The present invention relates to a process for producing 2-propionylalkanonitriles of the formula (I)

wherein R is C4-Ci6-alkyl, in particular C6-Cio-alkyl, especially n-octyl. The present invention relates in particular to the production of 2-propionyldecanonitrile, i.e. to a compound of formula (I), wherein R is n-octyl.

BACKGROUND OF I NVENTION β-Ketonitriles, in particular 2-propionylalkanonitriles of the above formula (I), are interesting starting materials for the preparation of heterocyclic active compounds, in partic- ular for the preparation of fungicidally active 7-aminoazolopyrimidines (see, for example, EP-A-1 41 31 7, WO2006/087325). β-Ketonitriles are usually prepared by condensation of nitriles having hydrogen atoms in the a-position to the nitrile group with carboxylic esters in the presence of a base, as shown in scheme 1 below. In scheme 1 , the variables R ^a and R ^b are hydrocarbon radicals, which may bear an ether group and R' is an inert radical which is attached via a carbon atom and generally has 1 to 4 carbon atoms.

Scheme 1 :

Thus, for example, EP 141 31 7 describes the preparation of β-acylated alkanonitriles by reacting alkanonitriles with carboxylic esters and strong bases, for example alkali metal hydrides, alkali metal amides and metal alkyls. However, such bases are relatively ex- pensive and difficult to handle, making it difficult to transfer this reaction to an industrial scale. US2004/0171863, for its part, describes the preparation of β-ketonitriles by reacting a carboxylic acid ester with an alkanonitrile which carries two hydrogen atoms in the exposition and a base at temperatures of from 145 to 300°C in a closed vessel, which gives the alkali metal salt of the β-ketonitrile which is then neutralized using an acid. However, the reaction conditions stated in this reference give only moderate yields, in particular for nitriles having four or more carbon atoms.

WO2008/107397 describes the preparation of β-ketonitriles by reacting a carboxylic acid ester with an alkanonitrile in the presence of a potassium alkoxide, wherein at least 80% of the nitrile of the formula II are added to the reaction under reaction conditions. The reaction is preferably carried out in the presence of additional alkanol. Example 4 of WO2008/107397 describes the preparation of 2-propionlydecanonitrile by reacting decanonitrile and ethyl propionate in the presence of potassium methoxide resulting in high yields of the 2-propionyldecanonitrile. However, potassium methoxide is used in large amounts, which leads to problems during workup and to large amounts of waste water.

Accordingly, it is an object of the present invention to provide a process for preparing β-ketonitriles of the general formula I which solves the problems of the prior art. In particular, the process is to permit avoidance of difficult to handle bases such as alka- limetal hydrides and to afford the desired products of the formula (I) in high yield and with good purities. Moreover, the process should allow for the reduction of waste-water.

SUMMARY OF I NVENTION

It was surprisingly found that the reaction of an alkanonitrile of formula (II), in which R has one of the meanings given herein with a Ci-C4-alkyl propionate of the formula

wherein R' is Ci-C4-alkyl, in particular methyl or ethyl, results in high yields of 85 % or higher of the title compounds of formula (I), if the reaction is preformed with 1.0 to 2.0 mol, in particular 1 .1 to 1.8 mol, especially from 1 .2 to 1.6 mol of potassium methoxide, based on 1 mol of the alkanonitrile of formula (II) provided that at least a portion of the low-boiling compounds which are contained in the reaction mixture is distilled off during or after the reaction of the alkanonitrile of the formula (II) and the Ci-C4-alkyl propionate of the formula (III).

The present invention therefore relates to a process for producing 2-propionyl- alkanonitriles of the formula (I) as defined herein, which comprises reacting an alkanonitrile of formula (II) as defined herein with an Ci-C4-alkyl propionate of the formula (III) as defined herein, which process is characterized in that the reaction is carried out in a reaction vessel in the presence of 1.0 to 2.0 mol, in particular 1 .1 to 1 .8 mol, especially from 1 .2 to 1.6 mol of potassium methoxide, based on 1 mol of the alkanonitrile of formula (II) and at least a portion of the low-boiling compounds which are contained in the reaction mixture is distilled off during or after the reaction of the alkanonitrile of the formula (II) and the Ci-C4-alkyl propionate of the formula (III).

