JPS58203951A - Preparation of substitution product from cyclopentenone - Google Patents

Abstract

NEW MATERIAL:A compound expressed by formula I (R<1> and R<2> are alkyl optionally may be linked through the O or N atom to form a 5- - 6-membered ring: R<3> is 1-6C alkyl). EXAMPLE:2-Dimethylamino-3-methyl-2-cyclopentenon-1-one. USE:An intermediate for preparing a 2-hydroxy-3-alkyl-2-cyclopenten-1-one useful as a food perfume. The aimed compound can be obtained in high purity and yield by using the above-mentioned intermediate. PROCESS:A novel aminodiketone expressed by formula II is subjected to the ring closure in the presence of an alkali, e.g. NaOH, to afford the aimed compound expressed by formula I . The reaction is carried out usually at 20-40 deg.C while keeping the inside of the reaction system at >=12pH. The novel compound expressed by formula II can be obtained by subjecting a furan substitution product of furan expressed by formula II to the ring opening in the presence of an acid, e.g. HCl.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing substituted cyclobentenones. More specifically, the present invention relates to a method for producing a substituted 2-cyclopenten-1-one, which is useful as an intermediate for producing 2-hydroxy-3-alkyl-2-cyclopenten-1-one.

2-hydroxy-3-alkyl-2-cyclopentene-
1-one is important as a food flavor (food flavor Fl).

Conventionally, the method for producing 2-hydroxy-8-alkyl-2-cyclohenten-1-one was as follows: ←) A method using adipic acid ester as a raw material [Japanese Patent Publication No. 41-14989, No. 4]
No. 8-17180, No. 44-6817, No. 45-10
No. 498, West German Publication No. 2,005,160 (197o
))↓(b) Method using geltaric acid ester and oxalic acid diester as raw materials (JP-A-50-98948,
56-88486, 56-88488); (c) Method for epoxidizing 3-methyl-2-cyclopenten-1-one "JAcs791488 (1957)
, West German Publication No. 2818594 (1978).

Special Publication No. 58-87886, No. 54-108842]
) A method using propionic acid ester and oxalic acid ester as raw materials (USP 2865962 No. 1 Journal of the Japanese Society of Agricultural Chemistry 44°46-50 (1970), Special Publication No. 52-
No. 116489] and a method using (po)2-methyl-5-carbalkoxycyclopentanone as a raw material (J,
Org, ChelTL85, 2374 (1970
), Special Publication No. 50-117749].

However, the method of Koguchi et al. has a high yield and purity in one reaction step.

There are many problems in implementation on an industrial scale in terms of reaction operations, raw material costs, etc.

The present inventors have conducted studies to find a new method for producing 2-hydroxy-3-alkyl-2-fuclopenten-1-one, and found that 2-hydroquine-3-alkyl-2-
-We have discovered a method for producing a substituted 2-fuclopenten-1-one useful as an intermediate for producing intermediates for producing cyclopente, and have arrived at the present invention.

-C-R3(1) is an alkali 1 (wherein, Hl and R2 are alkyl groups, and R1 and R2 are connected to each other via an oxygen atom or a nitrogen atom as the case may be). cyclobentenone, characterized in that it produces a 2-en clopenotenol l-ono substituted product represented by n and N together with 5 and t: may form a 6-membered ring; R3 is an alkyl group) The furano-substituted product represented by (3) of the substituent is ring-opened in the presence of an acid to obtain a nonketone, and the opening is then opened in the presence of an alkali and connected to each other via an oxygen or nitrogen atom. may be used to form a 5- or 6-membered ring together with N. R3 is an alkyl group] is a method for producing a cyclobentenone substituted product (second invention), which is characterized by producing a 2-cyclopentethyl-1-one substituted product represented by the following formula: R3 is an alkyl group.

In the general formula (1), the alkyl groups of Hl and R2 are commonly 'It';CI'e and preferably CI'M (methyl group).

(ethyl group, propyl group, etc.). Hl, R2
may be opposite groups or different groups.

R1 and R2 are optionally connected to each other via an oxygen atom or a nitrogen atom, and t: having 4 or 5 carbon atoms is C
The cyclic group may form a 5- or 6-membered ring together with N, and examples of this cyclic group include a piperidino group, a 9-mol polyno group, a piperazino group, and a pyrrolidino group. Preferred examples of R1 and R2 are a methyl group, an ethyl group, a 1 mol polyno group, and a piperidino group.

