CA1129864A - Process for preparing 3-(4-pyridinyl)aniline from 3- (4-pyridinyl)-2-cyclohexen-1-one oxime - Google Patents
Process for preparing 3-(4-pyridinyl)aniline from 3- (4-pyridinyl)-2-cyclohexen-1-one oximeInfo
- Publication number
- CA1129864A CA1129864A CA366,467A CA366467A CA1129864A CA 1129864 A CA1129864 A CA 1129864A CA 366467 A CA366467 A CA 366467A CA 1129864 A CA1129864 A CA 1129864A
- Authority
- CA
- Canada
- Prior art keywords
- pyridinyl
- aniline
- acetyl
- oxime
- process according
- 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
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07D—HETEROCYCLIC COMPOUNDS
- C07D213/00—Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members
- C07D213/02—Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members having three double bonds between ring members or between ring members and non-ring members
- C07D213/04—Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members having three double bonds between ring members or between ring members and non-ring members having no bond between the ring nitrogen atom and a non-ring member or having only hydrogen or carbon atoms directly attached to the ring nitrogen atom
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07D—HETEROCYCLIC COMPOUNDS
- C07D213/00—Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members
- C07D213/02—Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members having three double bonds between ring members or between ring members and non-ring members
- C07D213/04—Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members having three double bonds between ring members or between ring members and non-ring members having no bond between the ring nitrogen atom and a non-ring member or having only hydrogen or carbon atoms directly attached to the ring nitrogen atom
- C07D213/24—Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members having three double bonds between ring members or between ring members and non-ring members having no bond between the ring nitrogen atom and a non-ring member or having only hydrogen or carbon atoms directly attached to the ring nitrogen atom with substituted hydrocarbon radicals attached to ring carbon atoms
- C07D213/36—Radicals substituted by singly-bound nitrogen atoms
- C07D213/38—Radicals substituted by singly-bound nitrogen atoms having only hydrogen or hydrocarbon radicals attached to the substituent nitrogen atom
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Pyridine Compounds (AREA)
- Pharmaceuticals Containing Other Organic And Inorganic Compounds (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
An improved method of preparing 3-(4-pyridinyl)aniline comprises heating 3-(4-pyridinyl)-2-cyclohexen-1-one oxime with an excess each of acetic anhydride and anhydrous phosphoric acid, distilling off the acetic acid by-product and excess acetic anhydride, and hydrolyzing the remaining N-acetyl-3-(4-pyridinyl)aniline.
An improved method of preparing 3-(4-pyridinyl)aniline comprises heating 3-(4-pyridinyl)-2-cyclohexen-1-one oxime with an excess each of acetic anhydride and anhydrous phosphoric acid, distilling off the acetic acid by-product and excess acetic anhydride, and hydrolyzing the remaining N-acetyl-3-(4-pyridinyl)aniline.
Description
l~Z986~
This invention relates to an improved method for preparing 3~ pyridinyl)aniline, an intermediate for preparing rosoxacin, an antibacterial agent.
Gelotte et al United States Patents 4,Q26,900 and 4,075,217 disclose, and 4,075,217 claims, the process of heating the oxime of 3-(4-pyridinyl)-2-cyclohexen-l~one with an acetylatiny agent to produce the corresponding O-acetyl oxime and then heating the O-acetyl oxime under acidic conditions, preferably in the presence of a strong mineral acid. The acetylation and subsequent heating steps were preferably run in combination by heating the oxime with acetic acid, acetic anhydride and hydrogen halide, preferably hydrogen chloride gas. The reaction was run in the range of about 80 to 140C~, preferably 100 to 120C. The N-acetyl-3-(4-pyridinyl)aniline was then hydrolyzed to produce 3-(4-pyridinyl) aniline, an intermediate for preparing rosoxacin.
Newman and Hung [J. Org. Chem. 38, 4073-407~ ~1973)] showed the conversion of certain oximes of ~-tetralones (7-m~thyl- and 7-chloro-~-tetralones) to the corresponding N-(l-naphthyl) acetamides by heating the oxime in acetic anhydride and anhydrous phosphoric acid at 80C. for thirty minutes. Due to side-reactions, unsuccessful results were obtained using these reaction conditions with the oxime of 6-methoxy-~-tetralone. Phosphorus pentoxide was used to prepare the anhydrous phosphoric acid.
