CH511873A - Substituted imidazopyridines are herbicides - Google Patents
Substituted imidazopyridines are herbicidesInfo
- Publication number
- CH511873A CH511873A CH1737469A CH1737469A CH511873A CH 511873 A CH511873 A CH 511873A CH 1737469 A CH1737469 A CH 1737469A CH 1737469 A CH1737469 A CH 1737469A CH 511873 A CH511873 A CH 511873A
- Authority
- CH
- Switzerland
- Prior art keywords
- substituted
- anhydride
- acid
- alkyl
- reaction
- Prior art date
Links
- 150000005232 imidazopyridines Chemical class 0.000 title claims abstract description 11
- 239000004009 herbicide Substances 0.000 title abstract description 5
- 239000002253 acid Substances 0.000 claims abstract description 16
- 150000008064 anhydrides Chemical class 0.000 claims abstract description 16
- 125000000217 alkyl group Chemical group 0.000 claims abstract description 13
- -1 amino, thio Chemical group 0.000 claims abstract description 11
- 238000010992 reflux Methods 0.000 claims abstract description 9
- 125000003710 aryl alkyl group Chemical group 0.000 claims abstract description 8
- 150000001408 amides Chemical class 0.000 claims abstract description 6
- 125000003118 aryl group Chemical group 0.000 claims abstract description 6
- KXDHJXZQYSOELW-UHFFFAOYSA-M Carbamate Chemical compound NC([O-])=O KXDHJXZQYSOELW-UHFFFAOYSA-M 0.000 claims abstract description 5
- SOWBFZRMHSNYGE-UHFFFAOYSA-N Monoamide-Oxalic acid Natural products NC(=O)C(O)=O SOWBFZRMHSNYGE-UHFFFAOYSA-N 0.000 claims abstract description 5
- 125000004104 aryloxy group Chemical group 0.000 claims abstract description 5
- 125000003342 alkenyl group Chemical group 0.000 claims abstract description 4
- 125000002924 primary amino group Chemical group [H]N([H])* 0.000 claims abstract description 4
- 125000003545 alkoxy group Chemical group 0.000 claims abstract description 3
- 125000004414 alkyl thio group Chemical group 0.000 claims abstract description 3
- 125000003178 carboxy group Chemical group [H]OC(*)=O 0.000 claims abstract description 3
- 125000000753 cycloalkyl group Chemical group 0.000 claims abstract description 3
- 125000000449 nitro group Chemical group [O-][N+](*)=O 0.000 claims abstract description 3
- 125000000304 alkynyl group Chemical group 0.000 claims abstract 2
- 238000000034 method Methods 0.000 claims description 11
- 125000004435 hydrogen atom Chemical group [H]* 0.000 claims description 6
- 229910052757 nitrogen Inorganic materials 0.000 claims description 4
- 125000004433 nitrogen atom Chemical group N* 0.000 claims description 4
- 125000000547 substituted alkyl group Chemical group 0.000 claims description 3
- LSNNMFCWUKXFEE-UHFFFAOYSA-M Bisulfite Chemical compound OS([O-])=O LSNNMFCWUKXFEE-UHFFFAOYSA-M 0.000 claims description 2
- 125000000852 azido group Chemical group *N=[N+]=[N-] 0.000 claims description 2
- 150000002148 esters Chemical class 0.000 claims description 2
- 238000010438 heat treatment Methods 0.000 claims description 2
- 238000004519 manufacturing process Methods 0.000 claims description 2
- 125000005415 substituted alkoxy group Chemical group 0.000 claims description 2
- 125000003107 substituted aryl group Chemical group 0.000 claims description 2
- 125000001475 halogen functional group Chemical group 0.000 claims 1
- 125000004356 hydroxy functional group Chemical group O* 0.000 claims 1
- 125000002887 hydroxy group Chemical group [H]O* 0.000 abstract description 2
- CRMACCRNCSJWTO-UHFFFAOYSA-N 2h-pyridine-1,2-diamine Chemical compound NC1C=CC=CN1N CRMACCRNCSJWTO-UHFFFAOYSA-N 0.000 abstract 2
- 229910052736 halogen Inorganic materials 0.000 abstract 1
- 150000002367 halogens Chemical class 0.000 abstract 1
- 125000002577 pseudohalo group Chemical group 0.000 abstract 1