At R3, the alkyl group (methyl group, ethyl group, lopyl group, pentyl group, hexyl group, etc.) of CIi is open.

The aminodiketone represented by the general formula (1) is a new compound, such as 1-dimethylamino-2,5-hexadione; 1-dimethylamino-2,5-heptadione;
-morpholino-2,5-hexadione 91-dimethylamino-2,5-undecadione; 1-piperidino-2,
Examples include 5-hexadione; 1-diethylamino-2,5-hexadione; and 1-pyrrolidino-2,5-hexadione.

The 2-cyclopenten-1-one substituent represented by the general formula (2) is the aminodi-2-cyclopenten-1-one represented by the general formula (1).
' can be produced by ring-closing ' in the presence of an alkali. Caustic alkali (N
aOH, KOH, etc.) and alkali metal carbonates (Na
2CO3, K2CO3, etc.) is preferably a caustic alkali. Although the alkali may be 100% pure, it is usually used in the form of an aqueous solution, and its concentration is usually 1 to 50% by weight, and 2 to 5% by weight is sufficient.

The pH of the reaction system to which an alkali is added is preferably 12 or higher. The amount of alkaline aqueous solution used is such that the weight ratio of the alkaline aqueous solution and the compound of general formula (1) is usually 10:1.
The amount is 1:10, preferably 5:1 to 1:5. The ring closure is preferably carried out under stirring.

The temperature for ring closure is usually room temperature (20 to 40°C). The time depends on the quality of stirring efficiency, but usually 0.5 to 10 hours.
Preferably it is 1 to 5 hours. The pressure is usually normal pressure. The end point of the reaction can be determined by the disappearance of the raw materials by gas chromatography.

After the reaction is complete, a solvent such as ether or toluene is added to extract the reaction product. (If necessary, add a concentrated alkaline aqueous solution to improve separation of reactants dissolved in water). When the solvent is distilled off, the Schiff's 1-bentenone substituted product of general formula (2) is obtained, but as described in the examples, when R3 is ethyl or hexyl, 2-methyl-
8-dimethylaminomethyl-2-cyclopentene-1-
One or 2-pentyl-3-dimethylaminomethyl-2-cyclopenten-1-one is produced. The obtained crude reaction product can be distilled under reduced pressure to obtain a purified product of dicyclobentenone substituted product.

In the present invention, [1] the furan-substituted product represented by general formula (3) is ring-opened in the presence of an acid to obtain an aminodiketone represented by general formula (1); It is also possible to produce a 2-cyclopenten-1-one substituted product represented by general formula (2) by ring closure below (
2nd invention).

R1 in general formula (3). R2 and R3 are represented by the general formula (1
) in R1. It is the same group as R2 and R3.

Examples of the furan substituted n in general formula (3) include 2-methyl-5-dimethylaminomethylfuran, 2-ethyl-
5-dimethylaminomethylfuran-methyl-5-morpholinemethylfuranxyl-5-dimethylaminomethylfuran, 2-methyl-5-piperidinomethylfuran, 2-
Examples include methyl-5-diethylaminomethylfuran and 2-methyl-5-pyrrolidinomethylfuran.

The furan substituted product represented by the general formula (3) is 2-methylfuran and the general formula (2), where R1 and R2 are R1. R2
It is a group similar to . It can be synthesized by reacting a secondary amine shown in ] with formaldehyde. Specific examples include the method described in Japanese Patent Application No. 177,678/1982 and a method similar to the above (in this method, 2-hexylfuran is replaced with another 2-alkylfuran).

When ring-opening the furan substituted compound represented by general formula (3) to obtain an aminodiketone, the acid used may be an inorganic acid or an organic acid; preferably an inorganic acid. Examples of inorganic acids include hydrochloric acid, sulfuric acid, and phosphoric acid, with hydrochloric acid being preferred. The acid may be a dilute acid (concentration 5 to less than 30%) or a concentrated acid (concentration 80 to 100%);
In particular, a concentration of 5 to 15% by weight is preferred. In the case of a dilute acid, the molar ratio of the dilute acid to the furan substituted product is usually 3.
:1-1:1, preferably 2.5:1-1.5:
In the case of a concentrated acid, the molar ratio of the concentrated acid and the furan substitute is usually 10:1 to 1:1, preferably 8.
:1 to 3:1.

