GB941046A - Improvements in or relating to fungicides - Google Patents

Abstract

Compounds of the general formula: <FORM:0941046/C2/1> where R is an alkyl group and R1 is a hydrogen atom or an alkyl group, may be prepared by the cyclisation of naphthoquinone-(1,4) derivatives substituted by nitrogen-containing, oxygen-containing or sulphur-containing groups. For example, 4-ethyl-2, 3, 5, 10-tetrahydro-3, 5, 10-trioxo - naphthalinio [2, 3-b] 1, 4-thiazine is obtained from 2-carboxy-methylthio-3-ethyl-amino-naphthoquinone-(1 4). In an example the 4-methylthiazine compound is produced by reacting 2, 3-dichloro naphthoquinone with methylamine to produce 2-chloro-3 methylamine naphthoquinone which is treated with sodium sulphide and the resulting solution of 2-mercapto-3 methyl amino naphthoquinone is reacted with chloracetic acid and mixed with hydrochloric acid to precipitate 2-carboxy methyl thio-3 methyl amino naphthoquinine which is suspended in glazial acetic acid and heated to produce the required 4-methyl thiazine compound.ALSO:A fungicidal composition comprises as active ingredient one or more compounds of the general formula <FORM:0941046/A5-A6/1> where R is a hydrogen atom, an alkyl group or a cycloalkyl group and R1 is a hydrogen atom or an alkyl group, and an inert carrier therefor. The composition may be in the form of solutions, suspensions, emulsions or dusting agents e.g. with talc, kaolin or calcium silicate and may include a wetting agent such as alkylaryl sulphonates, or alkylbenzene polyoxyethylene adducts and sulphosuccinic acid esters and other fungicides and pest control agents. Specified active ingredients are 2,3,5,10-tetrahydro-3,5,10-trioxo-naphthalino [2,3-b] 1,4-thiazine, 4 - ethyl - 2,3,5,10 - tetrahydro - 3,5,10 - trioxo-naphthalino [2,3-b] 1,4-thiazine, 4-methyl-2,3, 5,10 - tetrahydro - 3,5,10 - trioxo - naphthalino [2,3-b] 1,4-thiazine.