JPS613891A - Production of nitrile - Google Patents

Abstract

PURPOSE:To obtain alkoxy nitrile at a good yield in short time by electrolyzing acetal having a specific structure in an org. solvent contg. trimethyl silyl cyanide and alkali metal perchlorate. CONSTITUTION:About 1.0-1.5 times equiv. trimethyl silyl cyanide, an org. solvent in about 10-100 times the amt. of the acetal and about 1-10mol% alkali metal perchlorate or ammonium perchlorate are added to the acetal, ketal or alkoxy compd. expressed by the formula II, for example, peptylaldehyde dimethl acetal. Electrolysis is executed with such liquid as an electrolyte under stirring to convert selectively the acetal, by which the alkoxy nitrile expressed by the formula I is yielded. In the formulas I, II, R<1> denotes an alkyl group of 2-9C having an alkoxy carbonyl group, R<2> an alkyl group of 1-4C, R<3> H or the same group as the group of R<1> and R<4> the same group as the group of R<3>.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention involves electrolyzing an acetal, ketal or alkoxy compound of formula (1) in an organic solvent in the presence of trimethylsilyl cyanide and a perchlorate to produce the corresponding nitrile compound of formula (1). Relating to a method of manufacturing.

(II) (I) Formula (1), (II>, where R1 optionally represents an alkyl group having 2 to 9 carbon atoms, an alkyl group, an arylalkenyl group, or a furyl group having an alkoxycarbonyl group. R2 represents an alkyl group having 1 to 4 carbon atoms.

R11 represents hydrogen or the same group as R1, or R
Both 1 and R8 represent a cyclohexyl group, a piperidyl group or a dihydrofuryl group, optionally having an alkoxycarbonyl group, an alkoxy group and/or an alkanoyloxy group.

R4 is the same as R8 or represents hydrogen if R3 is not hydrogen.

As the alkali metal perchlorate, lithium perchlorate, sodium perchlorate, potassium perchlorate, etc. are used.

- As the ammonium perchlorate salt, tetramethylammonium verchlorate, tetraethylammonium verchlorate, tetrabutylammonium verchlorate, etc. are used.

Alkoxynitriles have many uses as important synthetic intermediates for various pharmaceuticals, agricultural chemicals, fragrances, etc. Alkoxynitrile is converted to β-aminoacrylonitrile, which is an intermediate for the synthesis of nitrogen-containing heterocyclic compounds, by Thorpe condensation. Similarly, aminoalcohol derivatives, which are important synthetic intermediates, can be obtained by reducing alkoxynitriles.

Conventionally, a method for producing alkoxynitrile involves reacting orthoformic acid ester, which is a type of acetal, with hydrocyanic acid in the presence of a zinc chloride catalyst, and replacing only one alkoxy group with a cyano group (J, G).

Er1ckson; J, As, Ches+,,S
oc, +73+1338 (1951)) or with substituents such as N,N-dimethylamino-dimethoxymethane.

Method for reacting acids in an autoclave (H.

Bredereck et al., Chew, B.
er, +103+210 (1970)) and the like have been disclosed.

However, in general, it is difficult to produce alkoxynitrile by substitution reaction even if sodium cyanide or potassium cyanide is directly applied to acetal. Recently, acetals such as tin chloride and
vinegar? Luoroboron Aethera.

A method of synthesis by reacting trimethylsilyl cyanide with a Lewis acid catalyst such as
, Nozaki et al.
on Letters+22, 4279 (1981
)).

However, the alkoxynitrile obtained by the reaction of orthoformic acid ester and hydrocyanic acid is only a special compound that has another alkoxy group or dimethylamino group on the same carbon to which the cyano group is attached, and it also requires the use of toxic cyanide gas under pressure. This is not a desirable method.

In addition, the method of reacting with trimethylsilyl cyanide in the presence of a Lewis acid catalyst involves using 6 to 7 wt% of tin dichloride or trifluoroboron etherate and stirring for several hours.
Alkoxynitrile has been obtained with a yield of ~95%, but tin dichloride and trifluoroboron etherate are industrially problematic, as the former poses a problem in waste disposal, and the latter generates highly toxic gas when decomposed. Problems such as doing so arise. Further, the reaction time according to the present invention is about 1 minute to 35 minutes, but when the above-mentioned Lewis acid is used, several hours are required.

