Patent GB-974743-A (GB)
Title: New 4-substituted 1,2-diaryl-3,5-dioxopyrazolidines and processes for preparing same
IPC: C07D231/36
Filed: 1961-02-17
Abstract: The invention comprises compounds of formula <FORM:0974743/C1/1> wherein R1 represents hydrogen, an alkyl (1-6C) radical or a halogen atom and X represents SO or SO2, their tautomers, and their salts with inorganic or organic bases: and their preparation by; (1) converting a mercapto compound of formula <FORM:0974743/C1/2> wherein R3 represents an acyl radical which is easily split off or an a -alkoxy-alkyl radical in which the alkoxy groups and the alkyl group can also be bound together to form a ring, by hydrolysis and previous or subsequent oxidation into a compound I, the mercapto compound optionally being prepared by (A) reacting in the presence of an alkaline condensing agent a malonic acid diester of formula <FORM:0974743/C1/3> wherein Y1 represents a hydrocarbon radical, with a hydroxy-hydrazobenzene derivative of formula <FORM:0974743/C1/4> wherein R2 represents an a -alkoxy-alkyl radical in which the alkoxy group and the alkyl group can also be bound together to form a ring and one of the symbols Z1 and Z2 represents hydrogen and the other represents hydrogen or an acyl radical which is easily split off, or (B) reacting in the presence of an acid binding agent a malonic acid derivative of formula <FORM:0974743/C1/5> wherein Y2 represents chlorine, bromine or an acetoxy radical with a hydroxy-hydrazobenzene derivative of formula <FORM:0974743/C1/6> or (C) reacting in the presence of an acid binding agent a malonic acid derivative of formula <FORM:0974743/C1/7> with a hydroxy-hydrazobenzene derivative of Formula III and treating the reaction product so obtained with an alkaline condensing agent; or (2) condensing a substituted malonic acid of formula <FORM:0974743/C1/8> with a hydrazo compound of formula <FORM:0974743/C1/9> wherein R4 represents hydrogen or R3, by means of an N1N1-di-substituted carbodiimide and if necessary hydrolysing the condensation product; or (3) performing the previous condensation (2) with a starting material wherein X is s and oxidising the product; or (4) oxidising a compound of formula <FORM:0974743/C1/100> The description refers also to process (1) (B) performed without an acid binding agent by using as starting materials metal derivatives of compounds V wherein the N-hydrogen atoms have been replaced.  Malonic acid diesters II can be prepared by condensing C-unsubstituted diesters with phenylthioalkyl-halides; hydrolysis, and possibly oxidation, yields the malonic acids VIII and analogous compounds wherein X is S which on treatment with inorganic acid halides or acetic anhydride yield malonic qcid derivatives IV. Hydroxy-hydrazobenzene derivatives III, V and IX are made by reducing hydroxy-azobenzenes, first forming the acetal or acylated derivatives if appropriate.  Pharmaceutical compositions are mentioned comprising compounds I and their salts with bases together with carriers for oral (tablets, powders, capsules), parenteral (solutions) and rectal (suppositories) administration. The compounds have uricosuric, antiphlogistic and analgesic properties.  Specification 974,744 is referred to.