JPS6097939A - 2-oxocyclopentanecarboxylic acid derivative and its preparation - Google Patents

Abstract

NEW MATERIAL:The compound of formula I (R1, R2 and R3 are H or lower alkyl; R4 is lower alkyl; the dotted line is double or triple bond; when the line is double bond, Z is H). EXAMPLE:1-(2-Pentynyl)-2-oxocyclopentanecarboxylic acid allyl ester. USE:Intermediate of perfumery substance such as methyl jasmonate, cis-jasmone, etc. PREPARATION:The compound of formula I can be produced by reacting 1mol of the enol salt of 2-oxocyclopentanecarboxylic acid ester of formula II with 0.5-3mol, preferably 0.7-1.5mol of the halogenated unsaturated hydrocarbon of formula III at 0-200 deg.C, preferably 50-150 deg.C in an inert solvent (e.g. acetone, methyl ethyl ketone etc.). If necessary, the yield can be improved by adding a quaternary ammonium salt or quaternary phosphonium salt to the reaction system.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel 2-oxocyclopentanecarboxylic acid ester derivative and a method for producing the same, and more specifically,
The present invention relates to a 2-oxocyclopentanecarboxylic acid ester derivative useful as an intermediate for aromatic substances such as methyl jasmonate and cis-jasmonate, and an efficient method for producing the same.

Methyl jasmonate and cis-jasmonate are widely known as substances having a jasmine-like aroma. Then,
Various studies have been carried out since Jubei on methods of synthesizing such substances.1 For example, using cyclohexane-13-dione as a starting material, it undergoes alkylation, halo, genation, and ring condensation to form the intermediate ゛2-substituted=2 - Method for obtaining cyclobentenone (Japanese Patent Publication No. 53-2857), ■ Method C using 2-substituted-2-(benzothiazolyl-2-mercapto)cyclopentanone as an intermediate (Japanese Patent Publication No. 56-6421), Method using a saturated spiro derivative as an intermediate (Japanese Unexamined Patent Publication No. 1986-44
640) are known.

However, their number is still limited, and there has been a strong desire to develop a method for efficiently synthesizing desired useful substances through simpler reactions using cheaper intermediates.

Therefore, the present inventors conducted intensive studies in response to such requests, and as a result, recently reported a new method for synthesizing α,β-unsaturated ketones (for example, published in the Journal of the American Society). VOL, 14.
No. 21. 1982, pp. 5844-5846) was found to be effective, and the present invention was completed.Thus, according to the present invention, firstly, an intermediate of fragrant substances. 2-oxocyclopentanecarboxylic acid ester derivatives represented by the following general formula [II] which are particularly useful as compounds are provided, and secondly, the following general formula [II]
2-oxocyclopentanecarboxylic acid ester represented by the following general formula [I], which is produced by bringing an enol salt of 2-oxocyclopentanecarboxylic acid ester into contact with a halogenated unsaturated hydrocarbon represented by the following general formula [■] to cause an alkylation reaction. A method for producing a cyclopentane carboxylic acid ester derivative is provided.

z (In each of the above formulas, 1%+R* and R8 are both hydrogen atoms or lower alkyl groups, R4 is a lower alkyl group, awn is a double bond or triple bond, 2 is a hydrogen atom when ; is a double bond , X represents a halogen atom.) Here, the lower alkyl group in R11R1 and R, may be within a range that does not have an essentially adverse effect on the synthesis of 2-substituted-2-cyclobentenone in the next step. (Specific examples include methyl group, ethyl group, propyl group, inpropyl group, butyl group, etc.) The lower alkyl group in R4 is selected depending on the properties required for the target substance. , methyl jasmonate or cis-jasmonate is an ethyl group, and other groups such as a methyl group, a propyl group, an inpropyl group, etc. can also be selected.

