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

Abstract

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.