The author of 《Solvent-dependent regio- and stereo-selective reactions of 3-formylchromones with 2-aminobenzothiazoles and transacetalization efficiency of the product 3-((benzo[d]thiazol-2-ylimino)butyl)-4H-chromen-4-one》 were Ahmed, Owais; Cherkadu, Vandana; Kalavagunta, Praveen Kumar; Shang, Jing. And the article was published in RSC Advances in 2019. Application In Synthesis of 6-Chlorobenzothiazol-2-ylamine The author mentioned the following in the article:
Using 2-propanol as the solvent, 3-formylchromones I (R = H, 6-Cl, 6-Br, 6-OH, 6-Cl-8-Br) and 2-aminobenzothiazoles II [R1 = 4-Cl, 6-Br, 4,6-(F2), etc.] formed corresponding imines, (Z)-III while 1° and 2°-alcs. R2OH [R2 = CH3, CH(CH3)2, cyclohexyl, etc.] formed the corresponding 2-alkoxy-3-enamines IV with selectivity for the Z-isomer. Changing the substrates with similar mols. such as 3-formylchromone I with quinoline-, quinolone- and indole-3-carbaldehydes, e.g., 1,4-dihydro-4-oxoquinoline-3-carbaldehyde sometimes resulted in the formation of the corresponding imines, e.g., 3-((benzo[d]thiazol-2-ylimino)methyl)quinolin-4(1H)-one, whereas replacing 2-aminobenzothiazole with amides R3C(O)NH2 (R3 = H, Me, Ph) resulted in the formation of acetals V. Considering the effect of the solvent, replacing alcs. with the aprotic solvents THF and CH2Cl2 resulted in the formation of imines and enamines, which are the characteristic reactions of 2-propanol and other 1° and 2°-alcs., resp. 2-Alkoxy-3-enamines were found to undergo transacetalization with both short and long chain alcs. The novelty of these reactions is that they did not require an external catalyst, all the reactions were performed at the same temperature, and purification was achieved by filtration. The transacetalization has been performed as a new concept, which has not been reported to date. In contrast, other similar reactions, such as transalkoxylation, transalkylation, and transetherification, are performed on a com. scale using expensive catalysts such as Otera’s catalyst. The highly sensitive nature of 3-formylchromones towards variations in the substrates and solvents to form different products and the reason behind the selective formation of the Z-isomer of 2-alkoxy-3-enamines and its transacetalization efficiency need further studies to understand the reaction mechanism and possibly other factors such as solvent effects. The experimental part of the paper was very detailed, including the reaction process of 6-Chlorobenzothiazol-2-ylamine(cas: 95-24-9Application In Synthesis of 6-Chlorobenzothiazol-2-ylamine)
6-Chlorobenzothiazol-2-ylamine(cas: 95-24-9) belongs to thiazoles. Thiazoles are a class of five-membered rings containing nitrogen and sulfur with excellent antitumor, antiviral and antibiotic activities.Application In Synthesis of 6-Chlorobenzothiazol-2-ylamineTheir presence in peptides or their ability to bind proteins, DNA and RNA has led to many synthetic studies and new applications.
Referemce:
Thiazole | C3H3NS – PubChem,
Thiazole | chemical compound | Britannica