DE1021354B - Process for the production of unsaturated ketones - Google Patents

Description

The invention relates to a method for the production of unsaturated ketones, which is characterized is that one diketene with a propargyl alcohol disubstituted in the 1-position by hydrocarbon radicals converts and the acetoacetic ester of the disubstituted propargyl alcohol obtained to higher temperatures, preferably to 120 to 200 °, heated, carbon dioxide being split off from the condensation product will. The process according to the invention can be illustrated in the following reaction scheme:

R ₁ O

I Il

(A) HC = CC-OH + CH ₃ -C-CH = C = O

(I) R ₂

R ₁ OO

I Il Il

HC = CCOC-CH ₂ -C-CH ₃ (H) R ₂

Method of manufacture
of unsaturated ketones

Applicant:

F. Hoffmann-La Roche & Co.
Aktiengesellschaft, Basel (Switzerland)

Representative: Dr. G. Schmitt, lawyer,
Loerrach (Bad.), Friedrichstr. 3

Claimed priority:
V. St. v. America March 14 and May 15, 1952

Walter Kimel, Highland Park, N.J.,

and Norbert William Sax, Brooklyn, N.Y. (V. St. A.),

have been named as inventors

R ₁ -C = CH-CH = CH-C-CH ₃

R ₁

(B) HC = CCOC-CH ₂ -C-CH ₃

-CO,

(ΠΙ)

R ₁ -C = C = CH-CH ₂ -C-CH ₃

R,

(IV)

In this reaction scheme, R ₁ and R _{2 are} identical or different hydrocarbon radicals, preferably acyclic hydrocarbon radicals, such as ζ. Β. Methyl groups or those higher alkyl or alkenyl groups whose methylene group closest to the propargyl carbon atom is unsubstituted. Examples of such groups are the 4-methyl-penten-3-yl group or the 3,4-dimethyl-penten-3-yl group.

When carrying out the reaction sequence according to the invention an end product is usually obtained which mainly consists of the compound III. To that To obtain product III or the isomeric alkadienone IV in a substantially pure state, this final reaction mixture is left expediently fractional distillation under reduced pressure. Also the intermediate condensation product II can be used in an analogous manner z. B. by fractional distillation in a high vacuum in essential preserved in a pure state. However, this intermediate product does not need to be isolated; it can be converted into Form of the crude reaction product are subjected to decarboxylation.

The process for the production of the unsaturated ketones breaks down into two stages, namely the conversion of a disubstituted propargyl alcohol with diketene to form the acetoacetic acid ester of Propargyl alcohol and the elimination of carbon dioxide from the said acetoacetic acid ester of propargyl alcohol. There are probably already implementations of

709846/482

3 4

Diketene with various alcohols described, but catalyst) o-methyl-hepten-S-one ^, in any case there is no indication that the reaction by the semicarbazone from melting point 135 to 136 ° is also suitable for the production of acetoacetic esters of can be identified.
Propargyl alcohol is applicable. The 5 Example 2 produced by the process of German patent specification 717652
Acetoacetic acid esters are due to the lack of an in

The propargyl group in the α-position of the alcohol is not placed in one with a stirrer, thermometer, dropping funnel and

capable of pyrolysis in a, ^ -unsaturated ketones over-drying attachment provided 1-1-three-necked flask is allowed

approach. Furthermore, in the German patent 0.3 g of sodium to 152.2 g (1.0 mol) of racemic 1-methyl

706322 a process for the production of unsaturated io l- (4-methyl-penten-3-yl) -propargyl alcohol act. the

Ketones solution obtained by condensation of diketene with aldehydes is cooled to 0 ° and added dropwise

described, with the intermediately formed y-substi- with vigorous stirring in the course of 5 hours

In the case of acetoacetic acids, 109.1 g (1.3 mol) of diketene were added by normal decarboxylation. The stirring will

convert to cc, /? - unsaturated ketones. The invention for a further 40 hours at 0 ° and then during

Proper procedure differs from the listed 15 continued for 3 hours at 25 °.

Reaction sequence on the one hand by the fact that the reaction. Finally, the solution is diluted with 200 ecm

with a propargyl alcohol instead of an aldehyde pre-ether and washes them first 6 times with 200 ecm each

is taken and, on the other hand, through the various saturated sodium bicarbonate solution and then with water up

Reaction mechanism of carbon dioxide elimination. to the neutral reaction. The ether layer is over

While in the present process the carbon dioxide 20 calcium sulfate is dried, the solvent by distillation

cleavage with substantial intramolecular environmental lation removed and the residue, 238.8 g (101 ° / ₀

storage takes place, is in the known process from a theory), purified by high vacuum distillation. Of the

cleaved terminal carboxyl group carbon dioxide, obtained racemic acetoacetic acid-1-methyl-1 - (4-methyl-

without a rearrangement taking place. Pent-3-yl) propargyl ester is a colorless liquid

The new process according to the invention can be used with 25 from the boiling point 43 to 46 ° (0.007 mm); n ^z j = 1.4652;

Advantage for the production of pseudoionon and pseudoiron df = 0.9785. Yield = 90 to 95% of the crude product,

use; For this reason, the invention is for the In one with agitator, capillary tube, thermometer

Pharmaceutical and fragrance industry 1-1 three-necked flasks with special value and reflux condensers

fully. . 236.2 g (1 mol) of racemic acetoacetic acid-1-me-

Example 1 Filled in 3 ° ethyl-1- (4-methyl-penten-3-yl) propargyl ester.