Despite the comparatively low amounts of base used, the yields of the desired 2- propionylalkanonitriles of the formula (I) are rather high and normally exceed 88 %, based on the amount of alkanonitrile of formula (II) used as a starting material. This is rather surprising as the base is consumed during the reaction. Because the hydrogen atom in the a-position of the formed 2-propionylalkanonitriles of the formula (I) is rather acidic, it is quantitatively deprotonated by the potassium methoxide and therefore, it is deemed that the base is necessary to drive the reaction to the product side.

DETAILED DESCRIPTION OF THE I NVENTION

In the definitions of the substituents R and R' given in the formulae above and below, collective terms were used which are generally representative for specific organic radicals. Here, in the term C _n -C _m , the variables n and m each state the possible number of carbon atoms in the respective radical. Particular meanings are:

Ci-C4-Alkyl, which refers to a straight-chain or branched hydrocarbon radical hav- ing 1 to 4 carbon atoms such as methyl, ethyl, propyl, 1 -methylethyl, butyl, 1 - methylpropyl, 2-methylpropyl and 1 ,1 -dimethylethyl.

C4-Ci6-Alkyl, which refers to a straight-chain or branched hydrocarbon radical having 4 to 16 carbon atoms, in particular 6 to 12 or 6 to 10 carbon atoms such as butyl, 1 -methylpropyl, 2-methylpropyl, 1 ,1 -dimethylethyl, pentyl, 1 -methylbutyl, 2- methylbutyl, 3-methyl butyl, 2,2-dimethylpropyl, 1 -ethylpropyl, hexyl, 1 ,1 - dimethylpropyl, 1 ,2-dimethylpropyl, 1 -methylpentyl, 2-methylpentyl, 3-methylpentyl, 4-methylpentyl, 1 ,1 -dimethylbutyl, 1 ,2-dimethylbutyl, 1 ,3-dimethylbutyl, 2,2- dimethylbutyl, 2,3-dimethylbutyl, 3,3-dimethylbutyl, 1 -ethylbutyl, 2-ethylbutyl, 1 ,1 ,2- trimethylpropyl, 1 ,2,2-trimethylpropyl, 1 -ethyl-1 -methylpropyl, 1 -ethyl-2- methylpropyl and their isomers, 2-ethylhexyl, 3,5,5-trimethylhexyl, 3,5- dimethylhexyl, n-heptyl, 1 -methylheptyl, 2-methylheptyl, 2-ethylheptyl, 2- propylheptyl, n-octyl, 1 -methyloctyl, 2-methyloctyl, n-nonyl, 1 -methylnonyl, 2- methylnonyl, n-decyl, 1 -methyldecyl, n-undecyl, 1 -methylundecyl, n-dodecyl, n- tridecyl, isotridecyl, n-tetradecyl and n-hexadecyl.

In the process according to the invention, it was found beneficial to add the major amount, preferably at least 80%, in particular at least 90%, particularly preferably at least 95% and especially the total amount or at least 99% of the alkanonitrile of the formula (II) to the reaction under reaction conditions.

The term "under reaction conditions" is familiar to the person skilled in the art and means that in the reaction vessel or in the reaction zone in which the desired reaction is carried out, the conditions present are such that the desired reaction proceeds at a satisfactory reaction rate. In the process according to the invention, this means that in the reaction vessel or in the reaction zone in which the reaction of the alkanonitrile of the formula (II) with the alkyl propionate of the formula (III) is carried out are temperatures at which, in the presence of the potassium methoxide, a reaction of the alkanoni- trile of the formula (II) with the Ci-C4-alkyl propionate of the formula (III) with formation of the potassium salt of the compound of formula (I) can proceed at a rate which is sufficient for the reaction.

If the major amount of the alkanonitrile of the formula (II) is added during the course of the reaction, the addition may be in a plurality of portions or continuously. The period of addition may generally last from 15 minutes to 3 hours and in particular from 30 minutes to 120 minutes. Addition may be performed at a constant or changing rate of addition. In the process according to the invention, it was also found beneficial to add the major amount, preferably at least 80%, in particular at least 90%, particularly preferably at least 95% and especially the total amount or at least 99% of the Ci-C4-alkyl propionate of the formula (III) to the reaction under reaction conditions. If the major amount of the Ci-C4-alkyl propionate of the formula (III) is added during the course of the reaction, the addition may be in a plurality of portions or continuously. The period of addition may generally last from 15 minutes to 3 hours and in particular from 30 minutes to 120 minutes. Addition may be performed at a constant or changing rate of addition.

