136298-36-7Relevant academic research and scientific papers
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 (1991)
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.
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 (2020/04/10)
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 Bioactive Compounds. 23. Synthesis of Polyhydroxylated 2-Phenylbenzothiazoles and a Comparison of Their Cytotoxicities and Pharmacological Properties with Genistein and Quercetin
Stevens, Malcolm F. G.,McCall, Carol J.,Lelieveld, Peter,Alexander, Peter,Richter, Audrey,Davies, Donna E.
, p. 1689 - 1695 (2007/10/02)
A series of polyhydroxylated 2-phenylbenzothiazoles 3 has been prepared by demethylation of the precursor methoxylated 2-phenylbenzothiazoles 9.The key step in the construction of the benzothiazole nucleus involves a Jacobson cyclization of methoxylated thiobenzanilides 8.The target compounds inhibit WiDr human colon tumor cells and MCF-7 human mammary tumor cells in vitro with IC50 values in the low micromolar range, but the activity against MCF-7 cells is not related to estrogen receptor-binding affinity.None of the compounds showed selective cytotoxicity againstAbelson virus-transformed ANN-1 cells encoded with the pp120gag-abl tyrosine kinase compared with the parental 3T3 line.Compounds were only marginally inhibitory to the EGF receptor-associated protein tyrosine kinase from a membrane preparation of A431 cells.The most active compound was 4,6-dihydroxy-2-(4-hydroxyphenyl)benzothiazole (3b) which has the same overall hydroxyl substitution pattern as genistein (1a).The compounds were weakly cytotoxic for an EGF receptor, overexpressing cell line HN5, but when tested for differential toxicity against the EGF receptor tyrosine kinase or the PDGF receptor tyrosine kinase in a standard mitogenesis assay utilizing human fibroplasts, no discrimination was observed.In this assay, the compounds inhibited DNA synthesis when added to cells during S phase.This suggests that inhibition could not be interpreted in terms of tyrosine kinase inactivation but more likely as a relatively broad specificity for the ATP-binding domain of other kinases such as thymidine kinase.
