Patent GB-1099691-A (GB)
Title: Heterocyclic carbonates and thiocarbamates and their use as insecticides and nematocides
IPC: C07D307/86
Filed: 1965-01-22
Abstract: Novel carbamates and thiocarbamates of the formula <FORM:1099691/C2/1> <FORM:1099691/C2/2> wherein R1, R2, R3, R4, R5 and R6 are hydrogen or an aliphatic group of 1 to 3 carbon atoms, X is oxygen or sulphur, n is 0 or an integer of 1 to 3 and each Y is the same or different and is a lower aliphatic group of 1 to 3 carbon atoms, halogen or a haloalkyl, nitro, amino, substituted amino, alkoxycarbonyl, acyl, cyano, alkylmercapto, alkoxy or carbamate group, with the proviso that when R3 and R4 are hydrogen and R1 is methyl R2 is not hydrogen, are prepared by esterification of the appropriate 2,3-dihydrobenzofuranols or by hydrogenation of the corresponding benzofuranyl carbamates.  The esterification may be effected by reacting the dihydrobenzofuranol with an isocyanate or a carbamic acid derivative or by reacting it with phosgene or thiophosgene and reacting the benzofuranyl chloroformate or chlorothioformate produced with ammonia or an amine.  The dihydrobenzofuranol used may be prepared by rearrangement and cyclization of an allyloxyphenol, which may be obtained by reacting a dihydroxybenzene with an allyl halide or by reacting a hydroxyphenylacetic acid with a Grignard reagent, or by decarboxylating a corresponding dihydrobenzofuran carboxylic acid, and the benzofuranyl carbamate used may be obtained by decarboxylating a hydroxybenzofuran carboxylic acid and esterifying the benzofuranol produced.  The compounds of the above formula have insecticidal properties (see Division A5). 4 - Hydroxy - 2,3 - dihydro - 2,2 - dimethyl - 5 -benzofuran carboxylic acid is prepared by reacting methyl-b -resorcylate with 3-chloro-2-methyl propene, rearranging and cyclizing the methyl - 4 - [(2 - methylallyl)oxy]salicylate produced to give methyl 4-hydroxy-2,3-dihydro-2,2-dimethyl 5 - benzofuran carboxylate which is then hydrolysed; 7-hydroxy-2-benzofuran carboxylic acid is prepared by reacting 2-hydroxy-m-anisaldehyde with ethyl bromoacetate and sodium in ethanol and hydrolysing the 7-methoxy - 2 - benzofuran carboxylic acid produced; and the 4-chloro- and 5-chloro-2,3-dihydro-2,2-dimethyl-7 -benzofuranols are prepared reacting 2,3-dihydro-2,2-dimethyl-7-benzofuranol with sulphuryl chloride.ALSO:A pesticidal composition comprises an extender and an effective amount of a carbamate or thiocarbamate of the formula: <FORM:1099691/A5-A6/1> and <FORM:1099691/A5-A6/2> where R1, R2, R3, R4, R5 and R6 are hydrogen or a C1-C3 aliphatic group, X is oxygen or sulphur, n is O or an integer from 1 to 3 and each Y is the same or different and is halogen or a C1-C3 aliphatic, haloalkyl, nitro, amino, substituted amino, alkoxycarbonyl, acyl, cyano, alkylmercapto, alkoxy, or carbamate group, provided that, when R3 and R4 are hydrogen and R1 is methyl, R2 is not hydrogen.  The composition may be in the form of a powdery dust, a wettable powder, an emulsifiable concentrate, granules or a solution and it may be applied by spraying, e.g. by means of an aerosol.  Many solid and liquid carriers and emulsifying agents are specified.