The present invention provides an improvement in the process for preparing 3-~4-pyridinyl)anilinè by acetylating 3-(4-pyridinyl)-2-cyclohexen-1-oxime to produce the corresponding O-acetyl oxime and heating the latter under acidic conditions to produce N-acetyl-3-(4-pyridinyl)aniline and hydrolyzing the :
N-acetyl compound, the improvement consisting in heating 3-(4-pyridinyl)-2-cyclohexen-1-one oxime with an excess each of acetic anhydride and anhydrous phosphoric acid, distilling off the acetic acid by-product and excess acetic anhydride, sub~tantially neutralizing the remaining mixture by the addition of concentrated aqueous alkali, extracting N-acetyl-3-(~-pyridinyl)aniline rom the concentrated aqueous phosphate solution with a water-miscible lower alkanol, and hydrolyzing the remaining N-acetyl-3-(4-pyridinyl) aniline, preferably under alkaline conditions. In a preferred embodiment, the first step of the process may be run using about 7 to lO mole-equivalen-ts of acetic anhydride and about 3 to 10 mole-equivalents of anhydrous phosphoric acid per mole equivalent of oxime. A further preferred feature is to heat the reactants at about 90 to 120C., preferably 95 to 120C. in the first step.
The anhydrous phosphoric acid used in the process may be prepared by dehydrating 85% phosphoric acid by reacting it with acetic anhydride.
The first step of the process can be run using more acetic-anhydride and anhydrous phosphoric acid than indicated above as preferred ranges, vis., up to about 15-20 mole-equivalents of each per mole-equivalent of oxime, but to no particular advantage.
The extraction step is preferably carried out at 50 to 80C. Ethanol is a preferred extracting solvent.
The hydrolysis step is conveniently run using an aqueous alkali metal hydroxide, preferably sodium hydroxide. 35~ by weight aqueous sodium hydroxide solution is preferred, and the temperature is preferably between 50C and the reflux temperature of the ~ .
.
Z~38~
solution at this stage of the process The following examples will further illustrate the invention without, however, limiting it thereto.
Example 1 3-(4-Pyridinyl)aniline, alternatively named 3-(4-pyridinyl)benzeneamine - Anhydrous phosphoric acid was prepared by the addition of 1,020 g. (10 moles, d 1.082, 940 ml.) of ace-tic anhydride to 540 g. (4.68 moles, d 1.7, 320 ml.) of vigorously stirred 85% phosphoric acid over 20 minutes maintaining the temperature near 50C. with occasional cooling. To the clear warm solution was added 188 g. (1 mole) of 3-(4-pyridinyl)-2-cyclohexen-l-one oxime in one portion. The initially clear, yellow solution was heated on a steam bath to about 95C. where the steam was shut off. At this point the reaction mixture started to separate into two layers, eventually forming a mobile water-white upper layer and a yellow-brown viscous gum. The internal temperature of -2a-. _ ... .
- 3 ~.Z98~
the reaction mixture very gradually increased to about 110-120C. As soon as the temperature started to decrease, steam was again applied for 90 minutes.
The ge~eratcd acetic acid ~colorless ~Ipper layer, 650-700 ml.) was then re-moved by vacuum distillation followed by removal of the excess acetic anhydride in vacuo. l`he continuously stlrred and heated viscous residue was readily d:issolved in 500 ml. of warm water. The clear dark solution was treated gradually and with occasional cooling with about 800 ml. of 35%
aqueous sodium hydroxide at 60-80C. to a weakly basic pH (8-9). Some pre-cipitated solid was solubilized by the addition of 500 ml. of ethanol and heating to 80C. The colorless viscous lower layer containing mostly phos-phate salts was drawn off while hot ~1 1., 1,430 g.); it solidified at ambient temperature. To the remaining dark solution was added 320 ml. of 35% aqueous sodium hydroxide and the resulting two-phased reaction mixture was heated at reflux overnight ~about 16 hours). The dark, homogeneous solution was cooled to 5C. The crystallized solid was filtered, pressed well and then washed with the minimum amount (just the amount to cover the solid) of ice-methanol cooled 50% aqueous ethanol. To remove any remaining inorganic salts in the filter cake, the solid was washed exhaustively with warm water ~about 35 to 50 C.). The residue was dried in vacuo at 60C. to afford 134.5 g. ~79%) of the desired beige product, 3-(4-pyridinyl)aniline, m.p. 168-171; single spot on tlc ~silica; CHC13: CH30H: i-C3H7NH2 90:5:5; UV)-Example 2 3-~4-Pyridinyl)aniline was prepared in comparable yield on a pilot laboratory scale using the same procedure, as follows: Acetic anhydride, 55 kg., was charged to the 30 gallon glass-lined reactor of a distillation unit.
