Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07D—HETEROCYCLIC COMPOUNDS
  • C07D401/00—Heterocyclic compounds containing two or more hetero rings, having nitrogen atoms as the only ring hetero atoms, at least one ring being a six-membered ring with only one nitrogen atom
  • C07D401/02—Heterocyclic compounds containing two or more hetero rings, having nitrogen atoms as the only ring hetero atoms, at least one ring being a six-membered ring with only one nitrogen atom containing two hetero rings
  • C07D401/04—Heterocyclic compounds containing two or more hetero rings, having nitrogen atoms as the only ring hetero atoms, at least one ring being a six-membered ring with only one nitrogen atom containing two hetero rings directly linked by a ring-member-to-ring-member bond
• • A—HUMAN NECESSITIES
  • A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
  • A01N—PRESERVATION OF BODIES OF HUMANS OR ANIMALS OR PLANTS OR PARTS THEREOF; BIOCIDES, e.g. AS DISINFECTANTS, AS PESTICIDES OR AS HERBICIDES; PEST REPELLANTS OR ATTRACTANTS; PLANT GROWTH REGULATORS
  • A01N43/00—Biocides, pest repellants or attractants, or plant growth regulators containing heterocyclic compounds
  • A01N43/48—Biocides, pest repellants or attractants, or plant growth regulators containing heterocyclic compounds having rings with two nitrogen atoms as the only ring hetero atoms
  • A01N43/56—1,2-Diazoles; Hydrogenated 1,2-diazoles
• • A—HUMAN NECESSITIES
  • A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
  • A01N—PRESERVATION OF BODIES OF HUMANS OR ANIMALS OR PLANTS OR PARTS THEREOF; BIOCIDES, e.g. AS DISINFECTANTS, AS PESTICIDES OR AS HERBICIDES; PEST REPELLANTS OR ATTRACTANTS; PLANT GROWTH REGULATORS
  • A01N47/00—Biocides, pest repellants or attractants, or plant growth regulators containing organic compounds containing a carbon atom not being member of a ring and having no bond to a carbon or hydrogen atom, e.g. derivatives of carbonic acid
  • A01N47/40—Biocides, pest repellants or attractants, or plant growth regulators containing organic compounds containing a carbon atom not being member of a ring and having no bond to a carbon or hydrogen atom, e.g. derivatives of carbonic acid the carbon atom having a double or triple bond to nitrogen, e.g. cyanates, cyanamides

Definitions

• This application relates to efficient and economical synthetic chemical processes for the preparation of pesticidal thioethers and pesticidal sulfoxides. Further, the present application relates to certain novel compounds necessary for their synthesis. It would be advantageous to produce pesticidal thioether and pesticidal sulfoxides efficiently and in high yield from commercially available starting materials.
• alkyl denotes branched or unbranched hydrocarbon chains.
• alkynyl denotes branched or unbranched hydrocarbon chains having at least one C ⁇ C.
• cycloalkyl as employed herein alone is a saturated cyclic hydrocarbon group, such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl.
• thio as used herein as part of another group refers to a sulfur atom serving as a linker between two groups.
• halogen or "halo” as used herein alone or as part of another group refers to chlorine, bromine, fluorine, and iodine.
• R 1 is selected from the group consisting of Ci-C 4 -haloalkyl and Ci-C4-alkyl-C3- C6-halocycloalkyl, and
• R 2 is selected from the group consisting of C 1 -C 4 -alkyl and C 2 -C 4 -alkynyl can be prepared by the methods illustrated in Schemes 1 to 9.
• step a of Scheme 1 3-hydrazinopyridine dihydrochloride is reacted with methyl acrylate in the presence of a base such as sodium methoxide or sodium ethoxide to yield 1- (pyridin-3-yl)pyrazolidin-3-one followed by chlorination of l-(pyridine-3-yl)pyrazolidin-3-one with phosphoryl chloride (POCI 3 ) in a two-step process to yield dihydropyrazole chloride (5a).
• the first step may be conducted in a polar protic solvent such as, methanol (MeOH) or ethanol (EtOH), at a temperature from about 40 °C to about 80 °C.
• the second step may be conducted neat in phosphoryl chloride at a temperature from about 40 °C to about 80 °C.
• the second step can also be conducted in a solvent like acetonitrile (MeCN) at a temperature from about 40 °C to about 80 °C.
• MeCN acetonitrile
• step b of Scheme 1 3-(3-chloro-4,5-dihydro-lH-pyrazol-l-yl)pyridine (5a) is reacted with an oxidant to yield 3-(3-chloro-lH-pyrazol-l-yl)pyridine (5b).
• the oxidation may be conducted with potassium persulfate (K 2 S 2 O 8 ) in N,N-dimethylformamide (DMF) at about 80 °C to yield the product (5b).
