Nucleophilic substitution reactions amine synthesis

A great deal of work has been done on the in situ activation of carboxylic acids toward nucleophilic substitution by amines. This type of reaction is fundamental for synthesis of polypeptides (see also Section 13.3.1). Dicyclohexylcarbodiimide... 

The synthesis of nitro dyes is relatively simple, a feature which accounts to a certain extent for their low cost. The synthesis, illustrated in Scheme 6.5 for compounds 140 and 141, generally involves a nucleophilic substitution reaction between an aromatic amine and a chloronitroaromatic compound. The synthesis of C. I. Disperse Yellow 14 (140) involves the reaction of aniline with l-chloro-2,4-dinitroaniline while compound 141 is prepared by reacting aniline (2 mol) with compound 144 (1 mol). 

Ju and Varma envisioned that the nucleophilic substitution reaction of alkyl halides with amines may be accelerated by microwave energy because of their polar nature [88]. An environmentally friendly synthesis of tertiary amines via direct JV-alkylation of primary and secondary amines by alkyl halides under microwave irradiation was developed (Scheme 21), that pro-... 

Fluoroarene-Cr(CO)2L complexes 33p [L = CO, PPh3, P(OPh)3, P(pyrrolyl)3, P(pyrolyl)2 (NMeBn)], where L is a potential linker ligand for solid-phase synthesis, have been evaluated with regard to the rates of nucleophilic substitution by amines [35]. The preparative and kinetic results indicate that SNAr reactions on tris(pyrrolyl)phosphine-modified fluoroar-enechromium complexes proceed rapidly and with high efficiency, and are thus appropriate for the development of solid-phase versions for use in combinatorial synthesis (Scheme 18). 

Nucleophilic substitution reactions have been effectively exploited in the synthesis of several classes of polymers. However, only scanty reports are available on the application of such reactions to the displacement of chlorine in bisdichloromaleimides, although several examples of displacement of chloride by nucleophiles in N-substituted dichloromaleimides exist in literature. Amines (5), phenols (6), and alcohols and thiols (7) have been used as nucleophiles in such reactions. 

In primary synthesis 2-perimidinamines (660) can be prepared from the naphthalene diamine with bromocyanogen or cyanamide (Scheme 106). 2-Anilino derivatives have been obtained in reactions with aryl isothiocyanates. 2-iV,7V-Dimethylamino derivatives (662) have been obtained via the alkylated amine (661) using dimethylamino(trichloro)methane. Nucleophilic substitution by amine readily occurs in the 2-position when carrying a halo, sulfenyl, or sulfonyl substituent <81RCR816>. 

Arenesulfonyl derivatives are frequently employed in organic synthesis to activate hydroxy groups for nucleophilic substitution reactions or to protect primary and secondary amines. The PET cleavage of tosyl groups is closely related to reductions... 

Microwave-assisted solid-phase synthesis of purines on an acid-sensitive meth-oxybenzaldehyde (AMEBA)-linked polystyrene has been reported [50]. The heterocyclic scaffold was first attached to the polymer support via an aromatic nucleophilic substitution reaction by conventional heating in l-methyl-2-pyrrolidinone (NMP) in the presence of N,N-diisopropylethylamine. The key aromatic nucleophilic substitution of the iodine with primary and secondary amines was conducted by microwave heating for 30 min at 200 °C in l-methyl-2-pyrrolidone (Scheme 16.28). After reaction the products were cleaved from the solid support by use of trifluoroacetic acid-water at 60 °C. 

In the domino Michael/alkylation reaction applied to the synthesis of 3-(2H)-furanones, the ethyl 4-bromoacetoacetate 203 and nitrostyrene 204 were first trialed with a range of catalysts. In this instance, the so-called modified Feist Binary reaction was completed with an I-threonine bifunctional tertiary amine/thiourea catalyst 205 to produce the furanone 206 in excellent yield and high enantioselec-tivity (Scheme 7.42) [107]. In another report, the furan ring as part of other bicyclic or tricyclic systems was also prepared through an enantioselective Michael addi-tion/nucleophilic substitution reaction (Scheme 7.43) [108]. When diketones and ( )-P,P-bromonitrostyrenes 207 were stirred, again with a bifunctional thiourea... 

A great deal of work has been done on the in situ activation of carboxylic acids toward nucleophilic substitution by amines. This type of reaction forms the backbone of the methods for synthesis of peptides and proteins. (See also Section 13.6). DCC is very widely used for coupling carboxylic acids and amines to give amides. Because amines are better nucleophiles than alcohols, the leaving group in the acylation reagent need not be as reactive as is necessary for alcohols. The -nitrophenyl and 2,4,5-trichlorophenyl " ... 

Nucleophilic aromatic substitution reactions of haloarenes complexed to transition metal moieties with oxygen-, sulfin-, and nitrogen-containing nucleophiles allows for the synthesis of a wide variety of aryl ethers, thioethers, and amines. These metal-mediated reactions proceed under very mild conditions and allow for the incorporation of a number of different functional groups. Nucleophilic substitution reactions of chloroarenes complexed to the cyclopentadienyliron moiety have been the focus of many studies directed toward the design of functionalized organic monomers. ... 

Safrole, which is isolated from sassafras (Problem 21.36), can be converted to the illegal stimulant MDMA (3,4-methylenedioxymethamphetamine, Ecstasy ) by a variety of methods, (a) Devise a synthesis that begins with safrole and uses a nucleophilic substitution reaction to introduce the amine, (b) Devise a synthesis that begins with safrole and uses reductive amination to introduce the amine. 

Furazano[3,4-d]pyrimidine, 7-amino-synthesis, 6, 729 UV spectra, 6, 713 Furazanopyrimidines amine synthesis from, 5, 591 synthesis, 6, 418 Furazano[3,4-d]pyrimidines nucleophilic attack, 6, 719 nucleophilic substitution, 6, 713 reduction, 6, 402 7-substituted reactions, 6, 722 Furazano[3,4-a]quinolizines synthesis, 6, 730... 

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