Specific examples of such 2-oxocyclopentanecarboxylic acid ester derivatives include, for example, 1-(2-butenyl)-
2-oxocyclopentanecarboxylic acid, 1-(2-pentenyl)-2-oxocyclopentanecarboxylic acid, 1-
(2-hexenyl)-2-oxocyclopentanecarboxylic acid, 1-(2-butynyl)-2-oxocyclopentanecarboxylic acid, 1-(2-pentynyl)-2-, l-
Socyclopentanecarboxylic acid, 1-(2-hexynyl)
-2-oxocyclopentanecarboxylic acid etc. 1
Examples include esters of -substituted-2-oxocyclopentanecarboxylic acid and allyl alcohols such as allyl alcohol, methallyl alcohol, crotyl alcohol, 2-pentenyl alcohol, and 2-ethyl-2-butynol.

Among these, esters with allyl alcohol or 1-(2
Esters of -alkynyl)-2-oxocyclopentanecarboxylic acid are preferred, and 1-substituted-2-oxocyclopentanecarboxylic acid esters in which R4 is an ethyl group are preferred from the standpoint of usefulness in the final product.

□ The method for synthesizing the 2-oxocyclopentanecarboxylic acid ester derivative is not particularly limited, but generally, the enol salt of the 2-oxocyclopentanecarboxylic acid ester represented by the general formula (III) is synthesized with the general formula (III). It is synthesized by alkylation with a halogenated unsaturated hydrocarbon represented by the formula (1t[).

The enol salt to be subjected to the reaction may be any salt that can be alkylated with a halogenated unsaturated hydrocarbon,
Specific examples include alkali metal salts such as sodium salts and potassium salts, alkaline earth metal salts such as magnesium salts and calcium salts, and ammonium salts, among which alkali metal salts are particularly prized.

Such an enol salt may be synthesized according to a conventional method. For example, a 2-oxocyclopentanecarpodic acid ester represented by the general formula (IF) is mixed with water-volumized sodium, sodium alkoxide, potassium carbonate, etc. A method of reacting with a base, ■ A method of reacting cyclopentanone with the carbonic acid diester of the corresponding allyl alcohol in the presence of a base, ■ A method of subjecting the adipic acid diester of the applicable allyl alcohol to Diekman condensation in the presence of a base, etc. is exemplified.

The reaction between the enol salt and the halogenated unsaturated hydrocarbon is carried out in the presence of an inert solvent. The solvent used may be any solvent as long as it is inert to the reaction, but usually a polar or non-polar solvent such as acetone, methyl ethyl ketone, tetrahydrofuran, dioxale, dimethyl formamide, dimethyl sulfoxide, benzene, toluene, xylene, hexane, cyclohexane, etc. A solvent is used.

The amount of both components to be charged can be selected as appropriate, but it is usually 1.5 to 3 mol, preferably α7 to 15 mol of halogenated unsaturated hydrocarbon per mol of enol salt, and the reaction temperature is usually D
-200°C, preferably 50-150°C.

Further, if necessary, the yield of gold can be improved by adding a quaternary ammonium salt or a quaternary phosphonium salt such as trimethylbenzylammonium halide, tetrabutylammonium halide, tetrabutylphosphonium halide, or the like.

The 2-oxocyclopentanecarboxylic acid ester derivative of the present invention obtained in this manner is then subjected to vertical decarboxylation and dehydrogenation simultaneously in the presence of a palladium catalyst as shown in the following reaction formula. It is converted to 2-cyclopenten-1-one.

The palladium catalyst used in the z reaction is preferably a zero-valent olefin complex or a divalent organic compound.

As a specific example, tris(dibenzylideneacetone)
= palladium (0), palladium acetate, palladium acetylacetonate, etc., and depending on the required IC, triphenylphosphine, triphenylphosphite, α,
It is used in combination with ligands such as β-ethylenedi(diphenyl)phosphine, pyridine, etc.

