Two syntheses of 2S-[2-2H]-kynurenine

The synthesis of 2S-[2-2H]-kynurenine is described using two different routes. Diacetylation/racemisation of racemic kynurenine in deuterium oxide followed by acylase catalysed resolution is the most direct route. The alternative is to prepare 2S-[2-2H]-tryptophan by a similar procedure and then convert this through to 2S-[2-2H]-kynurenine via ozonolysis.