Abstract: Compounds of formula (I): [in which: X is a group of formula >CR1R2 or >SO2; Y is a group of formula >NH or >CR1R2; Z is a group of formula >C?O or >CH2 or a direct bond; R1 is hydrogen and R2 is hydrogen, carboxy or hydroxy; or R1 and R2 together represent an oxo group, a methylenedioxy group or a hydroxyimino group; R3 is hydrogen or lower alkyl; R4 represents two hydrogen atoms, or an oxo or hydroxyimino group; R5 is hydrogen, lower alkyl or halogen; R6 is hydrogen, lower alkoxy or carboxy; R7 and R8 are each hydrogen, lower alkyl or halogen; and pharmaceutically acceptable salts and esters thereof can be used for the treatment or prophylaxis of acute or chronic neurodegenerative diseases or conditions such as Alzheimer's Disease, Parkinson's Disease, Huntington's Chorea, Multiple Sclerosis or the sequelae to acute ischaemic events such as heart attack, stroke or head injury and for protection against ischaemic damage to tissues of peripheral organs.

Abstract: Compounds of formula (I): [in which: X is a group of formula >CR1R2 or >SO2; Y is a group of formula >NH or >CR1R2; Z is a group of formula >C?O or >CH2 or a direct bond; R1 is hydrogen and R2 is hydrogen, carboxy or hydroxy; or R1 and R2 together represent an oxo group, a methylenedioxy group or a hydroxyimino group; R3 is hydrogen or lower alkyl; R4 represents two hydrogen atoms, or an oxo or hydroxyimino group; R5 is hydrogen, lower alkyl or halogen; R6 is hydrogen, lower alkoxy or carboxy; R7 and R8 are each hydrogen, lower alkyl or halogen; and pharmaceutically acceptable salts and esters thereof can be used for the treatment or prophylaxis of acute or chronic neurodegenerative diseases or conditions such as Alzheimer's Disease, Parkinson's Disease, Huntington's Chorea, Multiple Sclerosis or the sequelae to acute ischaemic events such as heart attack, stroke or head injury and for protection against ischaemic damage to tissues of peripheral organs.

Abstract: The present invention relates to the preparation of substantially pure diastereoisomers of derivatives of tetrahydrofolate and the use of such diastereoisomers. More particularly the present invention provides a process for the preparation of a desired substantially pure (6R or 6S) diastereoisomer of a derivative of tetrahydrofolic acid or salt or ester. The process comprises the steps of: attaching a chiral auxiliary group at either N-5 or N-10 of a mixture of 6R and 6S diastereoisomers of tetrahydrofolic acid, separating the new diastereoisomers, recovering the desired new diastereoisomer (6R or 6S) corresponding to the desired (6R or 6S) diastereoisomer, and converting the substantially pure new diastereoisomer recovered into the corresponding diastereoisomer.

Abstract: The present invention related to the preparation of substantially pure diastereoisomers of derivatives of tetrahydrofolate and the use of such diastereoisomers. More particularly the present invention provides a process for the preparation of a desired substantially pure (6R or 6S) diastereoisomer of a derivative of tetrahydrofolic acid or salt or ester. The process comprises the steps of: attaching a chiral auxiliary group at either N-5 or N-10 of a mixture of 6R and 6S diastereoisomers of tetrahydrofolic acid, separating the new diastereoisomers, recovering the desired new diastereoisomer (6R or 6S) corresponding to the desired (6R or 6S) diastereoisomer, and converting the substantially pure new diastereoisomer recovered into the corresponding diastereoisomer.

Abstract: The present invention relates to the preparation of substantially pure diastereoisomers of derivatives of tetrahydrofolate and the use of such diastereoisomers. More particularly the present invention provides a process for the preparation of a desired substantially pure (6R or 6S) diastereoisomer of a derivative of tetrahydrofolic acid or salt or ester. The process comprises the steps of: attaching a chiral auxiliary group at either N-5 or N-10 of a mixture of 6R and 6S diastereoisomers of tetrahydrofolic acid, separating the new diastereoisomers, recovering the desired new diastereoisomer (6R or 6S) corresponding to the desired (6R or 6S) diastereoisomer, and converting the substantially pure new diastereoisomer recovered into the corresponding diastereoisomer.