The reaction is facilitated by bringing the 2-oxocyclopentanecarboxylic acid ester derivative into contact with the catalyst in the presence of a suitable solvent such as acetonitrile, dimethylformamide, tetrahydrofuran, benzene, etc. at 50 to 150°C for about 5 minutes to 3 hours. Proceed to.

The 2-substituted-2-cyclopenten-1one synthesized by this reaction can then be treated in a conventional manner to yield the desired substance.

For example, cisjasmone can be obtained by reacting 2-pentenyl-2-cyclopenten-1-one with methyllithium, or by Michael addition of dimethyl malonate to 2-pentenyl-2-cyclopenten-1-one, and then Methyl jasmonate can be compressed by decarboxylation.

In the case of 2-pentynyl-2-cyclopenten-1-one, hydrogenation 1.2-
The same objective as above can be obtained by converting the hentynyl group e2-pentenyl group.

The present invention will be explained in more detail with reference to Examples below. Note that parts in the examples are based on weight.

Example 1 10 parts of allyl 2-oxocyclopentanecarboxylate, 24 parts of potassium carbonate, and 50 parts of acetone were placed in a flask equipped with a reflux condenser, heated to 70°C with stirring, and then
6 parts of pentynyl chloride was gradually added dropwise. After starting the dropwise addition, the solid content in the reaction system was heated and stirred for 122 hours, and the filtrate was distilled to a boiling point of 129-130.
12.5 parts of a fraction of °C/3 wHg were obtained.

The physical properties of the fraction are as follows, and these properties confirm that it is allyl 1-(2-pentynyl)-2-oxocyclopentanecarboxylate (hereinafter referred to as the compound conversion type). Ta. The yield was 90%.

(1) NMR (Co/4): aO,9B(t,3H,
:f=7Hz), 175-2.50(m,8)1), 2.47(t,2H,:J=IH2), 4.45(+1
, 2H, J=5H2), 4.96-5.50 (m,
2H), 5.40-5.96 (m, IH) (2) Engineering R (neat): 30iS0, 2950, 1
740,1720°1640.1305,1140.1
0?5゜980.920,865,775儂-1(3)
Elemental analysis value "C14H1lO1l calculated value 0=717
7%, H=7.741 Actual value 0=7179%, H=7
．． 75 Example 2 A dispersion consisting of 55 parts of toluene and 6 parts of IJumt (65% hydrogenated) was heated to 95° C., and then 10 parts of dicrotyl adipate was added dropwise over 1 hour to perform Dieckmann condensation alloying. Next, the produced crotyl alcohol was azeotroped with toluene and distilled off, and then 12 parts of tetrabutylammonium bromide and 4 parts of pentynyl chloride were extracted.
After adding the metal and reacting at 110°C for 3.5 hours,
It was washed with an aqueous acetic acid solution and a saturated aqueous sodium bicarbonate solution. The obtained organic layer was distilled to a boiling point of 153 to 155°C.
8.0 parts of a fraction of /4.5 wm Hg were obtained.

The physical properties of the fraction were as follows, and these properties confirmed that it was crotyl 1-(2-pentynyl)-2-oxocyclopentanecarboxylate (hereinafter referred to as compound ■). . The yield was 83%.

(1) 1H-NMR (ODOj, ): Jt05(t
, 3H, J = 8Hz), 16B (d, AH, J = 5H2
), 185-2.55 (m, 8H), 2, +52 (t, 2H, J=IHz), 4.46 (d,
2H, J=5Hz), 5.50-5.90 (m, 21) (2) Engineering R (neat): 2240, 1760, 17
30,1320°1225.1195,1160,11
10゜1010.975,925,875 scratch-1 (3)
Elemental analysis value “CII”2゜0゜Calculated value 0=72.
55%, III=8.124 Actual value a=72.51
%, H=a1516 Example 3 The reaction with pentynyl chloride was carried out in the same manner as in Example 1 except that 11 parts of metaallyl 2-oxocyclopentanecarboxylate was used, and the boiling point was 143-145°C/4w.
Fractions 1 & 5 of m Hg were obtained.

