JP6397274B2 - Hydrogelator - Google Patents

Description

  The present invention relates to a hydrogelator, and more particularly to a hydrogelator containing two or more homologues of hydrogelators having different alkyl chain lengths, and a hydrogel obtained by the hydrogelator.

  Gelling agents are used to adjust fluidity in the fields of cosmetics, pharmaceuticals, agricultural chemicals, foods, adhesives, paints, resins, and the like. In addition to solidifying and recovering organic solvents and household waste oils that cause environmental pollution, the generated gel can be used as a chemomechanical system material, shock / vibration absorbing material, pharmaceutical sustained release imparting material, etc. ,Attention has been paid. Research and development on the above-mentioned gelling agent has been carried out mainly on polymer compounds, but in recent years, research and development on low-molecular compounds have been promoted because of their excellent properties as gelling agents.

  As described above, gels are used in a wide range of fields, and future expansion of the fields of use is expected. For this reason, gelling agents for low molecular weight compounds are required to have excellent performance such as continuous sol-gel conversion function (thixotropic property) and gel forming ability in expanding the use of the gel. Various low-molecular gelling agents have been proposed so far, and not only gelling agents composed of one single compound but also gelling agents composed of two or more compounds have been reported. ing. As such a gelling agent, for example, a gelling agent containing an alkyl hydrazide compound is disclosed (Patent Document 1).

  As other gelling agents, N-alkyl gluconamides (Non-Patent Document 1) and mixtures of N-octyl gluconamides and dodecyl gluconamides (Non-Patent Document 2) are also disclosed. However, the research content reported in these documents is not a study on the mechanical properties such as improvement of the gel forming ability of the gelling agent and thixotropic property of the formed gel.

  On the other hand, a mixture of two or three alkylamide compounds or a mixture of two alkylurea compounds has a gelling ability with respect to toluene, and the formed gel may have thixotropic properties. (Non-Patent Documents 3 and 4). However, the effects of these mixtures are the result only with organic solvent systems (organogel systems), and in water systems (hydrogel systems) that can be expected to be highly versatile in the above-mentioned application fields, the useful effects of such mixing are Not obtained.

JP2013-151628A

J. et al. -H. Fuhrhop et al. , Journal of the American Chemical Society, 1987, 109, 3387-3390. J. et al. -H. Fuhrhop et al. Journal of the American Chemical Society, 1990, 112, 1768-1776. Yutaka Ohsedo et al. RSC Advances, 2013, 3, 5803-5806. Yutaka Ohsedo et al. New Journal of Chemistry, 2013, 37, 2250-2253.

  An object of the present invention is to provide a hydrogelator containing two or more N-alkyl-D-glucamide derivatives capable of expressing thixotropic properties in the formed hydrogel.

  As a result of diligent research to solve the above problems, the present inventor mixed two or more kinds of homologous N-alkyl-D-glucamide derivatives having different alkyl chain lengths as compared with the case of one kind. The present inventors have found that a hydrogel can be formed at a low concentration, and that the formed hydrogel exhibits thixotropic properties, thereby completing the present invention.

That is, the first aspect of the present invention is the general formula [I].
(Wherein R represents a straight-chain alkyl group having 6 to 10 carbon atoms), and two or more types of N-alkyl-D-glucamide derivatives represented by It is related with the hydrogelator characterized.
As a second aspect, as described in the first aspect, a hydrogel can be formed at a lower concentration compared to a hydrogelator containing one N-alkyl-D-glucamide derivative represented by the general formula [1]. It relates to a hydrogelling agent.
As a third aspect, the R relates to a hydrogelator according to the first aspect or the second aspect, which represents a linear alkyl group having 6 to 8 carbon atoms.
As a fourth aspect, the hydrogelator is an N-alkyl-D-glucamide derivative in which R is a straight-chain alkyl group having 6 or 7 carbon atoms in the general formula [I], and R has 8 carbon atoms. The hydrogelator according to the third aspect, comprising an N-alkyl-D-glucamide derivative which is a linear alkyl group.
As a fifth aspect, the hydrogelator includes two types of N-alkyl-D-glucamide derivatives in which R represents a linear alkyl group having a different number of carbon atoms, wherein R is a straight chain having a large number of carbon atoms. The mixing ratio of the N-alkyl-D-glucamide derivative (A) representing an alkyl group and the N-alkyl-D-glucamide derivative (B) representing a linear alkyl group having a smaller number of carbon atoms than that of the alkyl group is: It is related with the hydrogelator as described in any one of the 1st viewpoint thru | or 4th viewpoint which is (A) :( B) = 10: 1 to 1-10 by mass ratio.
As a sixth aspect, the general formula [I]
(In the formula, R represents a linear alkyl group having 6 to 10 carbon atoms.)
The present invention relates to a hydrogel comprising two or more D-glucamide derivatives and exhibiting thixotropic properties.
Here, one of the preferred embodiments of the present invention is the general formula [I].
An N-alkyl-D-glucamide derivative represented by the formula (wherein R is a straight-chain alkyl group having 6 or 7 carbon atoms), and the general formula [I] (wherein R is 8 carbon atoms) And a N-alkyl-D-glucamide derivative represented by the formula (1), which exhibits thixotropic properties in the formed hydrogel.
Further, among the preferred embodiments of the present invention, the other is represented by the general formula [I].
An N-alkyl-D-glucamide derivative represented by the formula (wherein R is a straight-chain alkyl group having 6 or 7 carbon atoms), and the general formula [I] (wherein R is 8 carbon atoms) And a N-alkyl-D-glucamide derivative represented by the formula (1), which exhibits thixotropic properties.

