JP2009244094A - Indicator for determining damp-dry odor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an indicator capable of determining a damp-dry odor objectively and quantitatively, to provide a damp-dry odor determination method using the indicator, and to provide a pseudo damp-dry odor composition suitable for evaluating a damp-dry odor masking effect, or the like. <P>SOLUTION: The indicator for determining a damp-dry odor contains at least one type selected from a group comprising a carboxylic acid derivative, where an atom or an atomic group is introduced to a carboxylic acid expressed by a general formula (1) and a carboxy group of the carboxylic acid. The damp-dry odor determination method uses the carboxylic acid or its derivative as an index. The pseudo damp-dry odor composition contains the carboxylic acid. R<SP>1</SP>indicates a hydrogen atom, a methyl group, or a methylene group; R<SP>2</SP>and R<SP>3</SP>indicate a hydrogen atom or a methyl group, each; and a broken line indicates a possible double bond and at least one place is a double bond. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an indicator substance used for determining a raw dry odor generated from a textile product such as clothing by drying the room, a method for evaluating a raw dry odor using the indicator substance, and a simulated raw dry odor composition.

  "Dry odor" generated from textiles such as clothing, towels, bedding, etc. means that these textiles are dried after washing, especially in rainy season or in a closed room, etc. Is an unpleasant odor that is likely to occur when left untreated for a long time. In recent years, due to changes in lifestyles such as an increase in double-working households and high airtightness of houses, it is considered that an environment in which a dry odor of textile products tends to occur is becoming more likely.

  This freshly-dried odor (room-dried odor) is a “smell-like odor” such as medium-chain aldehydes, medium-chain alcohols, and ketones, a “sour odor” such as short-chain fatty acids and medium-chain fatty acids, and a “raw odor” such as nitrogen compounds. It is reported that the contribution of medium-chain fatty acids is particularly large (Non-patent Document 1).

  Non-Patent Document 1 presumes that the key component of the raw dry odor is “mixture of fatty acids containing 7 to 9 carbon atoms and containing unsaturation”, and these are also included in odors such as sweat. In other words, Non-Patent Document 1 does not suggest any existence of a component peculiar to a raw dry odor.

Sugawara, Sonoda, “Detergents that Control Room Drying Odors”, Fragrance, September 2004, No.223, p.109-116

  Conventionally, as a method for determining a raw odor of a textile product and an evaluation of the effectiveness of a treatment product for a textile product that prevents the generation of the raw odor, it relied on a sensory evaluation test in which the odor of clothing is actually judged. However, the sensory evaluation test has a problem that it is difficult to make a quantitative determination because the subjective judgment of the evaluator is large, and lacks objectivity.

  An object of the present invention is to provide an indicator substance capable of objectively and quantitatively determining a raw dry odor, a raw dry odor determination method using the same, and a simulated raw dry odor composition suitable for evaluation of a raw dry odor masking effect, etc. To provide things.

  The present inventors have studied the causative components of clothing having a strong raw dry odor. As a result, two types of methylhexenoic acid having a specific structure contribute greatly to the raw dry odor and can be quantified at a concentration. It has been found that a group of compounds having a structure close to those of these compounds can be used as an objective index for quantitatively determining the degree of raw dry odor.

  The present invention relates to determination of a raw dry odor containing at least one selected from the group consisting of a carboxylic acid represented by the general formula (1) and a carboxylic acid derivative obtained by introducing an atom or an atomic group into the carboxy group of the carboxylic acid. It provides an indicator substance for use.

[Wherein, R ¹ represents a hydrogen atom, a methyl group or a methylene group, R ² and R ³ represent a hydrogen atom or a methyl group, respectively, and a broken line represents that a double bond may be present, of which at least 1 The point is a double bond. ]

  The present invention also provides a raw dry odor determination method using the carboxylic acid or a derivative thereof as an index.

  Furthermore, this invention provides the pseudo-raw dry odor composition containing the said carboxylic acid.

  The carboxylic acid represented by the general formula (1) has an odor that is very close to the odor of a raw fiber product, and is useful as an indicator material for determining the raw odor. Therefore, the strength of the raw dry odor can be objectively and quantitatively evaluated based on the abundance of the compound.

