Hydrochloric Acid → 2-Methylthieno[2,3-c]pyridine

Participants

Reaction Conditions

Reaction Steps

76059-85: N-(2,2-Dimethoxy-ethyl)4-methyl-N-(5-methyl-thiophen-2-ylmethyl)-benzenesulfonamide (2) (50.56 g crude) was dissolved in dioxane (250 mL) and conc. HCl (200 mL) was added cautiously. The dark red solution was heated at gentle reflux (105 to 110° C.) for 24 hours. The volume was reduced by approximately half, then diluted with ether (200 mL). The pH was adjusted to between 7 and 8 using 50% NaOH/H2O and sat NaHCO3 solution with cooling. More ether (400 mL) was added, the mixture was filtered to remove insoluble material and the phases separated. The organic phase was washed with water (2×350 mL), dried (MgSO4) and condensed to dark red-brown oil. Purification was accomplished using Kugelrohr distillation (120 to 130° C.) to give 11.89 g of title compound as a pale yellow liquid.

Provenance & Evidence