  The hydrogelator of the present invention can form a hydrogel at a lower concentration than a hydrogelator containing one type of N-alkyl-D-glucamide derivative, and the formed hydrogel has thixotropic properties.

FIG. 1 is a photograph of each sample tube after cooling in a single-system gelation test of an N-alkyl-D-glucamide derivative (C6NG to C10NG) in Comparative Example 1 and after the passage of time (PG: partially gel) , K: crystallization, G: gelation). FIG. 2 is a photograph of each sample tube after cooling in the gelation test (mixed at a mass ratio of 1/1) of the N-alkyl-D-glucamide derivative mixed system in Example 1 and after a lapse of time. “Cn” in the photograph indicates CnNG). FIG. 3 shows the results of differential scanning calorimetry measurement of the sol-gel transition temperature and the gel-sol transition temperature of the N-alkyl-D-glucamide derivative hydrogel in Example 2. (A) Measurement result of single hydrogel, (b) Measurement result of mixed hydrogel. FIG. 4 is a photograph of the thixotropic test result [(a)] of the mixed hydrogel and the thixotropic test result [(b) and (c)] of the single hydrogel in Example 3 and Comparative Example 2. FIG. 5 is a photograph of a thixotropic test result of a hydrogel prepared from C8NG and a sodium dodecyl sulfate aqueous solution gel in Comparative Example 3. FIG. 6 is a diagram showing the results of evaluating viscoelastic properties of the N-alkyl-D-glucamide derivative single hydrogel (a) and mixed hydrogel (b) in Example 4 by measuring the frequency dependence [(a) C8NG. 3 wt% hydrogel and C6NG 7 wt% hydrogel, (b) C8NG / C7NG (mass mixing ratio 1/1) 5 wt% hydrogel and C8NG / C6NG (mass mixing ratio 1/1) 5 wt% hydrogel]. FIG. 7 is a diagram showing the results of evaluating viscoelastic properties of the N-alkyl-D-glucamide derivative single hydrogel (a) and mixed hydrogel (b) in Example 4 by measuring the strain dependency [(a) C8NG. 3 wt% hydrogel and C6NG 7 wt% hydrogel, (b) C8NG / C6NG (mass mixing ratio 1/1) 5 wt% hydrogel and C8NG / C7NG (mass mixing ratio 1/1) 5 wt% hydrogel]. FIG. 8 is a graph showing the thixotropic evaluation results by rheometer of N-alkyl-D-glucamide derivative mixed hydrogel (a) and single hydrogel (b) in Example 5 [(a) C8NG / C6NG (mass) Mixing ratio 1/1) 5 wt% hydrogel and C8NG / C7NG (mass mixing ratio 1/1) 5 wt% hydrogel, (b) C8NG 3 wt% hydrogel and C6NG 7 wt% hydrogel]. FIG. 9 is a photograph of a scanning electron microscope (SEM) image of a xerogel (prepared from a gel with the lowest gelation concentration) of the N-alkyl-D-glucamide derivative alone hydrogel and mixed hydrogel in Comparative Example 4 and Example 6. [(A) and (b) C8NG 3 wt% xerogel, (c) and (d) C6NG 7 wt% xerogel, (e) and (f) C8NG / C6NG (mass mixing ratio 1/1) 5 wt% Xerogel, (g) and (h) C8NG / C7NG (mass mixing ratio 1/1) 5 wt% xerogel] FIG. 10 is a diagram showing the X-ray diffraction measurement results of the N-alkyl-D-glucamide derivative single hydrogel, the mixed hydrogel, and the corresponding xerogel in Example 7 [(a) C8NG / C6NG ( Mass mixing ratio 1/1) 5 wt% hydrogel and C8NG / C7NG (mass mixing ratio 1/1) 5 wt% hydrogel, (b) C8NG 3 wt% hydrogel and C6NG 7 wt% hydrogel, (c) and (d) C8NG / C6NG ( Mass mixing ratio 1/1) 5 wt% xerogel and C8NG / C7NG (mass mixing ratio 1/1) 5 wt% xerogel, (e) and (f) C8NG 3 wt% xerogel, C7NG 3 wt% xerogel, and C6NG 7 wt% xerogel]. FIG. 11 is a diagram showing molecular models of C8NG, C7NG, and C6NG (molecular length is calculated by ChemDraw3D).

The present invention relates to a hydrogelator comprising two or more N-alkyl-D-glucamide derivatives represented by the above general formula [I].
Hereinafter, the present invention will be described in detail. In the present specification, the “N-alkyl-D-glucamide derivative represented by the general formula [I]” is also referred to as “derivative [1]”.

The linear alkyl group having 6 to 10 carbon atoms shown in the definition of R in the general formula [I] is specifically a linear hexyl group, heptyl group, octyl group, nonyl group, and decyl group. Is mentioned.
Among these, R is preferably a linear alkyl group having 6 to 8 carbon atoms, and specifically, an n-hexyl group, an n-heptyl group, and an n-octyl group are preferable.

  The N-alkyl-D-glucamide derivative represented by the general formula [1] can be synthesized by a known method, for example, a method described in Non-Patent Document 1.

