US3888871A - Process for the preparation of 4-chloro-2-hydroxybenzothiazole - Google Patents
Process for the preparation of 4-chloro-2-hydroxybenzothiazole Download PDFInfo
- Publication number
- US3888871A US3888871A US418733A US41873373A US3888871A US 3888871 A US3888871 A US 3888871A US 418733 A US418733 A US 418733A US 41873373 A US41873373 A US 41873373A US 3888871 A US3888871 A US 3888871A
- Authority
- US
- United States
- Prior art keywords
- solvent
- diazotisation
- process according
- chloro
- hydroxybenzothiazole
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 238000000034 method Methods 0.000 title claims abstract description 28
- MBFOZAKOORJAMK-UHFFFAOYSA-N 4-chloro-3h-1,3-benzothiazol-2-one Chemical compound C1=CC=C2SC(O)=NC2=C1Cl MBFOZAKOORJAMK-UHFFFAOYSA-N 0.000 title claims abstract description 21
- 238000002360 preparation method Methods 0.000 title description 4
- 239000002904 solvent Substances 0.000 claims abstract description 26
- 150000001338 aliphatic hydrocarbons Chemical class 0.000 claims abstract description 9
- 238000004519 manufacturing process Methods 0.000 claims abstract description 8
- 230000007062 hydrolysis Effects 0.000 claims abstract description 7
- 238000006460 hydrolysis reaction Methods 0.000 claims abstract description 7
- YMWUJEATGCHHMB-UHFFFAOYSA-N Dichloromethane Chemical group ClCCl YMWUJEATGCHHMB-UHFFFAOYSA-N 0.000 claims description 15
- 238000006243 chemical reaction Methods 0.000 claims description 13
- OEQQFQXMCPMEIH-UHFFFAOYSA-N 4-chloro-1,3-benzothiazol-2-amine Chemical compound C1=CC=C2SC(N)=NC2=C1Cl OEQQFQXMCPMEIH-UHFFFAOYSA-N 0.000 claims description 12
- 150000002148 esters Chemical class 0.000 claims description 11
- 150000003839 salts Chemical class 0.000 claims description 11
- WSLDOOZREJYCGB-UHFFFAOYSA-N 1,2-Dichloroethane Chemical group ClCCCl WSLDOOZREJYCGB-UHFFFAOYSA-N 0.000 claims description 10
- HEDRZPFGACZZDS-UHFFFAOYSA-N Chloroform Chemical compound ClC(Cl)Cl HEDRZPFGACZZDS-UHFFFAOYSA-N 0.000 claims description 8
- 150000001875 compounds Chemical class 0.000 claims description 8
- VZGDMQKNWNREIO-UHFFFAOYSA-N tetrachloromethane Chemical compound ClC(Cl)(Cl)Cl VZGDMQKNWNREIO-UHFFFAOYSA-N 0.000 claims description 8
- YZUKKTCDYSIWKJ-UHFFFAOYSA-N (2-chlorophenyl)thiourea Chemical compound NC(=S)NC1=CC=CC=C1Cl YZUKKTCDYSIWKJ-UHFFFAOYSA-N 0.000 claims description 7
- -1 trichloroethylene, perchloroethylene, 1,1,1-trichloroethane Chemical class 0.000 claims description 6
- 125000003178 carboxy group Chemical group [H]OC(*)=O 0.000 claims description 5
- PAAZPARNPHGIKF-UHFFFAOYSA-N 1,2-dibromoethane Chemical compound BrCCBr PAAZPARNPHGIKF-UHFFFAOYSA-N 0.000 claims description 4
- 239000003795 chemical substances by application Substances 0.000 claims description 4
- 125000005843 halogen group Chemical group 0.000 claims description 4
- 230000003301 hydrolyzing effect Effects 0.000 claims description 4
- QPFMBZIOSGYJDE-UHFFFAOYSA-N 1,1,2,2-tetrachloroethane Chemical compound ClC(Cl)C(Cl)Cl QPFMBZIOSGYJDE-UHFFFAOYSA-N 0.000 claims description 3
- 150000001408 amides Chemical class 0.000 claims description 3
- 125000004391 aryl sulfonyl group Chemical group 0.000 claims description 3
- 150000008280 chlorinated hydrocarbons Chemical group 0.000 claims description 3
- 150000002825 nitriles Chemical class 0.000 claims description 3
- 238000002955 isolation Methods 0.000 claims description 2
- 239000012429 reaction media Substances 0.000 claims description 2
- 229910052799 carbon Inorganic materials 0.000 claims 1
- NDNKHWUXXOFHTD-UHFFFAOYSA-N metizoline Chemical compound CC=1SC2=CC=CC=C2C=1CC1=NCCN1 NDNKHWUXXOFHTD-UHFFFAOYSA-N 0.000 abstract description 11
