Eco-friendly synthesis of 2-substituted benzothiazoles catalyzed by cetyltrimethyl ammonium bromide (CTAB) in water

Abstract

Uma série de benzotiazóis 2-substituídos foi sintetizada pela condensação de 2-aminotiofenol com aldeídos (RCHO: R = Alquil, Aril, Heteroaril, 2-Arilformil) na presença de quantidade catalítica de brometo de cetiltrimetil amônio (CTAB) em água e sem adição de solventes orgânicos e oxidantes. Assim, usando esse protocolo, 2-alquilbenzotiazóis foram sintetizados em altos rendimentos e 2-arilformilbenzotiazóis foram obtidos pela condensação de 2-aminotiofenol com arilformil aldeídos pela primeira vez.A series of 2-substituted benzothiazoles have been synthesized by the condensation of 2-aminothiophenol with aldehydes (RCHO: R = Alkyl, Aryl, Heteroaryl, 2-Arylformyl) in the presence of a catalytic amount of cetyltrimethyl ammonium bromide (CTAB) "on water" by a onepot procedure without additional organic solvents and oxidants. Thereinto, 2-alkylbenzothiazoles were synthesized in high yields and 2-arylformylbenzothiazoles were obtained from the condensation of 2-aminothiophenol with arylformyl aldehydes for the first time using the present protocol.

α-Keto Acids as Triggers and Partners for the Synthesis of Quinazolinones, Quinoxalinones, Benzooxazinones, and Benzothiazoles in Water

“…α-Keto acids bearing methyl and bromo groups were fully tolerated, providing the desired products 5bb and 5bh with 93 and 86% yields, respectively. Su reported that 2-substituted benzothiazoles were synthesized by the reaction of 2-aminothiophenol with aldehydes in water; however, 5 mol% cetyltrimethylammonium bromide should be added as a catalyst . Compared with Su′s method, here the reaction that proceeds in water under catalyst-free conditions is more green and sustainable.…”

“…Typical Procedure for the Synthesis of 5-(2-Ethoxyphenyl)-1methyl-3-propyl-1H-pyrazolo [4,3-d]pyrimidin-7(6H)-one (13). To a test tube (1.8 cm × 18 cm) were added 2-(2-ethoxyphenyl)-2-oxoacetic acid 12 (0.3 mmol, 1.5 equiv) followed by 4-amino-1-methyl-3-propyl-1H-pyrazole-5-carboxamide 11 (0.2 mmol, 1.0 equiv) and H 2 O (1 mL).…”

Green synthesis of bis‐coumarin derivatives using Fe(SD)3 as a catalyst and investigation of their biological activities

“…Also, the hydrophobic chain of SDS forms micelles in water, which can capsulate reactants in a tight place with a diameter of 10–28 Å for the reaction to occur (Scheme ). Moreover, these micelles in water increase the solubility of organic compounds in water …”

Synthesis of Novel Benzimidazole and Benzothiazole Derivatives Bearing a 1,2,3-triazole Ring System and their Acetylcholinesterase Inhibitory Activity

“…Synthesis of a third series of compounds 17 was performed as shown in thiazol-2-yl)phenol 15 25 was reacted with propargyl bromide 2 in the presence of K 2 CO 3 in DMF at 80 °C for 16 h to form 2-(4-(prop-2-yn-1-yloxy)phenyl) benzo[d]thiazole 16. A click reaction of 16 with an in situ prepared benzyl azide 6 gave the title compounds 17.…”

“…Pure products 14 were obtained by recrystallisation from a mixture of ethanol and ethyl acetate. 25 in DMF. The mixture was stirred at 80 °C for at least 12 h. After completion of the reaction (monitored by TLC), the mixture was diluted with EtOAc (25 mL) and water (25 mL) and the organic layer was extracted with EtOAc (2 × 25 mL).…”