JPS5978166A - Synthesis of intermediate useful for manufacture of 2-substituted imidazole - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The use of high efficiency products in the treatment of aqueous suspensions of particulate solid substances insoluble in water has become increasingly popular in recent years.

There is therefore a constant search in industry for new systems that can be used to facilitate the dewatering of aqueous suspensions of organic and inorganic materials in water and wastewater treatment, mineral processing, paper manufacturing, and the like.

Recently, polymer compositions based on imidacillin monomers have been
was introduced for the treatment of such suspensions. However, these imidazole-based polymers are unable to maintain their effectiveness at high pH due to their hydrolytic instability. The difficulties encountered in using polymers made from imidacillin monomers were disclosed by Lawson in U.S. Pat. This is largely overcome by the use of chemically related 2-vinylimidazole polymers and methods for their preparation modified by Oberberger as disclosed in Rimmer Letters Edition, Volume 11, Page 465 (1973). be able to. Although the use of these 2-vinylimidazole polymers overcomes the stability problems inherent in the use of imidacillin polymers, these 2-vinylimidazole polymers themselves are not suitable for processing such suspensions. They do not have the charge necessary to make these compositions highly effective. Thus, there is a need for other new monomers that can produce polymers that are effective in processing aqueous particulate suspensions.

The present invention provides synthetic methods that result in new intermediates useful in the preparation of 2-alkenylimidazoles that can be quaternized to give new 1,3-dialkyl-2-alkenylimidazolium salts. Both these salts and the 2-alkenylimidazole can be homopolymerized or copolymerized with each other or with other copolymerizable monomers,
It has found utility as a monomer that can provide compositions useful in the treatment of aqueous particulate suspensions.

According to the present invention, (1) a Diels-Alda compound between a conjugated diene or a compound that behaves similarly to a conjugated diene in the Diels-Alda reaction and a dienophylation selected from the group consisting of acrolein and methacrolein;
about 1 equivalent of an aldehyde cycloadduct derived from the reaction, where the aldehyde cycloadduct is represented by the general structure: R1-Cll0, where R1 is the non-aldehyde portion of the aldehyde cycloadduct. (2) about 1 equivalent of the general structure: R3-C-C-R" where Rs and R2 are individually selected from the group consisting of hydrogen, saturated aliphatic groups having 1 to 5 carbon atoms, and phenyl; , and (3) about 2 equivalents of ammonia are reacted.

A1 reactant: The aldehyde cycloaddition product used in the present invention is prepared by a conventional Diels-Alder reaction [Ann,
460.98 (1928); 470°62 (1929)
HBer, 62, 2081° 2087 (1929)].

Suitable conjugated dienes for the reaction in this case are 1°3-butazene; 1,3-pentadiene; 1,3-hexatsuene; 2-methyl-1,3-butazene; 2,3-dimethyl-1,3-butadiene. ; cyclopentadiene; 1-methylcyclopentadiene: y; 2-methylcyclobentasoene; cyclohexadiene and hihexachlorocyclopentasoene, but are not limited to these. Suitable compounds that behave similarly to conjugated dienes in Diels-Alder reactions and are therefore useful in the preparation of aldehyde adducts include, but are not limited to, acrolein, furan, and anthracene. Genophiles suitable for reaction with conjugated tzenes are limited to acrolein and methacrolein.

Diels-Alder between conjugate Tzen and Genophile
In carrying out the reaction, reaction conditions depend on the specific structure of the diene used and which genophile is used. Reactions using methacrolein generally require relatively long reaction times and high pressures. However, in general, the reaction is completed within 1 to 20 hours by varying the reaction temperature within the range of 20 to 250°C, varying the reaction pressure within the range of 0.1 to 20 atm, and without the need for a catalyst. .

Because of the complexity of aldehyde cycloadducts resulting from the use of some of the tsenes listed above, these aldehyde cycloadducts are referred to herein with the general formula: 7? represented by l-CHo, where R
1 is the non-aldehyde portion of the aldehyde cycloaddition product.

The alpha dicarbonyl compound reacted with the aldehyde cycloadduct has the general structure: 7?3-C-C-J? 2, where Bt and R3 have the same meanings as above. Although a preferred alpha dicarbonyl compound is glyoxal, any alpha dicarbonyl compound of the above general formula can be used.

Synthesis B1 The synthesis method consists of reacting an aldehyde cycloadduct with an alpha dicarbonyl compound in the presence of 2 equivalents of ammonia. In the reaction of the aldehyde cycloaddition-10- product with the alpha-socarponyl compound, it is preferable that the alpha radical maintains the molar ratio of the nyl compound to the aldehyde cycloaddition product within the range of about 0.9 to about 1=1. Although preferred, it is possible to vary this ratio. The molar ratio of ammonia to aldehyde cycloaddition should be about 2.2=1 to 20:1;
About 2.0:1 is preferred. Although the use of ammonia is preferred, the 1,2-disubstituted imidazole intermediate
It can also be prepared by substituting one equivalent of alkylamine for one equivalent of ammonia.

Although it is preferred that the synthetic reaction be carried out with the starting materials in solution, the reaction can also be carried out in a slurry or emulsion. Solvents useful for such use are generally those which dissolve all the reactants and do not react with them under the reaction conditions; water and suitable alcohols are preferred solvents. The exothermic synthetic reaction is generally carried out under stirring and atmospheric pressure within an excursion range of about -50 to 100°C; It is preferred to keep the synthesis reaction within a temperature of 25 to 25°C.

The synthesized 2-substituted imidazole intermediate is represented by -shell structure: where RIXR2 and R3 have the same meanings as above.