- BDHFUVZGWQCTTF-UHFFFAOYSA-N sulfonic acid Chemical compound OS(=O)=O BDHFUVZGWQCTTF-UHFFFAOYSA-N 0.000 abstract 1
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 12
- 125000004432 carbon atom Chemical group C* 0.000 description 6
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 5
- 239000000047 product Substances 0.000 description 5
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 5
- 239000000203 mixture Substances 0.000 description 4
- ZRCMCGQDIYNWDX-UHFFFAOYSA-N 5-chloropyridine-2,3-diamine Chemical compound NC1=CC(Cl)=CN=C1N ZRCMCGQDIYNWDX-UHFFFAOYSA-N 0.000 description 3
- 125000001495 ethyl group Chemical group [H]C([H])([H])C([H])([H])* 0.000 description 3
- 238000001914 filtration Methods 0.000 description 3
- 125000002496 methyl group Chemical group [H]C([H])([H])* 0.000 description 3
- 238000002360 preparation method Methods 0.000 description 3
- JUJWROOIHBZHMG-UHFFFAOYSA-N Pyridine Chemical compound C1=CC=NC=C1 JUJWROOIHBZHMG-UHFFFAOYSA-N 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- 125000001797 benzyl group Chemical group [H]C1=C([H])C([H])=C(C([H])=C1[H])C([H])([H])* 0.000 description 2
- 125000004803 chlorobenzyl group Chemical group 0.000 description 2
- 150000001875 compounds Chemical class 0.000 description 2
- XBDQKXXYIPTUBI-UHFFFAOYSA-N dimethylselenoniopropionate Natural products CCC(O)=O XBDQKXXYIPTUBI-UHFFFAOYSA-N 0.000 description 2
- 239000000706 filtrate Substances 0.000 description 2
- 125000005843 halogen group Chemical group 0.000 description 2
- KQNPFQTWMSNSAP-UHFFFAOYSA-N isobutyric acid Chemical compound CC(C)C(O)=O KQNPFQTWMSNSAP-UHFFFAOYSA-N 0.000 description 2
- 239000000155 melt Substances 0.000 description 2
- 125000001997 phenyl group Chemical group [H]C1=C([H])C([H])=C(*)C([H])=C1[H] 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- PGZVFRAEAAXREB-UHFFFAOYSA-N 2,2-dimethylpropanoyl 2,2-dimethylpropanoate Chemical compound CC(C)(C)C(=O)OC(=O)C(C)(C)C PGZVFRAEAAXREB-UHFFFAOYSA-N 0.000 description 1
- 125000001340 2-chloroethyl group Chemical group [H]C([H])(Cl)C([H])([H])* 0.000 description 1
- 125000000954 2-hydroxyethyl group Chemical group [H]C([*])([H])C([H])([H])O[H] 0.000 description 1
- 125000004200 2-methoxyethyl group Chemical group [H]C([H])([H])OC([H])([H])C([H])([H])* 0.000 description 1
- 125000003903 2-propenyl group Chemical group [H]C([*])([H])C([H])=C([H])[H] 0.000 description 1
- GPBZAKVUCIOOFH-UHFFFAOYSA-N 6-chloro-2-ethyl-1h-imidazo[4,5-b]pyridine Chemical compound C1=C(Cl)C=C2NC(CC)=NC2=N1 GPBZAKVUCIOOFH-UHFFFAOYSA-N 0.000 description 1
- HAXLILLUFUXGBU-UHFFFAOYSA-N 6-chloro-2-propan-2-yl-1h-imidazo[4,5-b]pyridine Chemical compound C1=C(Cl)C=C2NC(C(C)C)=NC2=N1 HAXLILLUFUXGBU-UHFFFAOYSA-N 0.000 description 1
- 150000008065 acid anhydrides Chemical class 0.000 description 1
- 125000002252 acyl group Chemical group 0.000 description 1
- 125000001246 bromo group Chemical group Br* 0.000 description 1
- 125000005997 bromomethyl group Chemical group 0.000 description 1
- 125000004106 butoxy group Chemical group [*]OC([H])([H])C([H])([H])C(C([H])([H])[H])([H])[H] 0.000 description 1
- 125000001309 chloro group Chemical group Cl* 0.000 description 1
- 125000004218 chloromethyl group Chemical group [H]C([H])(Cl)* 0.000 description 1
- 125000000068 chlorophenyl group Chemical group 0.000 description 1
- 125000000113 cyclohexyl group Chemical group [H]C1([H])C([H])([H])C([H])([H])C([H])(*)C([H])([H])C1([H])[H] 0.000 description 1
- 125000001511 cyclopentyl group Chemical group [H]C1([H])C([H])([H])C([H])([H])C([H])(*)C1([H])[H] 0.000 description 1
- 125000002534 ethynyl group Chemical group [H]C#C* 0.000 description 1