The present inventors have made extensive studies to improve the above problems and selectively produce the compound of formula (1) from the compound of formula (II) and trimethylsilyl cyanide. As a result, the compound of formula (II) and trimethylsilyl cyanide The present invention has been completed based on the discovery that the compound of formula (I) can be selectively produced in high yield by passing an electric current through a solvent containing the compound for a short period of time.

Specific examples of the compound of formula (II) (hereinafter simply referred to as acetals) in the present invention include heptylaldehyde-1,1-dimethylacecool, heptane-2,2-dimethylacetal, and 8-methoxycarbonyloctylaldehyde. 111°-dimethyl acetal, 2-methoxycarbonylacetaldehyde-1,1-dimethyl acetal, 2-(β-methoxycarbonyl)ethylcyclohexanone-1,1-dimethyl acecul, benzaldehyde dimethyl acecul, phenethylaldehyde dimethyl acetal , furfuryl aldehyde dimethyl acetal, cinnamic aldehyde dimethyl acetal, 2-methoxy-N-ethoxycarbonyl? Examples include veridine, 1,4-dimethoxy-1-(acetoxymethyl)-4-hydrofuran, and the like.

In the present invention, these acetals and
．． Add 5 equivalents of trimethylsilyl cyanide and 10 to 100 times the amount of Acekul as a chlorinated alkane solvent, and add a supporting salt of 1 mole percent to Acekul, and while stirring at room temperature, add 0.01 ~ 1 minute to 3 minutes using a platinum electrode with an amount of electricity of 5 F/mol
When electricity is applied for 5 minutes, acetal is selectively converted and 85%
Alkoxynitrile can be obtained with the above yield. Moreover, some alkoxy compounds are also converted into cyano compounds in high yield by the method according to the present invention.

As the chlorinated alkane solvent used in the present invention, methylene chloride, 1,2-dichloroethane, etc. are used.

As the electrolytic supporting salt, lithium perchlorate, sodium perchlorate, tetraethylammonium verchlorate, tetrabutylammonium verchlorate, tetraethylammonium tosylate, etc. are used.

The production of alkoxynitrile in the present invention is thought to be due to the conversion of acetal into alkoxynitrile by a certain kind of acid (called electrolytic acid) generated near the electrode by a small amount of current applied as a catalyst.

As described above, the present invention has the advantage that an alkoxynitrile can be produced in a short period of time under mild conditions such as room temperature, atmospheric pressure, and normal pressure with a small amount of electricity.

Examples will be described below.

Example 1 1 mmol of heptylaldehyde dimethyl acecur and 1.2 mmol of trimethylsilyl cyanide were placed in a single glass cell with a capacity of 5 - dissolved in 5 parts of methylene chloride, and lithium perchlorate was added to this in an amount of 8 parts of acecool. Add mole percent (0.08 mmol) or 20 mole percent (0.2 mmol) of tetraethylammonium barchlorate, insert two platinum electrode plates (1.5 aj) into the electrolytic cell solution, and leave at room temperature under -atmosphere. Electrolysis was performed while stirring the electrolyte solution using a magnet and a Kusterer. It was confirmed using thin layer chromatography that the raw material disappeared when the terminal voltage was set to 157 and a direct current of 8 to 10 mA was applied for 10 minutes (electricity consumption: 0.07 Farade - 1 mole).

Then, the electricity was turned off and the mixture was stirred for 5 minutes, and then a small amount of pyridine was added to neutralize the trace amount of acid and the reaction was terminated. After distilling off the solvent, the remaining liquid is purified using column chromatography or distillation to obtain the desired 1-methoxy-1
-Cyanoheptane was obtained with a yield of 95%. (boiling point 8
5℃/9 mmHg) infrared absorption spectrum (neat
): 2815cm-1, 22403-1 (characteristic absorption), NMR spectrum (Cα4): δ0.9
(t, 3H, CH3), 1.2~2.0 (
m, IOH, (CH2)8) 3.45 (S,
3H,0CHII), 3.95 (t,IH,CH)
.

Example 2 Phenethylaldehyde dimethyl acecool (1 mmol) and trimethylsilyl cyanide (1.3 mmol), with the addition of lithium perchlorate (0.08 mmol) and tetraethylammonium verchlorate (0.2 mmol) as supporting salts, When electricity was applied for 12 minutes in methylene chloride (electricity consumption: 0.03 F/+++ol), 1-cyano-1-methoxy-2-phenylethane (boiling point: 110°C/9 smlg) was obtained with a yield of 97%.

Infrared absorption spectrum (neat): 2815a1
-' + 2240e1m, 1600al (characteristic absorption), NMR spectrum (Cα4): 63.0
5 (d, 2H, CH2), 3.45 (S, 3H
,0CHa).

4.2, (t, IH, CI), 7.25 (m
,5H,Co)Is) Example 3 Methyl 3.3-dimethoxypropionate (1 mmol)
and trimethylsilyl cyanide (1.4 mmol) were electrolyzed for 18 minutes (0°15F/mol) according to the method of Example 1 to yield methyl 3-methoxy-3-cyanopropionate (boiling point 75°C 75 mmHg). It was obtained in 86%.

Infrared absorption spectrum (neat): 2815ai
-', 2240e1m, 1740c11-'
(Characteristic absorption), NMRxh)/I/ (Ccj
! a): δ2.85 (d, 2H, CHz), 3.
50 (S, 3H, 0CHa).

3.72 (S, 3H, 0COCHs), 4.50 (
t, IH, CH).

Examples 4 to 11 Following Example 1, alkoxynitrile derivatives of formula (1) were synthesized. The results are shown in a table, and the amount of 1-limethylsilyl cyanide, reaction time, amount of electricity consumed (F/mo+
), yield (acetal group f,) indicates the boiling point of the product.

(Left below) Procedural amendment 1. Indication of the case Patent Application No. 12.4177 of 19822, Name of the invention: Method for producing nitrile3, Relationship with the case by the person making the amendment Name of the patent applicant Name: Osaka Organic Chemical Industry Co., Ltd.4, Spontaneous by the agent6, Number of inventions increased by amendment None Contents of amendment 1. r73.1338J on page 4, line 8 of the specification has been changed to r73.1338J. ' Corrected to 1338J.

2. rN, N-dimethylamino- on page 4, line 8
"ditoximeta" is corrected to "rN,N-dimethylamino-dimethoxymetha".

3. Correct r103.210J on page 4, line 12 to read "Kanko 210".

4. r22.4279J on page 5, line 1 [mutual,
Corrected to 4279J.

5. “Heptane-2,2-
"dimethyl acetal" is corrected to "heptanone-2,2-dimethylacecool."

6. r (m, 5H, C0Hs) on page 10, line 7
It says J, r (1III5H1c6H6)' J
I am corrected.

7. Replace the table on page 12 with the attached one.

Claims (1)

[Claims] Formulas, ▲Mathematical formulas, chemical formulas, tables, etc.▼(II) (In the formula, R^1 is an alkyl group having 2 to 9 carbon atoms, an arylalkyl group, which optionally has an alkoxycarbonyl group,
Arylalkenyl group or furyl group, R^2 is an alkyl group having 1 to 4 carbon atoms, R^3 is hydrogen or the same group as R^1, or both R^1 and R^3, depending on the case. It represents a cyclohexyl group, piperidyl group or dihydrofuryl group having an alkoxycarbonyl group, an alkoxy group and/or an alkanoyloxy group, and R^4 is the same as R^3 or represents hydrogen if R^3 is not hydrogen. ) in an organic solvent in the presence of trimethylsilyl cyanide and an alkali metal perchlorate or an ammonium perchlorate salt,
Formula ▲Mathematical formulas, chemical formulas, tables, etc.▼(I) (The symbols in the formula are the same as above) A method for producing a compound.