Diaryl amide

A number of related couplings have been reported during the synthesis of the alkaloid ( )-cryptopleurine149 and also intramolecular coupling of diaryl amides to dibenzazepine and dibenzazodne structures.150 A versatile method for the preparation of tetrahydroquinolines and jololidines has been developed.151 The method involves the anodic oxidation of AT,AT-dimethyl-aniline in methanol to afford a-methoxylated or a, a -dimethoxylated compounds and subsequent treatment of products with Lewis acids in the presence of olefins. 

The carbanions derived from A,A-disubstituted amides and lactams react with certain aromatic halides in liquid ammonia under photostimulation [85,86] to form the expected a-arylated compounds in good yields. Unsymmetrical a, a-diaryl amides can be formed by reaction of aryl halides with the anion of the oc-aryl-A,7V-dimethyl acetamides [85]. 

Intramolecular anodic coupling of diaryl amides is a synthetically interesting reaction that may be applied to the synthesis of alkaloidal structures [210]. However, this aryl coupling is initiated by the oxidation of an aromatic ring (aryl ether or phenol) and not by oxidation of the nitrogen. Therefore, it is not discussed further in this chapter. 

Chapman rearrangement. Thermal rearran-agement of aryl imidates to /V,/V-diaryl amides. 

Scheme 6, equation 2) [12], The key step in Clive s sequence is the Hoftnann rearrangement of amide 17 to amine 18, followed by oxidation to quinone 19 with phenyliodme(ni) bis(triacetate). In like fashion, 4-bromo-5-hydroxyindole, 5-hydroxy-4-iodoindole, and 5-hydroxy-4-iodo-3-methylindole were prepared in this study. Nishiyama and coworkers adopted an electrochemical oxidation of diaryl amides to carbazoles (equation 3 and 21-22) [13]. 

Thermal rearrangement of aryl imidates to A,A-diaryl amides ... 

Sainsbury M, Wyatt J (1976) Intramolecular coupling of diaryl amides by anodic oxidation. J Chem Soc Perkin Trans 1 661-664... 

Unsymmetrical a,a-diarylated amides can be prepared by reaction of the anions derived from monoarylated products (Ar CHjCONMej) with haloarenes (Ar = 1-naphthyl, 9-phenanthryl, 9-anthra-cenyl and Ar = Ph Ar = Ph and Ar = 9-phenanthryl, 9-anthracenyl) ... 

No systematic study of the mass spectra of pyridopyrazines has been noted, but those of 2,3-dialkyl and 2,3-diaryl derivatives have been recorded 750MS97), and mass spectrometry has been used in the elucidation of problems in the reactions of pyrido[2,3-f ]pyrazines with amide ion (including use of and derivatives) (79JHC305), and of pyrido[2,3-f ]pyrazinium salts with indoles (78ZOR431). The mass spectra of some 1-deazaflavins have been recorded (74JCS(P1)1965). 

Bromination of the methyl group of (249) with A -bromosuccinimide, followed by reaction with excess secondary amine gave (250) which shows combined analgesic and antitussive properties. The Reformatsky reaction has also been used for the preparation of 2-amino-ethyl 3,3-diaryl-3-hydroxypropanates (251) as well as their dehydration products. The propene amides (252) have also been prepared for pharmacological evaluation. In l-methyl-3-bis (2-thienyl)-... 

The carbanion 5, formed from V,V-diethyl-5-phenyl-3//-azepin-2-amine (4) with potassium amide in liquid ammonia, or with lithium 2,2,6,6-tetramethylpiperidide in tetrahydrofuran, is thiolated by dialkyl or diaryl disulfides to yield 3-(alkylsulfanyl)-3//-azepines, e.g. 6.38... 

When secondary amines are treated with nitrous acid, N-nitroso compounds (also called nitrosamines) are formed. The reaction can be accomplished with dialkyl-, diaryl-, or alkylarylamines, and even with mono-N-substituted amides RCONHR -I-HONO RCON(NO)R. Tertiary amines have also been N-nitrosated, but in these cases one group cleaves, so that the product is the nitroso derivative of a secondary amine.The group that cleaves appears as an aldehyde or... 