• the oxidation may be conducted with about 0.3 equivalents to about 0.5 equivalents of a copper(I) salt, such as copper(I) sulfate (Cu 2 S0 4 ), or a copper(I) halide, such as copper(I) chloride (CuCl), in the presence of an oxygen source, such as air, in a polar aprotic solvent such as N,N-dimethylformamide, N-methylpyrrolidinone (NMP) or 1,4- dioxane at temperatures from about 25 °C to about 100 °C.
• a polar aprotic solvent such as N,N-dimethylformamide, N-methylpyrrolidinone (NMP) or 1,4- dioxane
• step c of Scheme 1 3-(3-chloro-lH-pyrazol-l-yl)pyridine (5b) is nitrated with nitric
• step d of Scheme 1 compound (5c) is reduced to yield 3-chloro-l-(pyridin-3-yl)-lH- pyrazol-4-amine (5d).
• compound (5c) may be reduced with iron in acetic acid (AcOH).
• Compound (5c) may also be reduced with iron and ammonium chloride (NH 4 C1).
• this reduction may occur using other techniques in the art, for example, compound (5c) may be reduced using palladium on carbon in the presence of hydrogen (H 2 ).
• R 1 is selected from the group consisting of C 1 -C 4 -haloalkyl and C 1 -C 4 -alkyl-C 3 - C6-halocycloalkyl; preferably, R 1 is selected from CH 2 CH 2 CF 3 or CH 2 (2,2- difluorocyclopropyl).
• a metal hydroxide such as lithium hydroxide (LiOH)
• UV light is sometimes called "black light” and ranges from about 400 to about 365 nanometers.
• the photochemical coupling is conducted in an inert organic solvent. Typical inert organic solvents must remain liquid to about -50 °C, must remain relatively inert to the free radical conditions and must dissolve the reactants at reaction temperatures. Preferred inert organic solvents are aromatic and aliphatic hydrocarbons like toluene. The temperature at which the reaction is conducted is not critical but usually is from about -50 °C to about 35 °C. Lower temperatures, however, are better for increased selectivity.
• the temperature is below the boiling point of 3,3,3-trifluoropropene, i.e., about -18 to about -16 °C.
• the inert organic solvent is cooled to less than about -50 °C and the 3,3,3- trifluoropropene is bubbled into the solvent.
• the 3-mercaptopropionic acid or esters thereof and 2,2-dimethoxy-2-phenylacetophenone are added and a long wave function (366 nm) UVP lamp (4 watt) is turned on. After sufficient conversion of 3-mercaptopropionic acid or esters thereof, the light is turned off and the solvent removed.
• 3-((3,3,3-Trifluoropropyl)thio)propanoic acid may also be prepared by the low temperature free-radical initiated coupling of 3-mercaptopropionic acid with 3,3,3- trifluoropropene in the presence of 2,2'-azobis(4-methoxy-2,4-dimethyl) valeronitrile (V-70) initiator at temperatures of about -50 °C to about 40 °C in an inert organic solvent. While stoichiometric amounts of 3-mercaptopropionic acid and 3,3,3-trifluoropropene are required, because of its low boiling point, excess 3,3,3-trifluoropropene is usually employed to compensate for routine losses.
• V-70 2,2'-azobis(4-methoxy-2,4-dimethyl) valeronitrile
• V-70 From about 1 to about 10 mole percent initiator, V-70, is typically used, with about 5 mole percent being preferred.
• the low temperature free-radical initiated coupling is conducted in an inert organic solvent.
• Typical inert organic solvents must remain liquid to about -50 °C, must remain relatively inert to the free radical conditions and must dissolve the reactants at reaction temperatures.
• Preferred inert organic solvents are toluene, ethyl acetate, and methanol.
• the temperature at which the reaction is conducted from about -50 °C to about 40 °C. Initially, it is important to keep the temperature below the boiling point of 3,3,3-trifluoropropene, i.e., about -18 to about -16 °C.
• the solution is cooled to less than about -50 °C and the 3,3,3-trifluoropropene is transferred into the reaction mixture. After stirring at room temperature for 24 hours, the reaction mixture is heated to about 50 °C for about 1 hour to decompose any remaining V-70 initiator followed by cooling and solvent removal.
• step f of Scheme 1 pesticidal thioether (3b) is alkylated with a R 2 -X 2 to yield pesticidal thioether (3c), wherein X is a leaving group.
• the leaving group may be selected from halo, mesylate, or tosylate.
• R is selected from Ci-C4-alkyl, C 2 -C 4 -alkynyl, preferably, methyl, ethyl, and propargyl.
• R 2 -X 2 may be selected from methyl iodide, ethyl bromide, ethyl iodide, propargyl chloride, propargyl bromide, ethyl mesylate, propargyl mesylate, ethyl tosylate and propargyl tosylate.
• the alkylation is conducted in the presence of an inorganic base, preferably, metal carbonates such as cesium carbonate (CS 2 CO 3 ), metal hydroxides, metal phosphates, metal hydrides, conducted in the presence of a polar solvent, such as N,N- dimethylformamide at temperature from about 0 °C to about 80 °C.
