CA1066291A - 3-formyl-4-methyl-2,6-dihydroxypyridine and a process for its preparation - Google Patents
3-formyl-4-methyl-2,6-dihydroxypyridine and a process for its preparationInfo
- Publication number
- CA1066291A CA1066291A CA284,121A CA284121A CA1066291A CA 1066291 A CA1066291 A CA 1066291A CA 284121 A CA284121 A CA 284121A CA 1066291 A CA1066291 A CA 1066291A
- Authority
- CA
- Canada
- Prior art keywords
- methyl
- dihydroxypyridine
- formyl
- formula
- alkali metal
- 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
- C07D213/60—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 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
- C07D213/62—Oxygen or sulfur atoms
- C07D213/69—Two or more oxygen atoms
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Pyridine Compounds (AREA)
- Pharmaceuticals Containing Other Organic And Inorganic Compounds (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
The present invention relates to a new 3-formyl-4-methyl-2,6-dihydroxypyridine of the formula I
I
its alkali metal and alkaline earth metal salts and their preparation by hydrolysing the 2,6-dihydroxypyridine derivative of the formula II
II
or one of its alkali metal or alkaline earth metal salts in a basic medium with the elimination of chloroform. The compound of formula I above is a valuable intermediate product especially for the production of dyestuffs.
The present invention relates to a new 3-formyl-4-methyl-2,6-dihydroxypyridine of the formula I
I
its alkali metal and alkaline earth metal salts and their preparation by hydrolysing the 2,6-dihydroxypyridine derivative of the formula II
II
or one of its alkali metal or alkaline earth metal salts in a basic medium with the elimination of chloroform. The compound of formula I above is a valuable intermediate product especially for the production of dyestuffs.
Description
-- 6~,,',2~L
.. . .
The invention concerns the new 3-formyl-~-methyl-2,6-dihydroxypyri-dine of the formula I -~
~ CHO
H ~ N ~ OH
and its alkali metal and alkaline earth metal salts. As alkali metal or alkaline earth metal salts, the sodium and potassium salts, especially, are significant.
The compound according to the present invention can exist in several tautomeric forms and this description obviously embraces all the possible tautomeric forms.
The subject of the invention is also a process for the preparation of 3-formyl-4-methyl-2,6-dihydroxypyridine of the formula I, which is charac-terized in that a 2,6-dihydroxypyridine derivative of the formula II
ll ¦ OH II
H ~ ~ H
or one of its alkali metal or alkaline earth metal salts is hydrolysed in a basic medium with the elimination of chloroform.
A process for the introduction of a formyl group into 2,6-dihydroxy-pyridine compounds, which are substituted in a specific way, is admittedly already known from the literature (DOS 2,025,427), the reaction being carried out in the presence of aci.d chlorides. Howeverj this method easily leads to decomposition reactions and does not produce the desired result. On the other hand, the hydrolysis in a basic medium, according to the present invention~ of 3-(~ -trichloro-~-hydroxy)ethyl ~-methyl-2,6-dihydroxypyridine of the formula II, with elimination of chloroform, gives the end product in good yield and free of substantial impurities. The reaction of the compound of the formula II with, for example, alkali metal hydroxide as the base is ~ ;
carried out in an aqueous alcoholic medium, preferably in aqueous-ethanolic potassium hydroxide solution, at the reflux temperature. The 3-formyl-4-methyl-2,6-dihydroxypyridine according to the invention is thus obtained in the form of the alkali metal salt, from which the metal-free compound can be prepared by acidification.
The conversion of the alkali metal or alkaline earth metal salts of the compound according to the invention into the metal-free compound is car-ried out by treatment of the aqueous solutions with an acid and isolation of the product by concentration. It is particularly advantageous to use acetic acid as the acid. Since the free compound of the formula ~ tends very easily, in particular in an acid medium, to undergo condensation or polymerization reactions with itself, it is especially advantageous that the alkali metal or ;;-alkaline earth metal salts should be very stable forms.
The 3-formyl-4-methyl-2,6-dihydroxypyridine according to the inven-tion is a valuable intermediate product, which is suitable for the preparation of dyestuffs, and plant protection agents. In this, it is of particular advantage that the compound should be in the form of its stable salt. The stable aIkali metal salt of 3-formyl-4-methyl-2,6-dihydroxypyridine, for example, shows all the reactions of a compound with an acidic CH- and can, in ;~
addition, be used for the customary carbonyl reactions at the formyl group.