Finally, the N-propargyl-P,P-dialkyl or diaryl phosphinous amides rearrange at room temperature to the P-(4-azabutadienyl)phosphanes 28 [127] (Scheme 29). Interestingly, this rearrangement did not occur in other structurally similar P-N functionalities (R=OEt, OTr, NEt2). 

Patent applications from Pfizer disclosed 1,5-diaryl-pyrazoles bearing bioisosteric replacements for the 3-carboxamide moiety. One application showed that the amide could be replaced by a-aminoketones as exemplified by compound (416) [284]. The corresponding alcohols and their ethers were also described, including compounds that allowed the amine substituent and ether to form a ring system, such as a morpholine unit. This application also allowed for the replacement of the 1,5-diaryl-pyrazole by a 1,2-diaryl-imidazole bearing a 3-carbonyl substituent, as exemplified by compound (417). A further patent application from Pfizer claims compounds in which imidazoles replace the 3-carboxamide moiety in the 1,5-diaryl-pyrazole... 

Electrophilic substitution of the ring hydrogen atom in 1,3,4-oxadiazoles is uncommon. In contrast, several reactions of electrophiles with C-linked substituents of 1,3,4-oxadiazole have been reported. 2,5-Diaryl-l,3,4-oxadiazoles are bromi-nated and nitrated on aryl substituents. Oxidation of 2,5-ditolyl-l,3,4-oxadiazole afforded the corresponding dialdehydes or dicarboxylic acids. 2-Methyl-5-phenyl-l,3,4-oxadiazole treated with butyllithium and then with isoamyl nitrite yielded the oxime of 5-phenyl-l,3,4-oxadiazol-2-carbaldehyde. 2-Chloromethyl-5-phenyl-l,3,4-oxadiazole under the action of sulfur and methyl iodide followed by amines affords the respective thioamides. 2-Chloromethyl-5-methyl-l,3,4-oxadia-zole and triethyl phosphite gave a product, which underwent a Wittig reation with aromatic aldehydes to form alkenes. Alkyl l,3,4-oxadiazole-2-carboxylates undergo typical reactions with ammonia, amines, and hydrazines to afford amides or hydrazides. It has been shown that 5-amino-l,3,4-oxadiazole-2-carboxylic acids and their esters decarboxylate. 

A synthesis of A-substituted a-aminobenzylphosphinic acids starts from ammonium hypophosphite this is allowed to react with primary amines together with aldehydes or ketones in the presence of HC1.60 The nature of the products and general success of the Atherton-Todd reaction for the preparation of dialkyl- and diaryl-phosphinic amides from secondary phosphine oxides depends on the order in which reactants are mixed and on the choice of polyhalogen reactant.61... 

Scheme 11 OCR between diaryl nitrones and methacrolein catalyzed by cationic Rh2 carbox-amidates...

Bahrami K, Khodaei MM, Farrokhi A (2009) Highly efficient solvent-free synthesis of dihydropyrimidinones catalyzed by zinc oxide. Synth Commun 39 1801-1808 74. Gross GA, Wurziger H, Schober A (2006) Solid-phase synthesis of 4,6-diaryl-3,4-dihydro-pyrimidine-2(lH)-one-5-carboxylic acid amide derivatives a Biginelli three-component-condensation protocol based on immobilized beta-ketoamides. J Comb Chem 8 153-155 Desai B, Dallinger D, Kappe CO (2006) Microwave-assisted solution phase synthesis of dihydropyrimidine C5 amides and esters. Tetrahedron 62 4651 664 Kumar A, Maurya RA (2007) An efficient bakers yeast catalyzed synthesis of 3,4-dihydro-pyrimidin-2-(lH)-ones. Tetrahedron Lett 48 4569-4571 77. Zalavadiya P, Tala S, Akbari J, Joshi H (2009) Multi-component synthesis of dihydropyrimidines by iodine catalyst at ambient temperature and in-vitro anti mycobacterial activity. Arch Pharm 342 469-475... 

The reaction of arylacetamides with ethyl phenylpropiolate gives 4,5-diaryl-l,5-dihydro-2//,67/-pyridine-2,6-diones (197). - It has been suggested that the pyridinediones in these reactions are formed through the initial addition of either the amide anion (195) or the carbanion (196), generated under basic conditions, to ethyl phenylpropiolate (Scheme 30). 

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