TV-substituted derivatives

TV-Substituted derivatives of 2-[(TV-acetyl)amino]pyridine (L) react with ZnCl2 to yield ZnLCl2 derivatives in which the ligand is chelate bound via pyridine N and amide O atoms.491... 

Dihydro-1,4-benzoxazines (e.g., 356) are prepared from 2-aminophenol and its TV-substituted derivatives with 1,2-dihalides under basic conditions as illustrated in Scheme 193 . 

Analogously, TV-substituted derivatives, e.g., 2. are obtained by reducing A -alkylamides of mandelic acid2. 

If an excess of Grignard reagent is added to an Ar-benzylproline ester, a tertiary alcohol is formed. Thus, methyl, ethyl, and phenyl groups have been introduced a to the hydroxy groups in this manner. The amino alcohols obtained can be modified analogously to prolinol itself, to give O- and TV-substituted derivatives, e.g., 23 and 2625. 

The use of 2-substituted amino-3-aminopyridines (or corresponding 3-substituted amino-2-amino, 3-substituted amino-4-amino and 4-substituted amino-3-amino derivatives) gives the corresponding TV-substituted pyridopyrazinones with esters or alloxan, or with diketones gives quaternary salts such as (403) or their anhydro bases (404) e.g. 56CB2684, 78HCA2452). 

TV-Substituted l,4-dihydro-l,4-diazocines 6 can be obtained by [TC2S + 2S + 2S] cycloreversion from. mi-benzene diimine (cA-bisazirinofa. c]benzene, diaza-c-bishomobenzene) derivatives 5 at room temperature or slightly elevated temperatures.2 - 5 The syn-benzene diimines (3,8-dia-zatricyclo[5.1.0.02,4]oet-5-enes), which are required for the valence isomerization, are available by two methods from benzene oxide derivatives. 

Condensation reactions of TV-substituted thioureas in dimethyl sulfoxide or methanol in the presence of DMSO-H+-X produce 1,2,4-thiadiazole derivatives (Scheme 64).150 151... 

Focants of substituents of symmetrically substituted derivatives of symmetrical amines are distinguished by primes or else the names of the complete substituted radicals are enclosed in parentheses. Unsymmetrically substituted derivatives are named similarly or as TV-substituted products of a primary amine (after choosing the most senior of the radicals to be the parent amine). For example,... 

On the basis of a comprehensive ECD study of chiral 2-alkyl-substituted piperidines92, such as (S -a-pipecoline [(5 )-2-methylpiperazine, (5 )-102] and their TV-methyl derivatives [(5)-103] in ethanol, the sign of the strong, long-wavelength CE near 200 nm, shifted to... 

Propanil (3,4-dichloropropionanilide) is an important arylamide herbicide that is used in rice, barley, oat and wheat fields. The 3,4-dichloroaniline moiety is also found in the TV-substituted phenylureas linuron, diuron and neburon. Hence, exposure to 3,4-dichloroaniline derivatives will be common and has been associated with methemoglobinemia in humans142. 

As with the reaction of pyrroles, diazoles and triazoles react with propargyl bromide to yield TV-substituted products and, depending upon the base strength, either TV-prop-2-ynylazoles or allenic derivatives are formed [30]. Generally, with potassium carbonate under soliddiquid two-phase conditions at room temperature in the absence of a solvent, the prop-2-ynyl compounds are formed as sole products, whereas with solid potassium hydroxide at elevated temperatures the allenes are obtained as the major products. Benztriazole produces a mixture of the N1- and N2-prop-2-ynyl, and N2-allenic derivatives, whereas with potassium hydroxide only the N -allenic derivative is obtained. The alkynes readily isomerize to the allenes in the presence of base and the quaternary ammonium salt, or upon treatment with methanolic sodium hydroxide. A series of l-(alk-2-ynyl)imidazoles have been prepared, as intermediates in the synthesis of imidazopyridines [31 ] and the reaction of 3-hydroxymethylpyrazoles with propargyl bromide leads to pyrazolooxazines [32]. 

Benzopyrmlo[l,2]azepines. Syntheses of benzopyrrolo[l,2]azepines in which pyrrole or indole N1 and C2 atoms serve as fusion sites usually involve preforming the TV-substituted pyrrole derivatives followed by intramolecular cyclization. 

Some difficulty has been encountered with the TV-alkylation (e.g. with ethyl bromoacetate) of 2,3,4,5-tetrahydro-l//-l-benzazepin-5-one (31 R = H) (74JCS(P1)1828). The pharmacological activity (Section 5.16.5) of TV-substituted 5H-dibenz[6,/]azepine and its 10,11-dihydro derivatives has resulted in an intensive study of the TV-alkylation of these ring systems (74CRV101). Generally, alkylation is effected with an alkyl halide or tosylate in the presence of base. Phase transfer TV-alkylations of 5H- dibenz[6,/]azepine have been reported. The method, however, is less successful with the 10,11-dihydro derivatives (79MI51600). 

The most frequent application of Larock s method is undoubtedly the conversion of o-haloanilines to indoles. The scope of this transformation covers a wide range of disubstituted acetylenes and anilines including both TV-substituted and unsubstituted derivatives. A schematic representation of... 

TV-substituted methylenephthalimide derivatives served as the starting material for the preparation of a series of tetracyclic systems. The intramolecular Heck reaction of these compounds (4.10.) led in each case to the formation of a carbon-carbon bond between the exocyclic carbon atom of the olefin bond and the aryl moiety. The formation of five, six and seven membered rings was achieved with near equal efficiency, enabling the preparation of some isoindolobenzazepine alkaloids.11... 

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