Patent GB-807682-A (GB)
Title: Production of new phosphate and thiophosphate esters containing a heterocyclic nitrogen ring
IPC: A01N57/16
Filed: 1956-03-14
Abstract: The invention comprises O,O-dialkyl O-(6-pyridazon-3-yl) phosphates and thiophosphates having the general formula <FORM:0807682/IV (b)/1> in which R and R1 are lower alkyl groups having from 1 to 4 carbon atoms, e.g. methyl, ethyl, propyl and butyl, X is sulphur or oxygen, Y and Y1 are hydrogen or halogen atoms and Z is phenyl, nitrophenyl, bromophenyl, chlorophenyl, or an alkyl group having from 1 to 12 carbon atoms.  The compounds may be obtained by reacting a dialkyl phosphoric or thiophosphoric chloride of the formula (RO)(R1O)P (X)Cl with an alkali metal or alkaline earth metal derivative of the corresponding oxypyridazone or with the corresponding hydroxypyridazone in which case the reaction is carried out in the present of a hydrogen chloride acceptor such as an alkali metal carbonate or an alkaline earth metal carbonate.  The reaction may be carried out at between 10 DEG  and 100 DEG  C. and is carried out in each case in the presence of an inert solvent, e.g. water, dimethyl formamide, dimethyl sulphoxide, dioxane, acetonitrile, benzene, toluene, xylene, a C1-C5 aliphatic monohydric alcohol, a ketone e.g. acetone, methyl ethyl ketone, methyl isobutyl ketone, methyl benzyl ketone, and cyclohexanone, or an aliphatic ester, e.g. ethyl acetate, 2-ethylhexyl acetate, methyl propionate- or ethyl- or isopropyl-butyrate.  Examples are given for the preparation of O,O-diethyl O-(1-phenyl-6-pyridazon - 3 - yl) phosphate and thiophosphate, O,O - dimethyl O - (1 - phenyl - 6-pyridazon - 3 - yl) thiophosphate, O,O - diethyl O - (1 - methyl (or dodecyl) - 6 - pyridazon - 3-yl) thiophosphate, O,O - diisopropyl O - (1-methyl - 6 - pyridazon - 3 - yl) thiophosphate, O,O - diethyl O - (1 - methyl 4,5 - dibromo - 6-pyridazon - 3 - yl) thiophosphate, O,O - diethyl O - (1 - phenyl - 4 (or 5) chloro - 6-pyridazon - 3 - yl) thiophosphate, O,O - diethyl O - (1 - p - bromophenyl - 6 - pyridazon - 3-yl) thiophosphate and O,O - dibutyl O - (1 - p-nitrophenyl - 6 - pyridazon - 3 - yl) phosphate.  The products are stated to be useful as pesticides (see Group VI).  The hydroxypyridazones used as starting materials may be obtained by reacting maleic anhydride or a substituted maleic anhydride with monosubstituted hydrazines or mineral acid salts thereof either in an aqueous medium or in a solvent such as alcohol or glacial acetic acid.  Thus 3-hydroxy-1-methyl-6-pyridazone may be obtained by reacting maleic anhydride with methylhydrazine sulphate.  The alkali metal salts of the hydroxypyridazones may be obtained by reacting the hydroxypyridazone with an alkali metal hydroxide in water followed by precipitation with acetone.ALSO:A pesticidal composition comprises as the active ingredient an O,O-dialkyl O-(6-pyridazon-3-yl) phosphate or thiophosphate having the formula <FORM:0807682/VI/1> in which R and R1 are lower alkyl groups having from 1 to 4 carbon atoms, X is oxygen or sulphur, Y and Y1 are hydrogen or halogen atoms and Z is phenyl, nitrophenyl, bromophenyl, chlorophenyl, or an alkyl group having from 1 to 12 carbon atoms (see Group IV (b)).  The compounds may be used as sprays in organic solvents, as emulsions in water or other non-solvents, or they may be on solid carriers such as clays, talcs or diatomaceous earths.  Specified compounds are: (1) and (2) O,O-diethyl O - (1 - phenyl - 6 - pyridazon - 3 - yl)-phosphate and thiophosphate; (3) O,O-dimethyl O - (1 - phenyl - 6 - pyridazon - 3 - yl)-thiophosphate; (4) and (5) O,O-diethyl O-(1-methyl (or dodecyl)-6-pyridazon-3-yl) thiophosphate; (6) O,O - diisopropyl O - (1 - methyl - 6 - pyridazon - 3 - yl) - thiophosphate; (7) O,O-diethyl O - (1 - methyl - 4,5 - dibromo - 6 - pyridazone - 3 - yl) - thiophosphate; (8) and (9) O,O - diethyl O - (1 - phenyl - 4 - (or 5 -) chloro-6 - pyridazon - 3 - yl) - thiophosphate; (10) O,O - diethyl O - (1 - p - bromophenyl - 6 - pyridazon - 3 - yl) - thiophosphate; and (11) O,O-dibutyl O - (1 - p - nitrophenyl - 6 - pyridazon - 3-yl) phosphate.  Specified pesticidal compositions are (a) 0.01 and 0.1 per cent solutions of compounds (1), (2), (4), (6) and (10) in a solvent carrier comprising 65 per cent acetone and 35 per cent water; and (b) products (1), (2), (4), (6) and (10) on solid carriers such as pyrophyllite, attapulgus clay, talc and fuller's earth.