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Thioindigoid dyestuffs are in an important class of compounds and are used as vat dyes for textile dyeing and printing. This chromophoric system has also found application in the pigment field, especially where suitable substituents in the aromatic nuclei bring about an increase in resistance to solvent bleed and migration. The best example is the reddish‐violet thioindigo bordeaux of light fastness comparable, even in light tints, with the phthalocyanine pigments.

Since knowing the effective role of amidic functions in producing new dye‐stuffs of high thermal fastness and low solubility (e.g. Hostaperm or PV Fast (Hoechst)), great attention has been directed towards the synthesis and use of several dyes and pigments having such moieties. The majority of these dyes are characterized by their tendency to form stable dimers. Sometimes, these dimeric monoazo pigments have the same thermal solvent fastness as disazo pigment dyes of the Cromophtal type (Ciba‐Geigy).

Since Victor Meyer's first report on coupling of diazonium salts with activated carbon compounds, a growing interest has appeared in literature for synthesis and use of different isolated and/or fused nitrogen‐containing heterocyclic dyestuffs as fluorescent whitening agents. A technically important class of these products is those embodying pyrido (1,2‐a) benzimidazole residue in their structure. The parent pyrido (1, 2‐a) benzi‐midazole itself has been previously used in the synthesis of a variety of dyes and pigments.

A series of novel anchored mono‐ and disarylazo cationic pigments embodying long chain aliphatic amine moiety, as deflocculating unit, were prepared by amination of the newly synthesized heterocyclic Hansa Yellow analogue derivatives IVa‐g followed by reacting the products with p‐nitroso‐N,N‐dimethyl aniline. Synthesis and spectral behaviour of these products as well as their precursors were fully investigated. The hitherto prepared organic colourants showed preliminary improved bleeding and fastness properties.

The purpose of this paper is to discuss the synthesis of new azo disperse dyes containing pyridine ring for dyeing acetate polyester and other fibres.

Cycloaddition reaction of 3-formylchromone (Compound 1) with ethyl vinyl ether (Compound 2) afforded 3-ethoxy-4,4a-dihyro-3H,10H-pyrano[4,3-b]chromen-10-one (Compound 3). Reaction of 3 with aqueous ammonium sulphite in ethanol furnishes 3-(2-hydroxybenzoyl)pyridine (Compound 5). Compound 5 was fully characterised by spectroscopic techniques. Ten arylazo derivatives of Compound 6 have been prepared for use as dyestuffs. The effect of the nature and orientation of substituents in the diazonium component on the colour of azo dyes is discussed. Dyeing performance of the dyes on different fibres has also been assessed.

Most of the dyes showed good affinity to polyester fibres. On the other hand, polyacrylic fibres were only stained to weak shades.

No details regarding the synthesis and dyeing performance of such dyes are reported before in the literature.

In light of the technological advancements and impact of the COVID-19 pandemic on educational systems, universities worldwide had to find new methods to ensure that the educational process continued. In many countries, including Egypt, it has become a priority to direct their institutions toward digital transformation, using electronic means in the educational process. A set of challenges emerged in the educational process, especially in architectural learning, focusing on the design studio; problems intensified and some professors rejected the idea of distance learning, announcing their strong adherence to traditional face-to-face learning. This research aims to find a methodology that informs the choice of digital technology in architectural design courses.

The researchers used both qualitative and quantitative methodology based on inductive, analytical, interview-questionnaire and empirical studies in Egypt.

Results show that many criteria affect the selection of proper applications. Also, using multiple applications in architecture design course helps students understand the material. However, hybrid learning is crucial in teaching architectural design since it cannot be effectively conveyed solely through distance learning.

The results of the research will help improve and develop the distance learning system in architectural education by proposing a methodology for choosing suitable electronic tools for architecture studio courses. These courses enhance the effectiveness of students' understanding and comprehension during the distance learning process to increase motivation for thinning development, imagination and educational skills.