The phosphoric acid was added over one-half hour, with temperature rising to 100C. The solution was heated to 120C. and the steam shut off. A solution ~298~i~
of 14.6 kg. of oxime in 36 1. of acetic acid was added at a rate to maintain reflux but not cause distillation. Approximately 3/4th of the solution was added over one ancl one-half hours resulting in a full kettle. PressurP steam ~35-~0lbs.) was applied to ~egin dlstillation of acetic acid. ~fter one-hal hour, there was room in the kettle and the remaining oxime solution was added 51OW1YJ maintaining distillation. The clear acetic acid layer was distilled off at atmosp}-eric pressure over two hours leaving a dark and viscous, but stirrable residue at 120C. Vacuum was applied gradually to remove the re-maining acetic acid and acetic anhydride, keeping the pot temperature over 100C. With the residue stirring at 100C., (heat off), 20 1. of water was added over 5 minutes. The temperature dropped to 85C. but stirring was main-tained. The kettle was cooled with water to 60C., and 54 kg. of 35% aqueous sodium hydroxide was added over one-half hour, temperature 50-65C. Ethanol, 20 1., was added and the mixture cooled to 30C. before being allowed to separate. A clear aqueous layer, 66 1., was drawn off and the very dark organic layer, 56 1., was transferred to a stainless steel kettle. 35%
aqueous sodium hydroxide, 34 kg., was added to the kettle and the mixture was refluxed ~83C.) for 12 hours. In the morning, the mixture was cooled from 60 to 5C. before filtration. The dark solids were washed with 3 x 6 1. of cold 25% ethanol to give a tan product. The wet cake was slurried in 40 l. of water at 30 C. for one-half hour and refiltered. The solids were washed generously with water and dried 60C./air/overnight. There resulted 10.08 kg., or 10080/77.8x170 = 76.3% of theory, of the tan product, 3-(4-pyridinyl) aniline, m.p. = 165-7C.
This invention relates to an improved method for preparing 3~ pyridinyl)aniline, an intermediate for preparing rosoxacin, an antibacterial agent.
Gelotte et al United States Patents 4,Q26,900 and 4,075,217 disclose, and 4,075,217 claims, the process of heating the oxime of 3-(4-pyridinyl)-2-cyclohexen-l~one with an acetylatiny agent to produce the corresponding O-acetyl oxime and then heating the O-acetyl oxime under acidic conditions, preferably in the presence of a strong mineral acid. The acetylation and subsequent heating steps were preferably run in combination by heating the oxime with acetic acid, acetic anhydride and hydrogen halide, preferably hydrogen chloride gas. The reaction was run in the range of about 80 to 140C~, preferably 100 to 120C. The N-acetyl-3-(4-pyridinyl)aniline was then hydrolyzed to produce 3-(4-pyridinyl) aniline, an intermediate for preparing rosoxacin.
Newman and Hung [J. Org. Chem. 38, 4073-407~ ~1973)] showed the conversion of certain oximes of ~-tetralones (7-m~thyl- and 7-chloro-~-tetralones) to the corresponding N-(l-naphthyl) acetamides by heating the oxime in acetic anhydride and anhydrous phosphoric acid at 80C. for thirty minutes. Due to side-reactions, unsuccessful results were obtained using these reaction conditions with the oxime of 6-methoxy-~-tetralone. Phosphorus pentoxide was used to prepare the anhydrous phosphoric acid.