Ring opening is preferably carried out under reflux, heating, and stirring. When using a dilute acid, the ring-opening temperature is reflux temperature (9
When using concentrated acid, usually 2
0-70'C, preferably 40-60'C. The ring opening time is usually 0.5 to 5 hours, preferably 1 to 3 hours. The pressure is usually normal pressure.

The end point of the reaction can be determined by the disappearance of the raw materials by gas chromatography.

After the ring-opening reaction, the reaction product containing the compound of general formula (1) is directly converted to the reaction product of general formula (1) from the reaction product of [1].
) without separating the compound [in the old ring-closing reaction]
), or the compound of general formula (1) may be separated and purified from the reaction product and subjected to the reaction of [111].

In the latter case, for example, cooling the reaction product of [11]
Add an alkaline aqueous solution dropwise to the reaction product at a low temperature (usually below 5°C) to make it neutral to weakly alkaline (pH 8-10).
After removing the water in the reaction solution by concentrating the reaction solution under reduced pressure, ether and toluene! (Extract with which solvent,
After removing the solvent, distillation is carried out under reduced pressure to obtain a purified aminodiketone represented by general formula (1). The obtained aminodiketone represented by the general formula (1) is ring-closed in an aqueous alkali solution in the same manner as described in the first invention, to form 2-cyclopentene-1 represented by the general formula (2). −
It can be an on substitution product.

When the reaction of [111] and the extraction of the aminodiketone represented by the general formula (1) are carried out continuously, after the completion of the ring-opening reaction of 11), the reaction solution as described above is prepared. A concentrated alkaline aqueous solution (concentration 30 to 50% by weight) is added dropwise to the reaction solution at room temperature to make it alkaline, preferably pH 12 or higher, using the same method as described in the first invention. It is preferable to carry out a ring-closing reaction of the aminodiketone represented by the general formula (1).

The reaction formula of the method of the present invention is as follows.The structure of the 2-cyclopenten-1-one substituted product represented by general formula (2) can be confirmed by infrared absorption spectrum and nuclear magnetic resonance absorption. I can do it.

The 2-cyclopenten-1-one substituted product represented by the general formula (2) obtained by the present invention is a new compound.

R1 in general formula (2). R2 and R3 are represented by the general formula (1
) in R1. It is the same group as R2 and R3.

The 2-cyclopenten-1-one substituent represented by general formula (2) is 2-dimethylamino-3-methyl-2-
Cyclopenten-1-one-2-dinothylamino-3-
Ethyl-2-cyclopentethyl-1-one; 2-morpholino-3-methyl-2-cyclopenten-1-one; 2-
dimethylamino-3-hexyl-2-cyclopentene-
1-one; 2-piperidino-3-methyl-2-cyclopenteno-1-one; 2-diethylamino-3-methyl-
2-cyclopenten-1-one; 2-pyrrolidino-3-
Methyl-2-cyclopenten-1-one 1 (opened).

The present invention describes a novel substance 2-cyclopenten-1-one which is extremely useful as an intermediate for the production of 2-hydroxy-3-alkyl-2-cyclopenten-1-one, which is a final substance useful as a food flavor (food fragrance). This has the effect that an on-substituted product can be produced. By using the 2-cyclobentele-1-one substituent represented by the general formula (2), the reaction is extremely simple compared to conventional methods, and a highly purified product can be obtained, making it suitable for industrial use. It is also extremely meaningful. Furthermore, since there are fewer reaction steps, the overall yield is also improved.

2-hydroxy-3 using the 2-cyclopenten-1-one substituted product represented by the general formula (2) obtained in the present invention
The method for producing -alkyl-2-cyclopentethyl-1-one is as follows.

That is, 2-hydroxy-3-alkyl-2-cyclopenten-1-one can be produced by hydrolyzing a 2-cyclobentele-1-one substituted product.

Hydrolysis can be carried out either under an acidic aqueous solution or an alkaline aqueous solution, but it is preferably carried out under an acidic aqueous solution.

When hydrolysis is carried out in an acidic aqueous solution, acids in the acidic aqueous solution include inorganic acids and organic acids, but inorganic acids are preferred. Hydrochloric acid is an inorganic acid.

Examples include sulfuric acid and phosphoric acid, with hydrochloric acid and sulfuric acid being preferred. The concentration of the acidic aqueous solution is usually 1 to 50% by weight, preferably 5 to 35% by weight. The amount of the acidic aqueous solution used is the molar ratio of the acidic aqueous solution to the 2-cyclopenten-1-one substituted product, which is usually 0.5:1 to 2:.

