The constituents of Gloriosa superba / by Hubert William Bentley Clewer, Stanley Jospeh Green and Frak Tutin.

  • Clewer, Hubert W. B.
Date:
1915.]
Catalogue details

Licence: Public Domain Mark

Credit: The constituents of Gloriosa superba / by Hubert William Bentley Clewer, Stanley Jospeh Green and Frak Tutin. Source: Wellcome Collection.

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    The acid melting at 135° was similar in appearance to salicylic acid, and yielded the same colour with ferric chloride. A mixture of it with the latter acid, however, melted at about 120°: 0-1018 gave 0*2132 C02 and 0‘0446 H20. C = 57T; H = 4‘8. 0-2393 „ 0-3269 Agl. MeO = 18 2. C8H804 requires C = 571; H = 4‘8; MeO = 18'4 per cent. It thus appeared that the acid melting at 135° was a methoxy- salicylic acid. The only known acid of this character with which the compound from Gloriosa agrees at all in its properties is 2-hydroxy-5-methoxybenzoic acid, which melts at 141°. A quantity of the latter was therefore prepared from quinol monomethyl ether by Korner and Bertoni’s method (Ann. di chum, median, 1881, 65), when the synthetic acid was found to differ from the naturally occurring one. Thus, a mixture of the two preparations melted at 118°, and the colour produced on treating the synthetic acid with ferric chloride was blue, whereas the natural acid yielded a violet colour identical with that furnished by salicylic acid. It therefore appeared that the acid melting at 135° occurring in Gloriosa must be 2-hydroxy-6-methoxybenzoic acid, a compound which has not hitherto been known. In order to confirm this assumption, resorcinol was heated at 120—130° with water and ammonium carbonate, when a mixture of 2:6- and 2 : 4-clihydroxybenzoic acids resulted (Senhoffer and Brunner, Wien. Akad., 1879, 80). This crude mixture was then vigorously methylated by means of methyl sulphate and potassium hydroxide, and the product was heated for some time in alcoholic solution with an excess of the alkali. Water was then added, and the mixture extracted with ether, when a quantity of a crude ester which had resisted hydrolysis by the alkali was obtained. This product was distilled under the ordinary pressure, when the por¬ tion of higher boiling point solidified on cooling. On crystallising this product from petroleum, long, colourless needles, melting at 88°, were obtained. This compound must be methyl 2 : 6-dimeth- oxybenzoate, a substance not hitherto known, the fact of its not being hydrolysed by alcoholic potassium hydroxide being evidently due to steric hindrance caused by the two methoxy-groups in the ortho-position with respect to the carboxyl group. An identical ester was obtained by the methylation of the 2-hydroxy-6-methoxy- benzoic acid occurring in Gloriosa : 0-1169 gave 0-2619 C02 and 0’0657 H20. C = 6M; H = 6'2. C]0H12O4 requires C=61*2; 11 = 6-1 per cent. The materials removed from the original ethereal extract of the aqueous liquid by the extractions with sodium carbonate and