- 229960002939 metizoline Drugs 0.000 abstract description 11
- GOJUJUVQIVIZAV-UHFFFAOYSA-N 2-amino-4,6-dichloropyrimidine-5-carbaldehyde Chemical group NC1=NC(Cl)=C(C=O)C(Cl)=N1 GOJUJUVQIVIZAV-UHFFFAOYSA-N 0.000 abstract 1
- 239000000203 mixture Substances 0.000 description 16
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 14
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 13
- 239000000047 product Substances 0.000 description 11
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 description 9
- UHOVQNZJYSORNB-UHFFFAOYSA-N Benzene Chemical compound C1=CC=CC=C1 UHOVQNZJYSORNB-UHFFFAOYSA-N 0.000 description 9
- 238000010992 reflux Methods 0.000 description 7
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 6
- 230000035484 reaction time Effects 0.000 description 6
- LPXPTNMVRIOKMN-UHFFFAOYSA-M sodium nitrite Chemical compound [Na+].[O-]N=O LPXPTNMVRIOKMN-UHFFFAOYSA-M 0.000 description 6
- WKBOTKDWSSQWDR-UHFFFAOYSA-N Bromine atom Chemical compound [Br] WKBOTKDWSSQWDR-UHFFFAOYSA-N 0.000 description 5
- GDTBXPJZTBHREO-UHFFFAOYSA-N bromine Substances BrBr GDTBXPJZTBHREO-UHFFFAOYSA-N 0.000 description 5
- 229910052794 bromium Inorganic materials 0.000 description 5
- 229960000583 acetic acid Drugs 0.000 description 4
- JJWANONAOYNRME-UHFFFAOYSA-N 2,4-dichloro-1,3-benzothiazole Chemical compound C1=CC=C2SC(Cl)=NC2=C1Cl JJWANONAOYNRME-UHFFFAOYSA-N 0.000 description 3
- ZWEHNKRNPOVVGH-UHFFFAOYSA-N 2-Butanone Chemical compound CCC(C)=O ZWEHNKRNPOVVGH-UHFFFAOYSA-N 0.000 description 3
- OYBFKJFWVAZRMI-UHFFFAOYSA-N 2-bromo-4-chloro-1,3-benzothiazole Chemical compound ClC1=CC=CC2=C1N=C(Br)S2 OYBFKJFWVAZRMI-UHFFFAOYSA-N 0.000 description 3
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 3
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 description 3
- ZMANZCXQSJIPKH-UHFFFAOYSA-N Triethylamine Chemical compound CCN(CC)CC ZMANZCXQSJIPKH-UHFFFAOYSA-N 0.000 description 3
- 239000002253 acid Substances 0.000 description 3
- 239000000460 chlorine Substances 0.000 description 3
- 239000012362 glacial acetic acid Substances 0.000 description 3
- 239000003960 organic solvent Substances 0.000 description 3
- FVAUCKIRQBBSSJ-UHFFFAOYSA-M sodium iodide Chemical compound [Na+].[I-] FVAUCKIRQBBSSJ-UHFFFAOYSA-M 0.000 description 3
- 235000010288 sodium nitrite Nutrition 0.000 description 3
- 235000015096 spirit Nutrition 0.000 description 3
- UOCLXMDMGBRAIB-UHFFFAOYSA-N 1,1,1-trichloroethane Chemical compound CC(Cl)(Cl)Cl UOCLXMDMGBRAIB-UHFFFAOYSA-N 0.000 description 2
- KNKRKFALVUDBJE-UHFFFAOYSA-N 1,2-dichloropropane Chemical compound CC(Cl)CCl KNKRKFALVUDBJE-UHFFFAOYSA-N 0.000 description 2
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 description 2
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 2
- CPELXLSAUQHCOX-UHFFFAOYSA-N Hydrogen bromide Chemical compound Br CPELXLSAUQHCOX-UHFFFAOYSA-N 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 125000001246 bromo group Chemical group Br* 0.000 description 2
- 239000006227 byproduct Substances 0.000 description 2
- 238000001816 cooling Methods 0.000 description 2
- 238000002474 experimental method Methods 0.000 description 2
- 239000012535 impurity Substances 0.000 description 2
- 239000010410 layer Substances 0.000 description 2
- BWHMMNNQKKPAPP-UHFFFAOYSA-L potassium carbonate Chemical compound [K+].[K+].[O-]C([O-])=O BWHMMNNQKKPAPP-UHFFFAOYSA-L 0.000 description 2
- 238000000746 purification Methods 0.000 description 2
- 239000007858 starting material Substances 0.000 description 2