• the alkylation of pesticidal thioether (3b) may be conducted in the presence of a base such as sodium hydride (NaH), in the presence of a polar aprotic solvent, such as N,N-dimethylformamide, tetrahydrofuran, hexamethylphosphoramide (HMPA), dimethylsulfoxide (DMSO), N-methyl-2-pyrrolidinone or sulfolane, at temperatures from about 0 °C to about 30 °C.
• a base such as sodium hydride (NaH)
• a polar aprotic solvent such as N,N-dimethylformamide, tetrahydrofuran, hexamethylphosphoramide (HMPA), dimethylsulfoxide (DMSO), N-methyl-2-pyrrolidinone or sulfolane
• step g of Scheme 1 pesticidal thioether (3c) is oxidized with hydrogen peroxide ( ⁇ 2 0 2 ) in methanol to yield pesticidal sulfoxides (3d).
• 3-(3-Chloro- lH-pyrazol- l-yl)pyridine (5b) in Scheme 1 may alternatively be prepared by reacting 3-hydrazinopyridine dihydrochloride with methyl 2-acetamidoacrylate to yield N- (3-oxo- l-(pyridin-3-yl)pyrazolidin-4-yl)acetamide and subsequent chlorination/elimination as shown in Scheme 2, step al .
• Pesticidal thioether (5f) may be prepared from amine (5d) through the reaction pathway disclosed in Scheme 3.
• 3-chloro-N-ethyl- l-(pyridin-3-yl)-lH-pyrazol- amine (5d) is reacted with between about 1 equivalent and about 2 equivalents of 3- chloropropionyl chloride in the presence of an inorganic base, preferably, metal carbonates, metal hydroxides, metal phosphates, metal hydrides, more preferably sodium bicarbonate (NaHC0 3 ) to yield 3-chloro-N-(3-chloro-l-(pyridin-3-yl)- lH-pyrazol-4-yl)-N- ethylpropanamide (5e).
• an inorganic base preferably, metal carbonates, metal hydroxides, metal phosphates, metal hydrides, more preferably sodium bicarbonate (NaHC0 3 ) to yield 3-chloro-N-(3-chloro-
• step e2 of Scheme 3 compound (5e) reacts with HSR 1 , wherein R 1 is defined above, in the presence of an inorganic base, preferably, metal carbonates, metal hydroxides, metal phosphates, metal hydrides, more preferably, potassium hydroxide (KOH).
• an inorganic base preferably, metal carbonates, metal hydroxides, metal phosphates, metal hydrides, more preferably, potassium hydroxide (KOH).
• KOH potassium hydroxide
• This reaction may be conducted in the presence of a polar solvent, preferably methanol, to yield pesticidal thioether (5f).
• 3-(3-Chloro-lH-pyrazol-l-yl)pyridine (5b) may be prepared through the reaction pathway disclosed in Scheme 4.
• step bl 3-(3-chloro-4,5-dihydro-lH-pyrazol-l-yl)pyridine (5a) is reacted with an oxidant to yield 3-(3-chloro-lH-pyrazol-l-yl)pyridine (5b).
• the oxidation may be conducted with about 2 equivalents to about 4 equivalents of potassium ferricyanide (K 2 FeCN 6 ) in water in the presence of about 2 equivalents to about 20 equivalents of an alkali metal base, such as potassium hydroxide, sodium hydroxide, or potassium carbonate, at temperatures ranging from about 50 °C to about 100 °C to yield the product (5b).
• K 2 FeCN 6 potassium ferricyanide
• an alkali metal base such as potassium hydroxide, sodium hydroxide, or potassium carbonate
• About 1.5 equivalents to 3.0 equivalents potassium persulfate can be added as a terminal oxidant in this oxidation.
• the amount of potassium ferricyanide can then be lowered to 1 equivalent with improved yield.
• 3-(3-Chloro-lH-pyrazol-l-yl)pyridine (5b) may be prepared through the reaction pathway disclosed in Scheme 5.
• step b2 3-(3-chloro-4,5-dihydro-lH-pyrazol-l-yl)pyridine (5a) is reacted with an oxidant to yield 3-(3-chloro-lH-pyrazol-l-yl)pyridine (5b).
• the oxidation may be conducted with about 1.5 equivalents to about 10 equivalents of manganese (IV) oxide (Mn0 2 ) in a solvent such as acetonitrile, tert-amy ⁇ alcohol, or chlorobenzene, at temperatures ranging from about 60 °C to about 90 °C to yield the product (5b).
• a strong acid such as hydrochloric acid (HCl) may provide the salt of the product (5b).
• 3-(3-Chloro-lH-pyrazol-l-yl)pyridine (5b) may also be prepared through a three step, no isolation reaction sequence as disclosed in Scheme 6.
