《1,6-Aza-Michael addition of para-quinone methides with N-heterocycles catalyzed by Zn(OTf)2: A regioselective approach to N-diarylmethyl-substituted heterocycles》 was written by Guin, Soumitra; Saha, Hemonta K.; Patel, Ashvani K.; Gudimella, Santosh K.; Biswas, Subhankar; Samanta, Sampak. Quality Control of 3,6-Dibromo-9H-carbazole And the article was included in Tetrahedron in 2020. The article conveys some information:
An efficient Zn(OTf)2-catalyzed regioselective C-N bond making reaction between a bunch of aryl/heteroaryl-substituted para-quinone methides as ideal 1,6-acceptors and various aromatic/non-aromatic aza-heterocycles bearing N-H moiety namely carbazoles, pyrazoles, indazole, benzotriazole and saccharin is reported. This 1,6-aza-Michael technique delivers predominantly N1-diarylmethyl-substituted heterocyclic scaffolds bearing a valuable phenolic moiety in good to high yields with an excellent regioselectivity. Furthermore, this LUMO lowering catalytic system allows different kinds of useful functionalities and excels with broad substrates under mild conditions. Importantly, control experiments suggested that N2-adducts of indazole, benzotriazole and 3-Me pyrazole as minor isomers were progressively converted into N1-adducts during the reaction via a retro-aza-Michael reaction triggered by Zn(OTf)2, offering excellent regioselectivities of the products. In the part of experimental materials, we found many familiar compounds, such as 3,6-Dibromo-9H-carbazole(cas: 6825-20-3Quality Control of 3,6-Dibromo-9H-carbazole)
3,6-Dibromo-9H-carbazole(cas: 6825-20-3) is used as a pharmaceutical intermediate, and also an important intermediate of synthesizing optoelectronic materials. It has been used as a reagent in the synthesis of P7C3-A20 which is a potent neuroprotective agent.Quality Control of 3,6-Dibromo-9H-carbazole
Referemce:
Bromide – Wikipedia,
bromide – Wiktionary