As the hydrogelator of the present invention, a mixture of two or more N-alkyl-D-glucamide derivatives represented by the above general formula [I] is used as a gelator.
Examples of the hydrogelator include a derivative [1] in which R is a linear alkyl group having 6 or 7 carbon atoms and a derivative [1] in which R is a linear alkyl group having 8 carbon atoms. preferable.

  The hydrogelator includes two types of N-alkyl-D-glucamide derivatives in which R represents a linear alkyl group having a different number of carbon atoms, where R is a linear alkyl group having a large number of carbon atoms. The mixing ratio of the N-alkyl-D-glucamide derivative (A) representing N and the N-alkyl-D-glucamide derivative (B) representing a linear alkyl group having a smaller number of carbon atoms than that of the N-alkyl-D-glucamide derivative (B) And (A) :( B) = 10: 1 to 1 to 10, preferably 5 to 1: 1 to 5, more preferably 2 to 1: 1 to 2.

The hydrogelator of the present invention comprising a mixture of two or more of these derivatives [1] gels water as a medium with a smaller amount of use compared to the case of using one single derivative [1]. It is possible.
Moreover, the hydrogelator which consists of a mixture of these 2 or more types of derivatives [1] can express thixotropic property in the formed hydrogel.

  The water that is the target of the gelation of the present invention can be used without particular limitation as long as it can form a gel, for example, purified water, purified water, hard water, soft water, natural water, deep ocean water, electrolytic alkali ions. Water, electrolytic acid ionic water, and ionic water are mentioned. These may be used alone or in combination of two or more.

In the hydrogelator of the present invention, the total amount of two or more N-alkyl-D-glucamide derivatives is 0.1 to 30% by mass, preferably 0.5 to 20% by mass, based on water as a medium. More preferably, it is used in an amount of 1 to 10% by mass.
A gelled product can be obtained by adding the hydrogelator of the present invention to water, which is a medium, and dissolving by heating and stirring as necessary, and then allowing to stand at room temperature. The gel strength can be adjusted by the concentration of the hydrogelator.

  In addition, the hydrogel formed by the hydrogelator of the present invention has various additives (surfactant, ultraviolet absorber, moisturizer, etc.) as required, such as its application, within a range that does not inhibit the gelation ability of the hydrogelator. Organic compounds such as agents, preservatives, antioxidants, fragrances, and physiologically active substances (medicinal ingredients), and inorganic compounds such as titanium oxide, talc, mica, and water) can be mixed.

  In addition, the hydrogel which contains 2 or more types of N-alkyl-D-glucamide derivatives represented by the said Formula [1] which is the hydrogelling agent of the said invention, and expresses thixotropic property is also the object of this invention.

EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated more concretely, this invention is not limited to the following Example.
The reagents described in the following examples were obtained from Tokyo Chemical Industry Co., Ltd., and the solvents were obtained from Wako Pure Chemical Industries, Ltd. and used as they were. Moreover, water (pure water) was refine | purified with the Elix UV3 Milli-Q pure water manufacturing apparatus (made by Nippon Millipore Corporation).

The apparatus and conditions used for various measurements and analyzes are shown below.
(1) Molecular structure identification ¹ H-NMR and ¹³ C-NMR spectrum: AVANCE 500 (500 MHz, B
ruker Biospin Co., Ltd.)
Mass spectrometry: LC-MS system, mass detector 3100, separation module e2695, UV / Vis detector s2489 (Nihon Waters Co., Ltd.)
Elemental analysis: Microcoder JM10 (manufactured by Jay Science Lab Co., Ltd.)
(2) Thixotropy test (observation of gel crushing and recovery behavior)
・ Equipment: Vortex mixer (Jenny 2), manufactured by ASONE Co., Ltd. (3) Differential scanning calorimetry ・ Equipment: EXSTAR6000 thermal analyzer, manufactured by Hitachi High-Tech Science Co., Ltd. ・ Container: Ag sealed sample container Temperature rate and temperature decrease rate: 2 ° C./min. The rising or falling temperature of the peak was defined as the transition temperature.
(4) Evaluation of viscoelasticity and thixotropy of gel using rheometer, rheometer viscoelasticity measuring device MCR-301, manufactured by Anton Paar Japan Co., Ltd., measuring condition: measuring jig 8 mm diameter circular parallel plate, 0. 50mm gap, measuring temperature 25 ° C, wiped off gel and measured ・ Frequency dependency measurement: measured at a constant 0.01% strain ・ Strain dependent measurement: measured at a constant angular frequency (1 rad / sec) ・ Thixotropic evaluation : Low shear (strain amplitude 0.01%, frequency 1 Hz) and high shear (shear rate 3000 sec- ¹ applied for 0.1 seconds) are repeatedly applied to measure the change in elastic modulus (5) Scanning electron microscope Photo / Equipment: SU-8000, manufactured by Hitachi High-Technologies Corporation / Acceleration voltage: 1.0 kV
Sample treatment: Sample treatment with a conductive substance (Pt) was performed (10 nm).
(6) X-ray diffraction measurement / D8 DISCOVER multi-functional thin film material evaluation X-ray diffractometer, manufactured by Bruker AXS Co., Ltd., measured at 26 ° C., sampled into 1 mm diameter capillary glass and measured

[Synthesis example]
[Synthesis of N-alkyl-D-glucamide derivative CnNG]
The N-alkyl-D-glucamide derivative CnNG (n represents the number of carbon atoms of the straight chain alkyl group) was prepared according to the method shown in Non-Patent Document 1 (Scheme 1), and the alkylamine (C _n H _{2n + 1} It was synthesized by amidation reaction of NH ₂ ) with an equivalent amount of D-(+)-glucono-1,5-lactone in a methanol solvent. Purification was performed by recrystallization from methanol.

