JPS6036416B2 - Method for producing 2-(cis-2-pentenyl)cyclopentanone derivative - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing 2-(cis-2-bentenyl)cyclobentanone derivatives.

The compound of the present invention is produced, for example, according to the following reaction formula.

(In the formula, R2 represents a lower straight chain or branched alkyl group) The above compound of the present invention is useful as the main aromatic component in starched jasmine oil.

Conventional purification methods for compound [3' include, for example, G. Buch
i, B, E Shigeru J, Crg. Chem, 36, 20
21* (1971) is known.

The reaction formula is shown below. In the above conventional method, even if the demethoxycarbonyl step yields 100%, the overall yield is 30% or less.

Furthermore, since the starting material is not easily obtained, the number of steps will further increase if calculated from the easily available starting material, and the overall yield will further decrease. Although many other methods have been reported, their yields are comparable to or lower than those of the above methods, and in addition, special reagents and... Reagents that cause pollution are often used, and the reaction operations are complicated. The present invention provides a method for obtaining a target compound in extremely high yield compared to conventional methods.

Compound '1}, which is a starting material in the present invention, is a new compound, and the compound can be obtained from known compounds, for example, in the following manner.

(In the formula, R, , R2 and R3 each represent a lower linear or branched alkyl group) Compound {4' is a cis-2-butenoic acid ester easily obtained by electrolytic oxidation of furfuryl alcohol, etc. It is a derivative, and by combining this with acetoacetate ■, the compound (6}
is obtained.

Compound '71 is obtained by reacting compound (6} with bentenyl halide, and compound '91 is obtained by directly or hydrolyzing it and then ring-closing it. Compound'
Compound '1}, which is the starting material of the present invention, is obtained by decarboxylating and then selectively reducing 9}. The oxidation reaction of compound '1} to compound (2) is advantageously carried out in the presence of a solvent and an oxidizing agent.

Examples of solvents include halogenated hydrocarbons such as dichloromethane and dichloroethane, aliphatic ethers such as tetrahydrofuran, dioxane, and ethyl ether, aliphatic hydrocarbons such as n-hexane and n-hebutane, and aromatics such as benzene and toluene. Inert solvents such as group hydrocarbons are used.
As an oxidizing agent, a combination of chromic acid and sulfuric acid (John's reagent), KMn04, potassium dichromate, lead tetraacetate, lead oxide,
Examples include peroxide and nitric acid. The amount of the oxidizing agent to be used is about 0.5 to 3 moles, preferably about 1 to 1.3 moles, based on Compound '1. The reaction temperature is not particularly limited, but is usually -20 to 50 qo, preferably 5 to 3
It is better to set it to 0qo. The cis reduction of compound ① to the compound lake is carried out in the presence of Lindlar catalyst.

A typical Lindlar catalyst is a palladium-calcium carbonate catalyst poisoned with lead acetate and quinoline.
The amount of Lindlar catalyst to be used is not particularly limited and can be selected as appropriate, but generally it may be used in an amount of 1 to 500% by weight, preferably 10 to 100% by weight based on compound (2). The reaction is preferably carried out in an organic solvent, and examples of such organic solvents include aliphatic alcohols such as methanol, ethanol, and propanol, aliphatic ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone, tetrahydrofuran, dioxane, and ethyl ether. , aliphatic hydrocarbons such as n-hexane and n-hebutane, dichloromethane, dichloroethane, etc.
Genated hydrocarbons and mixed solvents thereof can be exemplified. Further, the reaction may be carried out either under normal pressure or under increased pressure. Although the reaction temperature is not particularly limited, it is generally 10 to 60 qo, preferably 20 to 40 qo. Compounds [2] and {3] can be obtained by the above method.

