Patent GB-701111-A (GB)
Title: Improvements relating to 3-substituted 4-hydroxycoumarins and their application
IPC: C07D311/46
Filed: 1950-11-30
Abstract: The invention comprises compounds of the general formula <FORM:0701111/IV (b)/1> wherein R represents an alkyl or alkenyl radical containing at most 4 carbon atoms, or a phenyl or phenyl-alkyl radical which may be substituted by halogen, methyl, methoxy or nitro groups, R1 represents a halogen or nitro group and R2 represents hydrogen or a halogen or methyl group.  Such compounds are prepared by reacting 4-hydroxycoumarin with styryl ketones of the general formula <FORM:0701111/IV (b)/2> wherein R, R1 and R2 have the above significance. The reaction may be effected by heating a melt of the reactants at about 120 DEG  to 150 DEG  C., or in solution in, e.g. alcohol or water in the presence of a basic condensation catalyst such as pyridine or an alkali metal alcoholate.  The styryl ketones are obtained by reacting substituted benzaldehydes with ketones of the formula CH3COR.  In examples, 3 - [a  - (4 - chlorophenyl) - b  - acetyl - ethyl] - 4 - hydroxycoumarin is produced by reacting 4-hydroxycoumarin with chlorobenzalacetone (1) and (2) in pyridine, (3) in water and (4) as a melt, and purified by recrystallization or reprecipitation with acid from alkaline solution.  In example (5), 3-[a -(41-nitrophenyl)-b -acetyl-ethyl]-4-hydroxycoumarin is prepared by reacting 4-hydroxycoumarin with 4-nitrobenzalacetone.  Similarly prepared are 4-hydroxycoumarins substituted by 3-[a -(41-fluorophenyl)-b -acetyl ethyl]-, 3-[a -(41-chlorophenyl)-b -acrylyl ethyl], 3 - [a  - (41 - chlorophenyl) - b  - benzoyl ethyl], 3 - [a  - (41 - chlorophenyl) - b  - (411 - chlorobenzoyl) - ethyl], 3 - [a  - (41 - chlorophenyl) - b  - phenacetyl ethyl], 3 - [a  - (31 - chlorophenyl) - b  - acetyl ethyl], 3 - [a  - (21 - chlorophenyl) - b  - acetyl ethyl], 3 - [a  - (41 - bromophenyl) - b  - acetyl ethyl], 3 - [a  - (31 - methyl - 41 - chlorophenyl) - b  - acetyl ethyl], 3 - [a  - (31 - nitrophenyl) - b  - acetyl ethyl], 3 - [a  - (31 - nitro - 41 - methylphenyl) - b  - acetyl ethyl], 3 - [a  - 31 - nitro - 41 - chlorophenyl) - b  - acetyl ethyl], 3 - [a  - (41 - chlorophenyl) - b  - (411 - chlorobenzoyl) - ethyl], 3 - [a  - (41 - chloro - 31 - methylphenyl) - b  - acetyl ethyl], and 3 - [a  - (41 - chlorophenyl) - b  - trimethylacetyl ethyl groups.  The crude or purified products are used with lures and diluents as rodenticides (see Group VI). Reference has been directed by the Comptroller to Specification 638,303, [Group VI].ALSO:A rodenticide is characterized by containing compounds of the general formula <FORM:0701111/VI/1> wherein R represents an alkyl or alkenyl radical containing at most 4 carbon atoms or a phenyl or phenyl-alkyl radical which may be substituted by halogen, methyl, methoxy or nitro groups, R1 represents a halogen or a nitro group and R2 represents hydrogen or a halogen or methyl group in combination with carriers or lures.  The compounds may be used in the form of their alkali-metal salts.  Suitable ingredients are grain or synthetic grains containing starch, bread, flour, fat, meat, fish or water.  In dusting powders there may be incorporated inorganic carriers, e.g. talc, bentonite, ground limestone or whiting, or organic carriers, e.g. sawdust and Indian corn.  In an example (6) a rodenticide is prepared by mixing 3-[a-(41-chlorophenyl)-b -acetyl ethyl]-4-hydroxycoumarin with talc.  Instead of talc may be added sugar, synthetic sweet substances, milk power, Indian corn or fish meal to induce the contaminated animals to lick themselves.  A dyestuff may be incorporated.  The compound may also be formed into baits by mixing with corn, flour, fat, or by spreading on bread. Also mentioned are compounds of the above general formula wherein R1 and/or R2 represent fluorine, bromine, chlorine, methyl and nitro groups, and R.CO- represents acrylyl, benzoyl, chlorabenzoyl, phenacetyl, and trimethylacetyl radicals.  The preparation of the compounds is described (see Group IV (b).  Reference has been directed by the Comptroller to Specification 638,303.