[Synthesis of C5NG]
Pentylamine (3.00 g, 16.50 mmol) and D-(+)-glucono-1,5-lactone (1.54 g, 17.33 mmol) were added to methanol (10 mL), and the mixture was refluxed for 2 hours for reaction. After allowing to cool to room temperature, a white precipitate was collected by filtration and recrystallized from methanol to give C5NG represented by the above formula [A] (n = 5) (1.39 g, white crystals, yield 31.7). %).

¹ H-NMR (500 MHz, DMSO-d ₆ , TMS, δ, ppm): 7.61 (t, 1H, J = 5.8 Hz), 5.37 (d, 1H, J = 5.0 Hz), 4 .56 (d, 1H, J = 5.0 Hz), 4.49 (d, 1H, J = 5.0 Hz), 4.41 (d, 1H, J = 7.3 Hz), 4.36 (t, 1H, J = 5.7 Hz), 3.98 (t, 1H, J = 4.3 Hz), 3
. 90 (m, 1H), 3.58 (m, 1H), 3.47 (s (br), 2H), 3.36 (m, 1
H), 3.07 (m, 2H), 1.43 (m, 2H), 1.23 (m, 4H), 0.86 (t, 3H, J = 6.8 Hz).

¹³ C-NMR (125 MHz, DMSO-d ₆ , TMS, δ, ppm): 173.10, 74.49, 73.31, 72.38, 71.04, 64.26, 39.09, 29. 66, 29.41, 22.70, 14.75.

Mass analysis: m / z calculated value C ₁₁ H ₂₃ NO ₆ : 265.15, measured value: 264.2 [M−H]
⁺ .
Elemental analysis: calculated value C ₁₁ H ₂₃ NO ₆ : C, 49.80; H, 8.74; N, 5.28, measured value: C, 49.76; H, 8.61; N, 5.26 .

[Synthesis of C6NG]
1.19 g (11.55 mmol) of hexylamine and 2.00 g (11.00 mmol) of D-(+)-glucono-1,5-lactone were added to 10 mL of methanol, and the mixture was refluxed for 2 hours to be reacted. After allowing to cool to room temperature, a white precipitate was collected by filtration and recrystallized from methanol to give C6NG represented by the above formula [A] (n = 6) (1.68 g, white crystals, yield 54.7). %).

¹ H-NMR (500 MHz, DMSO-d ₆ , TMS, δ, ppm): 7.61 (t, 1
H, J = 5.8 Hz), 5.36 (d, 1H, J = 4.7 Hz), 4.56 (d, 1H,
J = 4.4 Hz), 4.49 (d, 1H, J = 4.4 Hz), 4.41 (d, 1H, J = 6.9 Hz), 4.36 (t, 1H, J = 5.0 Hz) ), 3.98 (t, 1H, J = 3.9 Hz), 3.90 (m, 1H), 3.57 (m, 1H), 3.47 (s (br), 2H), 3.35 (M, 1H), 3.07 (m, 2H), 1.40 (m, 2H), 1.26 (m, 6H), 0.86 (t, 3H, J = 6.9 Hz).

¹³ C-NMR (125 MHz, DMSO-d ₆ , TMS, δ, ppm): 173.10, 74.48, 73.31, 72.39, 71.05, 64.26, 39.14, 31. 88, 29.97, 26.88, 22.90, 14.75.

Mass analysis: m / z Calculated value C ₁₂ H ₂₅ NO ₆ : 279.17, measured value: 278.2 [M−H] ⁺ .
Calcd _{C 12 H 25 NO 6: C} , 51.60; H, 9.02; N, 5.01; Found: C, 51.21; H, 8.89 ; N, 5.00 .

[Synthesis of C7NG]
Heptylamine (2.04 g, 17.33 mmol) and D-(+)-glucono-1,5-lactone (3.00 g, 16.50 mmol) were added to methanol (15 mL), and the mixture was refluxed for 2 hours for reaction. After allowing to cool to room temperature, the white precipitate was collected by filtration and recrystallized from methanol to give C7NG represented by the above formula [A] (n = 7) (3.73 g, white crystals, yield 77.1). %).

¹ H-NMR (500 MHz, DMSO-d ₆ , TMS, δ, ppm): 7.61 (t, 1H, J = 5.8 Hz), 5.36 (d, 1H, J = 5.0 Hz), 4 .55 (d, 1H, J = 4.7 Hz), 4.48 (d, 1H, J = 5.4 Hz), 4.40 (d, 1H, J = 7.3 Hz), 4.35 (t, 1H, J = 5.7 Hz), 3.97 (t, 1H, J = 4.3 Hz), 3.90 (m, 1H), 3.60 (m, 1H), 3.47 (s (br) , 2H), 3.38 (m, 1H), 3.08 (m, 2H), 1.41 (m, 2H), 1.26 (m, 8H), 0.87 (t, 3H, J = 6.9 Hz).

¹³ C-NMR (125 MHz, DMSO-d ₆ , TMS, δ, ppm): 173.08, 74.48, 73.31, 72.39, 71.04, 64.26, 39.13, 32. 11, 30.01, 29.30, 27.18, 22.91, 14.79.

