Heterocycles coupling

Heterocyclic coupling components are widely used in the disperse dye field for the production of yellow dyes. Numerous conventional dyes are based on simple pyrazolones, often combined with an o-nitroaniline diazo component, the o-nitro group being particularly favourable in ensuring good light fastness. Cl Disperse Yellow 8 (4-73), which uses a very simple pyrazolone coupling component, is an example. 

A very noticeable feature has been the use of a wider range of heterocyclic coupling components than in water-soluble azo dyes. An early example of this trend was Cl Disperse Yellow 5 (4.74), which used 4-hydroxy-1-methylcarbostyril as coupling component. It was in... 

The basic hue of an azo pigment is primarily defined by the structure of the coupling component, since pigment manufacturers focus almost exclusively on substituted anilines as diazo components. Shades of yellow, for instance, are preferably produced by using acetoacetic arylides CH3COCH2CONH-Ar or heterocyclic coupling components based on the structure... 

Likewise, heterocyclic coupling components are derived from acetoacetic ester, diketene, or 2-hydroxy-3-naphthoic acid and a heterocyclic amine ... 

Supplement to c) Pyrazolone derivatives. Derivatives of pyrazolone-(5) are important heterocyclic coupling components. They are based on the following general structure ... 

Synthesis ofAzo Dyes. Processes to all the major benzene and naphthalene intermediates that are used in the commercial manufacture of azo dyes have been extensively reviewed. Description of the synthetic routes to heteroaromatic diazo components, such as those shown in Figure 2.8, are well covered in literature reviews, ° as are all the major heterocyclic coupling components. 

One long-term aim of dyestuffs research has been to combine the brightness and high fastness properties of anthraquinone dyes with the strength and economy of azo dyes. This aim is now being realized with heterocyclic azo dyes, which fall into two main groups those derived from heterocyclic coupling components, and those derived from heterocyclic dia/.o components. 

All the heterocyclic coupling components that provide commercially important azo dyes contain only nitrogen as the hetero atom. They arc indoles, pyrazolones, and especially pyridones they provide yellow to orange dyes for various substrates. 

In contrast to the heterocyclic coupling components, virtually all the heterocyclic diazo components that provide commercially important azo dyes contain sulfur, either alone or in combination with nitrogen (the one notable exception is the triazole system). These S or S/N heterocyclic azo dyes provide bright, strong shades that range from red through blue to... 

Monoazo dyes with heterocyclic coupling components, such as pyrazolone or pyridone, are yellow to greenish yellow. Other suitable coupling components include aniline and naphthylamine derivatives. Substituted anilines or amino-naphthalenesulfonic acids are employed as diazo components. Examples are C.I. Reactive Yellow4, C.I. Reactive Yellow 17 (see Section 3.1.5). 

Heterocyclic coupling components that have been coupled with diazotized ami-nophenyltrimethylammonium chloride are l-alkyl-6-hydroxy-2-pyridone [93], 1-amino-3-hydroxy-isoquinoline [94], and 2,4-diamino-6-hydroxypyrimidine [95], The trialkylammoniumaryl residue may also be connected to the aromatic diazo component via a sulfone or a sulfonamido function [96], Disazo dyes in this series (e.g., 34) [77901-21-4] may also be generated from monoazo dyes that still contain a primary amino group by dimerization using phosgene [97] or cyanuric chloride [98],... 

Use of 2-methylindole as the heterocyclic coupling component has led to commercially important dyes such as 36 [25784-16-1] [101],... 

Diazo Components With Cycloammonium Groups. Polynuclear N heterocycles that carry an amino group in the carbocyclic aromatic ring can be diazotized and then joined to azo dyes by using aromatic or heterocyclic coupling components. Quatemization at the heterocyclic nitrogen atom may occur before or after coupling. The azo dye 43, from 2-methyl-5-aminobenzimidazole and l-phenyl-3-methyl-5-pyrazolone, used in the form of its hydrochloride, dyes paper and leather in clear yellow shades [130],... 

Cheng, Q. Oritani, T. Horiguchi, T. Yamada, T. Mong, Y. Synthesis and biological evaluation of novel 9-functional heterocyclic coupled 7-deoxy-9-dihydropaclitaxel analogues. Bioorg. Med. Chem. Lett., 2000, 10 517-521. 

Heterocyclic coupling components have, in a similar manner as heterocyclic diazo components (sect. 2.1.4), recently become very important and are used in large scale industrial production of dyestuffs and chemicals. A recent review deals with the industrial um of pyrazolones 75, iminopyrazoles 76, pyridones 77, amino-pyrimidines 78, aminopyridines 79, hydrochinolines 80 and aminothiazoles 81 as coupling components. 

Heterocyclic coupling constants refer to the following atom labeling scheme ... 

R. Riva, L. Banfi, A. Basso, V. Cerulli, G. Guanti, M. Pani, A highly convergent synthesis of tricyclic N-heterocycles coupling an Ugi reaction with a tandem Sn2-Heck double cyclization, J. Org. Chem. 75 (2010) 5134-5143. 

H. Meng, D. F. Perepichka,M. Bendikov, F. Wudl,G. Z. Pan, W.Yu, W. Dong, andS. Brown. 2003. Solid-state synthesis of a conducting polythiophene via an unprecedented heterocyclic coupling reaction. / Am Chem Soc 125(49) 15151-15162. 

Rhodium-catalyzed oxidative biaiyl coupling is still in its infancy, given that it first started appearing in independent studies by Glorius, Miura and You in 2012. All of these studies used either Rh(i) or Rh(iii) catalysts and Cu(ii) oxidants to carry out aiylations of heterocycles, intramolecular couplings or dual heterocycle couplings. ... 

Table 16.5 Heterocyclic coupling with p-alko>y trifluoroborates.

Loucks, G.R. and White, D.M., Process of Forming Heterocyclic-coupled block polymers of poly(phenylene oxide), US 2826684, 1979. (General Electric Co.)... 

---