Sapiro, M.L.De Kock, G.v.d.W.2017-02-062017-02-0620171950Sapiro, ML 1950, 'Studies on the photosensitisation of animals in South Africa. XII. An attempt to identify the icterogenic factor in geeldikkop; the reaction of nitrous acid on chlorophyll’, Onderstepoort Journal of Veterinary Science and Animal Industry, vol. 24, no. 1-2, pp. 105-118.0330-2465http://hdl.handle.net/2263/58881The articles have been scanned in colour with a HP Scanjet 5590; 300dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.1. The reaction of nitrous acid on chlorophyll yielded four compounds, denoted for convenience as A, B, C and D. 2. The compounds are all distinctive in appearance, are highly coloured and three of them have sharp melting points. 3. A convenient process of separation of the compounds and easy methods for the purification of A, B and C have been found. 4. A, B, and C all appear to be tetra-substituted pyrrole derivatives. A and B each exhibit tautomerism, probably of the nitroso-isonitroso type, whereas C appears to have only one form. 5. A and B form mono-acetyl derivatives, but C yields no derivatives of this type. 6. Formulae have been tentatively proposed as follows: A (Molecular formula): C₁₄ H₁₃ N₃ O₃ B (Molecular formula): C₁₄ H₁₆ N₂ O. C (Empirical formula): C₁₃ H₁₀ N O or C₁₃ H₁₁ N O. 7. None of the compounds exhibited icterogenic or photosensitising properties when administered to sheep, either by subcutaneous injection or by oral administration.en© 1950 ARC - Onderstepoort and Faculty of Veterinary Science, University of Pretoria (original). © 2017 University of Pretoria. Dept. of Library Services (digital).Veterinary medicineVeterinary medicine -- South AfricaArticle