• step a2 3-hydrazinopyridine dihydrochloride is reacted with methyl acrylate in the presence of a base such as sodium methoxide or sodium ethoxide to yield l-(pyridin-3-yl)pyrazolidin-3-one, followed by chlorination of l-(pyridine-3-yl)pyrazolidin-3-one with phosphoryl chloride in a two-step process to yield 3-chloro-dihydropryazole (5a).
• a base such as sodium methoxide or sodium ethoxide
• step b2 3-(3-chloro-4,5-dihydro-lH- pyrazol-l-yl)pyridine (5a) is reacted with manganese (IV) oxide to yield the product (5b).
• Subsequent treatment of (5b) with an acid such as hydrochloric acid may provide the salt of the product (5b).
• the first step may be conducted in a polar pro tic solvent such as methanol or ethanol, at a temperature from about 40 °C to about 80 °C.
• the second step may be conducted in a solvent such as chlorobenzene at a temperature from about 70 °C to about 90 °C.
• the third step may be conducted in a solvent such as chlorobenzene at a temperature from about 70 °C to about 110 °C.
• 3-(3-Chloro-lH-pyrazol-l-yl)pyridine may also be prepared through a two-step reaction sequence as disclosed in Scheme 7.
• step a3 3-hydrazinopyridine- dihydrochloride is reacted with 3-ethoxyacrylonitrile or 3-methoxyacylonitrile in the presence of an alkali metal C C 4 alkoxide base such as sodium methoxide (NaOMe) or sodium ethoxide (NaOEt) to yield 3-(3-amino-lH-pyrazol-l-yl)pyridine (8a).
• an alkali metal C C 4 alkoxide base such as sodium methoxide (NaOMe) or sodium ethoxide (NaOEt
• step b3 3-(3-amino-lH-pyrazol-l-yl)pyridine (8a) is reacted with sodium nitrite (NaN0 2 ) in aqueous hydrochloric acid to provide the corresponding diazonium salt followed by treatment of the diazonium salt with copper chloride to yield the product (5b).
• the first step may be conducted in a C C 4 aliphatic alcohol solvent such as methanol or ethanol, at a temperature from about 25 °C to about 100 °C. It is most convenient that the alkoxide base and the alcohol solvent be the same, for example, sodium ethoxide in ethanol.
• the second step may be conducted at a temperature from about 0 °C to about 25 °C.
• 3-(3-amino-lH-pyrazol-l-yl)pyridine (8a) may be prepared by the coupling of 3-bromopyridine and 3-aminopyrazole in a water-miscible polar aprotic organic solvent at a temperature of about 75 °C to about 155 °C in the presence of a catalytic amount of copper chloride and a base. While stoichiometric amounts of 3-bromopyridine and 3-aminopyrazole are required, it is often convenient to use an excess of 3-aminopyrazole. An excess from about 10 mole percent to about 50 mole percent 3-aminopyrazole is preferred.
• the coupling is run in the presence of about 5 mole percent to about 50 mole percent copper chloride, preferably from about 15 mole percent to about 30 mole percent copper chloride.
• the copper chloride may be either copper (I) chloride or copper (II) chloride.
• the coupling is also run in the presence of a base. While stoichiometric amounts of 3-bromopyridine and base are required, it is often convenient to use about a 1.5 fold to about a 2 fold excess of base. Alkali metal carbonates are preferred bases.
• the coupling is performed in a water-miscible polar aprotic organic solvent.
• Polar aprotic organic solvents that are soluble in water include nitriles such as acetonitrile, sulfoxides such as dimethyl sulfoxide, and amides such as N- methylpyrrolidinone, N,N-dimethylformamide and N,N-dimethylacetamide. N,N- Dimethylformamide is particularly preferred.
• 3-(3-Amino-lH-pyrazol-l-yl)pyridine (8a) may also be prepared through a two-step reaction sequence as disclosed in Scheme 8.
• step a4 3-hydrazinopyridine dihydrochloride is treated with acrylonitrile in a CrC 4 aliphatic alcohol at a temperature of about 25 °C to about 100 °C in the presence of an alkali metal C C 4 alkoxide to provide l-(pyridin-3-yl)-4,5- dihydro-lH-pyrazol-3-amine (9a).
• step b4 l-(pyridin-3-yl)-4,5-dihydro-lH-pyrazol-3-amine (9a) is treated with an oxidant in an organic solvent at a temperature of about 25 °C to about 100 °C to provide 3-(3-amino- lH- pyrazol-l-yl)pyridine (8a).
• Suitable oxidants include manganese (IV) oxide, potassium
• Manganese (IV) oxide is preferred. It is often convenient to use about a 1.5 fold to about a 10 fold excess of oxidant.
• the oxidation is performed in a solvent that is inert to the oxidant. Suitable solvents include nitriles such as acetonitrile or halocarbons such as dichloromethane or chlorobenzene. With manganese (IV) oxide as the oxidant, acetonitrile is a preferred solvent.