The present invention provides an improvement in the process for preparing 3-~4-pyridinyl)anilinè by acetylating 3-(4-pyridinyl)-2-cyclohexen-1-oxime to produce the corresponding O-acetyl oxime and heating the latter under acidic conditions to produce N-acetyl-3-(4-pyridinyl)aniline and hydrolyzing the :
N-acetyl compound, the improvement consisting in heating 3-(4-pyridinyl)-2-cyclohexen-1-one oxime with an excess each of acetic anhydride and anhydrous phosphoric acid, distilling off the acetic acid by-product and excess acetic anhydride, sub~tantially neutralizing the remaining mixture by the addition of concentrated aqueous alkali, extracting N-acetyl-3-(~-pyridinyl)aniline rom the concentrated aqueous phosphate solution with a water-miscible lower alkanol, and hydrolyzing the remaining N-acetyl-3-(4-pyridinyl) aniline, preferably under alkaline conditions. In a preferred embodiment, the first step of the process may be run using about 7 to lO mole-equivalen-ts of acetic anhydride and about 3 to 10 mole-equivalents of anhydrous phosphoric acid per mole equivalent of oxime. A further preferred feature is to heat the reactants at about 90 to 120C., preferably 95 to 120C. in the first step.
The anhydrous phosphoric acid used in the process may be prepared by dehydrating 85% phosphoric acid by reacting it with acetic anhydride.
The first step of the process can be run using more acetic-anhydride and anhydrous phosphoric acid than indicated above as preferred ranges, vis., up to about 15-20 mole-equivalents of each per mole-equivalent of oxime, but to no particular advantage.
The extraction step is preferably carried out at 50 to 80C. Ethanol is a preferred extracting solvent.
The hydrolysis step is conveniently run using an aqueous alkali metal hydroxide, preferably sodium hydroxide. 35~ by weight aqueous sodium hydroxide solution is preferred, and the temperature is preferably between 50C and the reflux temperature of the ~ .
.
Z~38~
solution at this stage of the process The following examples will further illustrate the invention without, however, limiting it thereto.
Example 1 3-(4-Pyridinyl)aniline, alternatively named 3-(4-pyridinyl)benzeneamine - Anhydrous phosphoric acid was prepared by the addition of 1,020 g. (10 moles, d 1.082, 940 ml.) of ace-tic anhydride to 540 g. (4.68 moles, d 1.7, 320 ml.) of vigorously stirred 85% phosphoric acid over 20 minutes maintaining the temperature near 50C. with occasional cooling. To the clear warm solution was added 188 g. (1 mole) of 3-(4-pyridinyl)-2-cyclohexen-l-one oxime in one portion. The initially clear, yellow solution was heated on a steam bath to about 95C. where the steam was shut off. At this point the reaction mixture started to separate into two layers, eventually forming a mobile water-white upper layer and a yellow-brown viscous gum. The internal temperature of -2a-. _ ... .
- 3 ~.Z98~
the reaction mixture very gradually increased to about 110-120C. As soon as the temperature started to decrease, steam was again applied for 90 minutes.
The ge~eratcd acetic acid ~colorless ~Ipper layer, 650-700 ml.) was then re-moved by vacuum distillation followed by removal of the excess acetic anhydride in vacuo. l`he continuously stlrred and heated viscous residue was readily d:issolved in 500 ml. of warm water. The clear dark solution was treated gradually and with occasional cooling with about 800 ml. of 35%
aqueous sodium hydroxide at 60-80C. to a weakly basic pH (8-9). Some pre-cipitated solid was solubilized by the addition of 500 ml. of ethanol and heating to 80C. The colorless viscous lower layer containing mostly phos-phate salts was drawn off while hot ~1 1., 1,430 g.); it solidified at ambient temperature. To the remaining dark solution was added 320 ml. of 35% aqueous sodium hydroxide and the resulting two-phased reaction mixture was heated at reflux overnight ~about 16 hours). The dark, homogeneous solution was cooled to 5C. The crystallized solid was filtered, pressed well and then washed with the minimum amount (just the amount to cover the solid) of ice-methanol cooled 50% aqueous ethanol. To remove any remaining inorganic salts in the filter cake, the solid was washed exhaustively with warm water ~about 35 to 50 C.). The residue was dried in vacuo at 60C. to afford 134.5 g. ~79%) of the desired beige product, 3-(4-pyridinyl)aniline, m.p. 168-171; single spot on tlc ~silica; CHC13: CH30H: i-C3H7NH2 90:5:5; UV)-Example 2 3-~4-Pyridinyl)aniline was prepared in comparable yield on a pilot laboratory scale using the same procedure, as follows: Acetic anhydride, 55 kg., was charged to the 30 gallon glass-lined reactor of a distillation unit.