- 238000003756 stirring Methods 0.000 description 2
- VDZOOKBUILJEDG-UHFFFAOYSA-M tetrabutylammonium hydroxide Chemical compound [OH-].CCCC[N+](CCCC)(CCCC)CCCC VDZOOKBUILJEDG-UHFFFAOYSA-M 0.000 description 2
- UMGDCJDMYOKAJW-UHFFFAOYSA-N thiourea Chemical compound NC(N)=S UMGDCJDMYOKAJW-UHFFFAOYSA-N 0.000 description 2
- VZSRBBMJRBPUNF-UHFFFAOYSA-N 2-(2,3-dihydro-1H-inden-2-ylamino)-N-[3-oxo-3-(2,4,6,7-tetrahydrotriazolo[4,5-c]pyridin-5-yl)propyl]pyrimidine-5-carboxamide Chemical compound C1C(CC2=CC=CC=C12)NC1=NC=C(C=N1)C(=O)NCCC(N1CC2=C(CC1)NN=N2)=O VZSRBBMJRBPUNF-UHFFFAOYSA-N 0.000 description 1
- BMYNFMYTOJXKLE-UHFFFAOYSA-N 3-azaniumyl-2-hydroxypropanoate Chemical compound NCC(O)C(O)=O BMYNFMYTOJXKLE-UHFFFAOYSA-N 0.000 description 1
- DXXACNSRSDYMOR-UHFFFAOYSA-N 4-chloro-1,3-benzothiazol-2-amine;hydron;bromide Chemical compound Br.C1=CC=C2SC(N)=NC2=C1Cl DXXACNSRSDYMOR-UHFFFAOYSA-N 0.000 description 1
- LSRDBSOMEBHGMO-UHFFFAOYSA-N 4-chloro-2-phenyl-1,3-benzothiazole Chemical compound N=1C=2C(Cl)=CC=CC=2SC=1C1=CC=CC=C1 LSRDBSOMEBHGMO-UHFFFAOYSA-N 0.000 description 1
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 description 1
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 1
- 241000282320 Panthera leo Species 0.000 description 1
- CYTYCFOTNPOANT-UHFFFAOYSA-N Perchloroethylene Chemical group ClC(Cl)=C(Cl)Cl CYTYCFOTNPOANT-UHFFFAOYSA-N 0.000 description 1
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 description 1
- XSQUKJJJFZCRTK-UHFFFAOYSA-N Urea Natural products NC(N)=O XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 description 1
- 229910052783 alkali metal Inorganic materials 0.000 description 1
- 125000005907 alkyl ester group Chemical group 0.000 description 1
- 239000008346 aqueous phase Substances 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- 229910052801 chlorine Inorganic materials 0.000 description 1
- 125000001309 chloro group Chemical group Cl* 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- ZBCBWPMODOFKDW-UHFFFAOYSA-N diethanolamine Chemical compound OCCNCCO ZBCBWPMODOFKDW-UHFFFAOYSA-N 0.000 description 1
- 125000002147 dimethylamino group Chemical class [H]C([H])([H])N(*)C([H])([H])[H] 0.000 description 1
- VEUUMBGHMNQHGO-UHFFFAOYSA-N ethyl chloroacetate Chemical compound CCOC(=O)CCl VEUUMBGHMNQHGO-UHFFFAOYSA-N 0.000 description 1
- 125000004494 ethyl ester group Chemical group 0.000 description 1
- 238000000605 extraction Methods 0.000 description 1
- 150000008282 halocarbons Chemical class 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 239000004009 herbicide Substances 0.000 description 1
- 229930195733 hydrocarbon Natural products 0.000 description 1
- 150000002430 hydrocarbons Chemical class 0.000 description 1
- 229910052500 inorganic mineral Inorganic materials 0.000 description 1
- 125000001449 isopropyl group Chemical group [H]C([H])([H])C([H])(*)C([H])([H])[H] 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 125000002496 methyl group Chemical group [H]C([H])([H])* 0.000 description 1
- 239000011707 mineral Substances 0.000 description 1
- 235000010755 mineral Nutrition 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 239000012044 organic layer Substances 0.000 description 1
- 239000012074 organic phase Substances 0.000 description 1
- 229910052700 potassium Inorganic materials 0.000 description 1
- 239000011591 potassium Substances 0.000 description 1
- 229910000027 potassium carbonate Inorganic materials 0.000 description 1
- 239000011541 reaction mixture Substances 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 239000002002 slurry Substances 0.000 description 1