- 125000001153 fluoro group Chemical group F* 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 125000004029 hydroxymethyl group Chemical group [H]OC([H])([H])* 0.000 description 1
- 125000004857 imidazopyridinyl group Chemical group N1C(=NC2=C1C=CC=N2)* 0.000 description 1
- LSACYLWPPQLVSM-UHFFFAOYSA-N isobutyric acid anhydride Chemical compound CC(C)C(=O)OC(=O)C(C)C LSACYLWPPQLVSM-UHFFFAOYSA-N 0.000 description 1
- 125000001449 isopropyl group Chemical group [H]C([H])([H])C([H])(*)C([H])([H])[H] 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 125000006431 methyl cyclopropyl group Chemical group 0.000 description 1
- 125000000740 n-pentyl group Chemical group [H]C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])* 0.000 description 1
- 125000006501 nitrophenyl group Chemical group 0.000 description 1
- 125000000951 phenoxy group Chemical group [H]C1=C([H])C([H])=C(O*)C([H])=C1[H] 0.000 description 1
- IUGYQRQAERSCNH-UHFFFAOYSA-N pivalic acid Chemical compound CC(C)(C)C(O)=O IUGYQRQAERSCNH-UHFFFAOYSA-N 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 235000019260 propionic acid Nutrition 0.000 description 1
- WYVAMUWZEOHJOQ-UHFFFAOYSA-N propionic anhydride Chemical compound CCC(=O)OC(=O)CC WYVAMUWZEOHJOQ-UHFFFAOYSA-N 0.000 description 1
- 125000001436 propyl group Chemical group [H]C([*])([H])C([H])([H])C([H])([H])[H] 0.000 description 1
- UMJSCPRVCHMLSP-UHFFFAOYSA-N pyridine Natural products COC1=CC=CN=C1 UMJSCPRVCHMLSP-UHFFFAOYSA-N 0.000 description 1
- IUVKMZGDUIUOCP-BTNSXGMBSA-N quinbolone Chemical compound O([C@H]1CC[C@H]2[C@H]3[C@@H]([C@]4(C=CC(=O)C=C4CC3)C)CC[C@@]21C)C1=CCCC1 IUVKMZGDUIUOCP-BTNSXGMBSA-N 0.000 description 1
- 230000035484 reaction time Effects 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 239000007858 starting material Substances 0.000 description 1
- 125000000446 sulfanediyl group Chemical group *S* 0.000 description 1
- 125000003866 trichloromethyl group Chemical group ClC(Cl)(Cl)* 0.000 description 1
- 125000002023 trifluoromethyl group Chemical group FC(F)(F)* 0.000 description 1
- 125000000391 vinyl group Chemical group [H]C([*])=C([H])[H] 0.000 description 1
- 229920002554 vinyl polymer Polymers 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07D—HETEROCYCLIC COMPOUNDS
- C07D471/00—Heterocyclic compounds containing nitrogen atoms as the only ring hetero atoms in the condensed system, at least one ring being a six-membered ring with one nitrogen atom, not provided for by groups C07D451/00 - C07D463/00
- C07D471/02—Heterocyclic compounds containing nitrogen atoms as the only ring hetero atoms in the condensed system, at least one ring being a six-membered ring with one nitrogen atom, not provided for by groups C07D451/00 - C07D463/00 in which the condensed system contains two hetero rings
- C07D471/04—Ortho-condensed systems
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Nitrogen Condensed Heterocyclic Rings (AREA)
Abstract
Imidazopyridines are prepared by refluxing an o-diaminopyridine (II) with an anhydride of formula (III) in the presence of an acid of formula (RCOOH), the weight ratio of total anhydride:acid being in the range of 1:0.25 to 1:10: (where R = opt. substd. straight- or branched alkyl, alkenyl or alkynyl; or aryl, aralkyl or cycloalkyl; R1 = H, opt. substd. alkyl, aralkyl or aryl; or -COR; One of Z1-Z4 = N, the others are CR2, CR3, and CR4; R2, R3 and R4 are same or different H, opt. substd. alkyl, hydroxy, opt. substd. alkoxy or aryloxy; nitro, halogen, pseudo-halogen, carboxy, carboxyester, carboxyamide, amino, mono- or di-substd. amino, thio, alkylthio or its oxygenated derivs., its sulphonic acid or -ester, amides or substd. amides). The products are total and selective herbicides.