• step a of Scheme 9 3-hydrazinopyridine- dihydrochloride is treated with a di-C 1 -C 4 alkyl maleate such as diethyl maleate in a Ci-C 4 aliphatic alcohol at a temperature of about 25
• cyclization is run in the presence of an alkali metal CrC 4 alkoxide base such as sodium ethoxide. It is often convenient to use about a 2 fold to about a 5 fold excess of base.
• the cyclization is performed in a CrC 4 aliphatic alcohol such as ethanol. It is most convenient that the alkoxide base and the alcohol solvent be the same, for example, sodium ethoxide in ethanol.
• the pyrazolidine carboxylate (10a) may be treated with a chlorinating reagent in an inert organic solvent at a temperature of about 25 °C to about 100 °C to provide chlorinated dihydropyrazole carboxylate (10b).
• Suitable chlorinating reagents include phosphoryl trichloride and phosphorus pentachloride. Phosphoryl chloride is preferred. It is often convenient to use about a 1.1 fold to about a 10 fold excess of the chlorinating reagent.
• the chlorination is performed in an organic solvent that is inert to the chlorinating reagent. Suitable solvents include nitriles such as acetonitrile. With phosphoryl trichloride as the chlorinating reagent, acetonitrile is a preferred solvent.
• chlorinated dihydropyrazole carboxylate (10b) may treated with an oxidant in an organic solvent at a temperature of about 25 °C to about 100 °C to provide chlorinated pyrazole carboxylate (10c).
• Suitable oxidants include manganese (IV) oxide and sodium persulfate/sulfuric acid. It is often convenient to use about a 1.5 fold to about a 15 fold excess of oxidant.
• the oxidation is performed in an organic solvent that is inert to the oxidant.
• Suitable solvents include nitriles such as acetonitrile. With manganese (IV) oxide (Mn0 2 ) or sodium persulfate/sulfuric acid as the oxidant, acetonitrile is a preferred solvent.
• chlorinated pyrazole carboxylate (10c) may then be converted to the desired 3-chloro- l-(pyridin-3-yl)-lH-pyrazole-5-carboxylic acid hydrochloride (6e) by treatment in aqueous hydrochloric acid at a temperature of about 25 °C to about 100 °C. While stoichiometric amounts of reagents are required, it is often convenient to use an excess of reagents with respect to the chlorinated pyrazole carboxylate. Thus, aqueous hydrochloric acid is used in large excess as the reaction medium. Alternatively, chlorinated pyrazole carboxylate (10c) may then be converted to the desired 3-chloro- l-(pyridin-3-yl)-lH-pyrazole-5-carboxylic acid hydrochloride (6e) by treatment in aqueous hydrochloric acid at a temperature of about 25 °C to about 100 °C. While stoichiometric amounts of
• carboxylates may be saponified in the presence of an inorganic base, preferably metal hydroxides or their hydrates such as lithium hydroxide hydrate (LiOH H 2 0) in water and a polar solvent such as dioxane at temperatures from about 0 °C to about 30 °C to yield 3-chloro- l-(pyridin-3-yl)- lH-pyrazole-5-carboxylic acid (6e).
• an inorganic base preferably metal hydroxides or their hydrates such as lithium hydroxide hydrate (LiOH H 2 0) in water and a polar solvent such as dioxane at temperatures from about 0 °C to about 30 °C to yield 3-chloro- l-(pyridin-3-yl)- lH-pyrazole-5-carboxylic acid (6e).
• step e of Scheme 9 3-chloro-l-(pyridin-3-yl)-lH-pyrazole-5-carboxylic acid hydrochloride (6e) is decarboxylated in the presence of copper (II) oxide in polar solvents such as N,N-dimethylformamide at temperatures from about 80 °C to about 140 °C to yield 3-(3- chloro- lH-pyrazol-l-yl)pyridine (5b). It was surprisingly discovered that this decarboxylation only occurs in the presence of copper (II) oxide.
• polar solvents such as N,N-dimethylformamide
• the reaction mixture was slowly quenched into water (400 mL) at ⁇ 30 °C and the resulting solution was basified with 50 wt% sodium hydroxide solution to pH>10.
• the resulting solution was extracted with ethyl acetate (3 x 200 mL) and the organic layers were combined and concentrated to dryness.
• the residue was purified by flash column chromatography using 50-80% ethyl acetate/hexanes as eluent.
• the organic layer was analyzed by thin layer chromatography [Eluent: ethyl acetate], which showed that the desired product was formed as the major product, along with a trace of starting material and some minor impurities.
• the reaction mixture was cooled to 20 °C and diluted with water (50 mL). It was basified with 50% sodium hydroxide and extracted with ethyl acetate (4 x 30 mL). The organic layers were combined, concentrated to dryness, and purified by flash column chromatography using 30% ethyl acetate/hexanes as eluent.
• the reaction mixture was cooled to below 45 °C and filtered.
• the filter cake was washed with water (300 mL) affording crude product as a brown solid.
• the crude product was then dissolved in acetonitrile (400 mL) and filtered.
• the organic filtrate was dried and concentrated to afford the title product as a brown solid (28.8 g, 69%, 94% purity).
