Synthesis of benzothiazoles viaipso substitution of ortho-methoxythiobenzamides
作者:Nadale K. Downer、Yvette A. Jackson
DOI:10.1039/b410373d
日期:——
An efficient route to the synthesis of benzothiazoles from ortho-methoxythiobenzamides via the ipso substitution of an aromatic methoxy group is presented, and the mechanism of the Jacobson synthesis of benzothiazoles is further investigated.
Synthesis and structure verification of an analogue of kuanoniamine A
作者:Michael A. Lyon、Simon Lawrence、David J. Williams、Yvette A. Jackson
DOI:10.1039/a809203f
日期:——
Synthesis of 9-phenyl-7H-benzothiazolo[4,5,6-ij][2,7]naphthyridin-7-one 11, an analogue of kuanoniamine A 8, is described. The synthesis involves a hetero Diels–Alder reaction of crotonaldehyde dimethylhydrazone with 4,7-dioxo-2-phenylbenzothiazole 18a or with 6-bromo-4,7-dioxo-2-phenylbenzothiazole 18b followed by annelation of the appropriate adduct. Reaction with 18a produced two sets of regioisomers—the thiazoloquinolinediones 19a,b, and the dimethylamino dioxobenzothiazoles 23a,b. The structure of 23b was determined by single-crystal X-ray structure analysis. Verification of the other structures, and methods used to improve the Diels–Alder reaction are described.
Phenoxy‐ and Phenylamino‐Heterocyclic Quinones: Synthesis and Preliminary Anti‐Pancreatic Cancer Activity
作者:Patricio Sánchez、Cristian O. Salas、Sebastián Gallardo‐Fuentes、Alondra Villegas、Nicolás Veloso、Jessica Honores、Martyn Inman、Mauricio Isaacs、Renato Contreras、Christopher J. Moody、Jonathan Cisterna、Iván Brito、Ricardo A. Tapia
DOI:10.1002/cbdv.202101036
日期:2022.6
heterocyclic quinones were evaluated in vitro to determine their cytotoxicity by the MTT method in three pancreatic cancer cell lines (MIA-PaCa-2, BxPC-3, and AsPC-1). Phenoxy benzothiazole quinone 26a showed potent cytotoxic activity against BxPC-3 cell lines, while phenylamino benzoxazole quinone 20 was the most potent on MIA-PaCa-2 cells. Finally, electrochemical properties of these quinones were determined
A Green Approach to 2-Substituted Benzo- and Naphthothiazoles via N-bromosuccinimide/Bromide-Mediated C(aryl)-S Bond Formation
作者:Ainka T. Brown、Nadale K. Downer-Riley
DOI:10.3390/molecules27227876
日期:——
coupling of isothiocyanates with amines under mild conditions using N-bromosuccinimide/tetrabutylammonium bromide in 1,2-dimethoxyethane (DME) under ambient conditions. The reactions produce moderate to excellent yields with good functional group tolerance and avoid the use of harsh thermal conditions, corrosive reagents, halogenated solvents, toxic metal salts, and expensive metal catalysts, and are amenable
Heating N-(2-methoxyphenyl)benzenecarbothioamides in refluxing nitrobenzene for 24 hours gives the corresponding benzothiazoles with intramolecular ipso substitution of the orthomethoxy substituent. The thermal cyclization of various other N-arylthiobenzamides is also explored.