Compound ■ and (3' are each isolated compound '1}
It can also be obtained from (2) and (2), but it can of course also be obtained by using the reaction mixture as it is as a raw material without isolation. Further, each compound can be easily purified by known means such as extraction, distillation, chromatography, and recrystallization. Reference examples and examples of the present invention are listed below. Reference example 1 Potassium fluoride was heated for 40 minutes in a reaction melter above 500℃, and then dried at
t. -butanol (40%), methyl cis-4,4-dimethoxy-2-butenoate (123%) and acetoacetic acid at rt.
- Add 36 liters of butyl ester and heat in an oil bath at 10,000 ℃ for 2 days.

After completion of the reaction, ten. - Remove butanol. The residue is dissolved in ethyl acetate, washed with brine and dried. After removing the solvent, the residue was purified using a silica gel column and distilled under reduced pressure to obtain b. p. 72-7600/0.014 side Hg methyl 4-tert. -Butoxycarbonyl-3-dimethoxymethyl-5-oxohexanoate [compound side, R
,=t-Bu, R2=R3=CH3] in a yield of 95.4%.
Get it. Elemental analysis value C Daily measurement value (%) 56.658.13 Theoretical value (%) 56.598.23 m2851 skin-1 (CH30), 1736 arc-1 (>C
D.

) 1715 arc-1 (C-0) NMR (CC14) 1.43 (wide 9, C ratio), 3.19-3. Paper (m6, C
is ○) 3.58-3.72 (m3, C is OCO) 3.1
9-3.72 (ml, CH), 4.31 (tl, 5HZ
,〇CH〇) Reference example 2 Potassium carbonate 1.382, potassium iodide 3
Add 08 o, 30M acetone and 41 tert of methyl
．． -butoxycarbonyl-3-dimethoxymethyl-5-oxohexanoate 450 parts dissolved in acetone 1 part
Add 0 ground.

Next, Bennylfuromide 270x9 was added, stirred at room temperature for 1 hour, and then refluxed at 70°C for 13 hours. After the reaction is completed, the mixture is cooled to room temperature and solids are separated. It was concentrated under reduced pressure, and the residue was purified with a silica gel column to obtain methyl 4-acetyl-4-ten. with a yield of 90%. -butoxycarbonyl-3-dimethoxymethyl-6-noninoate [compound '9R,=t-Bu, R2=R3=CH3] is obtained. Elemental analysis value C Daily measurement value (%) 62.548.35 Theoretical value (%) 62.508.39 IR 2837 Hada-1 (CH30), 1729 Ka-1 (
>C ni.

) 17IOC-1 (>C2.), 1430 Skin-1 (C
H2) 1354 skin-1 (CQO) NMR (CC14) (
6 values) 1.11 (3 days, CH3-C) 2.26-2.55 (2 days, CH2COO) 2.55-
2.85 (CH2-C...) 3.61, 3.65 (Spot, CH30CO) 4.18-4.39 (CH<8) Reference example 3 Methyl 4-acetyl-4-tert-butoxycarbonyl-3- Dimethoxymethyl-6noninoate 546 was dissolved in 30% of tetrahydrofuran, added with 25% of a 1.5% aqueous perchloric acid solution, and incubated at 2800 °C for 1 hour.

The reaction solution is then neutralized with sodium bicarbonate and concentrated under reduced pressure. The residue was extracted with ethyl acetate, dried, concentrated, and dissolved in methyl 4-acetyl-4- at rt. -butoxycarbonyl-3-formyl-6 noninoate [compound {81,R,
=t-Bu, R2=CH3] is obtained. Crude yield 98%NM
R (CC14) 9.65 (CHO) IR (neat) 284Ika-1 (CH.

) 1733,1716 arc-1 (>Cd.) 790 9 of the compound 1 obtained above was dissolved in 50 ml of benzene containing 1 of acetic acid and 1 of piverizine, and refluxed for 4 hours.

