Iodine → HCID 131711668, compound

Participants

Reaction Steps

12.3 g. of freshly distilled and absolutely dry 3-(dimethylamino)propyl chloride (0.1 mol.) are added slowly with stirring and gentle heating to 2.4 g. of magnesium turnings in 70 ml. of dry tetrahydrofuran. A crystal of iodine and a few drops of ethyl iodide are employed as initiator. After all of the 3-(dimethylamino)propyl chloride is added, the reaction mixture is refluxed for two to three hours. To this Grignard reagent a solution of 10.8 g. of 4-chloro-1-ethyl-5,6-dihydrobenzo[5,6]cyclohepta[1,2-b]pyrazolo[4,3-e]pyridin-11(1H)-one (0.035 mol.), from example 1(e), in 70 ml. of dry tetrahydrofuran is added. The mixture is heated under reflux for 5 hours after which the solvent is evaporated and the residue treated with 150 ml. of water and 60 ml. of ammonium chloride solution (20%). The mixture is extracted with ether and the ethereal extract is washed with water and dried with Na2SO4. Then the etheral solution is allowed to stand over night in a refrigerator to separate unreacted starting material (2.6 g. of oil). The decanted solution is charcoaled, filtered and 8 ml. of ethereal hydrochloric acid (195 g./l.) are added. Stirring is continued for 40 minutes. The precipitated hydrochloride salt is filtered off, washed with ether, and recrystallized from ethyl acetate/ether (1:5) to yield 8.3 g. (55%) of 4-chloro-11-[3-(dimethylamino)propyl]-1-ethyl-1,5,6,11-tetrahydro[5,6]cyclohepta[1,2-b]pyrazolo[4,3-e]pyridin-11-ol, hydrochloride (1:1); m.p. 172°-176° (dec.).

Provenance & Evidence