The phosphoric acid was added over one-half hour, with temperature rising to 100C. The solution was heated to 120C. and the steam shut off. A solution ~298~i~
of 14.6 kg. of oxime in 36 1. of acetic acid was added at a rate to maintain reflux but not cause distillation. Approximately 3/4th of the solution was added over one ancl one-half hours resulting in a full kettle. PressurP steam ~35-~0lbs.) was applied to ~egin dlstillation of acetic acid. ~fter one-hal hour, there was room in the kettle and the remaining oxime solution was added 51OW1YJ maintaining distillation. The clear acetic acid layer was distilled off at atmosp}-eric pressure over two hours leaving a dark and viscous, but stirrable residue at 120C. Vacuum was applied gradually to remove the re-maining acetic acid and acetic anhydride, keeping the pot temperature over 100C. With the residue stirring at 100C., (heat off), 20 1. of water was added over 5 minutes. The temperature dropped to 85C. but stirring was main-tained. The kettle was cooled with water to 60C., and 54 kg. of 35% aqueous sodium hydroxide was added over one-half hour, temperature 50-65C. Ethanol, 20 1., was added and the mixture cooled to 30C. before being allowed to separate. A clear aqueous layer, 66 1., was drawn off and the very dark organic layer, 56 1., was transferred to a stainless steel kettle. 35%
aqueous sodium hydroxide, 34 kg., was added to the kettle and the mixture was refluxed ~83C.) for 12 hours. In the morning, the mixture was cooled from 60 to 5C. before filtration. The dark solids were washed with 3 x 6 1. of cold 25% ethanol to give a tan product. The wet cake was slurried in 40 l. of water at 30 C. for one-half hour and refiltered. The solids were washed generously with water and dried 60C./air/overnight. There resulted 10.08 kg., or 10080/77.8x170 = 76.3% of theory, of the tan product, 3-(4-pyridinyl) aniline, m.p. = 165-7C.
Claims (8)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS::
1. In the process for preparing 3-(4-pyridinyl)aniline by acetylating 3-(4-pyridinyl)-2-cyclohexen-1-one oxime to produce the corresponding O-acetyl oxime, heating the latter under acidic conditions to produce N-acetyl-3-(4-pyridinyl)aniline and hydrolyzing the N-acetyl compound, the improvement consisting in heating 3-(4-pyridinyl)-2-cyclohexen-1-one oxime with an excess each of acetic anhydride and anhydrous phosphoric acid, distilling off acetic acid by-product and excess acetic anhydride, substantially neutralizing the remaining mixture by the addition of concentrated aqueous alkali, extracting N-acetyl-3-(4-pyridinyl)aniline from the concentrated aqueous phosphate solution with a water-miscible lower alkanol, and hydrolyzing the N-acetyl-3-(4-pyridinyl)aniline.
2. The process according to claim 1 where about 7 to 10 mole equivalents of acetic anhydride and about 3 to 10 mole-equivalents of anhydrous phosphoric acid are used per mole-equivalent of oxime.
3. The process according to claim 1 where the reactants in the first step are heated at ahout 90 to 120°C.
4. The process according to claim 2 where the reactants in the first step are heated at about 95 to 120°C.
5. The process according to claim 1, 2 or 4 wherein the N-acetyl-3-(4-pyridinyl)aniline is hydrolysed with aqueous sodium hydroxide solution.
6. The process according to claim 1, 2 or 4 wherein the N-acetyl-3-(4-pyridinyl)aniline is hydrolysed with 35% by weight aqueous sodium hydroxide solution at a temperature between about 50°C. and the reflux temperature of the mixture.
7. The process according to claim 1, 2 or 4 wherein the extraction step is carried out at 50 to 80°C and ethanol is used as the extracting solvent.