Description
Procédé de préparation d'imidazopyridines
La présente invention a pour objet un procédé de préparation d'imidazopyridines substituées.
Dans notre brevet No 486 842 on décrit certaines imidazopyridines substituées et leur utilisation comme herbicides, ainsi que leur préparation par la réaction de l'orthodiaminopyridine correspondante avec un acide de formule RCOOH ou un de ses dérivés fonctionnels. Cette réaction se poursuit assez lentement et on n'obtient que des rendements de l'ordre de 7O0/o.
On a maintenant trouvé qu'en conduisant la réaction en utilisant un mélange de l'acide et de l'anhydride d'acide décrits ci-dessous, on peut obtenir les produits désirés après un temps réactionnel plus court et avec des rendement plus élevés.
Ainsi la présente invention a pour objet un procédé de préparation d'imidazopyridines substituées de formule:
EMI1.1
dans laquelle R est un groupe alcoyle à chaîne droite ou ramifiée (ayant par exemple de 1 à 6 atomes de carbone tel qu'un groupe méthyle, éthyle, isopropyle, tert.-butyle ou amyle), alcényle (ayant par exemple de 2 à 6 atomes de carbone, tel qu'un groupe vinyle ou allyle) ou alcényle (ayant par exemple de 2 à 6 atomes de carbone tel, qu'un groupe éthynyle) ou aryle (par exemple phényle), aralcoyle, (par exepmple benzyle) ou cycloalcoyle (ayant par exemple de 3 à 6 atomes de carbone tel que cyclopentyle ou cyclohexyle), tous ces groupes pouvant être non-substitués ou substitués (par exemple par des radicaux alcoyle, halogéno ou nitro, tels que nitrophényle, chlorobenzyle ou méthylcyclopropyle), R1 est un atome d'hydrogène,
un groupe alcoyle (ayant par exemple de 1 à 4 atomes de carbone, tel que méthyle ou éthyle), alcoyle substitué (par exemple bétaéthoxyéthyle ou alcoyle substitué par un groupe imidazopyridine additionnel), aralcoyle (par exemple benzyle), aralcoyle substitué (par exemple chlorobenzyle), aryle (par exemple phényle) ou aryle substitué (par exemple chlorophényle) ou -COR, et un des radicaux Z1, Z2, z3 ou Z4 est un atome d'azote et les autres sont des groupes CR2, CR3 et CR4 dans lesquels R2, R3 et R4 sont identiques ou différents et sont choisis parmi un atome d'hydrogène, un groupe alcoyle (par exemple ayant de 1 à 6 atomes de carbone, tel que méthyle, éthyle ou propyle), hydroxy, alcoxy (par exemple méthoxy, éthoxy ou butoxy), alcoxy substitué,
aryloxy (par exemple phénoxy) ou aryloxy substitué (par exemple chlorophénoxy), nitro, halogéno, (par exemple chloro, bromo ou fluoro), cyano, thiocyano, isothiocyano, azido, alcoyle substitué (par exemple trifluorométhyle, chlorométhyle, bromo méthyle, trichlorométhyle, hydroxyméthyle, 2-chloroéthyle, 2-hydroxyéthyle ou 2-méthoxyéthyle), carboxy, carboxyester, carboxyamide, carboxyamide N-monosubstitué ou di-substitué, amino ou amino mono-ou-disubstitué (par exemple méthylamino, diméthylamino, acétylamino, trifluoroacétylamino, benzènesulfonamido, paratoluènesulfonamido- méthanesulfonamido), thio,
alcoylthio et leurs dérivés oxygénés (par exemple -SORe ou SOIRS dans lesquels Rn est un groupe alcoyle) ou l'acide sulfonique ou ses esters, amides ou amides substitués (par exemple phénylsulfamyle ou éthylsulfamyle) ledit procédé est caractérisé en ce qu'on fait réagir une ortho-diaminopyridine de formule:
EMI1.2
avec un anhydride de formule (RCO)20 en présence d'un acide de formule RCOOH, le rapport en poids de la quantité totale d'anhydride/acide étant compris entre 1:0,25 et 1:10, avantageusement entre 1:0,25 et 1:4, et de préférence entre 1:0,5 et 1:2, R,Rl, Z1, Z2, Z3 et Z4 ayant la signification ci-dessus, la réaction étant conduite en chauffant.