Mass spectrometry: m / z calcd _{C 13 H 27 NO 6: 293,18} , Found: 292.2 [M-H
] ⁺ .
Calcd _{C 13 H 27 NO 6: C} , 53.23; H, 9.28; N, 4.77; Found: C, 53.36; H, 9.21 ; N, 4.78 .

[Synthesis of C8NG]
1.52 g (11.55 mmol) of octylamine and 2.00 g (11.00 mmol) of D-(+)-glucono-1,5-lactone were added to 10 mL of methanol and refluxed for 2 hours for reaction. After allowing to cool to room temperature, the white precipitate was collected by filtration and recrystallized from methanol to give C8NG represented by the above formula [A] (n = 8) (3.05 g, white crystals, yield 90.).
2%).

¹ H-NMR (500 MHz, DMSO-d ₆ , TMS, δ, ppm): 7.61 (t, 1H, J = 5.8 Hz), 5.36 (d, 1H, J = 5.0 Hz), 4 .55 (d, 1H, J = 5.0 Hz), 4.48 (d, 1H, J = 5.4 Hz), 4.41 (d, 1H, J = 6.9 Hz), 4.35 (d, 1H, J = 5.7 Hz), 3.98 (t, 1H, J = 4.3 Hz), 3.89 (m, 1H), 3.59 (m, 1H), 3.47 (s (br) , 2H), 3.35 (m, 1H), 3.07 (m, 2H), 1.45 (m, 2H), 1.25 (m, 10H), 0.86 (t, 3H, J = 6.9 Hz).

¹³ C-NMR (125 MHz, DMSO-d ₆ , TMS, δ, ppm): 173.08, 74.49, 73.31, 72.39, 71.04, 64.26, 39.14, 32. 13, 30.01, 29.62, 29.52, 27.24, 22.95, 14.78.

Mass analysis: m / z calculated value C ₁₄ H ₂₉ NO ₆ : 307.20, measured value: 306.2 [M−H
] ⁺ .
Calcd _{C 14 H 29 NO 6: C} , 54.70; H, 9.51; N, 4.56; Found: C, 54.61; H, 9.51 ; N, 4.55 .

[Synthesis of C9NG]
Nonylamine (2.53 g, 17.33 mmol) and D-(+)-glucono-1,5-lactone (3.00 g, 16.50 mmol) were added to methanol (20 mL), and the mixture was refluxed for 2 hours to be reacted. After allowing to cool to room temperature, the white precipitate was collected by filtration and recrystallized from methanol to give C9NG represented by the above formula [A] (n = 9) (4.79 g, white crystals, yield 90.4). %).

¹ H-NMR (500 MHz, DMSO-d ₆ , TMS, δ, ppm): 7.61 (t, 1H, J = 5.8 Hz), 5.36 (d, 1H, J = 4.7 Hz), 4 .55 (d, 1H, J = 4.4 Hz), 4.48 (d, 1H, J = 4.7 Hz), 4.40 (d, 1H, J = 6.9 Hz), 4.35 (t, 1H, J = 5.5 Hz), 3.97 (d, 1H, J = 3.9 Hz), 3.90 (m, 1H), 3.58 (m, 1H), 3.49 (s (br) , 2H), 3.37 (m, 2H), 3.07 (m, 2H), 1.40 (m, 2H), 1.26 (m, 12H), 0.86 (t, 3H, J = 6.8 Hz).

¹³ C-NMR (125 MHz, DMSO-d ₆ , TMS, δ, ppm): 172.67, 74.08, 72.91, 71.99, 70.64, 63.87, 38.73, 31. 76, 29.62, 29.44, 29.27, 29.14, 26.84, 22.55, 14.39.

_{LC-MS: calcd for C 15} H 31 NO 6 (MW = 321.22):
m / z = 320.2 [M ⁺ -H]. Elemental anal. _{calcd for C 15 H 31 NO 6} : C, 56.05; H, 9.72; N, 4.36; Fo
und: C, 55.90; H, 9.78; N, 4.37.

Mass analysis: m / z calculated value C ₁₅ H ₃₁ NO ₆ : 321.22, measured value: 320.2 [M−H
] ⁺ .
Calcd _{C 15 H 31 NO 6: C} , 56.05; H, 9.72; N, 4.36; Found: C, 55.90; H, 9.78 ; N, 4.37 .

[Synthesis of C10NG]
1.85 g (11.55 mmol) of decylamine and 2.00 g (11.00 mmol) of D-(+)-glucono-1,5-lactone were added to 10 mL of methanol, and the mixture was refluxed for 2 hours to be reacted. After allowing to cool to room temperature, the white precipitate was collected by filtration and recrystallized from methanol to give C10NG represented by the above formula [A] (n = 10) (1.37 g, white crystals, yield 37.1). %).

¹ H-NMR (500 MHz, DMSO-d ₆ , TMS, δ, ppm): 7.61 (t, 1H, J = 6.0 Hz), 5.36 (d, 1H, J = 4.4 Hz), 4 .55 (d, 1H, J = 4.4 Hz), 4.48 (d, 1H, J = 4.1H), 4.40 (d, 1H, J = 6.9 Hz), 4.35 (d, 1H, J = 5.5 Hz), 3.98 (s (br), 1H), 3.90 (s (br), 1H), 3.58 (s (br), 1H), 3.47 (s (Br), 2H), 3.34 (m, 1H), 3.07 (m, 2H), 1.42 (m, 2H), 1.25 (m, 14H), 0.86 (t, 3H) , J = 6.8 Hz).

