The configuration of tropine and [psi]-tropine and the resolution of atropine / by Marmaduke Barrowcliff and Frank Tutin.

Barrowcliff, Marmaduke.

Date:: [1909?]

Credit: The configuration of tropine and [psi]-tropine and the resolution of atropine / by Marmaduke Barrowcliff and Frank Tutin. Source: Wellcome Collection.

11/16 page 1974

$The Resolution of Atropine. Forty grams of atropine were neutralised with tZ-camphor- sulphonic acid, and the resulting salt was fractionally crystallised from ethyl acetate containing some alcohol. The first crop of crystals consisted of prismatic needles, and melted at 136—140°. This was recrystallised several times until no further change occurred; it then melted at 159°. 0*5072, made up to 25 c.c. with water, gave aD — 0° lO'S7 in a 2-dcm. tube, whence [a]D — 8'0° and MD —41*7°. Since the molecular rotation of cZ-camphorsulphonic acid is+ 51°, it is evident that the basic ion of the above salt has MD —92*7°, which corresponds with a specific rotatory power of — 32T°. It is seen, therefore, that resolution had been effected, and that the salt melting at 159° was \-hyoscyamine d-camphorsulphonate: 0*1302 gave 0'2974 C02 and 0*0902 H20. C = 62*3; H = 7*7. C17H23O3N,C10H16O4S requires C —62*4; 11 = 7*5 per cent. For the purpose of comparison a quantity of natural Z-hyos- ■cyamine was converted into the d-camphorsulphonate. The salt so obtained melted at 149—150°, and was somewhat impure; after recrystallisation, however, it melted at 159°, and was identical with the salt obtained from atropine. Z-Hyoscyamine d-camphor- sulphonate is extremely readily soluble in water, alcohol, or chloro¬ form, and very sparingly soluble in ethyl acetate, benzene, or xylene. The material contained in the mother liquors obtained during the separation of the Z-hyoscyamine d-camphorsulphonate from the original atropine salt, which would contain the salt of <d-hyoscyamine, was submitted to a very elaborate process of frac¬ tional crystallisation, whereby it was shown conclusively that the salts of only two bases were present. The product did not crystal¬ lise readily, and exhibited a considerable tendency to separate as an oil. After a large number of crystallisations, however, the salt of the d-base was obtained in a state of purity. d-Hyoscyamine d-camphorsulphonate forms small needles, which melt at 135°. Its solubilities are similar to, but rather greater than, those of the corresponding lsevo-salt: 0*1212 gave 0*2793 C02 and 0*0840 H20. C = 62*l; 11 = 7*7. C17H23O3N,C10HlcO4S requires C = 62*4; H = 7*5 per cent. 0*5229, made up to 20 c.c. with water, gave aD-f 1° 25*5r in a 2-dcm. tube, whence [a]D + 27*25° and MD+ 143*7°. From this result it is calculated that the basic ion has MD+92*7° and [a]D+ 32*1°, figures which are in exact agreement with the corresponding values obtained for the Z-base.$