The ureides of p-aminophenylstibinic acid / by W.H. Gray [and others].

Date:
[1931.]
Catalogue details

Licence: Public Domain Mark

Credit: The ureides of p-aminophenylstibinic acid / by W.H. Gray [and others]. Source: Wellcome Collection.

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    Chemical Seothin. 6. kC Urea stibamine (Brahmachari) 55 was analysed and gave the following results :— Table I. Batch No. Loss on drying. C. H. N. Sb. Atomic ratios. C: N. C : Sb. 425 10-38 6-75 44-19 __ 425 10-38 — — 6-77 44-49 — — 451 7-14 20-2 3-0 — — — —- 522 12-17 20-9 2-9 — — — — 522 14-07 20-5 2-8 — — — — / 522 12-17 20-9 3-0 — 46-4 — 4-57 : 1 \522 16-27 21-53 2-67 — — — — 926 10-12 21-16 2-8 — 46-8 — 4-59 : 1 1128 9-45 20-17 2-91 6-47 48-6 3•64 : 1 4-21 : 1 The value found for the ratio C : N shows that the product cannot be ammonium p-carbamidophenylstibinate, which requires 2*3:1 ; the value of the ratio C : Sb shows that it cannot consist of a pure arylstibinate, but must xlso contain antimony in inorganic combination. This is shown to be anti- monic acid (see § 9). In order that a determination of the ratio C : N should afford trustworthy information as to the nature of the organometallic constituent, the product was treated with dilute hydrochloric acid to remove ammonia or urea. The resulting solid contained C, 20*2 ; H. 2*4 ; N, 3*4 ; Sb, 52*2 per cent., atomic ratio C : N = 6*98 : 1, showing that the trypano- cidally active substance is not p-carbamidophenylstibinic acid, which requires C : N = 3*5 : 1. Further information was given by a prolonged treatment of “ urea stibamine 55 (4 g.) with dry alcohol, when the portion remaining un¬ dissolved (2*95 g.) was found to have the same composition as the solid obtained by the action of dilute acid (C, 20*5 ; H, 3*1 ; N, 3*5 ; Sb, 50*0 per cent., atomic ratio C : N = 6*91 : 1). The difference in the total nitrogen before and after extraction with alcohol consequently represents the ammonia originally present, removed by the alcohol and volatilised during the evapora¬ tion. Calculated on the basis of the total stibinic acid present, this corresponds to approximately 0 • 36 of a molecular proportion. The residue from the extracts (0*51 g.) contained urea (3*7 per cent, by weight of the original material*) * The statement of Ghosh and others (1928) that “ most of the free urea can be washed out in the cold ” is therefore not correct.