1, preferably 1:1 to 1.5:1.

The temperature of hydrolysis is usually 50 to 100°C, preferably 9
It is 0-100°C. The time is usually 1 to 10 hours, preferably 1 to 4 hours.

When hydrolysis is carried out in an alkaline aqueous solution, the alkali in the alkaline aqueous solution is caustic alkali') (Na
, OH, KOH, etc.) and alkali metal carbonates (tJ
a2cO3, K2CO3, etc.), and n1 caustic alkali is preferred. The concentration of the alkaline aqueous solution is usually 1 to 30%, preferably 5 to 10%. The amount of alkaline aqueous solution used is alkaline aqueous solution and 2-cyclopentene-1
The molar ratio with the -one substituent is usually 05:1 to 3:1, preferably 1:1 to 2.5:1.The hydrolysis temperature is usually 100 to 170°C, preferably 1 Or 100-1
It is 50°C. The time is usually 1 to 10 hours, preferably 3 to 7 hours.

The end point of hydrolysis (under acidic or alkaline conditions) can be determined by the disappearance of the raw material by gas chromatography.

After the reaction is complete, add ether to the acidified crude reaction product.

A purified product of 2-hydroxy-3-alkyl+L-2-cyclopenten-1-one can be obtained by adding a solvent such as toluene, performing solvent extraction, distilling off the solvent, and recrystallizing with water.

2-hydroxy-3-alkyl-2-cyclopentene-
The reaction formula for the synthesis of 1-one is 2-hydroxy-8-
As the alkyl-2-cyclopenten-1-one, 2-
Hydroxy-3-methyl-2-cyclopenten-1-one.

2-hydroxy-3-ethyl-2-cyclopentene-1
-one, 2-hydroxy-3-hexyl-2-cyclopenten-1-one, and the like.

The present invention will be further explained below with reference to Examples and Reference Examples, but the present invention is not limited to these examples.

Reference Example 1 Synthesis of 1-dimethylamino-2,5-hexadione 105.0 g of a 10% HC1 aqueous solution was added to a 200-me fourth flask equipped with a thermometer, a 9-drop load, a stirring device, and a reflux condenser. While stirring, the patent application
20.0 g of 2-methyl-5-dimethylamine methylfuran synthesized in accordance with the specification of 1776781 was added to t
It was dripped from the hei funnel.

After dropping F, the mixture was heated and the temperature was raised to reflux for 2 hours.

Next, the reaction solution was cooled to a 50% Na, OH aqueous solution of about 23%.
0g was added dropwise at 5°C to adjust the pH to 8-10.

Next, it was concentrated under reduced pressure and extracted with ether of 'IOme.

After removing the ether, vacuum distillation was performed to obtain 20.7 g of 1-dimethylamino-2,5-hexadione (yield: 91.5
%) was obtained.

l-dimethylamino-2,5-hexadione boiling point 10
7-110°c/11*m11g Elemental analysis value (%) Total p value as c8H15NO2 c, 61.12; H, 9,62; N, 8.
91 actual measurement value: 'c, 61.10; H, 9,70; N,
8.88TR (c-1') 1708, 1455, 140
0.1860,1165.1040,85ONMR(c
a]4) δ 2.1 j(S, 8T(, cl(3
-c) 2.24 (S, 6H, CH3N) 2.68 (S, 4H, C-cH2cH2-c) 8.0
2 (S, 2H, N-aH2-c) Reference Example 2 Synthesis of 1-dimethylamino-2,5-hebutadione 95.4 g of a 10% HCI aqueous solution was added to the same fourth flask as in Reference Example 1. Patent application 1986-177 while stirring
2-ethyl-5 synthesized by a method according to the specification of No. 678
-20.0 g of dimethylaminomethylfuran was added dropwise from the dropping funnel.

After the dropwise addition, the temperature was increased and the mixture was refluxed for 2 hours.

Next, the reaction solution was cooled and a 50% NaOH aqueous solution of approx.
g was added dropwise below 5°C to adjust the pH to 8-10.

Next, after concentration, the mixture was extracted with Tone ether.

After removing the ether, vacuum distillation was performed to obtain 20.8 g of 1-dimethylamino-2,5-hebutadione (yield: 4s90
．． 7%) said they were satisfied.