  The indicator substance for judgment of raw dry odor of the present invention is formed by introducing an atom or an atomic group into the carboxylic acid represented by the general formula (1) (hereinafter referred to as carboxylic acid (1)) and the carboxy group of the carboxylic acid. It contains at least one selected from the group consisting of carboxylic acid derivatives.

  Among the compounds included in the carboxylic acid (1), the causative substance of the raw odor found by the present inventors is 5-methyl-2-hexenoic acid represented by the following formula (1a) and the following formula (1b) These are 5-methyl-4-hexenoic acids, all of which have an odor very close to a raw dry odor.

  5-Methyl-2-hexenoic acid (1a) is known as a compound contained in tobacco (Phytochemistry, 12 (4), 835-47 (1973)), and 5-methyl-4-hexenoic acid (1b) Is a compound (Bioorganic & Medicinal Chemistry Letters, 15 (23), 5284-5287, (2005)) that is used as an intermediate for pharmaceuticals, etc. There is no.

  Since 5-methyl-2-hexenoic acid (1a) and 5-methyl-4-hexenoic acid (1b) have the following characteristics, the amount and state of presence in clothes with a raw dry odor are It is thought that it shows the degree of.

(I) Clothing in which 5-methyl-2-hexenoic acid and 5-methyl-4-hexenoic acid are not detected does not generate a dry odor, and 5-methyl-2-hexenoic acid and 5-methyl- Clothes that detect 4-hexenoic acid have a clear, dry odor. That is, the above two compounds are present specifically in the raw dry odor.

(B) Clothing that has a higher amount of 5-methyl-2-hexenoic acid and 5-methyl-4-hexenoic acid contained in clothing has a stronger odor.

  Carboxylic acid (1) includes, in addition to the above-mentioned 5-methyl-2-hexenoic acid and 5-methyl-4-hexenoic acid, compounds that are very similar in chemical structure. Specific examples of the carboxylic acid (1) include 5-methyl-2-hexenoic acid, 5-methyl-3-hexenoic acid, 5-methyl-4-hexenoic acid, 4-methyl-2-hexenoic acid, 4-methyl -3-hexenoic acid, 4-methyl-4-hexenoic acid, 2-hexenoic acid, 3-hexenoic acid, 4-hexenoic acid, 5-hexenoic acid, 2-heptenoic acid, 3-heptenoic acid, 4-heptenoic acid, 5-heptenoic acid, 6-heptenoic acid, 5-methyl-2-heptenoic acid, 5-methyl-3-heptenoic acid, 5-methyl-4-heptenoic acid, 5-methyl-5-heptenoic acid, 4-methyl- Examples include 2-heptenoic acid, 4-methyl-3-heptenoic acid, 4-methyl-4-heptenoic acid, and 4-methyl-5-heptenoic acid.

Of these, the closer to the chemical properties of 5-methyl-2-hexenoic acid and 5-methyl-4-hexenoic acid, the easier to use as an indicator substance. Accordingly, the carboxylic acid (1) preferably has 7 carbon atoms, preferably has one carbon-carbon double bond, and one of R ² and R ³ is a methyl group. Those are preferred.

  Carboxylic acid (1) can be synthesized by a known method, and is also an indicator substance in that it can objectively evaluate and determine a dry odor regardless of time and place by stably supplying a synthetic product of constant quality. Suitable as

For example, among the carboxylic acids (1), 2-ene type compounds represented by 5-methyl-2-hexenoic acid are represented by the following reaction formula A (R ¹ , R ² and R ³ are the same as described above). Can be synthesized by the Horner-Wadsworth-Emmons reaction [DJ Schauer, P, Helquist; Synthesis, 21, 3654-3660, (2006)].

Further, among the carboxylic acids (1), 4-ene type compounds represented by 5-methyl-4-hexenoic acid are as shown in Reaction Formula B (R ¹ , R ² and R ³ are the same as above). It can be synthesized by the Johnson-Klaisen rearrangement [S. Menon, D. Sinha-Mahapatra, and JW Herndon; Tetrahedron, 63, 8788-8793 (2007)].