Example 1 ;." : ' 272.5 parts of 3-(~ -trichloro-2-hydroxy)ethyl-4 methyl-2,6-dihydroxypyridine are introduced into 3,000 parts of ethanol and treated with a solution of 500 parts of potassium hydroxide in 400 parts of water and 1,700 parts of ethanol. The reaction mixture is kept at the boil under reflux for 30 minutes, with stirring, and is then cooled down to 20C. The product which has separated out in the course of this operation is filtered off, wash-ed with 200 parts of ethanol and dried. The crude product thus obtained can be freed from adhering excess potassium hydroxide by washing with dilute .
. , . . . .: , :.' , , .: . .,. .: : .
' ' " ' .' ' ' ' ' ' . . . , : :: ; i ' ' : ' .
~6162~
acetic acid until a neutral reaction is obtained. 94 parts are thus obtained of potassium 3-formyl-4-methyl-2,6-dihydroxypyridine (=~9% of the theoretical - yield) which possesses a melting point of above 350C after recrystallization from water.
Analysis: calculated: C 44.0% H 3.2% N 7.3%
found: C 44.2% H 3.4% N 7.3%
W and IR spectra confirm ~he assumed structure.
The conversion of the potassium salt into the metal-free compound is carried out as follows: 191.1 parts of the product obtained are suspended ~ ~
in 200 parts of a mixture of 160 parts of acetic acid and 40 parts of water, ~ -and the reaction mixture is concentrated to 50 parts under vacuum. On allow- ~ -ing the concentrated solution to stand, the metal-free compound crystallizes out. The pure 3-formyl-4-methyl-2,6-dihydroxypyridine, with a melting point of 180-182C, is obtained by redissolution and recrystallization from a mix-ture of 160 parts of ethanol and 40 parts of water.
Analysis: calculated: C 54.9% H 4.6% N 9.1%
found: C 55.1% H 4.7% N 9.0%
Example 2 -- .
; The initial compound named 3~ trichloro-~-hydroxy)ethyl ~-methyl-2,6-dihydroxypyrldine can be prepared as follows:
125 parts of 4-methyl-2,6-dihydroxypyridine dissolved in 400 parts of ethanol, 80 parts of sodium acetate dissolved in 100 parts of water and 148 parts of chloral dissolved in 400 parts of water are mixed together and the whole is stirred for eight hours at 20 CO The reaction mixture is allow- ~
ed to stand at room temperature for another 48 hours, the product which has ;
separated out in the course of this operation is filtered with suction, washed with water and dried _ vacuo at 30 ~
Obtained are 218 parts (= 80% of the theoretical) of 3~ tri-chloro-~-hydroxy)ethyl-4-methyl-2,6-dihydroxypyridine which, when recrystallized.
_ 3 -.- -. ~
~0~6'~
from ethyl acetate, has a melting point of 195 C.
Aralysis:calculated: N 5.4% Cl 39.9%
found: N 5.1% Cl 39.1%
.''~'' ~
''; ';''~' ~' . '"
. .~,.
- 4 ~ ..
......................... ............. ............................ .. . .
......................... ............. ............................ : .
,., , ':', '' , . ' . ' , . ,, , '' ~,',
.. . .
The invention concerns the new 3-formyl-~-methyl-2,6-dihydroxypyri-dine of the formula I -~
~ CHO
H ~ N ~ OH
and its alkali metal and alkaline earth metal salts. As alkali metal or alkaline earth metal salts, the sodium and potassium salts, especially, are significant.
The compound according to the present invention can exist in several tautomeric forms and this description obviously embraces all the possible tautomeric forms.
The subject of the invention is also a process for the preparation of 3-formyl-4-methyl-2,6-dihydroxypyridine of the formula I, which is charac-terized in that a 2,6-dihydroxypyridine derivative of the formula II
ll ¦ OH II
H ~ ~ H
or one of its alkali metal or alkaline earth metal salts is hydrolysed in a basic medium with the elimination of chloroform.