2-ethyl-5-dimethylaminomethylfuran boiling point 7
0-71.5℃/11IIIHgIR(d1)
1560, 1450. 1140, 1015,
845, 775NM d<(CC]4)δ
t. 22(t, 8H, cl(3-c)2, 14
(s, 6H, CH3-N)2, 58(q, 2H,
c-aH2-c) 8, 8 1(s, 2H, N-
cH2-c)5,85(q, 2H, C-CHCH
-c) 1-dimethylamino-2.5-hebutadione boiling point 120 ~ 121'C/18 intoxication Hg elemental analysis value (9b
) 09 Hl? Calculated value C. as N02. 68.15 H, 10.01; N, 8.18
Actual subvalue C. 68.08 strand H, 9.89; N, 8.0
5TR (clll) 1715, 1455, 14
10, 1275, 1115, 1045NMR (C
C14) δ 1.02 (t, 8H, OH3-0)
2, 2L (s, 6H, CH3-N) 2, 40 (m,
2H, OCH20) 2, 99(s, 2H, N
(EH2C) Reference Example 3 Synthesis of 1-morpholino-2,5-hexadione Reference Example 1
80.6 lO% MCI aqueous solution in a four-loaf flask similar to
200 g of 2-methyl-5-morpholinomethylfuran, which had been synthesized by a method similar to Japanese Patent Application No. 56-177678, was added dropwise from the dropping funnel while stirring.

After the dropwise addition, the temperature was increased and the mixture was refluxed for 1 hour.

Next, the reaction solution was cooled and a 50% NaOH aqueous solution was added.
7 g was added dropwise at 5° C. or lower to adjust the pH of the reaction solution to 8-1 ().

Next, it was concentrated under reduced pressure and extracted with IOyne ether.

After removing the ether, 1-morpholino-
17.6 g of 2.5-hexadione (yield: 80.θ) was obtained.

2-Methyl-5-morpholinomethylfurano boiling point 117
~b Engineering R (m 1) 1570, 1455, 1115, 1
010,935,865.78+INMR(0014)
δ 2.2g (s, 8H, CH3-c) 8, 2
9-1.21 (m, 8H, OCH2CH2N) 8,
84 (s, 2H, NCH2C) 5.72-6.08
(m, 2H,C-CHCH-C)1-morpholino-2
,5-hexadione elemental analysis value ('1li) Calculated value as CIOH17NO3 c, 60.28; H, 8,60; N, 7.0
8 actual measurement value C, 60, 25 layer 1 (, 8, 48i N, 6.94H
((m-1) 1710.1625.1870.1(
115,915,765NMR (CC1,4) δ 2
．． 09(s, 8H, cH,, -c) 2.80-8.7
2 (m, 8H, 0CH2CH2N) 2.62 (day,
4H,C0H20H20)8.07(s, 2H; N
-CH2-0) Reference Example 4 Synthesis of 1-dimethylamino-2,5-undecadione 698 g of 1096HO'l aqueous solution was added to the same four LoFura tubes as in Reference Example 1, and while stirring,
2-hexyl synthesized by the method described in No. 678)
20.0 g of 5-dinothylaminomethylfuran was added dropwise through the dropping funnel.

After the dropwise addition, the temperature was increased and the mixture was refluxed for 7 hours.

Next, the reaction solution was cooled and a 50% NaOH aqueous solution was added for about 15 minutes.
3 g was added dropwise at 5° C. or lower to adjust the pH of the reaction solution to 8-10.

Next, the mixture was concentrated under reduced pressure and extracted with TOme ether. After removing the ether, distillation was carried out under reduced pressure to obtain 1-dimethylamino-2
,5-undecadione 1'11.13 g, (yield 9
0.4%) were satisfied.

