Phosphoric Acid → trans-(+/-)-5-n-Propyl-4,4a,5,6,7,8,8a,9-octahydrothiazolo[4,5-g]quinoline

Beteiligte Stoffe

Reaktionsschritte

A solution of 0.24 g. of trans-(±)-2-amino-5-n-propyl-4,4a,5,6,7,8,8a,9-octahydrothiazolo[4,5-g]quinoline in 10 ml. of 85% phosphoric acid was cooled to about -8° C. A saturated solution of 1.17 g. of sodium nitrite in water was added below the surface of the phosphoric acid solution at such a rate as to keep the reaction temperature from going above about -4° C. The reaction mixture was then added in dropwise fashion to 10 ml. of 50% aqueous hypophosphorus acid kept at a temperature of about 0° C. This new reaction mixture was stirred until gas evolution had ceased, at which time it was poured over ice. The aqueous mixture was made strongly basic with aqueous ammonium hydroxide. The aqueous layer was extracted several times with chloroform. The chloroform extracts were combined, and the combined extracts washed, first with water and then with saturated aqueous sodium chloride, and then dried. Removal of the chloroform in vacuo yielded trans-(±)-5-n-propyl-4,4a,5,6,7,8,8a,9-octahydrothiazolo[4,5-g]quinoline free base having the following physical characteristics: tlc (9:1 CHCl3 /MeOH+Tr.NH4OH)Rf =0.70.

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