  The carboxylic acid (1) may be a simple substance or a mixture composed of a plurality of carboxylic acids (1). Moreover, although the purity is so preferable that it is high, as long as the odor is not affected, it may contain impurities.

  The carboxylic acid (1) may be used after chemical modification, that is, by introducing an atom or an atomic group into the carboxy group, as long as the detection function as an indicator compound is not lost. For example, to improve analytical sensitivity in instrumental analysis, acylation, esterification, trimethylsilylation, amidation, carboxylation of the carboxy group, or coloration of the carboxy group to enable visualization of the indicator substance You can also introduce teams.

  Derivatizing reagents include O- (p-nitrobenzyl) -N, N- (diisopropylisourea) (PNBDI), UV reagents such as p-bromophenacyl bromide (PBPB), 4-bromomethyl-7-methoxy Acylation of fluorescent reagents such as coumarin (Br-MmC), silylating agents such as N-trimethylsilylimidazole (TMSI) and N, O-bis (trimethylsilyl) acetamide (BSA), trifluoroacetic anhydride and trifluoroacetylimidazole An agent or the like can be used.

  When a chromophore in the visible region is used as the labeling compound for carboxylic acid (1), a concentration-coloring standard sample of the labeling compound is prepared, and the odorant extract collected from the sample is colored with the same reagent. It is also possible to judge the degree of raw dry odor visually.

As a method of determining the presence or amount of carboxylic acid (1) using a color reaction,
i) Method of introducing a chromophore directly into the carboxy group of carboxylic acid (1)
ii) Method of introducing a chromophore into the derivative after converting the carboxylic acid (1) into the derivative
iii) A method of introducing a chromophore into the decomposed product after decomposing the carboxylic acid (1).

  As a color reagent used in the method of i) for introducing a chromophore directly into the carboxy group of the carboxylic acid (1), a reagent that introduces a carboxylic acid into a chromogenic acid hydrazide in the presence of a condensing agent to cause coloration; There are a reagent for introducing a carboxylic acid into a chromogenic ester to cause coloration, a reagent for introducing a carboxylic acid into a chromogenic amide for coloring, and the like.

  Reagents that lead carboxylic acid to chromogenic acid hydrazide for coloration include 2-nitrophenylhydrazine, 6,7-dimethoxy-1-methyl-2 (1H) -quinoxalinone-3-propionylcarboxylic acid hydrazide (DMEQ- H), p- (4,5-diphenyl-1H-imidazol-2-yl) -benzohydrazide, p- (1-methyl-1H-phenanthro- [9,10-imidazol-2-yl) -benzohydrazide, and p- (5,6-dimethoxy-2-benzothiazoyl) -benzohydrazide.

  Reagents for introducing a carboxylic acid into a chromogenic ester to cause coloration include 9-anthryldiazomethane, 1-naphthyldiazomethane, 1- (2-naphthyl) diazoethane, 1-pyrenyldiazomethane, 4-diazomethyl-7-methoxy. Coumarin, 4-bromomethyl-7-methoxycoumarin, 3-bromomethyl-6,7-dimethoxy-1-methyl-2 (1H) -quinoxalinone, 9-bromomethylacridine, 4-bromomethyl-6,7-methylenedioxycoumarin N- (9-acridinyl) -bromoacetamide, 2- (2,3-naphthylimino) ethyl trifluoromethanesulfonate, 2- (phthalimino) ethyl trifluoromethanesulfonate, N-chloromethylphthalimide, N-chloromethyl-4-nitro Examples include phthalimide, N-chloromethyl isatin, o- (p-nitrobenzyl) -N, N′-diisopropylisourea and the like.

  Examples of the reagent that introduces a carboxylic acid into a chromogenic amide to cause coloration include monodansylcadaverine, 2- (p-aminomethylphenyl) -N, N′-dimethyl-2H-benzotriazol-5-amine, and the like. .

  In the method of converting the carboxylic acid of ii) to a derivative and then introducing a chromophore into the derivative, examples of the carboxylic acid derivative that can be used for the color reaction include inorganic salts and acid chlorides.

  Carboxylic acid inorganic salts can be reacted with aromatic halogens to give chromogenic esters and acid chlorides to chromogenic amides.