- 229910052708 sodium Inorganic materials 0.000 description 1
- 239000011734 sodium Substances 0.000 description 1
- 235000009518 sodium iodide Nutrition 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000011343 solid material Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- YBBRCQOCSYXUOC-UHFFFAOYSA-N sulfuryl dichloride Chemical compound ClS(Cl)(=O)=O YBBRCQOCSYXUOC-UHFFFAOYSA-N 0.000 description 1
- 238000003786 synthesis reaction Methods 0.000 description 1
- 229950011008 tetrachloroethylene Drugs 0.000 description 1
- 238000004448 titration Methods 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07D—HETEROCYCLIC COMPOUNDS
- C07D277/00—Heterocyclic compounds containing 1,3-thiazole or hydrogenated 1,3-thiazole rings
- C07D277/60—Heterocyclic compounds containing 1,3-thiazole or hydrogenated 1,3-thiazole rings condensed with carbocyclic rings or ring systems
- C07D277/62—Benzothiazoles
- C07D277/68—Benzothiazoles 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 in position 2
-
- 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
- A01N57/00—Biocides, pest repellants or attractants, or plant growth regulators containing organic phosphorus compounds
- A01N57/10—Biocides, pest repellants or attractants, or plant growth regulators containing organic phosphorus compounds having phosphorus-to-oxygen bonds or phosphorus-to-sulfur bonds
- A01N57/16—Biocides, pest repellants or attractants, or plant growth regulators containing organic phosphorus compounds having phosphorus-to-oxygen bonds or phosphorus-to-sulfur bonds containing heterocyclic radicals
Definitions
- Typical salts are alkali metal salts, for example sodium or, preferably, potassium. salts and amine salts for example triethylamine or diethanolamine or. preferably, dimethylamine salts.
- Typical esters are C, alkyl esters for example methyl, isopropyl or, preferably, ethyl esters. Benazolin and its esters and salts was originally described in British Pat. Specification No. 862,226. The
- the 4-chloro-2- hydroxybenzothiazole is contaminated with significant amounts of unacceptable by-products that have to be removed, generally at a later stage in the overall process for making benazolin or its esters or salts. This involves an extra purification step which is clearly timeconsuming and costly and which it would be desirable to avoid. Further, the formation of these unwanted byproducts represent a waste of starting material.
- the purpose of the invention has therefore been to devise a method of making 4-chloro-2- hydroxybenzothiazole in a higher degree of purity and in better yield and/or shorter reaction time than has been obtainable previously on a commercial scale as an intermediate in the preparation of benazolin and its esters and salts.
- a process for preparing 4-chloro-2-hydroxybenzothiazole comprises diazotising 2-amino-4-chlorbenzothiazole hydrolhalide and hydrolysing the product, the diazotisation being carried out in the presence of a halogenated aliphatic hydrocarbon in which the major products of the diazotisation reaction are soluble to the extent of at least 10% w/v at 20C.
- the major product of the diazotisation reaction are 2-halo-4-chlorobenzothiazoles.
- the major product is 2-bromo-4- chlorobenzothiazole.
- 2,4-Dichlorobenzothiazole is also usually formed.
- halogenated aliphatic hydrocarbons for use in the invention are chlorinated hydrocarbons, for example ethylene dichloride which is particularly preferred, methylene chloride, chloroform, carbon tetrachloride, tetrachlorethane, trichloroethylene, perchloroethylene, 1,2-dichloropropane and 1,1 ,1- trichloroethane.