A fine stream of nitrogen is allowed through

Flow through a capillary with a stirrer, dropping funnel, thermometer and heat the flask in the bath

1-1 three-necked flask fitted with a drying attachment is set to 150 to 200 °. At around 150 °, carbon begins

0.3g sodium to 118g (1.4MoI) 1,1-dimethyl-propargyl-dioxide to form, and the gas evolution is at 180 °

alcohol left to act. Once the implementation finishes 35 quite violently. The reaction mixture is kept on one

is, the solution is cooled to + 5 ° and drop-temperature from 180 to 200 ° for 90 minutes, d. H.

wise over the course of 5 hours with 141 g (1.68 mol) of diketene until the evolution of carbon dioxide has ceased. The

so offset that the temperature -f- does not exceed 10 °. The flask is now allowed to cool to room temperature,

Then you stop stirring at the specified temperature and you dissolve its contents in 250 ecm low-boiling

temperature for a further 24 hours. 40 petroleum ether is added. The solution is extracted 3 times with each

150 ecm of toluene and extracted the solution 4 times with 200 ecm of a saturated sodium bicarbonate solution and

150 ecm of a 5% sodium bicarbonate solution and then washes it with water until it reacts neutral,

then washes with water until the reaction is neutral. After drying the washed solution over CaI

The toluene is removed from the washed solution of calcium sulfate, the solvent is removed by distillation

by vacuum distillation and purifying the residue 45 lation and purifying the residue by fractionation,

by vacuum distillation. At 80 to 84 ° / 7 mm over- The product obtained consists of 6,10-dimethyl-unde-

going fraction consists of acetoacetic acid-1.l-dimethyl-catrien-3,5,9-one-2 (pseudoionone) from boiling point 90 to

propargyl ester. After standing for a short time, this ester solidifies at 92 ° (0.5 mm); ng = 1.5290. Yield = 86 g (44.8 ° / ₀

to a solid, white theory that melts at about 60 °. The semicarbazone from melting point 141 to

binding. Yield = 201.8 g (85% of theory). 50 143 ° gives no melting point depression in the mixture

185 g (1.1 mol) of acetoacetic acid-1,1-dimethylpropargyl- of an authentic sample. By-products are citral

esters are put into a stirrer and thermometer and the alien isomer of pseudoionone, i.e. H. 6.10-Di-

provided 1-1 three-necked flask, which is via a reflux methyl-undecatrien-4,5,9-one-2 from boiling point 60 to

cooler is connected to a gas meter, filled. 65 ° / 0.2 to 0.3 mm. Yield = 19.3 g (10 ⁰ Z ₀ of theory).

The flask is heated to 160 to 180 ° in an oil bath, 55

whereupon a violent evolution of carbon dioxide. Example 3
puts. As soon as the gas development has stopped (after

about 3 hours), the heating is interrupted and in one with a stirrer, thermometer, drying attachment

the remaining dark brown liquid in a vacuum and dropping funnel-equipped 1-1 three-necked flask leaves

fractionally distilled. First, an essentially 60 one goes 0.3 g of sodium to 166 g (1 mol) of racemic 1-Me-

small fraction of 6-methyl-heptadien-4,5-one-2, consisting of l- (3,4-dimethylpenten-3-yl) propargyl alcohol

tion at 62.5 to 66 ° / 7.5 irim [yield = 31.7 g (23.2% act. The solution obtained is cooled to + 5 ° and

of theory)] and then one essentially of 6-methyl dropwise with 100.8 g (1.2MoI) of diketene at one

heptadien-3,5-on-2 existing larger fraction at temperature between + 5 and + 10 ° in the course of

73 to 76 ° / 6.5 mm across; Yield = 35.9 g (26.3% of the 5 hours added. Stirring is then continued

Theory). Continued for 24 hours at + 10 °. 160 ecm of toluene are added

Each of these fractions provides here not claimed and extracts the solution 5 times with 150 ecm each

Way of hydrogenation with 1 mole of hydrogen (with saturated sodium bicarbonate solution, which is followed by

Washes room temperature under slightly increased pressure and in water until a neutral reaction. Man removed

In the presence of a poisoned palladium-calcium carbonate 70 the toluene in a vacuum and thus wins one from race-

mixed crude 1- methyl-1- (3,4-dimethyl-penten-3-yl) propargylic acetoacetate fraction; rig = 1.4717. Yield = 253 g (101% of theory).

250 g (1 mol) of the acetoacetic ester of rig = 1.4717 obtained above are filled into a 1-1 three-necked flask equipped with a stirrer and thermometer and connected to a gas meter via a reflux condenser. The flask is heated to 120 to 170 ° in an oil bath. The development of carbon dioxide begins at 120 ° and becomes quite violent at 150 to 160 °. After the evolution of gas has ceased (after 3 hours), the product is purified by distillation. The main product obtained in this way is 6,9,10-trimethyl-undecatrien-3,5,9-one-2 (pseudoiron) with a boiling point of 98 to 102 ° / 0.1 mm; rig = 1.5310 [Yield = 97 g (47.1 ° / ₀ of theory)], in addition to a non-distillable residue, and a lower boiling fraction, which partly from the Allenisomeren the pseudo Irons that is, the o ^ .LO-trimethyl- undecatrien ^^^ - on ^ from boiling point 68 to 71 ° / 0.11 to 0.2 mm; Yield = 10.7 g (5% of theory).

Claims (1)

PATENT CLAIM: Process for the preparation of unsaturated ketones, characterized in that one diketene with a disubstituted in the 1-position by hydrocarbon radicals Reacts propargyl alcohol and the acetoacetic ester of the disubstituted propargyl alcohol obtained heated to higher temperatures, preferably to 120 to 200 °. Considered publications:
German patent specifications No. 706 322, 717 652. © 709 84-6 / 482 12.57