¹³ C-NMR (125 MHz, DMSO-d ₆ , TMS, δ, ppm): 173.08, 74.49, 73.31, 72.39, 71.03, 64.26, 39.14, 32. 17, 30.02, 29.90, 29.87, 29.68, 29.57, 27.25, 22.96, 14.79.

Mass analysis: m / z calculated value C ₁₆ H ₃₃ NO ₆ : 335.23, measured value: 334.3 [M−H
] ⁺ .
Elemental analysis: calculated C ₁₆ H ₃₃ NO ₆ : 57.29; H, 9.92; N, 4.18;
C, 57.34; H, 9.94; N, 4.21.

[Comparative Example 1: Gelation test of N-alkyl-D-glucamide derivative (single system)]
Add water so that the added amount of N-alkyl-D-glucamide derivative (C5NG to C10NG) and N-alkyl-D-glucamide derivative (C5NG to C10NG) is a predetermined mass percent (wt%) in a 4 mL sample tube. And heat-dissolve at 100 ° C, N-alkyl-D
-An aqueous solution of glucamide derivative was prepared. Thereafter, these aqueous solutions were allowed to cool at room temperature (approximately 25 ° C.) to confirm gelation. In addition, after standing to cool, the fluidity of the solution was lost, and the state in which the solution did not flow down even when the sample tube was inverted was judged as “gelation”. This gelation test was performed on solutions of various concentrations, and the minimum concentration of N-alkyl-D-glucamide derivative required for gelation (w
t%) was defined as the minimum gelation concentration.
The obtained results are shown in Table 1. The obtained gel was cloudy. A photograph of each sample tube after cooling in the gelation test and after the passage of time is shown in FIG.

As shown in Table 1 and FIG. 1, the result was that the N-alkyl-D-glucamide derivative had gel forming ability with respect to an aqueous solvent. However, as can be seen from the results after the elapse of time shown in FIG. 1, these derivatives tended to separate from the gel or crystallize after the elapse of time. Among these results, C8NG has a report example in Non-Patent Document 1 described above.

[Example 1: Gelation test of N-alkyl-D-glucamide derivative (mixed system)]
In the same procedure as in Comparative Example 1, a gelation test of a two-component mixed system of N-alkyl-D-glucamide derivatives having different alkyl chain lengths was performed using water. A gelation test was conducted by preparing aqueous solutions of N-alkyl-D-glucamide derivatives having different alkyl chain lengths at various concentrations and a mixing ratio of 1/1 (mass mixing ratio, see Table 2).
The obtained results are shown in Table 2. A photograph of each sample tube after cooling in the gelation test and after a lapse of time is shown in FIG. Compared to the minimum gelation concentration of each of the N-alkyl-D-glucamide derivatives in the single system, the minimum gelation concentration of the C8NG / C7NG and C8NG / C6NG binary mixture systems is low, and it tends to form a gel. confirmed. In addition, the mixed gels did not separate even after at least half a year, and no crystallization was observed.

Thus, it was found that by mixing N-alkyl-D-glucamide derivatives having different alkyl chain lengths, a gelling agent having excellent gel-forming ability can be obtained as compared with a single system.
In addition, although there is a report example in Non-Patent Document 2 regarding the formation of fibrous structures of C8NG and C10NG and mixed hydrogels composed thereof, there is no description regarding improvement of gel forming ability by mixing as in this example. This result was a result showing the unique effect (improved gel forming ability) of the hydrogelator of the present invention.

[Example 2: Thermal behavior of single and mixed hydrogels of N-alkyl-D-glucamide derivatives]
From the mixed system of C8NG / C7NG and C8NG / C6NG in which the improvement of the minimum gelation concentration was recognized in Example 1 and those single systems, the same procedure as in Comparative Example 1 and Example 1 was performed.
An aqueous solution of an alkyl-D-glucamide derivative was prepared and then allowed to cool at room temperature to form a gel. Next, for each gel obtained, the sol-gel transition temperature and the gel-sol transition temperature were measured with a differential scanning calorimeter. The obtained results are shown in Table 3 and FIG. In addition, since C7NG only obtained the crystalline gel as mentioned above, this sample was measured.

As shown in Table 3 and FIG. 3, the single-system and mixed-system hydrogels using N-alkyl-D-glucamide derivatives as hydrogelators exhibit reversible heat transfer with almost the same amount of heat in and out. It was quantitatively confirmed that the sol-gel transition. In addition, since the transition temperature of the mixed hydrogel is shifted to a lower temperature compared with the corresponding transition temperature of the single hydrogel, the mixed hydrogel is formed from the fibrous material formed by the single hydrogelator. It is suggested that a new structure is formed, which is different from the network.

[Example 3: Thixotropy test of mixed hydrogel of N-alkyl-D-glucamide derivative]
The behavior of mixed hydrogels of N-alkyl-D-glucamide derivatives after gel grinding was evaluated. C8NG / C7NG and C8NG / C6NG mixed hydrogels in which improvement of the minimum gelation concentration was recognized in Example 1 were prepared in the same procedure as in Example 1. The mixing ratio was 1/1 by mass ratio, and the concentration was 5 wt% (the concentration was the concentration as a mixture).
Next, the sample tube is applied to a vortex mixer, the gel inside is pulverized for 10 seconds, allowed to stand for a predetermined time (1 minute, 10 minutes, 60 minutes, 90 minutes, 24 hours), and then the sample tube is inverted. It was confirmed whether the gel was flowing.
Table 4 shows the obtained results. FIG. 4 shows thixotropy test results of mixed hydrogels of various N-alkyl-D-glucamide derivatives. As a result, thixotropic properties were recognized in the mixed hydrogel.

