Patent GB-991821-A (GB)
Title: New herbicidal lactams
IPC: C07D211/76
Filed: 1962-12-19
Abstract: Novel lactams, of the formula <FORM:0991821/C1/1> wherein R is hydrogen or methyl, providing that one R is methyl; X is chlorine, methyl, methoxy, or methylthio, providing that when one X is methoxy or methylthio, the other is chlorine; and n is one or two, are incorporated in compositions with a carrier, which may be a fertilizer, for use as pre- or post-emergence herbicides or selective herbicides for control of weeds in crop-producing plants (see Division A5).  The compositions containing fertilizers are in granular or powder form, suitable fertilizers being ammonium sulphate, nitrate, or phosphate; potassium chloride or bromide, a calcium phosphate, or urea.  For example the lactam may be melted, or dissolved in acetone, and the resulting liquid admixed with prilled urea and then appropriately cooled or dried. Crops to which the compositions may be suitably applied as a pre- or post-emergence selective herbicide are carrots, cotton, peanuts, potatoes, rice, corn, Sudan grass and sugar cane, and as a pre-emergence herbicide, are alfalfa, barley, cow peas, oats, peas, rye, safflower, lima-, snap- and soy-beans, sorghum, tomatoes, and wheat.  For selective action, the lactam compositions are applied at a level below that which is phytotoxic to the crop plant.  Growth stimulatory effect was observed when the lactam compositions alone, with no added fertilizer, was applied as a pre-emergence treatment for corn.ALSO:The invention comprises compounds of the general formula <FORM:0991821/C2/1> wherein each R represents hydrogen or methyl, providing that one R at least is methyl; X represents chlorine, methyl, methoxy, or methylthio, with the proviso that if one X is methoxy or methylthio, the other X is chlorine; and n is/or 2 the compounds are prepared by reacting an appropriate aniline and appropriate lactone, at a temperature of about 100 DEG  to 250 DEG C. in the presence of an acid catalyst, for example: hydrochloric acid, hydrobromic acid, arenesulphonic acids, sulphuric acid, zinc chloride, formic acid, boron trifluoride, and mixtures of acidic substances such as sulphuric acid, arenesulphonic acid mixtures.  The compounds are intended for use as selective weedicides (see Division A5), and growth promoters (see Division C1).  In examples, 1,3,4 and 9, 1 - (3,4 - dichlorophenyl)-, 1 - (3 - chloro - 4-methyl phenyl)-, or 1-(3-chloro-4-methoxy phenyl) - 3 - methyl - 2 - pyrridinone, are prepared. Examples 5 and 6 give preparation of 1 - (3,4 - dichlorophenyl)- and 1 - (3 - chloro-4 - methyl phenyl) - 5 - methyl - 2 - pyrrolidinone and Examples 7 and 8 relate to 1-(3,4-dichlorophenyl) - 3,5 - dimethyl - 2 - pyrrolidinone and 1 - (3,4 - dichlorophenyl) - 3 -methyl - 2 - piperidinone, respectively. Numerous other pyrrolidinone and piperidinone derivatives of the invention are also listed.  Comparative experiments describe preparation, by the same methods, of 1-(2,5-dichlorophenyl)-3 - methyl - 2 - pyrrolidinone, 1 - (3,5 - dichlorophenyl) - 3 - methyl - 2 - pyrrolidinone, 1 - (3,5 - dichlorophenyl) - 3 - methyl - 2 - pyrrolidinone; 1 - (4 - bromophenyl) - 3 - methyl - 2 - pyrrolidinone, and 1-(3,4-dichlorophenyl)-2-pyrrolidinone. Lactone starting materials are prepared by (1) reacting ethyl-2-methyl-acetoacetate and ethylene oxide to give 3-methyl-butyrolactone; (2) reacting diethyl methyl malonate with 1-bromo-3-chloro-propane to give diethyl-a -methyl-a -3-chloro propyl malonate; this is then heated with sulphuric acid to give a -methyl-d -valerolactone.  2-Chloro-4-amino anisole is prepared by reacting 3,4-dichloronitrobenzene with sodium methoxide to give 2-chloro-4-nitro-anisole, which is then reduced with tin and hydrochloric acid.ALSO:Herbicidal lactam compositions for the control of weeds in pre- and post-emergence application to crop plants, comprise the novel lactams of formula <FORM:0991821/A5-A6/1> wherein each R is hydrogen or methyl, providing at least one of R is methyl; X is chlorine, methyl, methoxy, or methylthio, providing that if one X is methoxy or methylthio, the other X is chlorine; and n is 1 or 2, together with a conventional diluent or carrier.  The compositions may be in the form of a liquid or solid concentrate for dilution before us; e.g. emulsifiable concentrates or wettable powders, or alternatively may be put up ready for use as, e.g. dusts or granules. The carriers may be inert, or may contain other active ingredients, such as fertilizers (see Division C1), activators, synergists, adhesives, surfactants, or insecticides, fungicides, or other herbicides.  For selective herbicidal action, the compositions are applied at dosage rates that are below the phytotoxic level for the crop to be treated.