- Other halogenated hydrocarbons include bromine-containing hydrocarbons, for example ethylene dibromide. It is preferred that the solvent is one which has a boiling point of between 4090C, preferably 6090C.
- the diazotising reaction is preferably carried out at a temperature below 30C. e.g. at 2025C., usually in hydrochloric acid having a concentration greater than lN, preferably between 5.5 and 6.5N.
- the reaction is also preferably carried out in the presence of acetic acid.
- the quantity of organic solvent is not critical but is preferably at least 20% by volume of the total reaction mixture, for example 2560% by volume.
- the diazotisation reaction is generally continued for at least 2 but often less than 7 or even 5 hours. It is generally continued until there is substantially no solid material left suspended in the aqueous phase.
- the organic phase is then separated and is preferably evaporated to dryness before being hydrolysed.
- the hydrolysis may be carried out by reacting with a mineral acid, for ex- :ample concentrated hydrochloric acid, preferably in the presence of a water miscible solvent, for example methanol, ethanol or industrial methylated spirits.
- hydrolysis is suitably carried out at a temperature of 50-l50C. and preferably under reflux.
- the product can be isolated by conventional means and then, if desired, converted to benazolin; for example by the method described in British Pat. Specification No. 966,496.
- the method described in this specification comprises condensing the 4-chloro-2- hydroxybenzothiazole with a compound selected from ACH B or R OCH CN wherein A is a halogen atom, B is carboxyl group or the salt, ester, amide or nitrile thereof and R is an alkanesulphonyl or arylsulphonyl group, in the presence of an alkaline condensing agent to give a compound of formula I and if necessary converting B to give a desired group selected from carboxyl or the salts or esters thereof, such as those described above.
- the use of the halo genated aliphatic hydrocarbons as solvents in the invention has a further important advantage.
- the 2-amino-4-chlorobenzothiazole hydrohalide may be made by cyclising N-2-chlorophenylthiourea in the same organic solvent system as that used for the subsequent diazotisation reaction with the result that the 2-amino-4-ch]orobenzothiazole hydrohalide can be produced and reacted in the same organic solvent system without any necessity for isolating it before the diazotisation step.
- the overall yield and the overall time required for carrying out the production of benazolin from N-2- chlorophenylthiourea is improved still further.
- Preferred conditions for cyclising the N-2- chlorophenylthiourea to make 2-amino-4- chlorobenzothiazole hydrohalide comprise reacting the thiourea with a source of chlorine or bromine atoms in a halogenated aliphatic hydrocarbon solvent, such as those discussed above.
- the preferred source of chlorine atoms is sulphuryl chloride while the preferred source of bromine atoms is bromine.
- the reaction temperature is preferably 30 to 100C.
- the invention is illustrated in the following Examples in which percentages are by weight. The yields are of pure substance, so that the apparent yields (of impure material) are slightly higher than shown.
- Example 1 was repeated replacing the ethylene dichloride with in turn equivalent volumes of chloroform (Example 4); tetrachloroethylene (Example 5); 1,1,1- trichloroethane (Example 6); 1,2-dichloropropane (Example 7); ethylene dibromide (Example 8); and double the equivalent volume of carbon tetrachloride (Example 9).
- the 4-chloro-2-hydroxybenzothiazole obtained in each of these examples had a purity in the range 93 to 95% and gave yields of, respectively 73%, 66%, 65%, 72%, 61% and 71%. Higher yields may be obtained by conducting the diazotisation for a longer period.
- Aqueous sodium hydroxide (2.5N; 440 ml.) was added and refluxing continued for one-half hour. The solution was then cooled and acidified to pH 1 to 2 with hydrochloric acid. The resulting product was filtered off, washed with water and dried to give benazolin, m.p. l858C.
- Example 1 COMPARATIVE EXAMPLE Example 1 was repeated except that benzene was used instead of ethylene dichloride, the sodium nitrite addition took 5 hours instead of 2 and the stirring was continued for 16 hours instead of 2 hours.
- the 4- chloro-2-hydroxybenzothiazole was obtained in 77% yield and was only 87% pure and was contaminated inter alia with 8.3% of 4-chloro-2-phenylbenzothiazole which was difficult to separate at this stage.