Having set forth the precise scope of the invention in the claims, the following specific examples illustrate several aspects of the invention and more particularly point out ways in which the invention may be evaluated. . However, these examples are given by way of illustration only and should not be considered as limitations on the invention except as stated in the claims. Parts and percentages are by operculum unless otherwise specified.

Example 1 61 parts of 5-nor-2-cal-xaldehyde, a Diels-Alder addition plate of acrolein and cyclopentadiene, 36.2
Charge 5 parts of 80% glyoxal and 150 parts of methanol. After purging the reactor with nitrogen and cooling to -10°C, 17 parts of anhydrous ammonia are added under vigorous stirring and cooling. After continuing stirring for a further 4 hours and maintaining the temperature at -10°C, the mixture is gradually warmed to room temperature.

After driving off about half of the solvent from the reaction product, 200
0 parts of water, and then the precipitated solid was collected on sandpaper and dried under vacuum to obtain 74 parts of pure 2-(5-nor?runen-2-yl)imidazole with a melting point of 209-13-210°C. A rate of 93% is obtained.

Analysis shows that this product is endo and exo isomer 8'0/
20 mixture.

Example 2 Cycloaddition products of acrolein and butadiene, 1, 2,
The procedure of Example 1 is followed in detail except that 55 parts of 3.6-titrahydropenzaldehyde are used. This reaction gives 68 parts of 2-(3-cyclohexen-1-yl)imidazole, melting point 173-174°C. This corresponds to a yield of 92%.

Example 3 Methyl-4-nor derived from the Diels-Alder reaction between acrolein and a mixture of 1-methylcyclopentadiene and 2-methylcyclopentadiene was used as an aldehyde cycloaddition product. When following the procedure of Example 10 using a mixture of dioxyaldehydes, one obtains a mixture of 2-(methyl-5-norbornen-2-yl)imidazole isomers as a wax that melts at 70-85°C. .

Example 4 The procedure of Example 1 was followed using 1,2,3,6-tetrahydro-1-methylbenzaldehyde derived from the Diels-Alder reaction between 1,3-butadiene and methacrolein as the aldehyde cycloaddition product. When obeying, 2.
-(1-Methyl-3-cyclohexen-1-yl)imidazole is obtained.

Example 5 Using 4,5-tumethyl-1°2.3.6-titrahydropenzaldehyde derived from the Diels-Alder reaction between 2,3-zomethylptasoene and acrolein as the aldehyde cycloaddition product. When following the procedure of Example 1, 2-(3°4-trimethylcyclohexy-3-
en-1-yl)imidazole is formed.

Example 6 2-Methyl-5-nor A? derived from the Diels-Alder reaction between cyclopentatsuene and methacrolein as an aldehyde cycloaddition product? When lune-2-cal follows the procedure of Example 1 using xaldehyde,
2-(2-methyl-5-nor-lune-2-yl)imidazole is produced.

Example 7 When using bicycloIl'2.2.2]oct-5-ene-2-carboxaldehyde derived from the Diels-Alder reaction between 1,3-cyclohexazene and acrolein as the aldehyde cycloaddition product. is 2-(bicyclor2.2.2'loct-5-en-2-yl)
Imidazole is produced.

Example 8 3,4 derived from the Diels-Alder reaction between acrolein and acrolein as aldehyde cycloadducts
-dihydro-2R-bilan-2-cal when following the procedure of Example 1 using xaldehyde, 2-(3,
, 4-dihydro2H-pyran-2-yl)imidazole is produced.

Examples 9-13 When following the procedure of Example 1 using various other feed materials, a series of 2-substituted imidazoles are produced.

Those materials are shown in Table 1. 17-493 Table 1 Examples Diene Dienophilylanthracene Acrolein Furan Acrolein 1,3-Butadiene Acrolein Alpha Radical 2-Substituted Imidazole 18-

Claims (1)

[Scope of Claims] 1. (α) From a Diels-Alder reaction between a conjugated diene or a compound that behaves similarly to a conjugated diene in the Diels-Alder reaction and a diene Philyl selected from the group consisting of acrolein and methacrolein. induced, about 1
an equivalent of an aldehyde cycloadduct, the cycloadduct can be represented by the general structure: R'CHO, where Bl is the non-aldehyde portion of the aldehyde cycloadduct; (b) about 1 equivalent of a -membrane Structure: R8-C-C-R2 wherein R2 and R3 are each selected from the group consisting of hydrogen, a saturated aliphatic group having 1 to 5 carbon atoms, and phenyl; and (C) 1. A method for the synthesis of intermediates useful in the production of 2-alkenylimidazoles, characterized in that about two doses of ammonia are reacted. 2. The method of claim 1, wherein the compound which behaves similarly to the conjugated tsene in the Diels-Alder reaction is selected from the group consisting of acrolein, furan and anthracene. 3. The method of claim 1, wherein the diene is selected from the group consisting of cyclopentazene, methylcyclopentadiene, butadiene and substituted butatsuenes. 4. The method according to claim 1, wherein the dienephyle is either acrolein or methacrolein. 5. The method according to claim 1, wherein the alpha-socal compound is either glyoxal or methylglyoxal. 6. The method according to claim 1, wherein the diene is cyclopentadiene, the dienephile is acrolein, and the alpha dicarbonyl compound is glyoxal. 7. A product synthesized according to the method described in claim 1. 8. A product synthesized according to the method described in claim 3. 9. The product according to claim 8, wherein the intermediate is 2-(5-norbornen-2-yl)imidazole. 1 (l intermediate strength 2- (3-cyclohexene-1
-yl)imidazole. 11. The product of claim 8, wherein the intermediate is 2-(l-methyl-3-cyclohexen-1-yl)imidazole. 12 The intermediate is 2-(methyl-5-norbornene-2-
9. A product according to claim 8, which is a mixture of yl)imidazole isomers.