Trifluoroacetic acid → (R)-N5-[amino (nitroimino)-methyl]-N-[2-(4-hydroxyphenyl) ethyl]-ornithinamide trifluoroacetate

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Reaction Steps

To a solution of 0.8 g (1.82 mMol) of (R)-N5 -[amino(nitroimino)methyl]-N2 -(tert.-butoxycarbonyl)-N-[2-(4-hydroxyphenyl)ethyl]-ornithinamide in 20 ml of dichloromethane, externally cooled with crushed ice/ethanol, were added 2.5 ml of trifluoroacetic acid, then the mixture was allowed to come up to ambient temperature and stirred for a further 4 hours at this temperature. The clear solution obtained was evaporated down in a water jet vacuum and combined twice with 10 ml of water and once with 10 ml of toluene and then dried once more. The amorphous (R)-N5 -[amino(nitroimino)-methyl]-N-[2-(4-hydroxyphenyl)ethyl]-ornithinamide-trifluoroacetate obtained (0.61 g, 74% of theory), Rf 0.33 (test conditions as in Example 5d) was further processed without any more purification.

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