The physical properties of the fraction were as follows, and these properties confirmed that it was metaallyl 1-(2-pentynyl)-2-oxocyclopentanecarboxylate (hereinafter referred to as compound ■). . The yield was 70%.

(1) 1H-NMR (CDOf, ): 105 (t,
AH,, 7=8Z), 1.70 (8, AH), 185-2.55 (m, 8H), 2-62 (t, 2H, J=IHz), 4.45 (S, 2H), 4.80-4.95 (m, 2] 1f) (2) Engineering R (neat): 2250, 1760, 17
30,1665°1330.1255,1160,11
10゜1070.1015,975,915m-'(3
) Elemental analysis value: O-10.

Calculated value 0=72.554. H=8.12% actual value C
=72.59H, H=8.10% Example 4 The reaction was carried out in the same manner as in Example 1 except that 41 parts of 2-cispentenyl chloride was used in place of pentynyl chloride. As a result, the boiling point was 126-129℃/S
12.6 parts of allyl 1-(2-cispentenyl)-2-oxocyclopentanecarboxylate of m Hg were obtained. The yield was 90%.

(1)'H-NMR (C!Do/, ): 0.91 (t
, 3H, J=8Hz), 175-2.75(m, 10H
), 4.50 (d, 2H,, r=5Hz), 4.97-&0
3 (m, 5H) (2) Engineering R (neat): 1740, 1720, 16
40,1310°1265.1220,1145,10
9Q.

990.925,855,795,720儂-1(3)
Elemental analysis value ”C14T12D011 calculated value 0=7
1.16%, H=8.53 coefficient actual measurement value 0=7t15%,
H=8.52 Example 5 1 mole of the compound compound obtained in Example 1, 20 moles of acetonitrile, 0.01 mole of palladium acetate, and 1015 moles of triphenylphosphine. Charge Tic in a reaction vessel and stir immediately at room temperature. Thereafter, the temperature was raised to the boiling point of the solvent and the reaction was carried out under reflux for 50 minutes. After completion of the reaction, the reaction product was distilled under reduced pressure, and as a result, cyclopenten-1-one with a boiling point of 94~b was obtained in a yield of 87%. of Lindlar in n-butanol solvent.
Partial hydrogenation using a catalyst gave 2-(2-cispentenyl)-2-cyclopenten-1-one (yield 9B%)
Then, 2-(2-cispentenyl)-3-oxocyclopentyl dimethyl malonate was synthesized by Michael addition reaction of dimethyl malonate (yield: 98), and further heated in the presence of water to decarboxylate it. Thus, methyl jasmonate was obtained (yield: 90%).

Examples 6 to 8 Reactions were carried out in the same manner as in Example 5 except that 1 mol of each of the compounds It, l [[ or ■ obtained in Examples 2 to 4] was used. The results are shown in Table 1.

Table 1 From the results, it can be seen that any of the compounds can be used as an intermediate for aromatic compounds.

Patent applicant: Zeon Corporation

Claims (1)

[Claims] 1. A 2-oxocyclopentanecarboxylic acid ester derivative represented by the following general formula [I]. z (In the formula, R□s R* s R1 are all hydrogen atoms t
fc is a lower alkyl group, and R4 is a lower alkyl group. - Double bond 9 represents a triple bond, 2 represents a hydrogen atom when it is a double bond. ) 2. The enol salt of 2-oxocyclopentanecarboxylic acid ester represented by the following general formula (IF) is brought into contact with a halogenated unsaturated hydrocarbon represented by the following general formula [l11) to cause an alkylation reaction. A method for producing a 2-oxocyclopentanecarboxylic acid ester derivative represented by the general formula CI). z (wherein, X represents a halogen atom, and other symbols have the same meaning as in general formula CI). )