8. The process according to claim 1, 2 or 4 wherein the extraction step is carried out at 50 to 80°C, ethanol is used as the extracting solvent, and the N-acetyl-3-(4-pyridinyl)aniline is hydrolysed with 35% by weight aqueous sodium hydroxide solution at a temperature between about 50°C. and the reflux temperature of the mixture.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US10319179A | 1979-12-13 | 1979-12-13 | |
| US103,191 | 1979-12-13 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1129864A true CA1129864A (en) | 1982-08-17 |
Family
ID=22293865
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA366,467A Expired CA1129864A (en) | 1979-12-13 | 1980-12-10 | Process for preparing 3-(4-pyridinyl)aniline from 3- (4-pyridinyl)-2-cyclohexen-1-one oxime |
Country Status (22)
| Country | Link |
|---|---|
| JP (1) | JPS5687563A (en) |
| KR (1) | KR830004246A (en) |
| AR (1) | AR225058A1 (en) |
| AT (1) | ATA509880A (en) |
| AU (1) | AU532087B2 (en) |
| BE (1) | BE885570A (en) |
| CA (1) | CA1129864A (en) |
| DE (1) | DE3038778A1 (en) |
| DK (1) | DK432880A (en) |
| ES (1) | ES495606A0 (en) |
| FI (1) | FI803131L (en) |
| FR (1) | FR2471375A1 (en) |
| GB (1) | GB2065635A (en) |
| IL (1) | IL61089A (en) |
| IT (1) | IT1193982B (en) |
| LU (1) | LU82843A1 (en) |
| NL (1) | NL8005661A (en) |
| NO (1) | NO803010L (en) |
| NZ (1) | NZ194952A (en) |
| PT (1) | PT71818B (en) |
| SE (1) | SE8007188L (en) |
| ZA (1) | ZA806200B (en) |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4026900A (en) * | 1976-03-19 | 1977-05-31 | Sterling Drug Inc. | 3-(Pyridinyl)-2-cyclohexen-1-ones |
-
1980
- 1980-09-15 NZ NZ194952A patent/NZ194952A/en unknown
- 1980-09-19 IL IL61089A patent/IL61089A/en unknown
- 1980-09-19 PT PT71818A patent/PT71818B/en unknown
- 1980-09-22 AU AU62594/80A patent/AU532087B2/en not_active Ceased
- 1980-09-22 IT IT24826/80A patent/IT1193982B/en active
- 1980-09-30 GB GB8031533A patent/GB2065635A/en not_active Withdrawn
- 1980-10-02 FI FI803131A patent/FI803131L/en not_active Application Discontinuation
- 1980-10-03 ES ES495606A patent/ES495606A0/en active Granted
- 1980-10-08 BE BE1/9976A patent/BE885570A/en not_active IP Right Cessation
- 1980-10-08 ZA ZA00806200A patent/ZA806200B/en unknown
- 1980-10-08 FR FR8021517A patent/FR2471375A1/en active Pending
- 1980-10-09 NO NO803010A patent/NO803010L/en unknown
- 1980-10-09 JP JP14191380A patent/JPS5687563A/en active Pending
- 1980-10-13 DK DK432880A patent/DK432880A/en not_active Application Discontinuation
- 1980-10-13 KR KR1019800003934A patent/KR830004246A/en unknown
- 1980-10-13 LU LU82843A patent/LU82843A1/en unknown
- 1980-10-14 AT AT0509880A patent/ATA509880A/en not_active Application Discontinuation
- 1980-10-14 AR AR282874A patent/AR225058A1/en active
- 1980-10-14 NL NL8005661A patent/NL8005661A/en not_active Application Discontinuation
- 1980-10-14 DE DE19803038778 patent/DE3038778A1/en not_active Withdrawn
- 1980-10-14 SE SE8007188A patent/SE8007188L/en not_active Application Discontinuation
- 1980-12-10 CA CA366,467A patent/CA1129864A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| PT71818B (en) | 1981-07-07 |
| BE885570A (en) | 1981-04-08 |
| IL61089A (en) | 1983-11-30 |
| LU82843A1 (en) | 1981-06-04 |
| IT1193982B (en) | 1988-08-31 |
