IE43510B1 - Nitrile and production of nitriles - Google Patents

Abstract

3,7-Dimethyl-2-octenenitrile of the formula (II), a novel nitrile compound having a perfuming action, is obtained by a hydrogenation process from 3,7-dimethyl-3-hydroxy-6-octenenitrile, which gives the corresponding octanonitrile: from the latter, the compound of the formula (I) can be obtained by dehydration. The octanonitrile intermediate also possesses a characteristic pleasant odour.

Description

is invention relates to two nitriles, one of which is novel, and to their sduction. aspect of the present invention provides 3,7-dimethyl-3-hydroxy-octane-ltrile having the following formula:8 7 6 5 4 3 2 1 CHg-CH-CHg-CHg-CHg-C(OH)——CHg-CN (I) ch3 ch3 ter aspects of the present invention provide a process for producing compound nd a process for producing 3,7-dimethyl-oct-2-ene-l-nitrile having the lowing formula:8 7 6 5 4 3 2 1 CH,-CH—-CH,--CH,-CH,-C=CH—CN (11) CHg CHg compounds I and II—and more particularly compound II-—possess a characterically pleasant scent which enables them to be used as perfumes and for the nulation, in conjunction with other known compounds, of perfumed mixtures which be used for soaps, cosmetics and deodorants. In this sense, they can replace i advantage, 3,7-dimethyl-octa-2,6-diene-l-nitrile (III): CH-—C=CH—CH,—CH,—C=CH—CN Π ι CHg CHg - 2 43510 which is known as geranonitrile, in comparison.with which they have a sweeter fragrance and an improyed chemical stability.

In this connection, it should be noticed that, whereas geranonitrile, upon treatment for a few days at room temperature with a mixture of 98? HgSO^ and glacial CHjCOOH in the volume proportions of 5 to 25 gives rise, upon addition of water, to a slightly volatile pitchy substance, compound (II), which is saturated at the 6- and 7-positions, remains unaltered.

Another important application of compounds I and II is thfeir use as intermediates in a number of organic syntheses.

Compounds I and II can be produced by using as the starting material, 3,7di methyl-3-hydroxy-oct-6-ene-l-nitri 1e (IV): CH3—C=CH—CH2—CH2—C (OH)—CHg—CN ch3 ci!3 Compound IV can be obtained according to a synthesis disclosed in Patent No. 41921.

Thus compound I can be produced by hydrogenation of compound IV, and compound II can be produced by dehydration of compound I.

The following Examples illustrate the present invention.

EXAMPLE 1 .28 Grams of 3,7-dimethyl-3-hydroxy-oct-6-ene-l-nitrile (IV) in 25 ml hexane, supplemented by 0.52 gram of a catalyst comprising palladium on activated charcoal (containing 5% Pd by weight), were hydrogenated with stirring, in a glass apparatus, at room temperature, and under a hydrogen pressure of 760+100 millimetres of mercury, absolute pressure.

The absorption of the stoichiometric amount of hydrogen to saturate the double bond of compound IV took about one hour.

After this time, the catalyst was filtered off and the solvent was evaporated under vacuum, and 3,7-dimethyl-3-hydroxy-octane-l-nitrile (I) was collected; the conversion and the selectivity with respect to compound I were both over 90%.

On subsequent distillation in vaouo with a Vigreux column, a product was obtained - 3 £3Si.O rich, has a purity of ahout 98% and a boiling point of 83?C-84°C under an isolute pressure of 0,3 mmHg, EXAMPLE 2 ie compound I was obtained using the same ratio between the reactants as in «ample 1, but by carrying out the hydrogenation in a steel autoclave under an litial hydrogen pressure of 8,6 kilograms per square centimetre (gauge). The -ocedures for collecting and purifying the product were yery much the same as ir Example 1.

EXAMPLE 3 Grams of 3,7-dimethyl-3-hydroxy-octane-l-nitrile (I) and 3 grams of basic ielm aluminium oxide were maintained for 1.5 hours at 220°C-23Q°C under a Itrogen stream in a glass flask equipped with, a bubhle condenser which was ioled with water. :ter this stage, the mixture contents of the flask were allowed to cool to room ‘mperature, then the reaction mass was taken up with diethyl ether and filtered, id the solvent was then thoroughly evaporated. ius, 3,7-dimethyl-oct-2-ene-l-nitrile (II) was obtained, which was composed of mixture of the cis- and trans-isomers in a ratio of 45/55 approximately; the ilectivity with respect to compound II was not less than 90%. impound II was obtained at a purity of 98% approx, by subjecting the residue described hereinabove to distillation in vacuo and collecting the product n'ch boiled at 52°C-53°C under an absolute pressure of 0.1 mmHg. e characterization of compounds I and II was effected by IR, NMR and massectrography analyses, e IR spectrum confirmed the presence of the following functional groups: H 3460 cnr? =N (non conj.) 2252 cm-1 for compound (I) -0 of a tert.alcohol 1153 cm’1 —H 3045 cm-1) ΞΝ (conj, at alpha) 2215 cm-1 for compound (II) C (conj.) 1630 cm-1 Ji (stretching) 700 cm-]/ - 4 10 The NMR analysis (solvent CC14, internal standard hexamethyldisoloxane HMDS) indicated the following characteristic signals:-OH -Cr(2) -CH2-(4)J -CH -CH, -CH ) i—(5,6)( 3,23 parts ner million (ppm) 2.42 ppm’' 1.45 pm 1.24 ppm 7 for compound (I) / \ CH3 0.83 ppm =CH 5.03 ppnT’ -CHz-(4) 2.08 ppm -CHg(cis- or trans-)1.98 ppm -CHg(trans - or cis-)1.85 ppm -CH -(6)) 1.50 ppm -CH2-(5)J -CH 1.20 ppm CH, / 3 \ 0.81 PPm_ \h3 for the compound (II) Mass spectrometry confirmed the molecular weights (169 for I and 151 for II) and the respective expected structures.

Claims (3)

2. 2. 3,7-Dimethyl-3-hydroxy-octane-l-nitrile having the following formula:8 CH
3. 3. 7 6 5 4 3 2 1 ig—-C|i—“-CHg—-CHg—-CHg·- C (OH)——CHg—CN CHCH(I) . A process for producing the compound claimed in claim 1, which comprises /drogenating 3 s 7-dimethyl-3-hydroxy-oct-6-enenitrile with hydrogen. . A process according to claim 2, substantially as described in the foresing Example 1 or 2. . A process for producing 3,7-dimethyl-oct-2-ene-l-nitrile having the blowing formula:CHg—CH—CHg—CHg—CHg—j: cl, 3 2 1 :=CH—CN CH, (II) rich process comprises dehydrating the compound claimed in claim 1. , A process according to claim 4, substantially as described in the foreting Example 3. , 3,7-Dimethyl-oct-2-ene-l-nitrile whenever produced by a process according ι claim 4 or 5.