A process for the introduction of a formyl group into 2,6-dihydroxy-pyridine compounds, which are substituted in a specific way, is admittedly already known from the literature (DOS 2,025,427), the reaction being carried out in the presence of aci.d chlorides. Howeverj this method easily leads to decomposition reactions and does not produce the desired result. On the other hand, the hydrolysis in a basic medium, according to the present invention~ of 3-(~ -trichloro-~-hydroxy)ethyl ~-methyl-2,6-dihydroxypyridine of the formula II, with elimination of chloroform, gives the end product in good yield and free of substantial impurities. The reaction of the compound of the formula II with, for example, alkali metal hydroxide as the base is ~ ;
carried out in an aqueous alcoholic medium, preferably in aqueous-ethanolic potassium hydroxide solution, at the reflux temperature. The 3-formyl-4-methyl-2,6-dihydroxypyridine according to the invention is thus obtained in the form of the alkali metal salt, from which the metal-free compound can be prepared by acidification.
The conversion of the alkali metal or alkaline earth metal salts of the compound according to the invention into the metal-free compound is car-ried out by treatment of the aqueous solutions with an acid and isolation of the product by concentration. It is particularly advantageous to use acetic acid as the acid. Since the free compound of the formula ~ tends very easily, in particular in an acid medium, to undergo condensation or polymerization reactions with itself, it is especially advantageous that the alkali metal or ;;-alkaline earth metal salts should be very stable forms.
The 3-formyl-4-methyl-2,6-dihydroxypyridine according to the inven-tion is a valuable intermediate product, which is suitable for the preparation of dyestuffs, and plant protection agents. In this, it is of particular advantage that the compound should be in the form of its stable salt. The stable aIkali metal salt of 3-formyl-4-methyl-2,6-dihydroxypyridine, for example, shows all the reactions of a compound with an acidic CH- and can, in ;~
addition, be used for the customary carbonyl reactions at the formyl group.
Example 1 ;." : ' 272.5 parts of 3-(~ -trichloro-2-hydroxy)ethyl-4 methyl-2,6-dihydroxypyridine are introduced into 3,000 parts of ethanol and treated with a solution of 500 parts of potassium hydroxide in 400 parts of water and 1,700 parts of ethanol. The reaction mixture is kept at the boil under reflux for 30 minutes, with stirring, and is then cooled down to 20C. The product which has separated out in the course of this operation is filtered off, wash-ed with 200 parts of ethanol and dried. The crude product thus obtained can be freed from adhering excess potassium hydroxide by washing with dilute .
. , . . . .: , :.' , , .: . .,. .: : .
' ' " ' .' ' ' ' ' ' . . . , : :: ; i ' ' : ' .
~6162~
acetic acid until a neutral reaction is obtained. 94 parts are thus obtained of potassium 3-formyl-4-methyl-2,6-dihydroxypyridine (=~9% of the theoretical - yield) which possesses a melting point of above 350C after recrystallization from water.
Analysis: calculated: C 44.0% H 3.2% N 7.3%
found: C 44.2% H 3.4% N 7.3%
W and IR spectra confirm ~he assumed structure.
The conversion of the potassium salt into the metal-free compound is carried out as follows: 191.1 parts of the product obtained are suspended ~ ~
in 200 parts of a mixture of 160 parts of acetic acid and 40 parts of water, ~ -and the reaction mixture is concentrated to 50 parts under vacuum. On allow- ~ -ing the concentrated solution to stand, the metal-free compound crystallizes out. The pure 3-formyl-4-methyl-2,6-dihydroxypyridine, with a melting point of 180-182C, is obtained by redissolution and recrystallization from a mix-ture of 160 parts of ethanol and 40 parts of water.
Analysis: calculated: C 54.9% H 4.6% N 9.1%
found: C 55.1% H 4.7% N 9.0%
Example 2 -- .
; The initial compound named 3~ trichloro-~-hydroxy)ethyl ~-methyl-2,6-dihydroxypyrldine can be prepared as follows:
125 parts of 4-methyl-2,6-dihydroxypyridine dissolved in 400 parts of ethanol, 80 parts of sodium acetate dissolved in 100 parts of water and 148 parts of chloral dissolved in 400 parts of water are mixed together and the whole is stirred for eight hours at 20 CO The reaction mixture is allow- ~
ed to stand at room temperature for another 48 hours, the product which has ;
separated out in the course of this operation is filtered with suction, washed with water and dried _ vacuo at 30 ~
Obtained are 218 parts (= 80% of the theoretical) of 3~ tri-chloro-~-hydroxy)ethyl-4-methyl-2,6-dihydroxypyridine which, when recrystallized.
