Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07D—HETEROCYCLIC COMPOUNDS
  • C07D231/00—Heterocyclic compounds containing 1,2-diazole or hydrogenated 1,2-diazole rings
  • C07D231/02—Heterocyclic compounds containing 1,2-diazole or hydrogenated 1,2-diazole rings not condensed with other rings
  • C07D231/10—Heterocyclic compounds containing 1,2-diazole or hydrogenated 1,2-diazole rings not condensed with other rings having two or three double bonds between ring members or between ring members and non-ring members
  • C07D231/14—Heterocyclic compounds containing 1,2-diazole or hydrogenated 1,2-diazole rings not condensed with other rings having two or three double bonds between ring members or between ring members and non-ring members with hetero atoms or with carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, e.g. ester or nitrile radicals, directly attached to ring carbon atoms
  • C07D231/16—Halogen atoms or nitro radicals

Definitions

• This invention pertains to a new chemical process and some of the specific new practices thereof.
• the invention is more particularly directed to a new chemical process for preparing certain l-(substituted-hydrocarbyl)-3,4,5-tribromopyrazoles having the following structural formula:
• n is an integer O, l, 2, or 3
• R is hydrogen, alkyl of from 1 to 5 carbon atoms, inclusive, the total number of carbon atoms in the group being not more than 9
• A is the carboxyl group or a carboxylic amide group of the formula group is a saturated heterocyclic amino group of from 3 to 7 ring atoms, inclusive, having a total of not more than carbon atoms.
• the new process of the invention comprises a combination of reaction practices for preparing the l- (substituted-hydrocarbyl)-3,4,5-tribromopyrazoles of Formula I.
• the first practice of the integral process which pertains to preparation of pyrazole is known, and it is not critical in the process because pyrazole prepared in various ways can be used as the starting compound. This first practice is broadly described by Copenhaver in US. Pat. No. 2,515,160 issued July 1 l, 1950, for preparing pyrazole by reaction of a l,1,3,3-tetraalkoxypropane with a mineral acid addition salt of hydrazine hydrate.
• Copenhaver practice is advantageous in the combination process of this invention however, because it has been found that there is no necessity for separation and recovery of the pyrazole produced.
• the process of the invention is continued utilizing the aqueous reaction medium started with.
• the known Copenhaver practice is functionally combined with the second and a third specific reaction practices which are new according to this invention to give a new and better synthesis of the desired compounds.
• the new second reaction practice is directed to the bromination of pyrazole, and in contrast to published methods, furnishes tribromopyrazole in one step under exceedingly mild conditions.
• the yields of the desired product are excellent substantially quantitative in some cases.
• the third and final reaction practice of the combination process involves in situ N-alkylation of the 3,4,5-tribromopyrazole to give the desired compounds.
• the new process of this invention is characterized by utilization of the relatively inexpensive and ubiquitous reaction medium, water; the use of economical alkali metal hydroxide bases, preferably sodium hydroxide; and facile recovery of the desired product.
• These characteristics coupled with in situ preparation of pyrazole by the Copenhaver method and further in situ preparation of 3,4,5-tribromopyrazole by applicants new method provide a truly significant advance in the art of preparing the useful compounds of Formula I.
• the compounds are herbicides, especially the l-(alkanoamide)-3,4,5-tribromopyrazoles.
• a Copenhaver-type substantially aqueous reaction medium having the pyrazole in solution is first made alkaline to liberate the pyrazole from its hydrochloride salt. It is then treated with bromine and aqueous alkali metal hydroxide in order to impart a negative charge on the lnitrogen atom, which accelerates the bromination process. Furthermore the aqueous alkalimetal hydroxide also serves to neutralize the hydrogen bromide formed during the reaction. Bromine is added while the temperature of the aqueous mixture is maintained at about 35 C. Lower or higher temperatures can beused, but the guiding principle is to add the halogen slowly so that a runaway exothermic reaction will not occur.
• alkali metal hydroxide is added to the substantially aqueous reaction mixture in order to promote the prospective alkylation at the nitrogen atom of the pyrazole ring with an a, B, 'y, or A-monohalogenated alkanoamide or alkanoic acid.