After the reaction is complete, the solvent is removed and the residue is dissolved in ethyl acetate. Wash with water and sodium bicarbonate and dry. The residue was distilled under reduced pressure to give 5-rt. -Butoxycarbonyl-4-methoxycarbonylmethyl-5-(2-bentenyl)-2-cyclobentenone [Compound ■,R,=t-Bu,R
2=CH3]. b. p. 82-86qo/0.0
06 skin Hg, yield 78%. Elemental analysis value C Daily measurement value (%) 67.367.70 Theoretical value (%) 67.487.55 NMR (CC14) 1.02 (upper 3, CH3), 1.37 (bs9, CH3
) 1.76-2.73 (m.6, CH2C=C, C ratio C
O) 3.33-3.58 (m.1, CH), 3.66 (
s & CH30) 6.10 (ddl, 5HZ, 2HZ,
C=CHCO)7.50(ddl,5HZ,2HZ,H
C=CCO) Reference example 45-ten. -butoxycarbonyl-4-methoxycarbonylmethyl-151 (2-bentenyl)-2-cyclobentenone 800 to 50'
dissolved in benzene, p-toluenesulfonic acid 20 parts 9
and reflux for 3 minutes.

After the reaction, neutralize with sodium bicarbonate and remove the solvent. The residue was purified with a silica gel column and distilled under reduced pressure to obtain 4-methoxycarbonylmethyl-51(2-besotinyl)-2-cyclobentenone [compound plate, R2=CH3].
b. p. 102-103oo/3 skin Hg, yield 93%.
IR2230 Arc-1 (CEC) NMR (CDC13) 1-06 (t.7, 2Hz, Mother's Day, CH3) 1.44~
3.02 (m.12H) 3.70 (s, origin, CH30) Reference example 5 4-methoxycarbonylmethyl-5-(2-bentynyl)-2-cyclobentenone 890 female and sodium borohydride 350 9 was dissolved in 20 ml of methanol and refluxed at 80 qo for 1 hour.

After the reaction, the mixture was cooled to room temperature, 60% of acetic acid was added, and the mixture was left to stand for 30 minutes, and then concentrated under reduced pressure. The remaining bamboo was purified using a silica gel column and distilled under reduced pressure to obtain 3-methoxycarbonylmethyl-2
-(2-bentinyl)cyclobentanol [Compound '1
}, R2=CH3]. b. p. 65-6900/
0.015 side Hg, yield 94%. NMR (CC'4)0
．． 99 (t.3, CH3), 1.22-2.88 (m.
13) 3.61 (s.3, CH30), 2.55-2.
85(,CH2C3)Example 1 3-Methoxycarbonylmethyl-2-(2-bentinyl)cyclobentanol 670 parts 9 was dissolved in methylene chloride 10 parts, and 2 M chromic acid solution 2 parts was added dropwise. do.

After incubation at about 18 qo for 1 hour, it is extracted with ethyl acetate. Wash with saline, dry and concentrate. The residue is purified using a silica gel column and distilled under reduced pressure to obtain 3-methoxycarbonylmethyl-2-(2-benbenyl)cyclobentanone [compound '2', R2=CH3]. b. p. 10
2-103°C/3 days, yield 90%. NMR (CDC
13) 1.06 (t.7, 2nd 2, So, C is) 1.44-3.02 (m.12H) 3.70 (s. Thin, CH30) IR (neat) 223 ratio -1 (C Self-C) 9 of 670 of the compound (2) obtained above was added to n-hexane 5
Dissolve in a mixed solvent of 5 parts of 1 and 5 parts of acetone, add 2 parts of Lindlar's catalyst, and reduce at room temperature under normal pressure.

Claims (1)

[Claims] 1 A compound represented by the general formula ▲ includes numerical formulas, chemical formulas, tables, etc. ▼ in which R_2 represents a lower linear or branched alkyl group) is oxidized to produce the general formula ▲ mathematical formula,
There are chemical formulas, tables, etc. ▼ General formulas characterized by obtaining a compound represented by (in the formula, R_2 is the same as above) and then cis reduction ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (In the formula, R_2 is the same as above) A method for producing a 2-(cis-2-pentenyl)cyclopentanone derivative represented by (same as above).