The invention comprises compounds of the general formula: <FORM:0809023/IV (b)/1> (wherein B represents a methyl group or a substituted or unsubstituted alkoxy group of not more than 4 carbon atoms, R1 and R2 are the same or different and each represents hydrogen or an alkyl, hydroxyalkyl (including polyhydroxyalkyl) or alkoxyalkyl group of not more than 6 carbon atoms, A represents an unbranched saturated or ethylenically unsaturated hydrocarbon chain of 5 to 9 carbon atoms and R represents a mono- or di-acylamido group) and their acid addition salts, and the preparation thereof by condensing a compound of the formula: <FORM:0809023/IV (b)/2> with a compound of the formula Z2Y, wherein D represents the group B or (where B is alkoxy) a hydroxy or protected hydroxy group, X represents a tertiary amino group or an atom or group capable of being replaced by or converted into a primary, secondary or tertiary amino group, Y represents the group R or an atom or group which may be replaced by or converted into R, and Z1 and Z2 are atoms or groups capable of reacting together to produce the -O-A1- linkage in which A1 represents the group A or a corresponding less saturated hydrocarbon linkage, and if necessary effecting conversion of X, Y, A1 and D to R1R2N, R, A and B. Specific embodiments of X and Y are those enumerated in the parent Specification (with the exception of succinimido for Y). Where B is alkoxy and D is hydroxy or protected hydroxy, the latter may be converted into the former by alkylation (or hydrolysis and alkylation) at any convenient stage. The products may be used in pharmaceutical preparations for the treatment of bilharziasis. In examples: (1) 2-methoxy-4-nitrophenol is refluxed with 5-phthalimidopentyl bromide in 2-ethoxyethanol in the presence of NaOH to produce 1 - (2 - methoxy - 4 - nitrophenoxy) - 5-phthalimidopentane, which is reduced with hydrogen in the presence of Raney nickel in dimethylformamide to 1-(4-amino-2-methoxy-phenoxy)-5-phthalimidopentane similarly prepared are the corresponding 1 : 6-disubstituted hexanes and 1 : 8-disubstituted octanes, and the corresponding n-propoxy compounds (2) 4-nitrocatechol is refluxed with 5-phthalimidopentyl bromide in aqueous ethanolic caustic potash, and the product is methylated with methyl iodide in acetone in the presence of K2CO3 to give the methoxy-nitro compound of (1), which is reduced as in (1) (3) 2-methyl-4-nitrophenol is condensed as in (1) and the product reduced with hydrogen in the presence of platinum oxide in ethanol to 1-(4-amino-2-methylphenoxy) - 5 - phthalimidopentane (4) the product of (1) is refluxed with methyl iodide and Na2CO3 in ethanol, and the resulting quaternary iodide is pyrolysed to 1-(4-dimethylamino - 2 - methoxyphenoxy) - 5 - phthalimidopentane (5) the product of (1) is refluxed with ethylene chlorohydrin and CaCO3 in water to form 1 - (4 - di - b - hydroxyethylamino - 2 - methoxyphenoxy) - 5 - phthalimidopentane (6) the initial condensation product of (1) is refluxed with 60 per cent hydrazine hydrate in ethanol to remove the phthaloyl residue, this is replaced by a benzoyl group by the action of benzoyl chloride in dilute caustic soda, and the product is reduced as in (3) to 1-(4-amino-2-methoxyphenoxy) - 5 - benzamidopentane (7) 2 - methoxymethoxy - 4 - nitrophenol is reacted as in (1) (but using KOH instead of NaOH), and the product is reduced as in (1) to 1 - (4 - amino - 2 - methoxymethoxyphenoxy) - 5 - phthalimidopentane (8) the product of (7) is heated with an aqueous solution of acetic and hydrochloric acids to form 1-(2-hydroxy - 4 - nitrophenoxy) - 5 - phthalimidopentane, which is methylated and reduced as in (2) (9) the product of (1) is refluxed with propylene oxide in aqueous alcoholic hydrochloric acid to produce 1-(4-di-b -hydroxypropylamino - 2 - methoxyphenoxy) - 5 - phthalimidopentane (10) the product of (1) is converted to its salt with methanesulphonic acid. 2 - Methoxymethoxy - 4 - nitrophenol is prepared by alkaline hydrolysis of 1 : 2-di-(methoxymethoxy) - 4 - nitrobenzene, obtained by reacting the sodium derivative of 4-nitrocatechol with methyl chloromethyl ether in dry toluene.ALSO:Pharmaceutical compositions for the treatment of bilharziasis contain one or more compounds of the general formula: <FORM:0809023/VI/1> (wherein B represents a methyl group or a substituted or unsubstituted alkoxy group of not more than 4 carbon atoms, R1 and R2 are the same or different and each represents hydrogen or an alkyl, hydroxyalkyl (including polyhydroxyalkyl) or alkoxyalkyl group of not more than 6 carbon atoms, A represents an unbranched saturated or ethylenically unsaturated hydrocarbon chain of 5 to 9 carbon atoms and R represents a mono- or di-acylamido group, or an acid addition salt thereof, in association with a pharmaceutical carrier, which may be solid or liquid. The compositions may take the form of elixirs, tablets (using excipients such as starch, lactose, talc, stearic acid, magnesium stearate or gums), powders, capsules or other dosage forms suitable for oral ingestion, or mixtures with sterile liquids (e.g. water) for injection.