Il convient de conduire la réaction à la température du reflux. On peut conduire la réaction en faisant réagir ensemble l'ortho-diaminopyridine et un mélange de l'acide et de l'anhydride. Lorsque l'acide et l'anhydride sont tous deux des liquides, on préfère conduire la réaction en ajoutant lentement l'anhydride à une solution chauffée au reflux de l'orthodiaminopyridine dans l'acide. Si on le désire, on peut aussi utiliser des solvants pour la réaction, mais normalement ils ne sont pas nécessaires.
Généralement la quantité d'acide + anhydride utilisée dans la réaction excède l'équivalent molaire.
Lorsque la quantité -d'anhydride utilisée est sensiblement supérieure à l'équivalent molaire, et lorsque R1 dans la matière de départ est un atome d'hydrogène, il se forme le dérivé acyle correspondant, le substituant acyle étant en position 1 ou 3. Par conséquent, si l'on ne désire pas ce dérivé, lorsque R1 est un atome d'hydrogène la quantité d'anhydride utilisée ne doit pas sensiblement excéder l'équivalent molaire.
Avantageusement Z4 est l'atome d'azote, dans l'imidazopyridine substituée. Le composé préféré est la 6-chloro-2-tert.-butyl-imidazo (4,5-b) pyridine.
Les imidazopyridines substituées préparées selon le procédé de la présente invention se sont montrées particulièrement avantageuses comme herbicides sélectifs, pour l'utilisation avant et après la levée des semis. On peut aussi utiliser les composés comme herbicides totaux.
Les exemples suivants illustrent la présente invention. Les parties et les pourcentages sont en poids.
Exemple 1
A une solution de 143,5 parties de 5-chloro-2,3-diaminopyridine dans 143,5 parties d'acide pivalique chauffée au reflux, on ajoute goutte-à-goutte au cours d'une heure 191 parties d'anhydride pivalique. On sépare l'eau du mélange au moyen d'un appareil Dean Stark . On chauffe la solution au reflux pendant encore une heure puis la verse chaude dans 2500 parties d'une solution aqueuse d'hydroxyde de sodium 3 N puis ajoute 7000 parties d'eau chaude. On filtre ensuite la solution à travers du kieselguhr pendant qu'elle est encore chaude et fait précipiter le produit en ajoutant lentement de l'acide chlorhydrique concentré jusqu'à ce que le pH atteigne 7. On sépare le solide par filtration et le redissout dans de l'acide chlorhydrique dilué chaud.
On filtre la solution et précipite le produit désiré en ajoutant une solution aqueuse d'hydroxyde de sodium 10 N jusqu'à ce que le pH atteigne 7. On sépare le solide par filtration, le lave bien à l'eau puis le sèche à 600 C pour obtenir 177 parties (85 /o) de 6-chloro-2-tert.-butylimidazo (4,5-b) pyridine qui fond à 247-249 C.
Exemple 2
On ajoute goutte-à-goutte 55 parties d'anhydride isobutyrique à une solution de 50 parties de 5-chloro2,3-diaminopyridine dans 95 parties d'acide isobutyrique chauffée au reflux au cours de 45 minutes. On chauffe la solution au reflux pendant encore 3 heures puis la refroidit et la verse dans un excès de solution aqueuse d'hydroxyde de sodium 2N. On filtre la solution à travers du kieselguhr et précipite le produit du filtrat en ajoutant lentement de l'acide chlorhydrique concentré jusqu'à ce que le pH atteigne la valeur 7.