- the product was converted into benazolin as described in Example 1 1 it was necessary to remove this impurity by carrying out an extraction with methylene chloride after the hydrolysis with sodium hydroxide.
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Life Sciences & Earth Sciences (AREA)
- Agronomy & Crop Science (AREA)
- Pest Control & Pesticides (AREA)
- Plant Pathology (AREA)
- Health & Medical Sciences (AREA)
- Engineering & Computer Science (AREA)
- Dentistry (AREA)
- General Health & Medical Sciences (AREA)
- Wood Science & Technology (AREA)
- Zoology (AREA)
- Environmental Sciences (AREA)
- Thiazole And Isothizaole Compounds (AREA)
- Pharmaceuticals Containing Other Organic And Inorganic Compounds (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
- Low-Molecular Organic Synthesis Reactions Using Catalysts (AREA)
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB5568472A GB1397089A (en) | 1972-12-01 | 1972-12-01 | Preparation of benzothiazoles |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| US3888871A true US3888871A (en) | 1975-06-10 |
Family
ID=10474584
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US418733A Expired - Lifetime US3888871A (en) | 1972-12-01 | 1973-11-23 | Process for the preparation of 4-chloro-2-hydroxybenzothiazole |
Country Status (22)
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5594145A (en) * | 1993-04-28 | 1997-01-14 | Hoechst Ag | Process for the preparation of 2(3H)-benzothiazolones |
| CN104122341A (zh) * | 2014-04-30 | 2014-10-29 | 河南省农业科学院农业质量标准与检测技术研究所 | 一种植物源性食品中草除灵乙酸的检测方法 |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB966496A (en) * | 1962-05-15 | 1964-08-12 | Boots Pure Drug Co Ltd | 2,4-dichlorobenzothiazole and its use in the preparation of benzothiazoles |
-
1972
- 1972-12-01 GB GB5568472A patent/GB1397089A/en not_active Expired
-
1973
- 1973-11-20 NL NL7315862A patent/NL7315862A/xx not_active Application Discontinuation
- 1973-11-21 IE IE2116/73A patent/IE39320B1/xx unknown
- 1973-11-22 ZA ZA738920A patent/ZA738920B/xx unknown
- 1973-11-23 IL IL43690A patent/IL43690A/en unknown
- 1973-11-23 US US418733A patent/US3888871A/en not_active Expired - Lifetime
- 1973-11-27 CS CS8171A patent/CS175468B2/cs unknown
- 1973-11-27 BE BE138215A patent/BE807856A/xx unknown
- 1973-11-28 AT AT997673A patent/AT331240B/de not_active IP Right Cessation
- 1973-11-28 AU AU63005/73A patent/AU473940B2/en not_active Expired
- 1973-11-29 CA CA186,985A patent/CA1023749A/en not_active Expired
- 1973-11-29 FR FR7342591A patent/FR2208907B1/fr not_active Expired
- 1973-11-29 PL PL1973166924A patent/PL89548B1/pl unknown
- 1973-11-29 IT IT7353972A patent/IT1000168B/it active
- 1973-11-30 CH CH1687473A patent/CH587259A5/xx not_active IP Right Cessation
- 1973-11-30 SE SE7316243A patent/SE415098B/xx unknown
- 1973-11-30 FI FI3690/73A patent/FI56004C/fi active
- 1973-11-30 LU LU68895A patent/LU68895A1/xx unknown
- 1973-11-30 NO NO4587/73A patent/NO140102C/no unknown
- 1973-11-30 ES ES420999A patent/ES420999A1/es not_active Expired
- 1973-12-01 JP JP48134828A patent/JPS5824437B2/ja not_active Expired
- 1973-12-03 DE DE2360202A patent/DE2360202C2/de not_active Expired
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5594145A (en) * | 1993-04-28 | 1997-01-14 | Hoechst Ag | Process for the preparation of 2(3H)-benzothiazolones |
| CN104122341A (zh) * | 2014-04-30 | 2014-10-29 | 河南省农业科学院农业质量标准与检测技术研究所 | 一种植物源性食品中草除灵乙酸的检测方法 |
| CN104122341B (zh) * | 2014-04-30 | 2015-10-28 | 河南省农业科学院农业质量标准与检测技术研究所 | 一种植物源性食品中草除灵乙酸的检测方法 |
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