_ 3 -.- -. ~
~0~6'~
from ethyl acetate, has a melting point of 195 C.
Aralysis:calculated: N 5.4% Cl 39.9%
found: N 5.1% Cl 39.1%
.''~'' ~
''; ';''~' ~' . '"
. .~,.
- 4 ~ ..
......................... ............. ............................ .. . .
......................... ............. ............................ : .
,., , ':', '' , . ' . ' , . ,, , '' ~,',
Claims
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. 3- Formyl -4-methyl-2,6-dihydroxypyridine of the formula I
I
and its alkali metal and alkaline earth metal salts.
2. Process for the preparation of 3-formyl-4-methyl-2,6-dihydroxypyri-dine of the formula I
I
characterized in that 3-(.beta.,.beta.,.beta.-trichloro-.alpha.-hydroxy)ethyl-4-methyl-2,6-dihy-droxypyridine of the formula II
II
or one of its alkali metal or alkaline earth metal salts is hydrolysed in a basic medium with elimination of chloroform.
3. Process according to Claim 2, characterized in that the hydrolysis is carried out with an aqueous alcoholic solution of an alkali metal hydroxide at the boil under reflux.
4. 3-formyl-4-methyl-2,6-dihydroxypyridine as defined in Claim 1.
5. Potassium 3-formyl-4-methyl-2,6-dihydroxypyridine as defined in
Claim 1.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19762635206 DE2635206A1 (en) | 1976-08-05 | 1976-08-05 | 3-FORMYL-4-METHYL-2,6-DIHYDROXYPYRIDINE AND A METHOD FOR ITS PRODUCTION |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1066291A true CA1066291A (en) | 1979-11-13 |
Family
ID=5984778
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA284,121A Expired CA1066291A (en) | 1976-08-05 | 1977-08-04 | 3-formyl-4-methyl-2,6-dihydroxypyridine and a process for its preparation |
Country Status (9)
| Country | Link |
|---|---|
| JP (1) | JPS5321173A (en) |
| BE (1) | BE857479A (en) |
| BR (1) | BR7705105A (en) |
| CA (1) | CA1066291A (en) |
| DE (1) | DE2635206A1 (en) |
| FR (1) | FR2360577A1 (en) |
| GB (1) | GB1542818A (en) |
| IT (1) | IT1143754B (en) |
| NL (1) | NL7708447A (en) |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2230392A1 (en) * | 1972-06-22 | 1974-01-31 | Cassella Farbwerke Mainkur Ag | SUBSTITUTED PYRIDINE COMPOUNDS AND PROCESS FOR THEIR PRODUCTION |
-
1976
- 1976-08-05 DE DE19762635206 patent/DE2635206A1/en not_active Withdrawn
-
1977
- 1977-07-29 NL NL7708447A patent/NL7708447A/en not_active Application Discontinuation
- 1977-08-03 BR BR7705105A patent/BR7705105A/en unknown
- 1977-08-04 JP JP9304477A patent/JPS5321173A/en active Pending
- 1977-08-04 FR FR7724060A patent/FR2360577A1/en active Granted
- 1977-08-04 BE BE179909A patent/BE857479A/en unknown
- 1977-08-04 IT IT2648577A patent/IT1143754B/en active
- 1977-08-04 CA CA284,121A patent/CA1066291A/en not_active Expired
- 1977-08-04 GB GB3275677A patent/GB1542818A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| FR2360577B1 (en) | 1979-07-20 |
| JPS5321173A (en) | 1978-02-27 |
| FR2360577A1 (en) | 1978-03-03 |
| GB1542818A (en) | 1979-03-28 |
| BE857479A (en) | 1978-02-06 |
| NL7708447A (en) | 1978-02-07 |
| IT1143754B (en) | 1986-10-22 |
| BR7705105A (en) | 1978-05-02 |
| DE2635206A1 (en) | 1978-02-09 |
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