Preferably at least 80%, in particular at least 90%, particularly preferably at least 95% and especially the total amount or at least 99% of the alkanonitrile of the formula (II) and at least 80%, in particular at least 90%, particularly preferably at least 95% and especially the total amount or at least 99% of the Ci-C4-alkyl propionate of the formula (III) are metered in parallel to the reaction vessel under reaction conditions. Parallel addition means that the start and the end of the addition of the Ci-C4-alkyl propionate of the formula (III) does not differ from, or only by a few minutes, the beginning and the end of the addition of the alkanonitrile of the formula (II), frequently no more than 5 min., in particular no more than 2 min.. In particular, the addition of the alkanonitrile (II) and the addition of the Ci-C4-alkyl propionate of the formula (III) are initiated simultaneously (< + 2 min.), and also ended simultaneously (< + 2 min.).

Parallel addition may be achieved by mixing the alkanonitrile of the formula (II) with the alkyl propionate of the formula (III) beforehand and than metering the mixture to the reaction vessel. The alkanonitrile of the formula (II) and the alkyl propionate of the formula (III) may also be added in parallel via separate metering devices.

The temperatures required for the reaction can be determined by the person skilled in the art by routine experiments and are usually at least 50°C, in particular at least 80°C and particularly preferably at least 100°C. The reaction temperatures will generally not exceed 160°C and are preferably in the range of from 80 to 160°C and especially in the range of from 1 10 to 150°C.

The reaction pressure is of minor importance for the reaction. In general, the reaction is carried out in reactors where the pressure is equalized with the atmospheric pressure, so that the reaction is carried out at atmospheric pressure. For technical reasons, it may also be advantageous to carry out the reaction at slightly reduced pressure, for example in the range of from 0.5 bar (absolute) to atmospheric pressure.

The reaction of alkanonitrile of the formula (II) with the alkyl propionate of the formula (III) is preferably carried out in an inert solvent , which preferably has a boiling point of at least 100°C at normal pressure, e.g. from 100 to 250°C, in particular from 100 to 180°C. In this context, normal pressure means a pressure of 101 kPa. Examples of suitable inert solvents are aromatic hydrocarbons, in particular alkylaromatics, such as toluene, xylenes, 1 ,2-, 1 ,3- and 1 ,4-dimethylbenzene and mixtures thereof, mesitylene, ethylbenzene, isopropylbenzene (cumene), 1 ,2-, 1 ,3- and 1 ,4-methylisopropylbenzene (cymenes) and mixtures thereof, 1 ,3- and 1 ,4-diisopropylbenzene and mixtures thereof, 1 ,2-, 1 ,3- and 1 ,4-diethylbenzene and mixtures thereof, as well as mixtures thereof with aliphatic with cycloaliphatic hydrocarbons, such as hexane, heptane, octane, cyclohex- ane, cycloheptane and cyclooctane, furthermore dialkyl ethers and alicyclic ethers, such as di-n-propyl ether, diisopropyl ether, methyl tert-butyl ether, ethyl tert-butyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetrahydrofuran, 2- methyltetrahydrofuran, dioxane and tetrahydropyran. Also suitable are mixtures of the inert solvents mentioned above.

Preferred inert solvents are the alkylaromatics mentioned above and mixtures thereof with inert solvents different therefrom, for example with aliphatic and alicyclic hydrocarbons or the ethers mentioned above. Preferably, the inert solvent comprises at least 80% by weight and in particular at least 90% by weight, based on the total amount of inert solvent, of one or more alkylaromatics or a mixture of at least one alkylaromatic with one or more aliphatic or cycloaliphatic hydrocarbons. Very particularly preferably, the inert solvent comprises at least 80% by weight and in particular at least 90% by weight of alkylaromatics, in particular xylene or mesitylene. Preferably, the solvent or solvent mixture has a boiling point in the temperature range mentioned above.

