Amines as leaving group

Amines as Leaving Groups The Hofmann Elimination 904 Mechanism 19-4 Hofmann Elimination 904 19-15 Oxidation of Amines The Cope Elimination 907... 

Silylation-amination of 4(lH)-quinohnone 255 with a twofold excess of dopamine hydrochloride 256 as amine and an acidic catalyst affords, on heating with excess HMDS 2 for 21 h at 145 °C and subsequent transsilylation in excess boihng methanol, 75% of the crystalline hydrate of 257 (Scheme 4.28). The silylation-amination of 2-thio-6-azauracil 258 with homoveratrylamine 259, HMDS 2, and SnCLj as catalyst for 48 h at 145 °C furnishes 63% of the diamine 260, and MesSiOSiMes 7 and Me3SiSH or Me3SiSSiMe3 601 as leaving groups. 

Aryloxy groups have also been used as leaving groups. Reaction of 1-chloro- and l-methanesulfonyl[l,4]benzo-dioxino[2,3-r/]pyridazine 164 and 4-chloro[l,4]benzodioxino[2,3-Hpyridazine with NaOMe afforded ring-opened and cyclized pyridazines (Scheme 40). Their reaction with amines afforded 1-substituted [l,4]benzodioxino[2,3-rf]pyr-idazines 165, 4-substituted [l,4]benzodioxino[2,3-f]pyridazines 166, and/or 2-hydroxyphenoxypyridazines 167 (Scheme 41) <2004H(63)591>. 

Aryl- and heteroaryl halides can undergo thermal or transition metal catalyzed substitution reactions with amines. These reactions proceed on insoluble supports under conditions similar to those used in solution. Not only halides, but also thiolates [76], nitro groups [76], sulfinates [77,78], and alcoholates [79] can serve as leaving groups for aromatic nucleophilic substitution. 

A. Amination via Nitrile, Trichloromethyl, and Carboxy Moieties as Leaving Groups... 

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