79823-08-8Relevant articles and documents
Dihydropyridines, VI. - Derivatives of Diimido Malonic Acid in the Hantzsch Pyridine Synthesis
Meyer, Horst
, p. 1523 - 1533 (2007/10/02)
One-pot-condensation of aldehydes 6, 2,2'-methylenediimidazoline hydrochloride (7) and β-dicarbonyl compounds 10 leads to 1,2,3,7-tetrahydro-8-(2-imidazoline-2-yl)imidazopyridine hydrochloride 11.Michael addition of 7 to α,β-unsaturated ketones is followed by ring closure to give 16, 17, and 18.Condensation of the free base 8a with aldehydes 6 and 1,3-cyclohexanedione yields the fused imidazopyridines 19a-d.Compounds 20 and 21 are prepared by use of a second enamine in the one-pot-synthesis, thus furnishing another basic centre. 2,2'-Methylenedi(2-thiazo line) hydrochloride (22) is prepared by condensation of diethyl malonodiimidate and 2-aminoethanethiol hydrochloride. 22 can be converted to the free base 8b by treatment with aqueous NaOH.The 2,3-dihydro-8-(2-thiazoline-2-yl)-7H-thiazolopyridines 23, 25, 26, 28, and 29 are obtained by cyclising Michael addition of 8b to various α,β-unsaturated carbonyl compounds in ethanol or acetic acid.
