Use of cyclic phosphonic acid ester(s)

A method for treating cerebral function disorders and depression comprises administration of cyclic phosphonic acid esters (I). The use of cyclic phosphonic acid esters of formula (I) and their isomers or salts is claimed for treating cerebral function disorders and depression. R1 = 1-6C alkyl optionally substituted by one or more halo; R2= H or 1-6C alkylsulfonyl; or 1-4C alkyl optionally substituted by one or more halo; or (CH2)b-COR1O or CO-NR11R12, b = 0-6; R10 = 1-6C alkyl (optionally substituted by one or more halo) or 1-6C alkoxy; R11, R12 = H, 1-6C alkyl or phenyl; R4-R9 = H or 1-6C alkyl; a = 0-3; R3 = H, CH3, CF3 or ethyl; X = O or S. ORGANIC CHEMISTRY Preparation: (I) are prepared by conversion of compounds of formula (II) to (III)by reaction with PCl3 and water (for X = O) and H2S (for X = S), followed by reaction with aldehydes R1-CHO (IV) or (when R3 is not H) with ketones R1-CO-R3 (IVa), or (when R2 is not H) with compounds of R2'-Z (V)(R2' not defined other than the above restriction of R2), or (if R2 =(CH2)b-COR10) with carboxylic acid anhydrides of formula R2''-O-R2'' (VI)(R2" not defined).Z = halo (especially Cl). PHARMACEUTICALS - Preferred salts of (I) include those of e.g.HCl, HBr, phosphoric acid, sulfuric acid, acetic acid, maleic acid or fumaric acid, or metal (e.g. sodium), ammonium or organic amine salts.Rats were given the test compound as part of the rat forced swimming test (Porsolt et al, Nature 266, 730:732, (1977)). The animals were placed in glass cylinders which were filled with water, and monitored for five minutes to establish the length of time for which they remained immobile. (I) were found to reduce immobility, indicating that they had antidepressant activity. Intravenous dose is 0.001-1 (preferably 0.01-0.5) mg/kg while the oral dose is 0.01-20 (preferably 0.1-10) mg/kg. SPECIFIC SUBSTANCES - The use of twenty compounds is specifically claimed, e.g.1-(1-hydroxy-ethyl)-1-oxo-2,6-dioxa-1-phosphacyclohexane (Ia).