156086-12-3Relevant academic research and scientific papers
Iron-Catalyzed Regioselective Synthesis of 2-Arylbenzoxazoles and 2-Arylbenzothiazoles via Alternative Reaction Pathways
Henry, Martyn C.,Abbinante, Vincenzo Mirco,Sutherland, Andrew
, p. 2819 - 2826 (2020)
A one-pot regioselective method for the preparation of 2-arylbenzoxazoles from N-arylbenzamides has been developed using iron(III)-catalyzed bromination of the aryl ring, followed by copper(I)-catalyzed O-cyclization with the benzamide side chain. In contrast, reaction of N-arylthiobenzamides with N-bromosuccinimide and iron triflimide led directly to the isolation of the corresponding 2-arylbenzothiazoles via intramolecular C–S bond formation. Mechanistic and control experiments suggest that in this case, bromination occurs at the sulfur atom, resulting in a reactive intermediate that can undergo electrophilic aromatic substitution and S-cyclization. The scope of both processes was explored yielding a range of structural analogues, including a pharmaceutically active compound for the treatment of Duchenne muscular dystrophy and an affinity agent of the amyloid-beta protein in Alzheimer's disease.
Structural studies on benzothiazoles. Crystal and molecular structure of 5,6-dimethoxy-2-(4-methoxyphenyl)-benzothiazole and molecular orbital calculations on related compounds.
Yates,McCall,Stevens
, p. 6493 - 6502 (2007/10/02)
The benzothiazole derivatives reported here have structural similarities to the 2-phenylindole derivatives that are known to bind to oestrogen receptors. We report the synthesis of 5,6-dimethoxy-2-(4-methoxyphenyl)- benzothiazole together with the determination of its three dimensional crystal structure. Crystals are monoclinic, space group P21/c, a=17.142(1), b=11.165(1), c=7.683(2) A, β=101.34(1)°. 2307 Reflections were refined to R=0.039. The inter-ring twist angle is 21°, greater than in 2-(o-hydroxyphenyl)benzothiazole but similar to that in 2-(4'-bromophenyl)-4,6-dimethoxyindole. Molecular mechanics calculations predict a torsional barrier to inter-ring twist of 6.3 kcal mol-1 for unsubstituted benzothiazole. Molecular orbital calculations show that while hydrogen bonding can confer stability on substituted benzothiazoles, a greater number of non-hydrogen bonding groups as substituents can confer even greater stability.
