D). When the rearrangement is allowed, and it is greatest for the 3-phenyl, less for 3-benzyl, least for 3-methyl groups, two isomers have to be separated. As, in the present case, these will both be acids, an insoluble salt of one of them has usually been sought. 

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