The amount of solvent is generally chosen such that the total amount of materials used (i.e. the total concentration of compounds (II), (III) and potassium methoxide) is in the range of from 20 to 80% by weight, preferably in the range from 20 to 75% by weight, in particular in the range of from 25 to 70% by weight, based on the total amount of materials used and solvents.

According to the invention, the reaction is carried out in the presence of a potassium methoxide. Here, the potassium alkoxide serves as base. If appropriate, small amounts of other bases may also be present during the reaction. In general, at least 90% by weight, preferably at least 95% by weight and in particular at least 97% by weight of the base employed are potassium methoxide. Small amounts of potassium hydroxide resulting from the hydrolysis of the potassium methoxide don't generally interfere. However, preferably their proportion is not more than 3% by weight and in particular not more than 1 .5% by weight, based on the total amount of potassium methoxide.

Usually a major amount or the total amount of the potassium methoxide, preferably at least 80%, in particular at least 90 % of the potassium methoxide, especially all or at least 99 % of the potassium methoxide, based on the total amount of potassium meth- oxide used, is initially charged in the reaction.

It has furthermore been found to be advantageous for the reaction, if the organic sol- vent employed for the reaction does not contain more than 5 %, in particular not more than 2 % by weight of protic impurities such as water and Ci-C4-alkanol.

In the process of the invention the alkanonitrile of the formula (II) and the Ci-C4-alkyl propionate of formula (III) are reacted in such an amount that the molar ratio of the al- kanonitrile of the formula (II) to the Ci-C4-alkyl propionate of formula (III) is preferably in the range from 1 : 2 to 1 : 1 .1 , in particular from 1 : 1.6 to 1 : 1.2.

The reaction is carried out in reaction vessels customary for this purpose which are generally provided with conventional means for mixing the reactants, for example stir- rers, optionally means for adding the alkanonitrile of the formula (II) and the Ci-C4-alkyl propionate of formula (III), means for controlling the reaction temperature and the reaction pressure and the like. The reaction can be carried out continuously or discontinu- ously, i.e. batch-wise, the latter being preferred. In the customary batch-wise reaction, the reaction is usually carried out in a reaction vessel provided with suitable means for mixing the reactants, for example stirrers. If appropriate, the reaction vessel may have means for adding the alkanonitrile of the formula (II) and means for adding the alkyl propionate of formula (III). In general, in the batch-wise reaction, a major amount or the total amount of the potassium methoxide, preferably at least 80%, in particular at least 90 % of the potassium methoxide, especially all or at least 99 % of the potassium methoxide, based on the total amount of potassium methoxide used, is initially charged in the reaction vessel, if appropriate, with a partial amount or the total amount of inert solvent and, if appropriate, a partial amount, e.g. up to 20%, of the alkyl propionate of formula (III), if appropriate a partial amount, e.g. up to 20%, of the alkanonitrile of the formula (II). The mixture obtained in this manner is then heated to reaction temperature, and the addition of the remaining amount of potassium methoxide, if any, and the remaining amount of inert solvent, if any, is then initiated. Preferably, all of the methoxide and all of the inert solvent, if desired, are initially charged in the reactor. If a partial amount or in particular the major or total amount of the alkyl propionate of formula (III) and of the alkanonitrile of the formula (II) are added under reaction conditions, the addition of (II) and (III) is preferably carried out in parallel, as described above. In general, following the termination of the addition of the alkanonitrile (II) and, if appropriate, the alkyl propionate (III), there is a post-reaction phase during which the reaction mixture is kept at the reaction temperature for a certain period of time. In general, this period of time is at least thirty minutes and will generally not exceed 24 hours, in particular 12 h. In particular, this period is in the range of from 1 to 12 hours and especially in the range of from 2 to 8 hours. Espe- cially the total reaction time, i.e. the time starting with the beginning of the addition of at least one of the reactants (II) or (III) does not exceed 24 hours and is in particular in the range from 2.5 to 14 hours, especially from 3 to 12 hours.

According to the invention, at least a portion of the low-boiling compounds contained in the reaction mixtures is distilled off during or after the reaction of the alkanonitrile of the formula (II) and the Ci-C4-alkyl propionate of the formula (III).