• 3-(3-Chloro-4,5-dihydro- lH-pyrazol- l-yl)pyridine (362 mg, 2.0 mol) was introduced into a 25 mL vial.
• Potassium hydroxide solution (658 mg, 85% pure) in water (H 2 0) (4.0 mL) was added and the mixture was heated to 60 °C.
• Potassium ferricyanide solution (656 mg in 1.0 mL water) was added over 15 minutes leading to brown mixture. The mixture was stirred at 62 °C for another 15 minutes.
• Potassium persulfate solution (270 mg, 1.0 mmol, 0.5 eq.) in water (1.0 mL) was added in one portion.
• the resultant dark orange mixture was stirred for 1 hour between -5 °C and ⁇ 0 °C and then added dropwise into a suspension of copper(I) chloride (0.475 g, 4.80 mmol) in chloroform (CHC1 3 , 4.8 mL ) at 25 °C over 15 minutes.
• the dark green slurry was stirred at room temperature for 1 hour.
• Water (10 mL) and chloroform (10 mL) was added to the mixture leading to a dark green solution.
• the acidic aqueous solution was neutralized by sodium hydroxide (50% in water) to pH 8 and extracted with chloroform (2 x 10 mL) and ethyl acetate (3 x 20 mL).
• the paste-like solid (48.99 g) was air dried in a hood overnight, the hard solid crushed with a spatula, and further dried at 55 °C with a nitrogen purge to give the title compound as a light tan solid (15.2 g, LC internal standard analysis indicated a purity of 91.9 wt%, for a 64.7 % isolated yield of 3-(3-chloro- lH-pyrazol-l-yl)-pyridine hydrochloride starting from 3-hydrazinopyridine dihydrochloride) .
• the mixture was concentrated by rotary evaporation and 50 mL of 10% sodium hydroxide was added.
• the solution was washed with methyl ie/t-butylether (50 mL) then acidified to pH ⁇ 1 with 6 N hydrochloric acid.
• the reaction was stirred with the black light on for 4 hours. After 4 hours the black light was turned off and the reaction concentrated by rotary evaporation (41 °C, 6 mm Hg) giving a pale yellow oil (18.09 g, 51 : 1 lineanbranched isomer, 90 wt% linear isomer by GC internal standard assay, 16.26 g active, 93%).
• the crude material was dissolved in 10% sodium hydroxide w/w (37.35 g) and was washed with toluene (30 mL) to remove non-polar impurities. The aqueous layer was acidified to pH -2-3 with hydrochloric acid (2 N, 47.81 g) and was extracted with toluene (50 mL).
• a 100 mL stainless steel Parr reactor was charged with 3-mercaptopropionic acid (3.67 g, 34.6 mmol), toluene (30.26 g), and 2,2'-azobis(4-methoxy-2,4-dimethyl) valeronitrile (V-70, 0.543 g, 1.76 mmol) and the reactor was cooled with a dry ice/acetone bath, purged with nitrogen, and pressure checked.
• 3,3,3-Trifluoropropene (3.20 g, 33.3 mmol) was added via transfer cylinder and the reaction was allowed to warm to 20 °C. After 24 hours, the reaction was heated to 50 °C for 1 hour to decompose any remaining V-70 initiator.
• a 100 mL stainless steel Parr reactor was charged with azobisisobutyronitrile (0.465 g, 2.83 mmol), toluene (60 mL) and methyl-3-mercaptopropionate (7.40 g, 61.6 mmol) and was purged and pressure checked with nitrogen.
• the reactor was cooled with dry ice and the 3,3,3- trifluopropopene (5.7 g, 59.3 mmol) was condensed into the reactor.
• the ice bath was removed and the reactor heated to 60 °C and stirred to 24 hours. The heat was turned off and the reaction left at room temperature (about 22 °C) overnight.
• the mixture was removed from the reactor and concentrated to a yellow liquid.
• fraction 1 (1.3 g, 6.01 mmol, 10%, 70.9 area% by GC), fraction 2 (3.7 g, 17.1 mmol, 29%, 87 area% by GC), and fraction 3 (4.9 g, 22.7 mmol, 38 %, 90.6 area% by GC):
• the reaction reached 35 °C due to heat from the lamp. After 4 hours, all of the trifluoropropene was either consumed or boiled out of the reaction. The light was turned off and the reaction stirred at room temperature overnight. After 22 hours, more trifluoropropene (3.1 g) was bubbled through the mixture at room temperature and the light was turned on for an additional 2 hours. The reaction had reached 93% conversion, so no more trifluoropropene was added.
• the reaction was stirred at 40 °C for 2 hours, at which point thin layer chromatography analysis (Eluent: ethyl acetate) indicated that only a trace of starting material remained.
• the reaction mixture was cooled to 20 °C and water (20 mL) was added. It was extracted with ethyl acetate (2 x 20 mL) and the combined organic layer was concentrated to dryness at ⁇ 40 °C. The residue was purified by flash column chromatography using 0-100% ethyl acetate/hexanes as eluent.
• N-(3-Chloro-l-(pyridin-3-yl)- lH-pyrazol-4-yl)-N-ethyl-3-((3,3,3-trifluoropropyl)thio) propanamide (57.4 g, 141 mmol) was stirred in methanol (180 mL). To the resulting solution was added hydrogen peroxide (43.2 mL, 423 mmol) dropwise using a syringe. The solution was stirred at room temperature for 6 hours, at which point LCMS analysis indicated that the starting material was consumed. The mixture was poured into dichloromethane (360 mL) and washed with aqueous sodium carbonate (Na 2 C0 3 ).
• the resulting solid was slowly charged with phosphoryl chloride (29.2 g, 191 mmol).
• the reaction was stirred at 60 °C for 3 hours, at which point a sample of the reaction mixture was diluted with water and basified with 50 wt% sodium hydroxide solution.
• the resulting solution was extracted with ethyl acetate and the organic layer was analyzed by thin layer chromatography [Eluent: ethyl acetate], which indicated that the reaction was complete.
• the reaction mixture was concentrated at 40 °C to remove phosphoryl chloride and the residue was slowly quenched with water (40 mL) at ⁇ 30 °C.
• the resulting solution was basified with 50 wt% sodium hydroxide solution and the resulting suspension was extracted with ethyl acetate (3 x 50 mL). The organic layers were concentrated to dryness and the residue was purified by flash column chromatography using 40- 50% ethyl acetate/hexanes.
• the reaction was determined to be complete by 1H NMR (An aliquot of the reaction mixture was taken, and concentrated down via rotary evaporator). The reaction was allowed to cool to room temperature and the mixture was transferred to a dry 3 L round-bottom flask and concentrated via the rotary evaporator. This resulted in 95 g of a honey-colored oil. The contents were gravity filtered through paper and the paper rinsed with diethyl ether (10 mL). The rinse was added to the flask. This gave a clear yellow liquid. The liquid was placed on a rotary evaporator to remove the ether. This gave 92.4 g of a yellow oil.
• the solid was rinsed with water (2 x 50 mL) and dried to afford a pale green solid.
• the solid was suspended in water (200 mL) and the resulting suspension was heated at 90 °C for 2 hours and was filtered hot through a Celite ® pad. The pad was rinsed with hot water (50 mL). The combined filtrates were allowed to cool to 20 °C to afford a yellow suspension, which was stirred at 20 °C for 2 hours and filtered.
• the solid was rinsed with water (2 x 50 mL) and air dried to afford the desired product as a light yellow crystalline solid (11.6 g, 57%).
• Step 1 l-(Pyridin-3-yl)-4,5-dihydro- lH-pyrazol-3-amine (9a) To a 4-neck, round bottomed flask (250 mL) was charged sodium ethanolate (21 wt% in ethanol, 32 mL). 3-Hydrazinopyridine-dihydrochloride (5.00 g, 27.5 mmol) was added, causing an exotherm from 20 °C to 58 °C. The mixture was allowed to cool to 20 °C and acrylonitrile (2.91 g, 54.9 mmol) was added. The reaction was heated at 60 °C for 5 hours and cooled to 20 °C.
• Methyl 3-chloro-l-(pyridin-3-yl)- lH-pyrazole-5-carboxylate (3.83 g, 16.1 mmol) was stirred in dioxane (53.7 mL). The orange suspension was heated until a solution was achieved. Lithium hydroxide hydrate (1.01 g, 24.2 mmol) in water (26.9 mL) was added to afford a darker red solution. The reaction was stirred at room temperature for 1 hours, at which point LCMS showed the corresponding acid to be the major product. The orange mixture was concentrated to dryness and the residue was mixed with 4 N hydrochloric acid in dioxane (100 mL).
• Manganese (IV) oxide (3.43 g, 39.4 mmol) was added, causing an exotherm from 20 °C to 21 °C. The reaction was stirred at 60 °C for 18 hours. Additional manganese (IV) oxide (3.43 g, 39.4 mmol) was added and the reaction was stirred at 80 °C for 6 hours. The mixture was filtered through a Celite ® pad and the pad was rinsed with ethyl acetate (20 mL). The combined filtrates were concentrated to dryness and the residue was purified by flash column
• the reaction was cooled to 20 °C and poured into water (20 mL).
• the mixture was basified with sodium carbonate to pH 9 and extracted with ethyl acetate (2 x 20 mL).
• the organic layers were concentrated to a residue, which was purified by flash column chromatography using 50% ethyl acetate/hexanes as eluent to provide the title compound as a white solid (0.280 g, 56%).
• Example PE-1 Prophetic preparation of 2,2-difluorocyclopropyl)methanethiol
• a solvent such as methanol (at a concentration ranging from about 0.01 M to about 1 M)
• a base such as potassium carbonate (about 1 equivalent to 2 equivalents).