• the N-alkylation reaction is promoted by heating the substantially aqueous reaction medium containing 3,4,5-tribromopyrazole, alkali metal hydroxide, and haloalkanoamide or haloalkanoic acid.
• the reaction is completed within an hour and upon cooling, followed advantageously by chilling, the desired l-(substitutedhydrocarbyl)-3,4,5-tribromopyrazole is recovered by conventional methods.
• alkali metal hydroxide component of the reaction mixtures sodium hydroxide is preferred. Potassium hydroxide can be used in the same way. Other alkali'metal hydroxides are suitable but relatively expensive.
• Copenhaver pyrazole synthesis and use in situ is an optional, though advantageous, step even though the remainder of the process of the invention can be utilized separately.
• the halogenation procedure and subsequent N-alkylation are effected in the same advantageous way no matter what the source of the pyrazole.
• alkenyl groups of from 3 to 8 carbon atoms, inclusive are for example: allyl, l-methylallyl, 2-methylallyl (methallyl), 2butenyl (crotyl), 3- butenyl, 1,2-dimethylallyl, 3-methyl-2-butenyl, 3- pentenyl, 2,3-dimethyl-2-butenyl, 1,l,2,-trimethylallyl, l,3-dimethyl-2-butenyl, l-ethyl-2-butenyl, 4-methyl-2- pentenyl, 2-ethyl-2-pentenyl, 4,4-dimethyl-2-pentenyl, Z-heptenyl, Zoctenyl, 5-octenyl, l,4-dimethyl-4- hexenyl, and the like.
• Some specific alkynyl groups of from 3 to 8 carbon atoms, inclusive, are 2-propynyl, 3-butynyl, 2- pentynyl, 1,1-dimethyl-2-propynyl, 2-hexynyl, 2- heptynyl, 2-octynyl, 1,1,3-trimethyl-4-pentynyl, and the like.
• Some specific aralkyl groups of from 7 to 13 carbon atoms, inclusive, are for example: benzyl, phenethyl, l-phenylethyl, Z-phenylpropyl, 4-phenylbutyl, 6- phenylhexyl, 5phenyl-2-methylpentyl, benzhydryl, 1- naphthylmethyl, 2-( 1-naphthyl)ethyl, 2-( 2- napthyl)ethyl, and the like.
• aryl of from 6 to 10 carbon atoms, inclusive includes for example, phenyl, the tolyls, the xylyls, mesityl, 4-tert-butylphenyl, 2,5-dichlorophenyl, 3-anisyl, 4-ethylphenyl, 3,4,5-trimethoxyphenyl 4-bromo-2-methoxyphenyl, 2-chloro-4-tolyl, and the like.
• cycloalkyl of from 3 to 8 carbon atoms, inclusive includes for example, cyclopropyl, Z-methylcyclopropyl, 2,2-dimethylcyclopropyl, 2,3-diethylcyclopropyl, 2-butylcyclopropyl, cyclobutyl, 2-methylcyclobutyl, 3-propylcyclobutyl, 2,3,4-trimethylcyclobutyl, cyclopentyl, 2,2-dimethylcyclopentyl, cyclohexyl, 3-methylcyclohexyl, 2,2-dimethylcyclohexyl, cycloheptyl, cyclooctyl, and the like.
• Cycloalkenyl groups of from 4 to 8 carbon atoms, inclusive are for example, 2-cyclobutenyl, 3- cyclopentenyl, 3-cyclohexenyl, 2-ethyl-3-cyclohexenyl, and the like.
• the phrase saturated heterocyclic amino group of from 3 to 7 ring atoms, inclusive, having a total of not more than 15 carbon atoms includes for example, aziridinyl, lower-alkylaziridinyl, for example, 2- methylaziridinyl, 2-ethylaziridinyl, and 2- butylaziridinyl, polylower-alkyl aziridinyl, for example, 2,3-dimethylaziridinyl and 2,2-dimethylaziridinyl, azetidinyl, lower-alkylazetidinyl, for example, 2- methylazetidinyl, 3-methylzetidienyl, and octylazetidinyl, polyloweralkylazetidinyl, for example, 2,2-dimethylazetidinyl, 3,3-diethylazetidinyl, 2,4,4- trimethylazetidinyl, and 2,3,4-trimethyl
• methylpiperidino 3-methyl-piperidino, .4- methylpiperidino, 3-isopropylpiperidino, and 4-tertbutylpiperidino, polylower-alkylpiperidino, for example, 3,4-diethylpiperidino, 2-methyl-S-ethylpiperidino,
• 2,3,5-triethylpiperidino hexamethyleneimino, loweralkylhexamethyleneimino, for example, 2- ethylhexamethyleneimino, 4-tertbutylhexamethyleneimino, and v 3-heptylhexamemethylmorpholino, 3,3-dimethylmorpholino, and 2,6-di-tert-butylmorpholino, thiamorpholino, loweralkylthiamorpholino, for example, 3- methylthiamorpholino, and polyloweralkylthiamorpholino, for example, 2,3,6- trimethylthiamorpholino and 2,3,5,6-tetramethylthiamorpholino.
• the saturated amino heterocycle can be other than alkyleneamino and there can be a second hetero atom in the ring, i.e., an oxygen atom, a sulfur atom, or a second nitrogen atom as a ring member.
• the second hetero atom is preferably in the 4-position of a six-membered ring, but it can be in the 3-position. Accordingly, referring to the phrase Collectively the group is saturated heterocyclic amino group of from 3 to 7 ring atoms, inclusive, it will be recognized that the R and R chain can be alkylene, oxadialkylene,50
• R and R taken as a unit with the atom are saturated heterocyclic amino groups of from 3 to 7 ring atoms, inclusive, such group having a total of not more than carbon atoms, one
• 2-ethyl-S- of the ring atoms being selected from carbon, oxygen, sulfur, or a second nitrogen atom, the other ring atoms being carbon, so that R,-R as a unit, is alkylene, oxadialkylene, thiadialkylene, or N- alkylazadialkylene, respectively.