  Examples of the method for converting the carboxylic acid into an inorganic salt include a method in which the carboxylic acid is mixed with an alkaline substance such as a sodium hydrogen carbonate solution, a sodium carbonate solution, a sodium hydroxide solution, a potassium hydroxide solution and neutralized. Aromatic halogens that can be converted to chromogenic esters by reacting with inorganic salts of hydroxycarboxylic acids include p-nitrobenzyl bromide, phenacyl bromide, p-chlorophenacyl bromide, p-bromophenacyl bromide, p-iodo Examples thereof include phenacyl bromide, p-nitrophenacyl bromide, p-phenylphenacyl bromide, p-phenylazophenacyl bromide, N, N′-dimethyl-p-aminobenzeneazophenacyl chloride.

  Examples of the method for converting carboxylic acid to acid chloride include a method of reacting carboxylic acid with oxalyl chloride. Examples of the method for converting the acid chloride to a color-forming amide include a method of reacting with 9-aminophenanthrene in the presence of triethylamine.

  After degrading the carboxylic acid of iii), a chromophore can be introduced into the degradation product by acyl-CoA synthetase in the presence of adenosine triphosphate (ATP) and coenzyme CoA in the carboxylic acid. To produce acyl-CoA, then treated with acyl-CoA oxidase to produce enoyl-CoA and hydrogen peroxide, which is further treated with catalase to formaldehyde. There is a method in which a color reagent, 4-amino-3-hydrazino-5-mercapto-1,2,3-triazole (AHMT), is reacted to colorize the resulting purple color.

  Thus, in the present invention, the reagent used for the color reaction of the carboxylic acid is not particularly limited as long as it reacts with any of carboxylic acid, a carboxylic acid derivative, and a carboxylic acid decomposition product to develop a color.

  In other words, the raw dry odor detection reagent that colors carboxylic acid (1) can reliably and quickly determine the degree of raw dry odor without using expensive analytical instruments such as gas chromatography and liquid chromatography. Therefore, it can be used when determining in an environment where there is no special analytical instrument.

  In the present invention, in order to objectively and quantitatively determine the extent of the raw dry odor of clothes, the synthesized carboxylic acid (1) or a derivative thereof is used to add a carboxylic acid (1 ) Is quantified, and its presence state is observed.

  The method of using the carboxylic acid (1) or its derivative as an indicator substance for determining a dry odor is not particularly limited, and may be used in conformity with various known evaluation methods. For example, when measuring the content of carboxylic acid (1) contained in clothing with a dry odor by GC-MS, use carboxylic acid (1) or its derivative as a standard substance (standard) to create a calibration curve To do. The calibration curve may be used to identify the peak of carboxylic acid (1) contained in the collected clothing and measure the amount.

  When performing sensory evaluation, carboxylic acid (1) or a derivative thereof is diluted in several stages to prepare odor standard samples at various concentrations. Then, the odor of the evaluation sample prepared from the clothing having a raw dry odor is checked against the standard sample, and the amount of the carboxylic acid (1) contained in the clothing may be determined by sensory evaluation.

  In this way, the degree to which the raw dry odor of clothing is determined is quantitatively determined using odors or parameters other than odors.

  In addition, if there is a large amount of carboxylic acid (1) produced in clothing but it has no odor such as salt or has changed to a weak derivative, there must be a latent state of raw dry odor. However, even if sensory evaluation is performed in such a case, the latent state of the raw dry odor may not be accurately evaluated. In contrast, in the present invention, by measuring the carboxylic acid (1) or a derivative thereof that can be analyzed by a necessary chemical treatment, whether or not the evaluation sample is a sample that may generate a raw dry odor, that is, Potential evaluation can be performed.

  As described above, the index substance of the present invention can be used for any of chemical analysis, instrumental analysis, sensory evaluation, etc. and can be quantitatively determined with high objectivity. By expressing the value as the abundance of carboxylic acid (1), it is possible to exclude subjectivity from the determination result.

  Furthermore, in the present invention, the effectiveness of the fiber product treating agent product targeting a raw dry odor can be objectively and quantitatively determined using an indicator substance containing carboxylic acid (1) or a derivative thereof. .

  In the method for determining the effectiveness of the treatment product for textile products, the indicator substance may be used as a single substance, and other components such as solvents for dissolution or dilution, stabilizers, antibacterial agents, antibacterial agents In addition, additives such as surfactants, antioxidants, fragrances, plant extracts, etc. may be blended to prepare a composition suitable for practical use such as storage or use in a judgment test.

  A treatment for textile products that targets a raw dry odor is a type that disinfects bacteria attached to clothing and prevents the decomposition of sweat, sebum, etc. remaining on clothing, and a type that decomposes or changes to a derivative that does not smell odor components Alternatively, any type of mechanism of action may be used, such as a type that masks odors. The method of using carboxylic acid (1) or a derivative thereof as an index substance for determining the effectiveness of a fiber product treatment product is not particularly limited, and is used in conformity with the action mechanism and evaluation method of the fiber product treatment product. That's fine.

  For example, an index substance containing carboxylic acid (1) or a derivative thereof as an active ingredient, preferably 5-methyl-2-hexenoic acid, 5-methyl-4-hexenoic acid or a derivative thereof in a predetermined concentration is applied to a fiber such as clothing. The effectiveness of the fiber product treating agent sample can be objectively and quantitatively determined by adhering, adding a predetermined amount of the fiber product treating agent sample, and quantifying the change state of the indicator substance by an appropriate method.

  As a method for quantifying the change state of the indicator substance, if the treatment sample for textile products is of the type that degrades carboxylic acid (1) or induces it to another compound to reduce odor, the indicator substance calibration curve May be prepared in advance, and an instrumental analysis may be performed using this calibration curve, or a changed or unchanged substance of the indicator substance may be quantified by chemical analysis such as titration or extraction. If the treatment sample for textile products is of the type that masks the raw dry odor, the indicator substance is diluted in several stages to prepare odor standard samples of each concentration, and the indicator substance to which the treatment sample for textile products is added. The odor is checked against a standard sample, and the masking effect may be determined by sensory evaluation.

  Furthermore, the present invention provides a simulated raw dry odor composition containing carboxylic acid (1), which can be used for deodorizing raw dry odor and evaluating the masking effect. By using this simulated raw dry odor composition, the screening of the deodorant base and the deodorizing effect of the raw dry odor of the deodorant composition can be evaluated accurately and with good reproducibility.

  When this carboxylic acid (1) is used for judgment of raw odor in sensory evaluation etc., known raw dry odor components are mixed in an appropriate ratio to reproduce the raw dry odor close to the actual situation, and simulated raw dry It can also be used as an odor composition.

  That is, the simulated raw dry odor composition of the present invention contains the carboxylic acid (1) as the component (A), and appropriately contains the following compounds (B), (C), and (D). be able to.

  Component (B) is a lower fatty acid having 2 to 5 carbon chains, and by adding these compounds to the composition, a sweat-like sour odor is imparted, which can be brought closer to an actual raw dry odor. Examples of the component (B) include acetic acid, propionic acid, butyric acid, valeric acid, and isovaleric acid, and any of these can be used alone or in combination of two or more.

  In the present invention, the ratio (mass ratio) of component (B) to component (A) is preferably in the range of 0.01 to 100 for (B) / (A), more preferably from 0.1 to (B) / (A). The range is 30.

  Ingredient (C) is a saturated and unsaturated linear aldehyde having 6 to 14 carbon chains. By adding these compounds to the composition, the dustiness peculiar to textile products and the old-fashioned blue-like odor are imparted. And can be brought closer to the actual raw dry odor. Examples of the component (C) include hexanal, heptanal, octanal, nonanal, decanal, undecanal, dodecanal, tridecanal, tetradecanal, 2-hexenal, 2-heptenal, 2-octenal, 2-nonenal, and 2-decenal. , 2-undecenal, 2-dodecenal and the like, and any of them can be used alone or in combination of two or more.

  In the present invention, the ratio (mass ratio) of component (C) to component (A) is preferably in the range of 0.001 to 100 for (C) / (A), more preferably from 0.01 to (C) / (A). The range is 10.

