Synthesis of cotarnine / by Arthur H. Salway.

  • Salway, Arthur H. (Arthur Henry)
Date:
[1910?]
Catalogue details

Licence: In copyright

Credit: Synthesis of cotarnine / by Arthur H. Salway. Source: Wellcome Collection.

    8/16 (page 1213)
    0*1206 gave 0*3066 C02 and 0*0669 H20. C = 69*3; H = 6*2. C18H1904N requires C = 69*0; H = 6*l per cent. Phenylacetyl - f3-3-methoxy-4:: b-methylenedioxyphenylethylamine is readily soluble in chloroform or alcohol, but only moderately so in water or cold benzene. Condensation of Phenylacetyl ethoxy A : 5-methylenedioxy- plienyl ethyl amine. The condensation of this substance to the corresponding dihydro- isoquinoline was conducted according to a method first proposed by Bischler and Napieralski, and recently modified by Pictet and Kay (Ber., 1909, 42, 1973). Sixty-five grams of phenylacetyl /3-3-methoxy-4 : 5-methylenedioxyphenylethylamine were dissolved in 500 c.c. of xylene, and 100 grams of phosphoric oxide then added. After heating the mixture for about fifteen minutes a further 80 grams of phosphoric oxide were added, and the heating con¬ tinued until a small portion of the xylene gave no precipitate of un¬ changed substance on the addition of light petroleum. The xylene was then decanted from the yellow mass of phosphorus compound, and the latter extracted with hot water until only an insoluble resin remained undissolved. The aqueous extract was shaken with ether to remove adhering xylene, then rendered alkaline with sodium hydroxide, and the oil, which was thus precipitated, extracted with ether. After the ethereal solution had been washed, dried, and the solvent removed, there remained a viscid, brown oil, which did not solidify, and amounted to 40 grams. Separation of Two Isomeric Methoxymethylenedioxybenzyldihydro- isoquinolines (VIII and IX, p. 1209). Since the condensation of phenylacetyl /3-3-methoxy-4: 5- methylenedioxyphenylethylamine can proceed in two directions, it was to be expected that the above brown, oily condensation product would consist of a mixture of two isomeric bases. In order to effect a separation of these compounds, the oil was dissolved in dry ether and a current of dry hydrogen chloride passed into the solution, when the hydrochlorides were precipitated as a light brown solid. This mixture of crude hydrochlorides was then fractionally crystallised from a mixture of absolute alcohol and ethyl acetate. After considerable fractionation, two distinct hydrochlorides were isolated, one of which crystallised in colourless prisms, melting and decomposing at 192°, whilst the other separated in pale yellow, slender needles, which melted and decomposed at 174°. These compounds were analysed: