Naphthoquinone derivatives

Claim 2

Compounds of formula (I) and physiologically acceptable salts thereof wherein either R 1 is hydrogen and R 2 is selected from C 1-6 alkoxy, aralkoxy, C l-6 alkyl-C l-6 alkoxy, phenyl substituted by one or two groups selected from halogen and C 1-6 alkyl, halogen and perhalo-C I-6 alkyl; or R 1 and R 2 are both C 1-6 alkyl or phenyl; and n is 0 or 1.

Claim 3

Compounds as claimed in claim 1 wherein n is 0.

Claim 4

Compounds as claimed in claim 1 wherein n is 1.

Claim 5

Compounds as claimed in any of the preceding claims wherein R 1 is hydrogen and R 2 is tert-butoxy or a phenyl group substituted by one or two groups selected from chlorine and methyl in the 3- and/or 4-position(s).

Claim 6

Compounds as claimed in any of claims 1 to 3 wherein R 1 is hydrogen and R 2 is a phenyl-C 1-6 alkyl group optionally substituted by one or two halogen atoms.

Claim 7

A process for the preparation of compounds of formula (I) and physiologically acceptable salts thereof which comprises:- a) hydrolysing the corresponding 3-X-substituted compound (wherein X represents a group which is hydrolysable to a hydroxy group) or the corresponding 2,3-epoxide; b) oxidising a compound of formula (II) (wherein n, R 1 and R 2 are as hereinbefore defined); c) reacting a compound of formula (III) (wherein Y represents a hydroxy group or a group hydrolysable thereto) with a donor compound providing the R 1- and R 2- substituted-cyclohexyl or cyclohexylmethyl residue wherein R and R 2 are as hereinbefore defined) and (when Y represents a hydrolysable group) hydrolysing the said group to a hydroxy group; d) converting a compound of formula (I) (wherein n is 1) to a corresponding compound of formula (I) (wherein n is 0) by Hooker oxidation; and optionally converting a resulting compound of formula (I) into a physiologically acceptable salt thereof; e) converting a compound of formula (IV) wherein R and R 2 are as hereinbefore defined, to a compound of formula (I) wherein n = 1 by reduction of the oxomethyl group.

Claim 8

A process for the preparation of compounds of formula (I) and physiologically acceptable salts thereof which comprises:- a) hydrolysing the corresponding 3-X-substituted compound (wherein X represents a group which is hydrolysable to a hydroxy group) or the corresponding 2,3-epoxide; b) oxidising a compound of formula (II) (wherein n, R 1 and R 2 are as hereinbefore defined); c) reacting a compound of formula (III) (wherein Y represents a hydroxy group or a group hydrolysable thereto) with a donor compound providing the R 1- and R 2- substituted-cyclohexyl or cyclohexylmethyl residue wherein R and R 2 are as hereinbefore defined) and (when Y represents a hydrolysable group) hydrolysing the said group to a hydroxy group; d) converting a compound of formula (I) (wherein n is 1) to a corresponding compound of formula (I) (wherein n is 0) by Hooker oxidation; and optionally converting a resulting compound of formula (I) into a physiologically acceptable salt thereof; e) converting a compound of formula (IV) wherein R and R 2 are as hereinbefore defined, to a compound of formula (I) wherein n = 1 by reduction of the oxomethyl group.

Claim 9

Therapeutic formulations comprising at least one compound of formula (I) or a physiologically acceptable salt as claimed in any of claims 1 to 5 together with one or more physiologically acceptable carriers therefor.

Claim 10

Compounds of formula (I) as claimed in any of claims 1 to 5 for use as therapeutic agents.

Claim 11

Compounds as claimed in claim 8 for use in the treatment or prophylaxis of a protozoal disease.

Claim 12

Compounds as claimed in claim 9 for use in the treatment or prophylaxis of malaria in man.