GB1010743A - Uracil derivatives - Google Patents

Abstract

The invention comprises uracil derivatives of the general formula <FORM:1010743/C2/1> wherein R1 has a molecular weight of 15 to 250 and is a substituted or unsubstituted alkyl, cycloalkyl, cycloalkyl alkyl, cycloalkenyl alkyl, alkenyl, cycloalkenyl, alkynyl, aralkyl or aryl radical in which any substituents are flourine, bromine or chlorine atoms or nitro, cyano, mercapto, hydroxy, alkyl or alkoxy radicals; R2 has a molecular weight of up to 250 and is a hydrogen or halogen atom, a nitro, thiocyano or alkylthio radical or a substituted or unsubstituted alkyl, alkoxy or alkenyl radical, in which any substituents are flourine, bromine or chlorine atoms or cyano, mercapto or hydroxy radicals; R3 has a molecular weight of up to 200 and is a hydrogen, chlorine or bromine atom or an alkyl, haloalkyl or alkoxy radical; or R2 and R3 together form a divalent alkylene bridge of formula (CH2)n, where n is 3, 4 or 5; R4 is a hydrogen atom or a C1 to C5 alkyl group; X is oxygen or sulphur; and A is boron trifluoride or an acid having an ionization constant in water at 25 DEG C. greater than 2 x 10-5 and is a halogenated C2 to C5 aliphatic acid, a halogenated benzoic acid, a halogenated phenylacetic acid, a halogenated phenoxy acetic acid, an organic sulphonic acid, an organic phosphonic acid or an inorganic phosphoric acid. Preferred acids are those of the formula <FORM:1010743/C2/2> W is halogen; Y is halogen, alkyl or haloalkyl and Z is halogen or alkyl, and RSO3H, wherein R is an aliphatic or a substituted or unsubstituted aryl radical. The compounds of the invention may be prepared by mixing, suitably at room temperature, a substituted uracil of the formula <FORM:1010743/C2/3> with an appropriate acid in an inert diluent, preferably a liquid aromatic or halogenated aromatic hydrocarbon which is liquid between 20 DEG and 30 DEG C. The addition compounds are precipitated from the reaction mixture or may be precipitated by the addition of excess non-solvent liquid paraffin or separated by vacuum evaporation at low temperatures, preferably below 50 DEG C. Said addition compounds have herbicidal activity. Specifications 968,661, 968,662, 968,663, 968,664, 968,665 and 968,666 also are referred to.