Organic compounds -- part of the class 532-570 series – Organic compounds – Chalcogen in the nitrogen containing substituent
Reexamination Certificate
2002-03-08
2004-01-06
Raymond, Richard L. (Department: 1624)
Organic compounds -- part of the class 532-570 series
Organic compounds
Chalcogen in the nitrogen containing substituent
C544S218000
Reexamination Certificate
active
06673922
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a process for preparing a triazine compound in a high yield, said triazine compound being useful as an intermediate of pharmaceuticals or agricultural chemicals, and a process for preparing a quaternary ammonium salt using the triazine compound obtained by the above process, said quaternary ammonium salt being useful as a condensation agent.
BACKGROUND ART
A quaternary ammonium salt wherein a nitrogen atom at the 4-position of morpholine such as 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride is quaternized and to the nitrogen atom are bonded a 4,6-dialkoxy-1,3,5-triazin-2-yl group and an alkyl group is a useful compound as a condensation agent for preparing an ester compound or an amide compound.
The quaternary ammonium salt can be prepared by reacting 2-halo-4,6-dialkoxy-1,3,5-triazine with 4-alkylmorpholine, and as a process for preparing the triazine compound, there is known a process comprising allowing an alcohol compound to act on cyanuric chloride in the presence of 3 mol of sodium hydrogencarbonate and 2.7 mol of water based on 1 mol of the cyanuric chloride (SYNTHETIC COMMUNICATIONS, Vol. 26, No. 18, pp. 3491-3494, 1996).
In the above process, however, the yield of the triazine compound is as low as 65% and is not satisfactory. The present invention overcomes this shortcoming by providing a process for preparing the triazine compound in a high yield and, in addition, provides a process for efficiently preparing the quaternary ammonium salt.
SUMMARY OF THE INVENTION
The present invention recognizes that the yield of the triazine compound is remarkably increased when the water content present in the reaction system at the beginning of the reaction or the water content present in the reaction system during the period of the reaction is greatly decreased by the use of a hydrogencarbonate in the form of an organic solvent suspension or the like. This is in contrast to the conventional process wherein an alcohol compound is reacted with cyanuric chloride, wherein the hydrogencarbonate is used in the form of an aqueous solution and, hence, a large amount of water is present in the reaction system. The present invention recognizes that when the water content at the beginning of the reaction is controlled to not more than a specific value, the desired product can be obtained in a high yield even if water formed by the reaction as a by-product is not removed.
Briefly stated, the present invention is a process for preparing a triazine compound (2-halo-4,6-dialkoxy-1,3,5-triazine) represented by the following formula (I):
wherein
R
1
is an alkyl group of 1 to 4 carbon atoms or an aryl group of 6 to 8 carbon atoms, and X is a halogen atom,
said process comprising reacting a cyanuric halide with an alcohol compound represented by the following formula:
R
1
OH
wherein
R
1
is an alkyl group of 1 to 4 carbon atoms or an aryl group of 6 to 8 carbon atoms,
in the presence of an alkali to prepare the triazine compound represented by the above formula (I),
wherein the water content present in the reaction system at the beginning of the reaction is not more than 0.5 mol based on 1 mol of cyanuric halide.
Another embodiment of the present invention is a process for preparing the triazine compound, comprising reacting a cyanuric halide with the alcohol compound in the presence of an alkali to prepare the triazine compound, wherein the water content present in the reaction system during the period of the reaction is not more than 2.5 mol based on 1 mol of cyanuric halide.
In the present invention, a hydrogencarbonate is particularly preferably used as the alkali.
According to the process of the invention for preparing a triazine compound, the desired product can be obtained in a high yield.
The present invention further provides a process for preparing a quaternary ammonium salt represented by the following formula (III):
wherein
R
1
is an alkyl group of 1 to 4 carbon atoms or an aryl group of 6 to 8 carbon atoms, R
2
is an alkyl group of 1 to 4 carbon atoms, and X is a halogen atom,
said process comprising extracting a triazine compound represented by the above formula (I) from the reaction solution containing the triazine compound using a slightly water-soluble organic solvent and then mixing the resulting slightly water-soluble organic solution of the triazine compound with a morpholine compound represented by the following formula (II) to perform reaction;
wherein R
2
is an alkyl group of 1 to 4 carbon atoms.
According to the above process, production efficiency of the triazine compound is high, and hence, from the viewpoint of the total production process starting from the primary materials such as an alcohol compound and a cyanuric halide, the quaternary ammonium salt that is the final desired product can be prepared efficiently.
DETAILED DESCRIPTION OF THE INVENTION
The process for preparing a triazine compound according to the invention is not particularly different from the conventional process comprising reacting a cyanuric halide with an alcohol compound in the presence of an alkali, except that the amount of water present in the reaction system at the beginning of the reaction is controlled to not more than a specific value or the amount of water present in the reaction system during the period of the reaction is controlled to not more than a specific value.
That is to say, as the cyanuric halide, conventionally known compounds are employable without any restriction, and examples thereof include cyanuric chloride, cyanuric bromide and cyanuric iodide. Of these, cyanuric chloride that is particularly easily obtainable can be preferably employed.
As the alcohol compound, an alcohol compound represented by the following formula is employable.
R
1
OH
wherein R
1
is an alkyl group of 1 to 4 carbon atoms or an aryl group of 6 to 8 carbon atoms.
Examples of the alcohol compounds employable in the invention include methanol, ethanol, propanol, isopropyl alcohol, butanol, tert-butyl alcohol, phenol, cresol and xylenol. Of these, an alkyl alcohol compound of 1 to 4 carbon atoms, such as methanol, ethanol, propanol, isopropyl alcohol or butanol, is preferably used from the viewpoint of usefulness of the quaternary ammonium salt (final desired product) as the condensation agent.
In the present invention, the alcohol compound has only to be used in an amount of 2 mol or more based on 1 mol of the cyanuric halide from the viewpoint of the stoichiometry. From the viewpoint of high reaction efficiency, however, it is preferable that the alcohol compound also have a function of a reaction solvent. When using the alcohol compound as the reaction solvent, too small amount of the alcohol causes aggregation or solidification to bring about troubles in stirring or the like, and hence, it is preferable to use the alcohol compound in an amount of 5 to 50 mol, particularly 5 to 30 mol, based on 1 mol of the cyanuric halide.
The alkali employable in the invention is, for example, a basic salt such as a hydrogencarbonate, an organic amine or an inorganic amine, and a hydrogencarbonate is particularly preferably employed. As the hydrogencarbonate, conventionally known compounds are employed without any restriction. Examples of the hydrogencarbonates employable in the invention include sodium hydrogencarbonate, potassium hydrogencarbonate and ammonium hydrogencarbonate. Of these, sodium hydrogencarbonate and potassium hydrogencarbonate are preferably employed.
If the amount of the alkali is too small, hydrogen chloride formed by the reaction of the alcohol compound with the cyanuric halide is not neutralized, and thereby the progress of the reaction becomes difficult. If the amount thereof is too large, the slurry viscosity becomes high to cause troubles in stirring or the like. Hence, the amount of the alkali is desirably selected from the range of 2 to 3 mol, preferably 2.05 to 2.8 mol, based on 1 mol of the cyanuric halide.
In the process for preparing a triazine compound according to the invention, an inert organic solvent is
Hirano Naoki
Saijo Masako
Balasubramanian Venkataraman
Raymond Richard L.
Tokuyama Corporation
Webb Ziesenheim & Logsdon Orkin & Hanson, P.C.
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