Patent GB-864925-A (GB)
Title: Novel compounds of the lactone type
IPC: C07D311/94
Filed: 1959-06-18
Abstract: The invention comprises saturated and unsaturated bicyclic lactones of formula:  <FORM:0864925/IV (b)/1> wherein Z represents a hydrocarbon group or a substituted p  hydrocarbon group which, with the two carbon atoms to which it is linked, completes a non-aromatic carbocyclic ring; n is 0 or 1, and when n is 0:-Z does not complete a saturated six-membered ring, R1 and R2 are hydrogen or alkyl, R3 and R4 are hydrogen, and when n is 1:- R1 is hydrogen or alkyl, R1 and R2 are hydrogen or alkyl, R3 and R4 are hydrogen, or R3 and R4 together form a bond between their respective carbon atoms, or R2 and R4 together form a bond between their respective carbon atoms.  A disclaimer is present for natural iridomyrmecin, for synthetic products having an identical structure and for iso-iridomyrmecin. The compounds of the invention are prepared by (1) reacting a non-aromatic carbocyclic ketone in which the carbon atom of the carbonyl group forms part of the ring with an ester of an alpha-halogenated saturated carboxylic acid of formula: <FORM:0864925/IV (b)/2> Hlg being preferably chlorine or, more preferably, bromine, in the presence of a metallic halogen acceptor such as zinc, preferably in a solvent, followed by the addition of water, preferably with an acid, to give a hydroxy ester, the formula of which may formally be derived from the cyclic ketone by substituting:  <FORM:0864925/IV (b)/3> for the carbonyl group; (2) dehydrating the hydroxy ester to form an unsaturated ester, e.g. with H2SO4, KHSO4 or POCl3; (3) hydrolysing the unsaturated ester to form the free acid in acid or alkaline medium, e.g. KOH in aqueous ethanol; (4) treating the unsaturated acid with an agent to effect ring closure to produce the bicyclic lactone, an aldehyde R1CHO being present when n in the product is 1; the specified ring closure agent is H2SO4 in water or glacial acetic acid; (5) if desired hydrogenating the unsaturated lactone obtained in step (4) when an adlehyde is present.  Intermediates prepared in Examples are: as products of step (1) above; ethyl-a -(1-hydroxy-cyclohexyl) propionate, ethyl a -(1-hydroxycyclopentyl) propionate, ethyl a -(1-3-methyl-cyclopentyl) propionate, ethyl (1-hydroxycyclohexyl) acetate, ethyl a -(1-hydroxy-4-methylcyclohexyl) propionate, ethyl a -(1-hydroxy-3-methylcyclo-hexyl) propionate, ethyl a -(1-hydroxycyclopentyl) isobutyrate, ethyl a -(1-hydroxycyclohexyl) isobutyrate, and ethyl a -(1-hydroxycycloheptyl) isobutyrate; as products of steps (2) and (3) above, the ethyl esters of the following acids and the free acids themselves:- a -(cyclohexene-1-yl) propionic, a -(-cyclopentene-1-yl) propionic, a -(4-methylcyclopentene-1-yl) propionic, a -(3-methylcyclopentene-1-yl) propionic, a -(3-methylcyclopentylidene) propionic, cyclohexene-1-yl acetic, a -(4-methylcyclohexene-1-yl) propionic, a -(3-methylclohexene-1-yl) propionic, a -(5-methylcyclohexene-1-yl) propionic, a -(cyclopentene-1-yl) isobutyric, a -(cyclohexene-1-yl) isobutyric, and a -(cycloheptene-1-yl) isobutyric.  Specification 715,546 is referred to.ALSO:Insecticidal compositions comprise a saturated or unsaturated bicyclic lactone of formula <FORM:0864925/VI/1> wherein Z represents a hydrocarbon group or a substituted hydrocarbon group which, with the two carbon atoms to which it is linked, completes a non-aromatic carbocyclic ring; n is 0 or 1, and when n is 0:- Z does not complete a saturated 6-membered ring, R1 and R2 are hydrogen or alkyl, R3 and R4 are hydrogen, and when n is 1:- R1 is hydrogen or alkyl, R1 and R2 are hydrogen or alkyl, R3 and R4 are hydrogen, or R3 and R4 or R2 and R4 together form a bond between their respective carbon atoms. Compositions comprising natural iridomyrmecin, synthetic products of identical structure and isoiridomyrmecin are disclaimed.  Solid or liquid carriers may be used and adjuvants such as spreading or wetting agents may be present, e.g. fatty acid soaps, rosin salts, saponins, gelatin, casein, long-chain fatty alcohols, alkyl aryl sulphonates, long-chain alkyl sulphonates, phenolethylene oxide condensates, C12-20 amines and ammonium salts.  Other insecticides may be present, e.g. pyrethrum, rotenone, sobadilla, DDT, benzene hexachloride, aldrin, dieldrin, endrin, thiophenylamine, cyanides, tetraethyl phosphate, diethyl p-nitrophenyl thiophosphate, azobenzene and compounds of arsenic, lead and/or fluorine.  Specification 715,546 is referred to.