Low boilinig compounds are in particularly those, which have a boiling point of at most 1 10°C at normal pressure. They include in particular water, C1-C4 alkanols, in particular methanol or ethanol, Ci-C4-alkyl propionate of the formula (III), in particular methyl propionate and ethyl propionate, and inert solvents, if any.

The amount of low boilers, which are distilled off is generally at least 10 g, in particular at least 20 g/kg and especially at least 50 g/kg of the reaction mixture. In particular the portion of the low boilers, which is distilled of is from 10 to 250 g/kg, more particularly 20 to 200 g/kg and especially from 50 to 150 g/kg of the reaction mixture.

Preferably, the distillation of the portion of the low-boiling compounds contained in the reaction mixtures is only started, when at least 40 %, e.g. from 40 to 100 % or from 40 to 90 % of the total amount of alkanonitrile of the formula (II) have been converted to the 2-propionylalkanonitriles of the formula (I). The amount of alkanonitrile of the formula (II), which is consumed in the reaction as well as the amount of 2-propionylalkanonitriles of the formula (I) formed (in the form of its salt) can be determined by routine methods, e.g. by Gas Chromatography (GC) or HPLC of analytical samples taken from the reaction mixture or online by ATR-FTIR (attenuated total reflection fou- rier transform infrared spectroscopy). Usually, the distillation of the portion of the low- boiling compounds is performed, before the reaction mixture is worked-up, i.e. before the initially formed potassium salt of the 2-propionylalkanonitrile of the formula (I) and any potassium methoxide present is neutralized.

After the reaction has ended, the reaction mixture can be worked up in a customary manner and the β-ketonitrile of the formula I can be isolated, if required. For work-up of the reaction mixture, the potassium salt initially formed of the 2- propionylalkanonitrile of the formula (I) and any potassium methoxide present will generally be neutralized. To this end, the reaction mixture is mixed with water or an aqueous acid, for example an aqueous hydrochloric acid or an aqueous sulfuric acid. Pref- erably, during mixing, the pH is monitored, and the pH should not be lower than a value of preferably pH = 2, in particular not lower than pH = 3, especially not lower than pH = 5. To this end, a procedure may be adopted, for example, where a dilute aqueous acid is introduced into the reaction mixture in an amount such that the pH of the resulting aqueous phase is in the range of from pH 3 to 10 and in particular in the range of pH 5 to 9. Alternatively, the reaction mixture may be introduced into water or into an aqueous acid, and the pH of the aqueous phase may, if required, be readjusted by addition of acid to a pH in the range of pH 3 to 10 and in particular pH 5 to 9. The organic phase now comprises the desired 2-propionylalkanonitrile of the formula (I), if appropriate dissolved in an organic solvent.

After drying, if appropriate, the 2-propionylalkanonitrile of the formula (I) can be isolated in a customary manner from the organic phase, for example by distilling off the organic solvent. The 2-propionylalkanonitrile of the formula (I) that remains can then be subjected to a further purification. However, it has been found that, under the reaction con- ditions according to the invention, the 2-propionylalkanonitrile of the formula (I) is obtained in a purity which is generally sufficient for further reactions. Frequently, even a removal of the organic solvent can be dispensed with.

The process according to the invention is suitable in particular for preparing 2- propionylalkanonitrile of the formula (I) in which R is C6-Cio-alkyl, especially n-octyl.

In a particularly advantageous manner, the 2-propionylalkanonitrile of the formula (I) which has been prepared by the process according to the invention can be employed for preparing 7-aminotriazolopyrimidines of the general formula (IV).

In formula (IV), R is C4-Ci6-alkyl, in particular C6-Cio-alkyl and especially n-octyl. Therefore, the invention also relates to a process for preparing 7-aminotriazolo- pyrimidines of the general formula (IV), which comprises: a) preparing a 2-propionylalkanonitrile of the formula (I) by a process as described herein and b) reacting the 2-propionylalkanonitrile of the formula (I) with 5-amino-1 H-1 ,2,4- triazole of the formula V

The reaction of the 2-propionylalkanonitrile of the formula (I) with the compound of the formula (V) or its tautomer can be carried out by analogy to known processes for preparing 7-aminotriazolopyrimidines of the general formula (IV), e.g. by process described in EP-A 141317 and WO2006/0873, respectively.