| AU532087B2 (en) | 1983-09-15 |
| DK432880A (en) | 1981-06-14 |
| ES8107188A1 (en) | 1981-09-01 |
| IL61089A0 (en) | 1980-11-30 |
| GB2065635A (en) | 1981-07-01 |
| SE8007188L (en) | 1981-06-14 |
| ES495606A0 (en) | 1981-09-01 |
| DE3038778A1 (en) | 1981-06-19 |
| NL8005661A (en) | 1981-07-16 |
| JPS5687563A (en) | 1981-07-16 |
| KR830004246A (en) | 1983-07-09 |
| PT71818A (en) | 1980-10-01 |
| FR2471375A1 (en) | 1981-06-19 |
| AR225058A1 (en) | 1982-02-15 |
| ATA509880A (en) | 1983-09-15 |
| NO803010L (en) | 1981-06-15 |
| ZA806200B (en) | 1981-09-30 |
| FI803131L (en) | 1981-06-14 |
| IT8024826A0 (en) | 1980-09-22 |
| AU6259480A (en) | 1981-06-25 |
| NZ194952A (en) | 1982-09-07 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| EP0274379B1 (en) | Process for preparing pyridine-2,3-dicarboxylic acid compounds | |
| JPS6338035B2 (en) | ||
| CA1129864A (en) | Process for preparing 3-(4-pyridinyl)aniline from 3- (4-pyridinyl)-2-cyclohexen-1-one oxime | |
| HU200446B (en) | Process for production of 1-alkyl-5-nitro-imidasoles | |
| SU1657058A3 (en) | Method for obtaining 1-oxyethyl-2-methyl-5- nitroimidazole | |
| US4351944A (en) | Improved process for preparing 3-(4-pyridinyl)aniline | |
| US4296243A (en) | Process for producing sorbic acid or its derivatives | |
| CN113292487A (en) | Preparation method of pyroxsulam intermediate | |
| CA1170271A (en) | Process for the manufacture of p-hydroxyphenylacetic acid | |
| IE50928B1 (en) | Substituted tetrahydroquinaldines and their use in the preparation of flumequine | |
| CA1153378A (en) | Process for 6,7-dihydro-9-fluoro-5-methyl-1-oxo-1h,5h- benzo¬ij|quinolizine-2-carboxylic acid | |
| US4689423A (en) | Process for the preparation of 2,3,4,5-tetrafluorobenzoyl acetates | |
| US4409389A (en) | Preparation of imidazoles | |
| CA1159832A (en) | Process for preparing flumequine | |
| WO1995023787A1 (en) | Process for producing 5,7-dichloro-4-hydroxyquinoline | |
| CN114736116B (en) | Preparation method of high-purity palmitic anhydride | |
| US3843687A (en) | Method for the preparation of derivatives of 5-hydro xy-2-carboxychromone | |
| CA1042894A (en) | Process for the production of 1,2-dihydro-2-oxo-4-methyl-7-amino-quinoline and a related compound | |
| JP2843621B2 (en) | Method for producing α-amino-ε-caprolactam | |
| US4082767A (en) | Production of alpha-amino acids | |
| CN113999169B (en) | Preparation method of fluroxypyr-meptyl | |
| US4301291A (en) | Intermediates for 6,7-dihydro-9-fluoro-5-methyl-1-oxo-1H,5H-benzo(ij)quinolizine-2-carboxylic acid | |
| SU509588A1 (en) | Method for preparing imidazo (4,5-c) quinolines | |
| SU375933A1 (en) | METHOD FOR OBTAINING 1,7-BIS- (HYDROXYTETRAORGANOSYOXANYL) -CARBORANE 12 The invention relates to the field of producing hydroxyl-containing organosilicon derivatives of carboran. which can be used as monomers for the synthesis of carboransiloxane polymers. A method is known for producing siloxanilcarboranes, in particular, 1.7-b "c- (hydroxytetraorgano-siloxanil) -carborane with the general formula 5: BUT - V.? ^? SiO-Sl-CB, oH, oC-Si-0-StO 1 I '' '',} [Л ЕR R •• В | |
| US4212973A (en) | Preparation of cyclopentane-1,1-diacetic acid and intermediate |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |