DE2108926B2 - Process for the preparation of 3-acyl-4-hydroxy-buten (2) acid lactones - Google Patents

Description

R ³

R ⁴

in which R ¹ , R ² , R ³ and R ⁴ each denote a hydrogen atom or an alkyl radical having 1 to 7 carbon atoms, characterized in that an -oxo-carboxylic acid of the general formula

R ¹ -C COOH

Il ο

(D

R ³

R ⁴

HR ²

C = C-C = O

(U)

wherein R ¹ , R ² , R ³ and R ^{4 have} the aforementioned meaning, reacts at temperatures between 40 and 200 ° C. without using a catalyst

Hydrogen bromide (Houben-Weyl, methods of organic Chemistry, Volume VI / 2.4. Edition [1963J pages 658, 712 ff).

It has now been found that 3-acyl-4-hydroxybutene (2) acid lactones the general formula

with a «^ -unsaturated carbonyl compound of the general formula

It is known from Houben-Weyl, Methods of Organic Chemistry, 4th Edition Volume 7/1 (1954), pages 85 ff and Organic Reactions, Volume 16, pages 15 ff (John Wiley & Sons, Inc., New York 1968) that «, / ^ - unsaturated aldehydes or ketones which carry at least two hydrogen atoms on the ^ carbon atom enter into an aldol reaction with aldehydes under the influence of a basic catalyst. The condensation takes place at the y position which is adjacent to the double bond. In the case of ketones, there is the additional possibility of attack on the second carbon atom to the keto group if it bears at least two hydrogen atoms. Polyene -carbonyl compounds are obtained in mostly unsatisfactory yields, which in turn can continue to react using the same reaction principle. Depending on the constitution of the starting materials, mixtures of different components that are difficult to separate are often obtained, and polymerization or resinification also occurs as side reactions.

4-Hydroxy-butene (2) acid lactones have so far only been produced in a cumbersome, multi-stage and uneconomical way, e.g. B. starting from 3-chloropropanediol (l, 2) and potassium cyanide or by reacting 2,3-epoxy-butanoic acid esters with glacial acetic acid and R ² -C

R '

C =
C.

R ³

\ n /

= C

I. c

(III)

o ^/ χ

R ⁴

in which R ¹ , R ² , R ³ and R ⁴ each represent a hydrogen atom or an alkyl radical having 1 to 7 carbon atoms, advantageously obtained by using an -oxocarboxylic acid of the general formula

R ¹ -C-COOH

with a «, ^ - unsaturated carbonyl compound of general formula

R ³

R ⁴

HR ²

I I

C-C-C = I.

(H)

wherein R ¹ , R ² , R ³ and R ^{4 have} the aforementioned meaning, reacts at temperatures between 40 and 200 ° C. without using a catalyst.

The implementation is carried out for the case of the use of crotonaldehyde and glyoxylic acid the following reaction equation is illustrated.

OHC

OHC-CH

OCH -H, O

H ₁ C-CH HOOC

With regard to the known processes, the process according to the invention surprisingly yields 3-acyl-4-hydroxy-buten (2) acid lactones («-Butenolide) in a simpler and more economical way in better yield and purity. The carbonyl group of «-Oxocarboxylic acid reacts with the« position of the carbonyl compound, which is according to the state of the art was not to be expected. Since both starting materials are polyfunctional, it had to be assumed that various reactions in the reaction mixture

bo would occur to each other, e.g. B. Aldolization of the Carbonyl compound, formation of polyene carbonyl compounds, Diels-Alder reactions, and one accordingly Mixtures of different end products would be obtained. The inventive method is therefore with

b5 surprising its favorable results.

The starting materials can be used in stoichiometric amounts or in excess, preferably in one Ratio of 1 to 5 moles of one starting material to 1

Moles of the other starting material.

Suitable «« -Qxo-carboxylic acids are z. E.g .: glyoxylic acid, pyruvic acid, isobutylglyoxylic acid.

Suitable "^ -unsaturated carbonyl compounds are, for example, acrolein, crotonaldehyde, dimethylacrolein; Methyl vinyl ketone, pent-3-en-2-one, mesityl oxide.

Another surprising advantage of the process according to the invention is that it can be used of catalysts is not necessary

The reaction is generally carried out without pressure or under pressure, advantageously under the pressure of the reaction mixture established at the reaction temperature, continuously or batchwise, preferably at temperatures between 80 and 130 ^° C. If appropriate, a solvent such as water is used under the reaction conditions ; aliphatic ethers such as diethyl ether; aromatic hydrocarbons such as benzene, toluene; Halogenated hydrocarbons such as trichlorethylene; Esters, such as ethyl acetate; or corresponding mixtures. The solvent is expediently used in an amount of 1 to 5% by weight, based on the Λ-oxocarboxylic acid.

In general, the reaction is carried out as follows: A mixture of the starting materials, optionally together with a solvent, is kept at the reaction temperature for 2 to 4 hours. Expediently, the starting mixture is given a substance which stabilizes the unsaturated carbonyl compound, e.g. B. hydroquinone, too. One of the starting materials can also be added to the remainder of the mixture over a period of 15 to 45 minutes at the beginning of the reaction. If the boiling range of the mixture is above 100 ^° C., the water of reaction can be distilled off from equilibrium at normal pressure or in vacuo. The water can also be obtained by azeotropic distillation with an additional component, e.g. B. benzene, can be removed. In continuous operation, the starting ^ emisch is expediently introduced into the reactor at the reaction temperature and at the same time the reaction mixture is let down in a column for distillation. B. separated by distillation or crystallization

An excess of starting material can either

by distillation or in the case of an α-oxo-carboxylic acid re also by extraction with sodium bicarbonate solution removed.

The manufacture according to the method according to the invention

Process products are valuable starting materials for the production of solvents, dyes, plastics, paints, pesticides, fragrances and cosmetics. For example can by splitting off the 3-acyl group in

is Ulimann's Encyclopedia of Technical Chemistry, Volume 14 (1963), pages 769 ff described lactones can be obtained.

In the following examples, parts mean parts by weight.

example 1

70 parts (1 mol) of crotonaldehyde, stabilized with 0.1% by weight of Hydrochi, are added to 92 parts of glyoxylic acid hydrate (1 mol) at 80 ^{° C. within 30 minutes} non, added in portions with stirring. The reaction mixture is kept for 1 V2 hours at 100 ⁰ C and then distilled to give 93 parts (74% of Theori) 4-methyl-3-formyl-4-hydroxy-butene (2) from -säurelacton Kp ^ _- S 95 to 97 ° C. The phenylhydra-

so zonderivat this compound melts at 183.5 to 185 ° ":.

Example 2

With stirring, glyoxylic acid hydrate 70 parts of methyl vinyl ketone are added over 45 minutes in portions at 8O ⁰ C for 92 parts. The temperature is then still holds for 15 minutes at 8O ⁰ C, 15 minutes at 95 ° C and then increased to 110 ° C. After an additional 2 hours by distillation 89 parts (71% of theory) of 3-acetyl-4-hydroxy buten (2) acid lactone with a boiling point of 121 ° C. The phenylhydrazone of this compound melts at 193.5 to 194 ^° C.

Claims (1)

Claim: Process for the preparation of 3-acyl-4-hydroxybutene- (2) -acid lactones ler general formula Il R ² -CR ¹ C = C I I C C (III)