• R,-R as a unit, is alkylene, oxadialkylene, thiadialkylene, or N- alkylazadialkylene, respectively.
• N,N-dimethy1-2-chloropropionamide was added to the filtrate dropwise during 5 min. This reaction mixture was heated at the reflux temperature for 45 min. with vigorous stirring and then 75 ml. water was added.
• EXAMPLE 6 3 ,4,5-tribromo-5-pentylpyrazolel 5- EXAMPLE 7
• N-( 1 ,1-dimethyl-2-propynyl)-2- chloropropionamide N-isopropyl-Z- chloropropionamide, N,N-diisopropyl-Z- chlorpropionamide, N,N-dibutyl-2- chloropropionamide, N,N-dipentyl-Z- chloropropionamide, N,N-dihexyl-Z- chloropropionamide, N-benzyl-2-chloropropionamide,
• the new l-(substituted-hydrocarbyl)- tribromopyrazoles of this invention have been found to be active as herbicides and plant growth regulators.
• the new compounds can be used to prevent damage to field crops due to weed competition, and they can be used to prevent unsightly and deleterious growths of weeds on home lawns, golf courses, cemeteries, railroad rights-of-way, and parks.
• 3,4,5-tribrom- N,N-a-trimethylpyrazolel -acetamide and 3 ,4,5-tribromopyrazole-l-acetic acid are especially active against various weeds, e.g., crabgrass (Digitaria sanguinalis L.), yellow foxtail (Setaria glauca L.), wild oats (Avena fazua L.), bindweed (Convolvulus arvens is L.), Johnson grass (Sorghum halepense L.), buckhorn plantain (Plantago lanceolata L.), curly dock (Rumex crispus L.), wild mustard (Brassica kaber DG.), purslane (Portulaca oleracea L.), and barnyard grass (Enchinochloa crusgalli L.).
• crabgrass Digitaria sanguinalis L.
• yellow foxtail Setaria glauca L.
• Wild oats Avena fazua L.
• control and significiant growth retardation of the foregoing weed species has been achieved using the named compounds and other specific compounds of this invention at rates of from 1 to 12.5 lbs. per acre.
• the compounds of this invention can be applied to soil, germinating weed seeds, weed seedlings, plant growth media, growing plants, or any other selected situs for control of weeds at rates ranging from about A to k lb. per acre up to about 50 lbs. per acre.
• the situs will be soil, but this term is used in the broad sense anywhere where weed growth might be a problem, e.g., gravel driveways, railroad beds, fiat built-up roofs, ponds, lakes, streams, and canals.
• Aquatic applications effectively use about 2 to about 10,000 or more, parts per million (ppm), by weight.
• a suitable dispersible powder formulation is obtained by blending and milling 327 lbs. of Georgia Clay, 4.5 lbs. of isooctylphenoxy polyethoxy ethanol (Triton X- 100) as a wetting agent, 9 lbs. of a polymerized sodium salt of substituted benzoid long-chain sulfonic acid (Daxad 27) as a dispersing agent, and 113 lbs. of the active ingredient.
• the resulting formulation has the following percentage composition (parts herein are by weight unless otherwise specified):
• alkyl of from 1 to 5 carbon atoms, inclusive, the sum of carbon atoms in the group being not more than 9; and A is the carboxyl group or a carboxylic amide group of the formula wherein R and R are hydrogen atoms or substituent groups more fully described as follows:
• R and R are lower-alkyl of from 1 to 8 carbon atoms, inclusive; alkenyl of from 3 to 8 carbon atoms, inclusive; alkynyl of from 3 to 8 carbon atoms, inclusive; aralkyl of from 7 to 13 carbon atoms, inclusive; aryl of from 6 to 10 carbon atoms, inclusive (provided both R and R are not aryl at the same time); cycloalkyl of from 3 to 8 carbon atoms, inclusive, cycloalkenyl of from 4 to 8 carbon atoms, inclusive; cycloalkenyl of from 4 to 8 carbon atoms, inclusive; and Collectively, the
• group is a saturated heterocyclic amino group of from 3 to 7 ring atoms, inclusive, having a total of not more'than 15 carbon atoms.

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Cited By (4)

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  • BE BE795881D patent/BE795881A/xx unknown
• 1972
  • 1972-02-23 US US00228770A patent/US3855236A/en not_active Expired - Lifetime
• 1973
  • 1973-01-23 CA CA161,885A patent/CA980784A/en not_active Expired
  • 1973-02-02 AR AR246402A patent/AR196513A1/es active
  • 1973-02-20 JP JP48019834A patent/JPS4896585A/ja active Pending
  • 1973-02-21 SU SU731886459A patent/SU625605A3/ru active
  • 1973-02-21 PL PL1973160847A patent/PL94636B1/pl unknown
  • 1973-02-22 RO RO7300073942A patent/RO62467A/ro unknown
  • 1973-02-22 FR FR7306295A patent/FR2177759B1/fr not_active Expired
  • 1973-02-22 CS CS731275A patent/CS194159B2/cs unknown
  • 1973-02-23 BR BR731368A patent/BR7301368D0/pt unknown
  • 1973-10-17 FR FR7337101A patent/FR2193823B1/fr not_active Expired

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