Methyl p-toluenesulfonate → HCID 15475887, compound

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Reaction Steps

In the first step, 2-methylthiobenzothiazole (Aldrich Chemical Company, Milwaukee, Wis. is quaternized by heating at 120° C. with an equivalent of methyl p-toluenesulfonate (Compound 1A, also commercially available from TCI, Portland, Oreg.). N-(3-iodopropyl)-4-methylquinolinium iodide (Compound 1B) is prepared by heating lepidine (5.0 g, 35 mmol) with 100 g (340 mmol) of diiodopropane at about 100° C. for one hour. Ethyl acetate is added and filtered. Compounds 1A and 1B are condensed to yield 4-(3-methyl-2,3-dihydro-(benzothiazol)-2-yliden-(4)-methyl)-1-(3'-iodopropyl)-quinolinium iodide (compound 1C) using methods known in the art [e.g. Brooker, et al., supra]. For instance when 12.0 g (27.3 mmol) of 1B is stirred with 10.0 g (27.2 mmol) of 1A in 200 mL of methylene chloride in the presence of 3.8 mL of triethylamine overnight at room temperature, 11.14 g of 1C is obtained by filtration. A mixture of 0.72 g of 1C is then dimerized by heating in a sealed tube with 69 mg of N,N,N',N'-tetramethylpropanediamine in 5 mL of DMF at 130° C. for one hour. After the reaction mixture cools down to room temperature, 40 mL of MeOH is added and stored at -20° C. overnight. The red solid is filtered and recrystallized from DMF/MeOH again to yield the pure product. TOTO-1 TM has a quantum yield of 0.34 bound to calf thymus DNA.

Provenance & Evidence