• the reaction may be stirred until it is determined to be complete.
• the product may then be obtained using standard organic chemistry techniques for workup and purification.
• Example CE- 1 Oxidation of 3-(3-chloro-4,5-dihydro- lH-pyrazol-l-yl)pyridine (5a) to 3-(3- chloro- lH-pyrazol-l-yl)pyridine (5b) using iron (III) chloride
• Example CE-2 Oxidation of 3-(3-chloro-4,5-dihydro- lH-pyrazol-l-yl)pyridine (5a) to 3-(3- chloro- lH-pyrazol-l-yl)pyridine (5b) using iron (III) chloride
• Example CE-3 Oxidation of 3-(3-chloro-4,5-dihydro- lH-pyrazol-l-yl)pyridine (5a) to 3-(3- chloro- lH-pyrazol-l-yl)pyridine (5b) using catalytic copper (I) chloride
• Example CE-4 Oxidation of 3-(3-chloro-4,5-dihydro- lH-pyrazol-l-yl)pyridine (5a) to 3-(3- chloro- lH-pyrazol-l-yl)pyridine (5b) using catalytic copper (I) chloride
• Example CE-5 Oxidation of 3-(3-chloro-4,5-dihydro- lH-pyrazol-l-yl)pyridine (5a) to 3-(3- chloro- lH-pyrazol-l-yl)pyridine (5b) using potassium persulfate in acetonitrile
• Example CE-6 Alkylation versus retro-Michael-like decomposition
• Example CE-7 3-Chloro-N-ethyl-l-(pyridin-3-yl)-lH-pyrazol-amine
• GPA is the most significant aphid pest of peach trees, causing decreased growth, shriveling of leaves, and the death of various tissues. It is also hazardous because it acts as a vector for the transport of plant viruses, such as potato virus Y and potato leafroll virus to members of the nightshade /potato family Solanaceae, and various mosaic viruses to many other food crops. GPA attacks such plants as broccoli, burdock, cabbage, carrot, cauliflower, daikon, eggplant, green beans, lettuce, macadamia, papaya, peppers, sweet potatoes, tomatoes, watercress and zucchini among other plants. GPA also attacks many ornamental crops such as carnations, chrysanthemum, flowering white cabbage, poinsettia and roses. GPA has developed resistance to many pesticides.
• the seedlings were infested with 20-5- GPA (wingless adult and nymph stages) one day prior to chemical application.
• Test compounds (2 mg) were dissolved in 2 mL of acetone/methanol (1: 1) solvent, forming stock solutions of 1000 ppm test compound.
• the stock solutions were diluted 5X with 0.025% Tween 20 in water to obtain the solution at 200 ppm test compound.
• a hand-held aspirator-type sprayer was used for spraying a solution to both sides of the cabbage leaves until runoff.
• Reference plants (solvent check) were sprayed with the diluent only containing 20% by volume acetone/methanol (1: 1) solvent. Treated plants were held in a holding room for three days at approximately 25 °C and ambient relative humidity (RH) prior to grading. Evaluation was conducted by counting the number of live aphids per plant under a microscope. Percent Control was measured by using Abbott's correction formula (W.S. Abbott, "A Method of Computing the Effectiveness of an Insecticide" J. Econ. Entomol 18 (1925), pp.265-267) as follows.
• Table 1 GPA (MYZUPE) and sweetpotato whitefly-crawler (BEMITA) Rating Table.
• Bemisia tabaci The sweetpotato whitefly, Bemisia tabaci (Gennadius), has been recorded in the United States since the late 1800s. In 1986 in Florida, Bemisia tabaci became an extreme economic pest. Whiteflies usually feed on the lower surface of their host plant leaves. From the egg hatches a minute crawler stage that moves about the leaf until it inserts its microscopic, threadlike mouthparts to feed by sucking sap from the phloem.
• Adults and nymphs excrete honeydew (largely plant sugars from feeding on phloem), a sticky, viscous liquid in which dark sooty molds grow.
• honeydew can stick cotton lint together, making it more difficult to gin and therefore reducing its value.
• Sooty mold grows on honeydew-covered substrates, obscuring the leaf and reducing photosynthesis, and reducing fruit quality grade. It transmitted plant-pathogenic viruses that had never affected cultivated crops and induced plant physiological disorders, such as tomato irregular ripening and squash silverleaf disorder. Whiteflies are resistant to many formerly effective insecticides.
• the stock solutions were diluted 10X with 0.025% Tween 20 in water to obtain a test solution at 200 ppm.
• a hand-held Devilbliss sprayer was used for spraying a solution to both sides of cotton leaf until runoff.
• Reference plants (solvent check) were sprayed with the diluent only.
• Treated plants were held in a holding room for 8-9 days at approximately 82°F and 50% RH prior to grading. Evaluation was conducted by counting the number of live nymphs per plant under a microscope. Pesticidal activity was measured by using Abbott's correction formula (see above) and presented in Table 1.

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• 2014
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