Abstract: The present invention provides inhibitors of kynureninase having the formula ##STR1## where X is CHOH, S, SO.sub.2, SO, SONH, PO.sub.2 H or PONH.sub.2, R.sub.A and R.sub.B, independently of one another, are H, a halogen, CF.sub.3 or a small alkyl group having one to three carbon atoms; A is a H or an acetyl group; R.sub.1 is H, NH.sub.2, NR.sub.6 R.sub.7, NO.sub.2, halogen, CF.sub.3 or a small alkyl group having from one to three carbon atoms, wherein: R.sub.6 and R.sub.7, independently of one another, are H, a formyl group or a small alkyl group having from one to three carbon atoms with the exception that only one of R.sub.6 or R.sub.7 can be a formyl group; R.sub.2 is OH, H, halogen, CF.sub.3 or a small alkyl group having from one to three carbon atoms; and R.sub.3, R.sub.4 and R.sub.5, independently of one another, are H, halogen, CF.sub.3, NO.sub.2, NH.sub.2, or small alkyl group having from one to three carbon atoms. In particular, compounds of this formula in which X is CHOH, S or SO.sub.

Abstract: The present invention provides inhibitors of kynureninase having the formula ##STR1## where X is CHOH, S, SO.sub.2, SO, SONH.sub.2, PO.sub.2 H or PONH.sub.2, R.sub.a and R.sub.b, independently of one another are H, a halogen, CF.sub.3 or a small alkyl group having one to three carbon atoms; R.sub.1 is H, NH.sub.2, NR.sub.6 RT, NO.sub.2, halogen, CF.sub.3 or a small alkyl group having from one to three carbon atoms, wherein: R.sub.6 and R.sub.7, independently of one another, are H, a formyl group or a small alkyl group having from one to three carbon atoms with the exception that only one of R.sub.6 or R.sub.7 can be a formyl group; R.sub.2 is OH, H, halogen, CF.sub.3 or a small alkyl group having from one to three carbon atoms; and R.sub.3, R.sub.4 and R.sub.5, independently of one another, are H, halogen, CF.sub.3, NO.sub.2, NH.sub.2, or small alkyl group having from one to three carbon atoms. In particular, compounds of this formula in which X is CHOH, S or SO.sub.2 are provided.

Abstract: The present invention provides inhibitors of kynureninase having the formula ##STR1## where R.sub.a and R.sub.b, independently of one another are H, a halogen, CF.sub.3 or a small alkyl group having one to three carbon atoms; R.sub.1 is NH.sub.2, NR.sub.6 R.sub.7, halogen, CF.sub.3 or a small alkyl group having from one to three carbon atoms, wherein R.sub.6 and R.sub.7, independently of one another, are H, a formyl group or a small alkyl group having from one to three carbon atoms with the exception that only one of R.sub.6 or R.sub.7 can be a formyl group; R.sub.2 is OH, H, halogen, CF.sub.3 or a small alkyl group having from one to three carbon atoms; and R.sub.3, R.sub.4 and R.sub.5, independently of one another, are H, halogen, CF.sub.3 or small alkyl group having from one to three carbon atoms. In particular, compounds of formula I having the (.alpha.S,.gamma.S) configuration or (.alpha.R,.gamma.R) configuration when R.sub.A or R.sub.B is a halogen are more potent inhibitors of kynureninase.