The reaction of the 2-propionylalkanonitrile of the formula (I) with the compound of the formula (V) is preferably carried out in the presence of an acid. Suitable acids are, in principle, carboxylic acids, and also sulfonic acids. In the case of the sulfonic acids, catalytic amounts are typically employed, which are usually in the range of from 1 to 40 mol%, based on one mole of aminotriazole of the formula (V). In the case of the carboxylic acids, these carboxylic acids may also act as solvents.

Examples of suitable sulfonic acids are methanesulfonic acid, chlorosulfonic acid, tri- fluoromethanesulfonic acid, benzenesulfonic acid, 2,3-dimethylbenzenesufonic acid, 3,4-dimethylbenzenesulfonic acid and p-toluenesulfonic acid. Particular preference is given to chlorosulfonic acid. Suitable organic carboxylic acids are formic acid, acetic acid, propionic acid, 2-methylpropionic acid, benzoic acid and mixtures thereof.

The reaction of the compound of formula (V) with the 2-propionylalkanonitrile of the formula (I) is preferably carried out in an organic inert solvent. Preference is given to those organic solvents in which the starting materials are at least partially or fully soluble. Examples of suitable solvents are in particular Ci-C4-alkanols, such as methanol, ethanol, propanol, isopropanol, n-butanol, isobutanol, tert-butanol, the acyclic and ali- cyclic ethers mentioned above, aromatic hydrocarbons, in particular alkylaromatics as mentioned above, and also halogenated aromatics, for example chlorobenzene, dichlo- robenzene, furthermore glycols and glycol monoalkyi ethers, diethylene glycol and their monoalkyl ethers, amides and lactams, in particular N,N-di-Ci-C4-alkylamides of aliphatic carboxylic acids having 1 to 4 carbon atoms, such as dimethylformamide, dieth- ylformamide, dibutylformamide, Ν,Ν-dimethylacetamide, the carboxylic acids mentioned above and mixtures of these solvents, and also mixtures of these solvents with water. In a preferred embodiment, the inert solvent consists to at least 80% by weight and in particular to at least 90% by weight of aromatic solvents, in particular alkylaro- matics.

The reaction of the compound of formula (V) with the compound of formula (I) is pref- erably carried out at temperatures in the range of from 80 to 250°C, in particular in the range of from 120 to 220°C and especially in the range of from 140 to 180 °C.

In the reaction of the compound of formula (V) with the compound of formula (I), the water formed during the reaction is advantageously removed, if appropriate distilled off, for example as an azeotrope with the solvent used.

According to a preferred embodiment, step b) is carried out immediately after step a), without it being necessary to isolate the compound of formula (I). In particular, for step b) of the process, a solution, obtained after neutralization of the potassium salt of the compound of formula (I) formed in step a) of the 2-propionylalkanonitrile of the formula (I), in an inert organic solvent is used. This is in particular a solution in an inert solvent which consists to at least 80% by weight and in particular to at least 90% by weight of one or more alkylaromatics. The reaction of the aminotriazole of formula (V) or its tautomer can be carried out either batch-wise or else continuously. It is usually carried out batch-wise. To this end, the aminotriazole (V) and the 2-propionylalkanonitrile of the formula (I) are generally initially charged in a reaction vessel, if appropriate together with solvent and, if appropriate, acid, and the mixture is heated to reaction temperature. If appropriate, part of the sol- vent is distilled off together with the water of reaction formed. Suitable reaction vessels are the reactors mentioned for step a) which, if appropriate, may also be provided with means for distillative removal of solvents.

From the reaction mixture obtained in this manner, the 7-aminotriazolopyrimidine com- pound of the formula (IV) can be isolated in a customary manner, for example by aqueous work-up, if appropriate followed by a crystallization for purification or by removal of the solvent and subsequent recrystallization of the product. The examples below serve to illustrate the invention.