2-hexyl-5-dimethylamitsunotylfuran boiling point 71-b Engineering RCex 1) 1560,1470,1450
,1015,845,78ONMR(c,c14)δ
0.90(t, 8H, CH3-0)1, :l1
7 (m, 8H,0H3-C)2.15 (s', 6
H,CH3-N)2.56(t, 2H,=c-CH
2-c) 8J4 (s, 2H, N-0H2-C) 574
~6.05 (q, 2H, c-cHcH-c) 1-dimethylamino-2,5-undecadione boiling point 110-11
Elemental analysis value (calculated value c as gradient Cl5H25NO2, 68.68 groups H, 11, +18
; N, 6.16 Actual t1 value C, 68, 61i H, 11, 21i N, 6.14
IRCcs-1) 1720.1460.1410.
1870.1280.105ONMR(105ONδ
0.91 (t, 8 H, c) (3-C) 1.80
(m, 8H, C-CH2-0-)2.22(s,
6H,0)13N) 2.60 (s, 4H,c-cH2cH2-c)8.
00(s, 2H,N cH2-c)2.80(m,
2H, -C-CH2-C Example 1 Synthesis of 2-dimethylamino-3-methyl-2-cyclopenteno-1-one
20.0 g of 1-dimethylamino-2,5-hexadione and 20.0 g of 2% NaOH aqueous solution in 11 flasks.
and stirred at room temperature for 2 hours.

Next, 20.0 g of 50% NaOH aqueous solution and 40 g of ether
．． 0 rw was added and the reaction product was extracted with ether.

After removing the ether, distillation under reduced pressure yields 2-cynothiJ rare-3-methyl-2-cyclobenten-1-one 16
．． 5 g (yield 93.0%) was obtained.

2-dimethylamino-8-methyl-2-cyclopenten-1-one Boiling point 110-118°c/17x #Hg elemental analysis value) Calculated value as C8H13NO (!, 69.08 i H, 9, 41i N, 10
．． 06 actual measurement value c, 69. il; H, 9,57; N, 9.9
9IR(ffi”) 1700.1625.145
0.1885.1850.1165゜07O NMR(OC'l,)δ 2.05(s, 8H,C
H3C) 2.10-2.55 (m, 4H, C-CH2C
H2-C) 2.70 (s, 6H, OH3N) Example 2 Synthesis of 2-') Methylamino-3-ethyl-2-cyclobenotecy-1-one 1-dimethylamino was placed in a four-loaf flask similar to Example 1. -2,5-hebutadione 20.0 g and 2% NaOH2
00g was added to the inlet and stirred at room temperature for 2 hours.

Next, 20.0 g of 50% Na, OH aqueous solution and ether 4
0- was added, and the reaction product was extracted with ether.

After removing the ether, distillation under reduced pressure yielded 7.2 g of 2-dimethylamino-3-ethyl-2-cyclopentethyl-one (boiling point 88 ~ go'c/ll! Ig) (yield 40
．． 1%) was obtained.

2-methyl-8-dimethylaminomethyl-2-cyclopenten-1-one ([j93-95'C
/11+ullll) 6°8g was obtained by fractional distillation.

2-dimethylamino-3-ethyl-2-cyclobenten-1-one Boiling point 88-90'c/1111111 + elemental analysis value ((6) Calculated value as 09H15NO2 C, 70,55; H, 9,87; N, 9.14 Actual value c, 70.48; H, 9,99; N, 9.0
2IR (α-1) 1700, 1615.1445,
1170.1045NMR (1045Nδ 1.14
(t, 8H, CH3-C 2.05-2.60 (m,
6H, COH2CH2G.

c-CH2-C) 2.67(a, 6H, CH3N) Example 3 2-morpholino-3-methyl-2-cyclopentene-1
Synthesis of -one In a four-loaf flask similar to Example 1, 1-morpholino-2
, 5-hexadione 2 (10 g and 2% NaOH aqueous solution 2
0.0 g was added thereto, and the mixture was stirred at room temperature for 2 hours.

Next, 50% NaOH20,0@; and ether 4Q+++
C was added, and the reaction product was extracted with ether.
) After removing the ether, distillation under reduced pressure yields 2-morpholino-8-methyl-2-cyclopentene-
16.1 g (yield 88.7%) of 1-one was obtained.

2-morpholino-3-methyl-2-cyclopentene-1
-On boiling point 152-154'c/1'l+mHg Elemental analysis value (%) Calculated value as CIOHISNO2 c, 66.2796; H, 8J4%i N, 7.
7396 actual measurement value C, 66, 29%i H, 8, 47%i N, 7.5
9% Engineering R (i →) 1695, 1625, 1380.
1265,1195,1115°1015,88O NMR (CC14) δ 2.09 (s, 3H,,C
H3'C)2.12-2.56(m, 4H,C-CH
2CH2-C) 2.85-3.75(m, 8H,N-
CH2CH2-0) Example 4 Synthesis of 2-dimethylamino-3-hexyl-2-cyclopenten-1-one 20.0 g of 1-dimethylamino-2,5-boushitecadione was placed in a four-loaf flask similar to Example 1. , 2-96N
200 g of aOH water bath solution and 20 me of methanol were added, and the mixture was stirred at room temperature for 4 hours.

