Thenylene ,Abbott,US,1947
Antihistaminic;Histamine H1 antagonist
Methapyrilene is used as antihistaminic agent.
ChEBI: A hydrochloride that is the monohydrochloride salt of methapyrilene.
To a slurry of sodamide in 200 cc of toluene representing 6.7 g of sodium was added at 30° to 40°C, 32.3 g (0.31 mol) of 2-aminopyridine. The mixture was heated to reflux temperature and was refluxed for 1? hours. To the resulting mixture was added over a period of approximately one hour a solution of 32 g of freshly distilled N,N-dimethyl-β-chloroethylamine in 40 to 50 cc of dry toluene, The reaction mixture was then heated for 2 hours at reflux temperature. Thereafter, 200 cc of water was added and the toluene layer was separated and washed with water. The toluene was stripped from the mixture by distillation and the residue was distilled under reduced pressure. The distillate was refractionated and the portion distilled at 93° to 103°C/1 mm was recovered. Yield of N-(2-pyridyl)-N',N'-dimethyl-ethylenediamine, 60%.
A solution of 20 g (0.121 mol) of N-(2-pyridyl)-N',N'-dimethylethylenediamine in 25 cc of toluene was added to a slurry of sodamide in 100 cc of toluene representing 2.8 g of sodium. The mixture was refluxed for one hour. To this mixture was added over a period of ? hour a solution of 16 g (0.121 mol) of 2-thenyl chloride in 25 cc of toluene. The resulting reaction mixture was refluxed for 3 hours. Thereafter, water was added and the toluene layer was separated and washed with water.
The toluene was then stripped off by distillation and the residue was distilled under reduced pressure. The main fraction was redistilled. Yield of N-(2- pyridyl)-N-(2-thenyl)-N',N'-dimethyl-ethylenediamine was 69%; BP 130° to 140°C/0.4 mm. A portion of the product was dissolved in ether and an ether solution of hydrogen chloride was added. The monohydrochloride of N-(2- pyridyl)-N-(2-thenyl)-N',N'-dimethyl-ethylenediamine which separated was washed with ether and dried.
Methapyrilene hydrochloride,2-[[2-(dimethylamino)-ethyl]-2-thienylarnino]pyridine monohydrochloride (Histadyl) is available as the bitter-tasting, white crystalline powder that is soluble in water(1:0.5), in alcohol (1:5), and in chloroform (1:3). Its solutionshave a pH of about 5.5. It differs structurally from tripelennaminein having a 2-thiophene—methylene group in placeof the benzyl group. The thiophene ring is considered isostericwith the benzene ring, and the isosteres exhibit similaractivity. A study of the solid-state conformation of methapyrilenehydrochloride showed that the trans-conformation is preferredfor the two ethylenediamine nitrogen atoms. The Foodand Drug Administration declared methapyrilene a potentialcarcinogen in 1979, and all products containing it have beenrecalled.
White crystalline powder or solid with a faint odor. Bitter taste. pH (aqueous solution) 5.5.
METHAPYRILENE HYDROCHLORIDE is light sensitive. Solutions of METHAPYRILENE HYDROCHLORIDE in water, DMSO, 95% ethanol or acetone should be stable for 24 hours under normal lab conditions. . Organosulfides are incompatible with acids, diazo and azo compounds, halocarbons, isocyanates, aldehydes, alkali metals, nitrides, hydrides, and other strong reducing agents. Reactions with these materials generate heat and in many cases hydrogen gas.
Flash point data for METHAPYRILENE HYDROCHLORIDE are not available; however, METHAPYRILENE HYDROCHLORIDE is probably combustible.
