Amines capable of coupling

Phenols (capable of coupling) Fast blue salt B, fast blue salt BB, fast black salt K, diazotized sulfanilic acid (Pauly s reagent) diazotized sulfanilamide or 4-nitroaniline Intensely colored azo dyes are formed. Catecholamines [20, 3S], imidazoles [21] and amines capable of coupling also react. [3, 17]... 

Phenols and amines capable of coupling [4, 8] e.g. aniline derivatives, aminophenols [5]... 

Phenols and amines capable of coupling [4. 8] e.g. aniline derivatives, aminophenols [5] such as tyramine [9] phenolcaihoxylic acids [1, 3] such as gallic acid, caffeic acid, chlorogenic acid PHB esters [7] phenolic aldehydes... 

Amines (capable of coupling) Fast blue salt B and BB, fast black salt K, diazosulfanilic acid, diazosulfanilamide, 4-nitroaniline Formation of azo dyes... 

Figure 20.3 The reaction of SMCC with the amine groups on enzyme molecules yields a maleimide-activated derivative capable of coupling with sulfhydryl-containing antibody molecules.

The primary aromatic amines which will be preferentially nitrosated rather than diazotized are those which do not bear strongly electron-withdrawing substituents and are capable of coupling with diazonium salts to give azo dyes. 

Direct dyes (see Section 3.3) that contain aromatic amino groups can be diazo-tized on the fiber after dyeing and then coupled with a developer (a phenol, naphthol, or aromatic amine). Wetfastness, in particular, is improved by such an enlargement of the molecule, and the shade also changes (see Section 2.2). Conversely, water-soluble, substantive azo dyes which bear amino or hydroxyl groups capable of coupling can also be used, followed by aftertreatment with a diazo-nium compound. The resulting polyazo dye shows excellent wetfastness (see also Section 4.8). 

Nolan s heterocyclic carbene-based system (7 + KOf-Bu/Pd2(dba)3) was effective in the coupling of secondary amines with aryl chlorides at elevated temperatures, Eq. (47) [52]. This protocol could be used for the room-temperature ami-nation of aryl bromides as well. Hartwig reported that the saturated heterocyclic carbene ligand prepared by deprotonation of 16 forms a catalyst that is considerably more reactive than the system reported by Nolan. The resulting complex formed was capable of coupling aryl chlorides with cyclic amines at room temperature [76]. 

Nolan reported that the use of the carbene ligand derived from the deprotonation of 7 results in the formation of an efficient catalyst for the reaction of aryl chlorides and acyclic secondary amines [52]. For example, di- -butylamine efficiently reacts with 4-chloroanisole at 100°C in the presence of this catalyst, Eq. (54). Hartwig disclosed that the saturated carbene Hgand derived from the deprotonation of 16 yields a considerably more reactive catalyst which is capable of coupling acycHc secondary amines and aryl chlorides at room temperature [76]. 

Aminophosphine 4 is an excellent supporting ligand in the room-temperature reaction of aryl bromides and primary amines [42]. The 4/Pd-catalyst is capable of coupling a hindered aryl bromide such as 2-bromo-raefa-xylene with -butylamine in excellent yield, Eq. (76). 

Scheme 12.14 Cross-coupling of two amines capable of dehydrogenation.

---