On sépare le précipité par filtration, le lave à l'eau et le sèche à 60 C pour obtenir 60,7 parties (rendement de 89 /o) de 6-chloro-2-isopropylimidazo (4,5-b) pyridine qui fondent à 187-189 C.
Exemple 3
On ajoute goutte-à-goutte 169 parties d'anhydride propionique à une solution de 200 parties de 5-chloro2,3-diaminopyridine dans 160 parties d'acide propionique, chauffée au reflux au cours de 45 minutes.
On chauffe au reflux la solution pendant encore deux heures puis la verse dans 6000 parties d'une solution aqueuse d'hydroxyde de sodium aqueux 2 N.
On ajoute encore 4000 parties d'eau et filtre le mélange. On isole 181 parties (rendement de 72 /o) du produit, c'est-à-dire la 6-chloro-2-éthylimidazo(4,5-b) pyridine qui fond à 239-240 C, du filtrat comme il est décrit dans l'exemple 1.
Process for preparing imidazopyridines
The present invention relates to a process for the preparation of substituted imidazopyridines.
In our patent No. 486,842 we describe certain substituted imidazopyridines and their use as herbicides, as well as their preparation by the reaction of the corresponding orthodiaminopyridine with an acid of formula RCOOH or one of its functional derivatives. This reaction proceeds quite slowly and only yields of the order of 700 / o are obtained.
It has now been found that by carrying out the reaction using a mixture of the acid and the acid anhydride described below, the desired products can be obtained after a shorter reaction time and in higher yields.
Thus, the subject of the present invention is a process for the preparation of substituted imidazopyridines of formula:
EMI1.1
in which R is a straight or branched chain alkyl group (for example having from 1 to 6 carbon atoms such as a methyl, ethyl, isopropyl, tert.-butyl or amyl group), alkenyl (having for example from 2 to 6 carbon atoms, such as a vinyl or allyl group) or alkenyl (for example having 2 to 6 carbon atoms such as an ethynyl group) or aryl (for example phenyl), aralkyl, (for example benzyl) or cycloalkyl (having for example from 3 to 6 carbon atoms such as cyclopentyl or cyclohexyl), all these groups possibly being unsubstituted or substituted (for example by alkyl, halo or nitro radicals, such as nitrophenyl, chlorobenzyl or methylcyclopropyl) , R1 is a hydrogen atom,
an alkyl group (for example having 1 to 4 carbon atoms, such as methyl or ethyl), substituted alkyl (for example betaethoxyethyl or alkyl substituted with an additional imidazopyridine group), aralkyl (for example benzyl), substituted aralkyl (for example chlorobenzyl), aryl (eg phenyl) or substituted aryl (eg chlorophenyl) or -COR, and one of the radicals Z1, Z2, z3 or Z4 is a nitrogen atom and the others are groups CR2, CR3 and CR4 in which R2, R3 and R4 are the same or different and are chosen from a hydrogen atom, an alkyl group (for example having from 1 to 6 carbon atoms, such as methyl, ethyl or propyl), hydroxy, alkoxy (for example methoxy, ethoxy or butoxy), substituted alkoxy,
aryloxy (eg phenoxy) or substituted aryloxy (eg chlorophenoxy), nitro, halo, (eg chloro, bromo or fluoro), cyano, thiocyano, isothiocyano, azido, substituted alkyl (eg trifluoromethyl, chloromethyl, bromo methyl, trichloromethyl , hydroxymethyl, 2-chloroethyl, 2-hydroxyethyl or 2-methoxyethyl), carboxy, carboxyester, carboxyamide, N-monosubstituted or di-substituted carboxyamide, amino or mono-or-disubstituted amino (for example methylamino, dimethylamino, acetylamino, trifluoroacetylamino, benzenesulfonamido, paratoluenesulfonamido- methanesulfonamido), thio,
alkylthio and their oxygenated derivatives (for example -SORe or SOIRS in which Rn is an alkyl group) or sulfonic acid or its esters, amides or substituted amides (for example phenylsulfamyl or ethylsulfamyl) said process is characterized in that one makes react an ortho-diaminopyridine of formula:
EMI1.2
with an anhydride of formula (RCO) 20 in the presence of an acid of formula RCOOH, the weight ratio of the total amount of anhydride / acid being between 1: 0.25 and 1:10, advantageously between 1: 0 , 25 and 1: 4, and preferably between 1: 0.5 and 1: 2, R, R 1, Z1, Z2, Z3 and Z4 having the above meaning, the reaction being carried out with heating.