Example 1 : Preparation of 2-Propionyldecanonitrile In a 500 ml. jacketed vessel fitted with stirrer, reflux condenser, distillation bridge and two metering pumps, 1 15 g of o-xylene were initially charged, 42.3 g (0.6 mol) of solid potassium methoxide were added and the mixture was heated to 1 15°C (internal temperature). Then 62 g (0.4 mol) of decanonitrile and 58.0 g (0.56 mol) of ethyl propionate were added via the metering pumps over a period of 80 minutes with constant addition rate while maintaining the reaction temperature. Ethyl propionate was added via a dipped tube. After the addition had ended, the mixture was kept at 1 15 °C for further 20 minutes. Then distillation of low boiling components was started. The reaction temperature was slowly increased to 128°C within 2.5 h and a total of 27.8 g of low boiling components were distilled off. The distillate contained methyl propionate, meth- anol and ethanol as main components. Then the reaction mixture was cooled to below 80°C.

120 g of water were added and adjusted to a pH of 6 by addition of about 59.3 g of a 0.52 mol/L aqueous hydrochloric acid and the mixture was stirred for 15 minutes at 75°C. Then, the (lower) aqueous phase was removed. This gave 206.3 g of a light- yellow solution having a content of product of value of 36.25 % a/a (GC), which can be reacted further as such. The yield of 2-propionyldecanonitrile, based on decanonitrile starting material, was 89.7 %. For purification, the organic solvent may be removed from the organic phase evaporation and the residue may be distilled under high vacuum, with the product passing over at 130 to 140°C/1 mbar. The product can be identified by NMR-spectroscopy:

H-NMR: 0.9 (t, 3H); 1.1 1 (t, 3H), 1.2-1.4 (m, 10H); 1.4-1 .55 (m, 2H); 1.8-2.0 (m, 2H); 2.75 (q, 2H), 3.40 (t, 1 H).

Example 2: Preparation of 2-Propionyldecanonitrile (Comparative experiment)

In a 500 ml_l jacketed vessel fitted with stirrer, reflux condenser, distillation bridge and two metering pumps, 1 15 g of o-xylene were initially charged, 42.3 g (0.6 mol) of solid potassium methoxide were added and the mixture was heated to 1 15°C (internal temperature). Then 62 g (0.4 mol) of decanonitrile and 58.0 g (0.56 mol) of ethyl propionate were added via the metering pumps over a period of 84 minutes and 82 minuteswith constant addition rate while maintaining the reaction temperature. Ethyl propionate was added via a dipped tube. After the addition had ended, the mixture was kept at 1 15 °C for further 120 minutes. Then the reaction mixture was cooled to below 80°C. 100 g of water were added and adjusted to a pH of 6 by addition of about 46.5 g of a 0.41 mol/L aqueous hydrochloric acid and the mixture was stirred for 15 minutes at 75°C. Then, the (lower) aqueous phase was removed. This gave 207.9 g of a light- yellow solution having a content of product of value of 30.18 % a/a (GC), which can be reacted further as such. The yield of 2-propionyldecanonitrile, based on decanonitrile starting material, was 75.2 %.

The comparison of Example 1 and comparative Example 2 reveals that yields of the product 2-propionyldecanonitrile can be significantly increased, if at least a portion of the low boiling compounds contained in the reaction mixture is distilled off.

Example 3: 5-Ethyl-6-octyl-[1 ,2,4]triazolo[1 ,5-a]pyrimidin-7-ylamine:

In a 0.5 L jacketed vessel fitted with condenser and water separator (Dean-Stark trap), 55 g of o-xylene was initially charged, and 6.3 g of chlorosulfonic acid was added. 31.8 g of 3-amino-1 ,2,4-triazole and 55 g of o-xylene were added and the thus obtained mixture was heated to 55-60°C. Then 204.6 g of a solution of 2-propionyldecanonitrile (36.3% by weight in o-xylene, obtained from example 1 ) were added within 35 minutes, while maintaining the internal temperature in the range from 51 -60°C. The mixture was then heated to reflux and stirred under reflux for 10 hours, while the water of reaction formed was removed via a phase separator at a temperature of 145-147°C. The mixture was allowed to cool to below 140°C and 7.3 g of triethylamine were added drop- wise at a temperature of 128-131 °C. On further cooling, the product precipitated in the form of colorless crystals. At a temperature 105°C, 15 g of methanol were added. The mixture was cooled further to 17°C, and after 48 h the solid formed was separated off. The filtercake was washed with a mixture of 100 g of methanol and 30 g of water followed by further 100 g of water. The product was dried under reduced pressure. This gave 90.7 g of colorless crystals having a content of 98.0% a/a (HPLC).