3-Pyridinecarboxaldehyde → HCID 65645406, compound

Participants

Reaction Steps

3-(3-chloro-1,2,5-thiadiazol-4-yl-pyridine (compound 1) was synthesized from 3-pyridinecarboxaldehyde following, except with slight modification, from the published procedure as provided in Sauerberg et al, Journal Medicinal Chemistry, 1992, Vol. 35, Page 2274. 3-(3-Chloro-1,2,5-thiadiazol-4-yl)pyridine was reacted with a diol (compound 2, wherein n=6, 7, 8, 9, 10 or 12) in the presence of sodium hydride in refluxing THF to yield bis[3-(pyridin-3-yl)-1,2,5-thiadiazol-4-yl]alkyl-diethers (compound 3, wherein n=6, 7, 8, 9, 19 or 12) in 75-90% yield. These diethers were treated with excess methyl iodide in acetone or chloroform to give bis-quaternary ammonium iodides (compound 4, wherein n=6, 7, 8, 9, 10 or 12) in 96-100% yield. The quaternary salts were then treated with 5 equivalents of sodium borohydride in a mixture of methanol and chloroform to yield the compounds 5, wherein n=6, 7, 8, 9, 10 or 12 in 50-60% yield. Dry hydrogen chloride gas was then bubbled through the methanolic solution of compounds 5 at 0° C. to give compounds 6, wherein n=6, 7, 8, 9, 10 or 12 in 95-100% yield.

Provenance & Evidence