The reaction should be carried out at reflux temperature. The reaction can be carried out by reacting together the ortho-diaminopyridine and a mixture of the acid and the anhydride. When the acid and the anhydride are both liquids, it is preferred to conduct the reaction by slowly adding the anhydride to a refluxed solution of the orthodiaminopyridine in the acid. If desired, solvents can also be used for the reaction, but normally they are not necessary.
Usually the amount of acid + anhydride used in the reaction exceeds the molar equivalent.
When the amount of anhydride used is substantially greater than the molar equivalent, and when R 1 in the starting material is hydrogen, the corresponding acyl derivative is formed, the acyl substituent being at the 1 or 3 position. Therefore, if this derivative is not desired, when R1 is a hydrogen atom the amount of anhydride used should not substantially exceed the molar equivalent.
Advantageously, Z4 is the nitrogen atom, in the substituted imidazopyridine. The preferred compound is 6-chloro-2-tert.-butyl-imidazo (4,5-b) pyridine.
The substituted imidazopyridines prepared according to the process of the present invention have proved particularly advantageous as selective herbicides, for use before and after the emergence of seedlings. The compounds can also be used as total herbicides.
The following examples illustrate the present invention. Parts and percentages are by weight.
Example 1
To a solution of 143.5 parts of 5-chloro-2,3-diaminopyridine in 143.5 parts of pivalic acid heated to reflux, 191 parts of pivalic anhydride are added dropwise over the course of one hour. . The water is separated from the mixture using a Dean Stark apparatus. The solution is heated under reflux for a further hour and then poured hot into 2,500 parts of a 3N aqueous sodium hydroxide solution and then 7,000 parts of hot water are added. The solution is then filtered through kieselguhr while still hot and the product precipitated by slowly adding concentrated hydrochloric acid until the pH reaches 7. The solid is separated by filtration and redissolved in hot dilute hydrochloric acid.
The solution is filtered and the desired product precipitated by adding 10 N aqueous sodium hydroxide solution until the pH reaches 7. The solid is separated by filtration, washed well with water and then dried at 600. C to obtain 177 parts (85 / o) of 6-chloro-2-tert.-butylimidazo (4,5-b) pyridine which melts at 247-249 C.
Example 2
55 parts of isobutyric anhydride are added dropwise to a solution of 50 parts of 5-chloro2,3-diaminopyridine in 95 parts of isobutyric acid heated to reflux over 45 minutes. The solution was heated under reflux for a further 3 hours then cooled and poured into an excess of 2N aqueous sodium hydroxide solution. The solution is filtered through kieselguhr and the product precipitated from the filtrate by slowly adding concentrated hydrochloric acid until the pH reaches the value 7.
The precipitate is separated by filtration, washed with water and dried at 60 ° C. to obtain 60.7 parts (yield 89 / o) of 6-chloro-2-isopropylimidazo (4,5-b) pyridine which melt. at 187-189 C.
Example 3
169 parts of propionic anhydride are added dropwise to a solution of 200 parts of 5-chloro2,3-diaminopyridine in 160 parts of propionic acid, heated to reflux over 45 minutes.
The solution is refluxed for a further two hours and then poured into 6000 parts of a 2N aqueous sodium hydroxide solution.
Another 4000 parts of water are added and the mixture is filtered. 181 parts (yield 72 / o) of the product, i.e. 6-chloro-2-ethylimidazo (4,5-b) pyridine which melts at 239-240 C, are isolated from the filtrate as it is. described in Example 1.