  Ingredient (D) is a saturated fatty acid having 6 to 12 carbon chains detected from human sebum and sweat, and by adding these compounds to the composition, the sweetness peculiar to human-derived odors and a sour acid odor Can be brought closer to the actual raw dry odor. Examples of the component (D) include hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, undecanoic acid, dodecanoic acid and the like, and any of them can be used alone or in combination of two or more. .

  In the present invention, the ratio (mass ratio) of component (D) to component (A) is preferably in the range of 0.01 to 1000 for (D) / (A), more preferably from 0.1 to (D) / (A). The range is 100.

  Compounds other than these (A) to (D) may be used as the simulated raw dry odor composition, such as compounds derived from mold odor such as pyrazines, pyridines, dimethyl disulfide, dimethyl trisulfide, myristic acid, palmitic acid. When higher fatty acids such as palmitoyl acid, stearic acid, oleic acid, and linoleic acid are added, it can be brought closer to the actual raw dry odor.

  In addition, the simulated raw dry odor composition of the present invention contains a diluent such as water, diethyl phthalate, dipropylene glycol, propylene glycol, triethyl citrate, butyl diglycol or a solvent such as ethanol, if necessary. Can be made. The amount can be appropriately determined according to the intended use, intended purpose, etc. of the composition of the present invention.

  These compositions include deodorants that target mixed odor deodorization, nursing odor deodorization, indoor deodorants, clothing cleaning agents, clothing deodorants, and residential cleaning agents. It may be applied to the development of

Test example 1
100 g of jeans that gave a strong, dry odor (dry room odor) were cut, and the odor components were extracted and concentrated with dichloromethane. Subsequently, only the acidic component was selectively extracted and concentrated by an acid-base extraction method using an aqueous alkaline solution, and the key component of the raw dry odor was concentrated. Furthermore, the GC retention time of the component which becomes the key of a live-dry odor was specified by the evaluation by the expert evaluator using odor sniffing gas chromatography (sniffing GC). The key component with a characteristic raw dry odor evaluated by sniffing GC this time was a compound with a very low threshold, and it was a trace component that could not be confirmed as a peak in the detector.
Therefore, the concentration time around the retention time of the compound was concentrated using a Gestel Preparative Fraction Collector (PFC) device, and the resulting odor concentrate was then analyzed using a gas chromatography-mass spectrometer (GC-MS). Analyzed. As a result of analysis, a compound peak that could not be detected by a conventional method was observed.
Some of these trace-eluting components had strong odors that looked very similar to raw odors and room odors in odor sniffing gas chromatography. These unknown peaks are compounds that are not in the general library of GC-MS, and as a result of chemical synthesis by analogizing unknown components from mass fragments and GC retention times, these unknown peaks are 5-methyl-2- It was found to be hexenoic acid and 5-methyl-4-hexenoic acid.
Although 5-methyl-2-hexenoic acid and 5-methyl-4-hexenoic acid have never been reported as constituents of odors in clothing, they were detected at each site from the sample clothing detected this time. .
Next, the same odor extraction operation was performed on clothes that do not have a raw dry odor, and odor components were extracted and GC-MS analysis was performed. As a result, 5-methyl-2-hexenoic acid and 5-methyl-4-hexenoic acid were Not detected.

Production Example 1 Synthesis of 5-methyl-2-hexenoic acid
5-Methyl-2-hexenoic acid was synthesized according to the method described in DJ Schauer, Paul Helquist; Synthesis, 21, 3654-3660, (2006).
Under a nitrogen atmosphere, 2.4 g of zinc trifluoromethanesulfonate (Wako Pure Chemical Industries), 0.48 mL of (diethoxyphosphinoyl) acetic acid (Wako Pure Chemical Industries), N, N, N ', N'-Tetra in a three-necked flask Methylethylenediamine (Wako Pure Chemical Industries) 0.5 mL, 1,8-diazabicyclo [5.4.0] undec-7-ene (DBU) (Wako Pure Chemical Industries) 1.79 mL and anhydrous THF (Wako Pure Chemical Industries) 25 mL were added. Thereafter, 0.35 mL of isovaleraldehyde (Tokyo Chemical Industry) was added dropwise and stirred for 20 hours. The reaction was then terminated with 1N hydrochloric acid, extracted with 50 mL × 2 dichloromethane, washed with 50 mL × 2 water, dried over magnesium sulfate, and the solvent was distilled off to give 0.42 g of 5-methyl-2-hexenoic acid (yield). 99%).
The resulting compound was raw and had an animal odor and was very similar to the scent of clothes.