Next, after removing methanol under reduced pressure, the reaction solution was
+/extracted with ether.

After removing the ether, distillation under reduced pressure yields 2-dimethylamino-3-hexyl-2-cyclopenteno-1-one and the by-product 2-pentyl-3-dimethylamino! Chi J Ray 2
14 Jg of a mixture of -cyclopenten-1-one was obtained. This was dissolved in methanol and a 1/1O normal aqueous hydrochloric acid solution was added dropwise to adjust the pH to 56. The methanol was then distilled off, followed by extraction with n-hexane, the n-hexane was removed, and the residue was distilled under reduced pressure. 7.4 g of 2-dimethylamino-3-hexyl-2-cyclopenten-1-one (yield: 4
o, 3%) was obtained.

2-dimethylamino-3-hexyl-2-cyclopentenon-1-one Boiling point 91-92'C/lmHg Elemental analysis value Calculated value as Cl5H23NO C, 74,59i H, 11,07i N, 6.69
Actual value c, 74.55; H, 11,17-N, 6.56
TR(cIn-1) 1705.1620.1450
．． 1875.1055h++, AIt(cc]4)δ
0.91 (t, al(,CH3-C)1.87(
m, 8H, CCH2-C) 2.04-2.56 (m,
6H,CCH2CH2C=ccH,c) 2.66(s, 6H,CH3-N) Example 5 2-dimethylamino-3-methyl-2-'/ri.

Synthesis of Penten-1-one (2-Methyl-5-dimethylaminomethylfuran continuous process) 10% hydrochloric acid 105. 2-methyl-
200 g of 5-dimethylaminomethylfuran was added dropwise.

After dropping F, the mixture was heated to raise the temperature and refluxed for 2 hours.

Next, after cooling to room temperature, approximately 40 g of a 30% aqueous sodium hydroxide solution was added dropwise to make it alkaline (pH 12 or higher).

The mixture was stirred as it was for 2 hours.

Next, 40 g of 50% aqueous sodium hydroxide solution and 1 ether
00- was added and extracted with ether.

After removing the ether, it was distilled under reduced pressure to obtain 2-dinothylamino-3-methyl-2-cyclopenten=1-one (boiling point 1
10~118'C/1? m+Ig) 18.2 g(
A yield of 91.2%) was obtained.

Example 6 Synthesis of 2-dimethylamino-8-ethyl-2-cyclopenten-1-one.

(Continuous method using 2-ethyl-5-dimethylaminomethylfuran) Into a fourth flask similar to Example 5, 95.4 g of 10% hydrochloric acid was added.
200 g of 2-ethyl-5-dimethylaminomethylfuran was added dropwise thereto.

After the dropwise addition, the mixture was heated and the temperature was raised to reflux for 2 hours.

Next, after cooling to room temperature, about 36 g of a 30% aqueous sodium hydroxide solution was added dropwise to make it alkaline (pH 12 or higher, 1-).

The mixture was stirred for 12 hours.

Next, 40 g of a 50% aqueous sodium hydroxide solution and 1 m/ml of ether HH were added, followed by ether extraction.

After removing the ether, distillation was carried out under reduced pressure to obtain 92 g of 2-dibutylamino-3-ethyl-2-cyclopenten-1-one (
(yield 462%) and 7.2 g of 2-methyl-3-dimethylaminomethylfury 2-cyclopenten-1-one were obtained.

Example 7 2-morpholino-3-methyl-2-cyclopentacyl
Synthesis of -one (continuous method from 2-methyl-5-morpholinomethylfuran) 807 g of 10% hydrochloric acid was placed in the same fourth flask as in Example 5.
Then, 200 g of 2-methyl-5-morpholinomethylfuran was added dropwise.

After heating to 11X F, the temperature was increased and the mixture was refluxed for 1 hour.

Next, after cooling in a room temperature chamber, 80 g of 30% sodium hydroxide was added dropwise to make it alkaline (pH 12 or higher).

The mixture was stirred as it was for 2 hours.

Next, 40 g of 5096 sodium hydroxide aqueous solution and 100% of ether were added and extracted with ether.