Claims (1)
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB5542268 | 1968-11-22 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CH511873A true CH511873A (en) | 1971-08-31 |
Family
ID=10473858
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CH1737469A CH511873A (en) | 1968-11-22 | 1969-11-21 | Substituted imidazopyridines are herbicides |
Country Status (3)
| Country | Link |
|---|---|
| CH (1) | CH511873A (en) |
| ES (1) | ES373778A1 (en) |
| NL (1) | NL6917115A (en) |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1994022859A1 (en) * | 1993-03-26 | 1994-10-13 | Bayer Aktiengesellschaft | Substituted heteroannulated imidazoles and their use as herbicides |
| US6448281B1 (en) | 2000-07-06 | 2002-09-10 | Boehringer Ingelheim (Canada) Ltd. | Viral polymerase inhibitors |
| US7576079B2 (en) | 2001-07-25 | 2009-08-18 | Boehringer Ingelheim (Canada) Ltd. | Viral polymerase inhibitors |
| US7582770B2 (en) | 2004-02-20 | 2009-09-01 | Boehringer Ingelheim International Gmbh | Viral polymerase inhibitors |
| US7838537B2 (en) | 2003-01-22 | 2010-11-23 | Boehringer Ingelheim International Gmbh | Viral polymerase inhibitors |
| US7888363B2 (en) | 2003-01-22 | 2011-02-15 | Boehringer Ingelheim International Gmbh | Viral polymerase inhibitors |
| US8076365B2 (en) | 2005-08-12 | 2011-12-13 | Boehringer Ingelheim International Gmbh | Viral polymerase inhibitors |
-
1969
- 1969-11-13 NL NL6917115A patent/NL6917115A/xx unknown
- 1969-11-21 ES ES373778A patent/ES373778A1/en not_active Expired
- 1969-11-21 CH CH1737469A patent/CH511873A/en not_active IP Right Cessation
Cited By (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1994022859A1 (en) * | 1993-03-26 | 1994-10-13 | Bayer Aktiengesellschaft | Substituted heteroannulated imidazoles and their use as herbicides |
| US6448281B1 (en) | 2000-07-06 | 2002-09-10 | Boehringer Ingelheim (Canada) Ltd. | Viral polymerase inhibitors |
| US6479508B1 (en) | 2000-07-06 | 2002-11-12 | Boehringer Ingelheim (Canada) Ltd. | Viral polymerase inhibitors |
| US6794404B2 (en) | 2000-07-06 | 2004-09-21 | Boehringer Ingelheim (Canada) Ltd. | Viral polymerase inhibitors |
| US7439258B2 (en) | 2000-07-06 | 2008-10-21 | Boehringer Ingelheim (Canada) Ltd | Viral polymerase inhibitors |
| US7576079B2 (en) | 2001-07-25 | 2009-08-18 | Boehringer Ingelheim (Canada) Ltd. | Viral polymerase inhibitors |
| US7803944B2 (en) | 2001-07-25 | 2010-09-28 | Boehringer Ingelheim International Gmbh | Viral polymerase inhibitors |
| US7893084B2 (en) | 2001-07-25 | 2011-02-22 | Boehringer Ingelheim Canada Ltd. | Viral polymerase inhibitors |
| US7888363B2 (en) | 2003-01-22 | 2011-02-15 | Boehringer Ingelheim International Gmbh | Viral polymerase inhibitors |
| US7838537B2 (en) | 2003-01-22 | 2010-11-23 | Boehringer Ingelheim International Gmbh | Viral polymerase inhibitors |
| US7582770B2 (en) | 2004-02-20 | 2009-09-01 | Boehringer Ingelheim International Gmbh | Viral polymerase inhibitors |
| US7879851B2 (en) | 2004-02-20 | 2011-02-01 | Boehringer Ingelheim International Gmbh | Viral polymerase inhibitors |
| US8030309B2 (en) | 2004-02-20 | 2011-10-04 | Boehringer Ingelheim International Gmbh | Viral polymerase inhibitors |
| US8076365B2 (en) | 2005-08-12 | 2011-12-13 | Boehringer Ingelheim International Gmbh | Viral polymerase inhibitors |
Also Published As
| Publication number | Publication date |
|---|---|
| NL6917115A (en) | 1970-05-26 |
| ES373778A1 (en) | 1972-04-01 |
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