Abstract: The substituted N-acyl homoserine lactones have the formula (I) wherein R is a saturated or unsaturated straight chain or branched chain aliphatic hydrocarbyl group containing from 5 to 14 carbon atoms; R2 is H or a 1-4C alkyl group; R3 is H or F; and any enantiomer thereof. These compounds exhibit immunosuppressant activity while exhibiting reduced biosensor (autoinducer) activity compared to known N-acyl homoserine lactones.

Abstract: The substituted N-acyl homoserine lactones have the formula (I) wherein R is a saturated or unsaturated straight chain or branched chain aliphatic hydrocarbyl group containing from 5 to 14 carbon atoms; R2 is H or a 1-4C alkyl group; R3 is H or F; and any enantiomer thereof. These compounds exhibit immunosuppressant activity while exhibiting reduced biosensor (autoinducer) activity compared to known N-acyl homoserine lactones.

Abstract: Substituted-4-quinolones of the formula (I): wherein R1 is a straight or branched chain, saturated or ethylenically-unsaturated aliphatic hydrocarbyl group containing 1 to 18 carbon atoms which may optionally be substituted by one or more substituent groups selected from halo, 1-6C alkoxy, carboxy, 1-6C alkoxycarbonyl and NR6R7, wherein each of R6 and R7 is independently selected from H and 1-6C alkyl or R6 and R7 together with the N atom to which they are attached form a saturated heterocyclic group selected from piperidino, piperazino and morpholino; R2 is a group selected from H, —OH, halo, —CHO, —CO2H and CONHR8 wherein R8 is H or a 1-6C alkyl; each of R3, R4 and R5 is independently selected form H, —CH3, —OCH3 and halo; or a non-toxic pharmaceutically-acceptable salt thereof, have use in the manufacture of a medicament for the treatment of a disease of a living animal body, including a human, which disease is responsive to the activity of an immunosuppressant.

Abstract: Substituted-4-quinolones of the formula (I): wherein R1 is a straight or branched chain, saturated or ethylenically-unsaturated aliphatic hydrocarbyl group containing 1 to 18 carbon atoms which may optionally be substituted by one or more substituent groups selected from halo, 1-6C alkoxy, carboxy, 1-6C alkoxycarbonyl and NR6R7, wherein each of R6 and R7 is independently selected from H and 1-6C alkyl or R6 and R7 together with the N atom to which they are attached form a saturated heterocyclic group selected from piperidino, piperazino and morpholino. R2 is a group selected from H, —OH, halo, —CHO, —CO2H and CONHR8 wherein R8 is H or a 1-6C alkyl; each of R3, R4 and R1 is independently selected form H, —CH3, —OCH3 and halo; or a non-toxic pharmaceutically-acceptable salt thereof, have use in the manufacture of a medicament for the treatment of a disease of a living animal body, including a human, which disease is responsive to the activity of an immunosuppressant.

Abstract: New N-acyl homoserine lactone compounds of the formula (I) in whichR is an acyl group of the formula (II) wherein one of R1 and R2 is H and the other is selected from OR4, SR4 and NHR4, wherein R4 is H or 1-6C alkyl, or R1 and R2 together with the carbon atom to which they are joined form a keto group, and R3 containing from 8 to 11 carbon atoms and is optionally substituted by one or more substituent groups selected from halo, 1-6C alkoxy, carboxy, 1-6C alkoxycarbonyl, carbamoyl optionally mono- or disubstituted at the N atom by 1-6C alkyl and NR5R6 wherein each of R5 and R6 is selected from H and 1-6C alkyl or R5 and R6 together with the N atom form a morpholino or piperazino group, or and enantiomer thereof, with the proviso that R is not a 3-oxododecanoyl group, having immuosuppressant properties are disclosed. The compounds are shown to have an inhibitory effect on lymphocyte proliferation and down-regulate TNF-&agr; secretion by monocytes/macrophages in the animal body, including the human body.