Patent GB-775360-A (GB)
Title: Improvements in or relating to polyoxygenated cyclic compounds
IPC: C07F1/00
Filed: 1954-02-22
Abstract: The invention comprises compounds of the formula: <FORM:0775360/IV(b)/1> wherein R is an alkyl group having up to six carbon atoms, an ethylene group attached to the 3-position of the saturated ring and to the carbon atom in question, e.g. as in compounds of the formula: <FORM:0775360/IV(b)/2> or R is hydrogen, R1 is hydrogen or an alkyl group having up to six carbon atoms in its chain and R11 is hydrogen or an alkyl group having up to six carbon atoms, or an alkylene group may take the place of the two groups R and R1, e.g. in compounds of the formula: <FORM:0775360/IV(b)/3> R111 is hydrogen, an alkyl group or an acyl group of a carboxylic acid. An ester, ether or hydroxyl function may be adjacent to the keto group in the acyl side chain.  2-Acyl tetralones having a hydroxyl, ether or ester function in the 8-position are prepared by a process which comprises reacting a tetralone having a hydroxyl, ether or ester function in the 8-position with a carboxylic ester in the presence of an alkalimetal-containing condensing agent such as sodium metal, sodium alkoxide or sodamide.  An excess of the ester acylating agent may be used as solvent rather than an inert solvent such as an aromatic hydrocarbon or an ether.  Alternatively the acylation may be carried out with a carboxylic acid anhydride in the presence of boron trifluoride, e.g. 2-(2-carboxycyclohexene) 8-ethoxy tetralone is prepared by condensing 1,2,3,6-tetrahydrophthalic anhydride with -8 ethoxy tetralone. The aromatic ring of the tetralone may bear one or more halogen atoms, e.g. at either or both of the 5 and 7 positions and alternatively or in addition the tetralone may bear 4-hydroxy and 4-methyl substituents.  Ester acylating agents specified include cycloalkane carboxylic acid esters, e.g. cyclohexene and cyclohexane carboxylic esters, ethyl and phenyl acetates and phenyl propionate. The compound of the formula: <FORM:0775360/IV(b)/4> is formed when a cyclohexane carboxylic acid ester is employed as the acylating agent and the aromatic ring may bear one or more halogens and the saturated ring of the tetralone may bear a methyl and a hydroxyl group at the 4-position.  An intramolecular condensation of an ester of 8-hydroxy tetralone 3-(g -butyric acid), e.g. the methyl ester, in the presence of an alkali metal containing condensing agent may be employed to form 1,2,3,4,9,10-hexahydroanthradione-4,10.  The aromatic ring may be substituted by one or more halogens or other substituents and the tetralone ring may have 4-methyl and 4-hydroxyl substituents and the position adjacent to the carbonyl group of the butyryl side chain may be substituted with R1 and R11 group defined above.  If a benzyls ether is used as starting material the benzyl group may be removed by selective hydrogenation without reduction of the keto groups. Polyvalent metallic salt complexes of the acylated tetralones are prepared by contacting the tetralones with the metallic salts in a suitable solvent, e.g. in aqueous media or organic solvents such as lower alcohols.  In examples: 2-acetyl-8-hydroxy tetralone is prepared by heating a mixture of 8-hydroxy tetralone, ethyl acetate and sodium, the reaction mixture is acidified with acetic acid, the product is extracted with ether, neutralized and the copper chelate formed by the treatment of the ether solution with copper acetate in methanol, the free 2-acetyl-8-hydroxy tetralone is obtained by acidification with sulphuric acid and the nickel chelate formed from it; 5-bromo-3,8-dimethoxy tetralone is similarly reacted to obtain 2-acetyl5-bromo-7,8-dimethoxy-tetralone (I); the copper chelate is prepared from 2-acetyl-8-hydroxytetralone and copper acetate in methanol solution (II); 2-acetyl-8-benzyl oxytetralone is prepared from 8-benzyloxy-tetralone and phenyl acetate by a similar process to (I) and purified, forming the copper complex intermediately (III); 2-propionyl-4-hydroxy-8-methoxy-4-methyl tetralone is prepared from 4-hydroxy-8-methoxy-4-methyl tetralone and phenyl propionate by a process similar to (I); the formation of complex compounds with polyvalent metals, e.g. copper, is mentioned (IV); 2-cyclohexane carboxyl-8-ethoxytetralone is prepared from 8-ethoxy tetralone and ethyl cyclohexane carboxylate by a process similar to (I) and the formation of chelate compounds with polyvalent metals is mentioned (II).