After removing the ether, distillation under reduced pressure yields 2-morpholino-3
-Methyl-2-cyclopenten-1-one 15.7 g
(yield 78.5%) was obtained. Boiling point is 1'52~15
It was a 4"C/18 bait.

Reference example 5 2-hydroxy-3-methyl-2-cyclopentacyl
- 200 units equipped with on-synthesis thermometer, stirrer and reflux condenser
me 200 g of 2-dibutylamino-3-methyl-2-cyclopene nor-1-one and 10% H
58.8 g of C1 aqueous solution was added and refluxed for 2 hours.

After cooling, the reaction solution was extracted with 100 ml of ether.

After removing the ether and recrystallizing from water, 2-hydroxy-3-
15.7 g of methyl-2-cyclopenten-1-one (
A yield of 97.5% was obtained. Melting point halo5~107
It was ℃.

Reference Example 6 2-hydroxy-3-ethyl-2-cyclobentele-1
Synthesis of -one In a fourth flask similar to Reference Example 5, 20.0% of 2-dimethylamino-3-ethyl-2-cyclopenten-1-one was added.
g and 52.5 g of a 10% HC'l aqueous solution were added thereto, and the mixture was refluxed for 2 hours.

After cooling, the reaction solution was extracted with 100 ml of ether, the ether was removed, and the ether was distilled under reduced pressure to obtain 16.0 g (yield: 97.2%) of 2-hydroquine-3-ethyl-2-cyclopenten-1-one. Ta. Boiling point is 78-80'C/4
mm1IQ, and the melting point was 38-40°C.

Patent applicant: Sanyo Chemical Industries, Ltd. Showa Ma July lv-day Commissioner of the Patent Office Kazuo Wakasugi Shell 1.Display of the incident 1986 Patent a No. 86197 No. 2, title of invention Process for producing substituted nclobentenone 3. Person who makes corrections August 13, 1981 7. Contents of correction

Claims (1)

[Claims] 1. An aminodiketone represented by the general formula is ring-closed in the presence of an alkali (wherein Hl, R2 is an alkyl group, R] and R2
1 may be interconnected, optionally via an oxygen atom or a nitrogen atom, to form a 5- or 6-membered ring with N. A method for producing a cyclobentenone substituted product, which comprises producing a 2-cyclopenten-1-one substituted product represented by n (R3 is a C1-6 alkyl group). 2. The manufacturing method according to claim 1, wherein R1 and R2 are C, -3 alkyl groups. 8. R' and R2 are connected to each other, optionally via an oxygen atom or a nitrogen atom, to form a piperidino group. The manufacturing method according to claim 1, wherein a morpholino group, a piperazino group, or a pyrrolidino group is formed. 4. The manufacturing method according to any one of claims 1 to 3, wherein R3 is a C, to 6 alkyl group. 5. The manufacturing method according to any one of claims 1 to 4, wherein the alkali is an aqueous caustic alkali solution. Claim 1 in which the ring closure is carried out at a pH of 6.12 or higher.
The manufacturing method according to any one of Items 1 to 5. ? , [+1] The furan-substituted compound represented by the general formula is ring-opened in the presence of an acid to obtain an aminodiketone represented by the general formula %. General formula (wherein, HI and R2 are alkyl groups, and R1 and R2 may be connected to each other via an oxygen atom or a nitrogen atom, as the case may be, to form a 5- or 6-membered ring with N. . R3 is an alkyl group.) 2-cyclopenten-1-one substituted product is produced. 8. The manufacturing method according to claim 7, wherein g, Hl, and R2 are C1-3 alkyl groups. 9. The production method according to claim 7, wherein R'kR2 is optionally connected to each other via an oxygen atom or a nitrogen atom to form a piperidino group, a molporino group, a piperazino group, or a pyrrolidino group. . 10. The production method according to any one of claims 7 to 9, wherein R3 is an alkyl group of CI''T+. 11. Claims 7 to 9, wherein the acid is an aqueous inorganic acid solution.
The manufacturing method according to any one of Item 10. 12. The production method according to any one of claims 7 to 11, wherein the alkali is an aqueous caustic alkali solution. 18. Claim 7, wherein the reactions of [+1 and [Ij] are carried out continuously without separating the aminodiketone represented by the general formula (1) from the reaction product of III.
The manufacturing method according to any one of Items 1 to 12.