Production Example 2 Synthesis of 5-methyl-4-hexenoic acid
5-Methyl-4-hexenoic acid was synthesized according to the method described in S. Menon et al, Tetrahedron, 63, 8788-8793, (2007).
A cooling tube was attached to the eggplant flask, and 1.82 mL of 2-methyl-3-buten-2-ol (Wako Pure Chemical Industries), 29.8 mL of triethyl orthoacetate (Aldrich), and 0.16 g of 2-nitrophenol (Tokyo Chemical Industry) And heated to reflux for 36 hours. After returning to room temperature, 25 mL of a mixture of methanol: water = 1: 1 was added and acidified with 5N hydrochloric acid. Thereafter, extraction was performed with 100 mL of diethyl ether, and after washing with 100 mL of water, the organic layer solution was concentrated under reduced pressure.
Next, the concentrated organic layer was transferred to an eggplant flask equipped with a condenser, and 1.25 g of sodium hydroxide, 30 mL of ethanol and 5.5 mL of water were added, and the mixture was heated to reflux for 24 hours. The obtained solution was returned to room temperature, acidified with 5N hydrochloric acid, extracted with 100 mL of diethyl ether, washed with 100 mL of water, and dried over magnesium sulfate. The solution was distilled off under reduced pressure to obtain 1.67 g (yield 67%) of 5-methyl-4-hexenoic acid.
The resulting compound had a cinnamon-like sweetness with a sweat-like acid odor. Furthermore, at low concentrations, a tone reminiscent of the smell of raw dryness was felt.

Production Examples 3-8
Other branched unsaturated fatty acids were synthesized.
5-Methyl-3-hexenoic acid was synthesized based on the description in WO2006 / 083030A1, and 5-methyl-5-hexenoic acid was synthesized from Bull. Chem. Doc. Jpn, 80 (8), 1597-1604, (2007) Was synthesized as described in In addition, 4-methyl-2-hexenoic acid, 4-methyl-3-hexenoic acid, 4-methyl-4-hexenoic acid, 4-methyl-5-hexenoic acid is prepared by Synthesis Example 1 or 2, or the same method as described above. Was synthesized.
A sensory evaluation by a professional evaluator was performed on the odor of each compound. The results are shown in Table 1.

Examples 1-7
A simulated raw dry odor (room-dried odor) composition shown in Table 2 was prepared and subjected to sensory evaluation based on the following evaluation method. The content of each component in Table 2 is mass%.
(Evaluation methods)
In a room kept at room temperature (25 ° C) and humidity of 65%, each simulated fresh dry odor composition was diluted 1000 times with ion-exchanged water into a 5 x 5 cm unused towel (made of cotton). 0.1 mL was applied. About how close the smell of this towel is to the dry-smelling odor, 10 expert evaluations (10: very dry-smelling odors to 1: not dry-smelling odors) were performed by 4 expert evaluators, and the average The values are shown in Table 2.

Claims (6)

An indicator substance for judging a dry odor containing at least one selected from the group consisting of a carboxylic acid represented by the general formula (1) and a carboxylic acid derivative obtained by introducing an atom or an atomic group into the carboxy group of the carboxylic acid.

[Wherein, R ¹ represents a hydrogen atom, a methyl group or a methylene group, R ² and R ³ represent a hydrogen atom or a methyl group, respectively, and a broken line represents that a double bond may be present, of which at least 1 The point is a double bond. ]   A raw dry odor determination method using the carboxylic acid or derivative thereof according to claim 1 as an index.   (A) A simulated raw dry odor composition comprising the carboxylic acid according to claim 1.   Furthermore, (B) The simulated raw dry odor composition of Claim 3 containing a C2-C5 lower fatty acid.   Furthermore, (C) The simulated raw dry odor composition of Claim 3 or 4 containing a C6-C14 aliphatic aldehyde.   Furthermore, (D) The pseudo | simulation raw dry odor composition in any one of Claims 3-5 containing a C6-C12 saturated fatty acid.