[Comparative Example 2: Thixotropic test of single hydrogel of N-alkyl-D-glucamide derivative]
In order to compare with the C8NG / C7NG and C8NG / C6NG mixed hydrogels in which the improvement of the minimum gelation concentration was recognized in Example 1, each single hydrogel of C8NG, C7NG and C6NG was subjected to the same procedure as in Example 1. Made. Concentrations were 5 wt% where thixotropy was observed in the above mixed hydrogel for C8NG, and 7 wt% of the minimum gelation concentration for C6NG.
Next, the sample tube is applied to a vortex mixer, the internal gel is pulverized for 10 seconds, and allowed to stand for a predetermined time (1 minute, 10 minutes, 1 hour or 24 hours), then the sample tube is inverted and the gel flows. Confirmed whether or not.
Table 4 shows the obtained results. FIG. 4 shows thixotropy test results of single hydrogels of various N-alkyl-D-glucamide derivatives.
In various single-system hydrogels of N-alkyl-D-glucamide derivatives, the gel hangs down after standing for any predetermined time when inverted after pulverization, and the single-system hydrogel did not exhibit thixotropic properties.

[Comparative Example 3: Thixotropic test of hydrogel containing C8NG and sodium dodecyl sulfate]
Journal of the American Chemical Society, 1990, 112, 4307-4312. The hydrogel formed from an aqueous solution in which C8NG and a low molecular weight surfactant, sodium dodecyl sulfate, are mixed, as described in the above. As in Comparative Example 2, the evaluation was performed.
Table 4 shows the obtained results. In FIG. 5, the thixotropy test result of the hydrogel of the comparative example 3 is shown.

As shown in Table 4 above, although a single hydrogel using one N-alkyl-D-glucamide derivative does not exhibit thixotropic properties (Comparative Example 2), it can be made into a mixed hydrogel such as C8NG / C7NG. It was confirmed that thixotropy may be expressed (Example 3). Further, the C8NG 5 wt% / sodium dodecyl sulfate 1 wt% hydrogel was confirmed to have weak thixotropic properties compared to the mixed hydrogel (Comparative Example 3), but the mixed hydrogel was superior in thixotropic properties. Indicated.

Note that studies on mixed gels using low-molecular gelling agents are described in Journal of Chemical Society, Chemical Communications, 1993, 1382-1383. , Langmuir, 2009, 25, 8579-8585. Chemistry A European Journal, 2005, 11, 5496-5508. , Soft Matter, 2007, 3, 956-970. , And Chemical Society Reviews, 2012, 41, 6089-6102. Examples of reports on new effects (thixotropic properties) obtained by mixing two or more N-alkyl-D-glucamide derivatives with different alkyl chain lengths as in the present invention. There is no. Further, in the above-mentioned Non-Patent Document 2, there is a report on the formation of fibrous materials after mixing with different alkyl chain lengths, but there is no description on the mechanical properties such as thixotropic properties. Thus, the present Example brought the result which shows the peculiar effect which the hydrogelator of this invention has.

[Example 4: Evaluation of viscoelastic properties of N-alkyl-D-glucamide derivative single hydrogel and mixed hydrogel]
It was confirmed that the gel state was obtained by evaluating viscoelastic properties of the N-alkyl-D-glucamide derivative single hydrogel and the mixed hydrogel. The obtained results are shown in FIGS.
In the frequency dependence measurement of FIG. 6, since it shows flat storage elastic modulus (G ′) and loss elastic modulus (G ″) regardless of frequency, and G ′> G ″, the measurement sample is It was confirmed to be in a gel state (solid state).
In the strain dependence measurement of FIG. 7, when the strain increases, the flat G ′ and the loss elastic modulus G ″ and G ′> G ″ become G ′ <G ″. Thus, the sample changed from a gel state (G ′> G ″) to a liquid state (G ′ <G ″). From this, it was confirmed that the gel-sol transition occurs by applying strain to the gel sample.

[Example 5: Evaluation of thixotropic properties of single-type hydrogel and mixed-type hydrogel of N-alkyl-D-glucamide derivative by rheometer]
The thixotropy was quantitatively evaluated by measuring the time-dependent change in elastic modulus before and after gel crushing due to cyclic large deformation application in single and mixed hydrogels of N-alkyl-D-glucamide derivatives. . The obtained result is shown in FIG.
As shown in FIG. 8, in the C8NG / C6NG mixed hydrogel, it was found that the recovery of the storage elastic modulus (G ′) and the loss elastic modulus (G ″) was large even when a large amount of periodic deformation was applied. However, in the C8NG / C7NG mixed hydrogel, only one recovery was observed, and it was found that G ′ ≧ G ″ (gel state to liquid state).
Further, even with a single hydrogel, the elastic modulus recovered after large deformation, and the measurement result was G ′> G ″ (gel state). However, in the thixotropy test of Comparative Example 2 described above, no thixotropy was observed in the single hydrogel, so the data for the small gel obtained by this rheometer measurement shows the behavior of the large gel at the sample tube level. It is presumed that this is not reflected.
From the above results, good thixotropy of the mixed hydrogel was quantitatively confirmed by a rheometer.

[Comparative Example 4: Microstructure observation of single hydrogel formed using N-alkyl-D-glucamide derivative]
A hydrogel was formed at the lowest gelation concentration of N-alkyl-D-glucamide derivatives (C8NG and C6NG) by the same procedure as in Comparative Example 1 described above. The state of the xerogel obtained by freeze-drying the hydrogel thus obtained was observed with a scanning electron microscope (SEM). The obtained results are shown in FIG. As shown in FIG. 9, it was confirmed that the xerogel of the N-alkyl-D-glucamide derivative was composed of a network of fibrous materials having a sub-macrometer diameter. Regarding C7NG, macroscopic crystallization proceeds within several hours after the formation of the hydrogel as described above, so SEM observation is not performed.

The above results correspond to the C8NG fibrous structure formation reported in Non-Patent Document 1 or Non-Patent Document 2 described above. The hydrogel composed of N-alkyl-D-glucamide derivative is presumed that the fibrous material composed of N-alkyl-D-glucamide derivative forms a network structure like polymer hydrogel .

[Example 6: Microstructure observation of N-alkyl-D-glucamide derivative mixed hydrogel]
A hydrogel of a mixed system of C8NG and C7NG, C8NG and C6NG was formed in the same procedure as in Example 1 described above. The hydrogel thus obtained was freeze-dried to obtain a xerogel, and SEM observation of the obtained xerogel state was performed. The obtained results are shown in FIG.
As shown in FIG. 9, it was confirmed that the xerogel of the mixed system of N-alkyl-D-glucamide derivatives was composed of a network of fibrous materials having a submicrometer diameter similar to that of the single xerogel.

The above results correspond to the C8NG fibrous structure formation reported in Non-Patent Document 1 or Non-Patent Document 2 described above. The hydrogel composed of N-alkyl-D-glucamide derivative is presumed that the fibrous material composed of N-alkyl-D-glucamide derivative forms a network structure like polymer hydrogel .

[Example 7: X-ray diffraction measurement of N-alkyl-D-glucamide derivative mixed hydrogel]
In order to obtain knowledge about the fibrous substance, X-ray diffraction measurement was performed on the mixed hydrogel of the N-alkyl-D-glucamide derivative described above and the corresponding single xerogel. The measurement results are shown in FIG. 10 together with the single hydrogel sample and the corresponding single xerogel sample. FIG. 11 shows the molecular length of the N-alkyl-D-glucamide derivative calculated by ChemDraw3D.
From FIG. 10, it was confirmed that the peaks of the xerogel sample, the single gel sample, and the mixed gel sample matched well. As shown in FIG. 11, these peaks are consistent with the molecular length (and the length of the two) and the alkyl site length. From these facts, even in the N-alkyl-D-glucamide derivative mixed hydrogel, as described in Non-Patent Document 1 or Non-Patent Document 2 described above, the N-alkyl-D-glucamide derivative is hydrogenated even in the crystalline state. It was found that there is a fibrous material composed of a lamellar structure or a bilayer structure obtained by forming a dimer through a bond.

From the results of Example 6 and Example 7 above, it was confirmed that in the mixed hydrogel of N-alkyl-D-glucamide derivatives, the fibrous material constitutes a network as in the case of the single hydrogel. In the non-patent document 2 mentioned above, in the mixed xerogel, the fibrous substance formed independently by each individual component is confirmed from the SEM image. However, in the mixed system of this example, it consists of a single component. Fibrous material could not be confirmed.
However, even in the mixed system of this example, there is a possibility that a single constituent component uniquely forms a fibrous material. If, as in the mixed xerogel of Non-Patent Document 2 described above, a single constituent component uniquely forms a fibrous material, the performance improvement in the mixed hydrogel of N-alkyl-D-glucamide derivatives ( Gel-forming ability and thixotropic expression) serve as a cross-linking agent that allows the network of constituent fibrous materials to efficiently form a network of other constituent fibrous materials, It is inferred that this was caused by increasing the quality of the network, leading to gel formation at a lower concentration and expression of thixotropy.

Claims (4)

Formula [I]
An N-alkyl-D-glucamide derivative represented by the formula (wherein R is a straight-chain alkyl group having 6 or 7 carbon atoms) and the general formula [I] (wherein R is 8 carbon atoms) and a N- alkyl -D- glucamide derivative represented by a is) straight chain alkyl group, characterized by expression thixotropy in the formed hydrogel, the hydrogel agent. Compared with a hydrogelator comprising one N-alkyl-D-glucamide derivative represented by the general formula [1] ( wherein R represents a linear alkyl group having 6 to 8 carbon atoms). The hydrogelator according to claim 1, capable of forming a hydrogel at a low concentration. The hydrogelator comprises an N-alkyl-D-glucamide derivative in which R is a linear alkyl group having 6 or 7 carbon atoms, and N-alkyl-D- in which R is a linear alkyl group having 8 carbon atoms. and a glucamides derivative, wherein the R is a linear alkyl group having a carbon number of 8 N-alkyl -D- glucamide derivative (a), R is a straight chain alkyl group having a carbon number of 6 or 7 The hydrogelation according to claim 1 or 2, wherein a mixing ratio with the N-alkyl-D-glucamide derivative (B) is (A) :( B) = 10: 1 to 1 to 10 in mass ratio. Agent. Formula [I]
An N-alkyl-D-glucamide derivative represented by the formula (wherein R is a straight-chain alkyl group having 6 or 7 carbon atoms) and the general formula [I] (wherein R is 8 carbon atoms) A hydrogel comprising a N-alkyl-D-glucamide derivative represented by formula (1) and a thixotropic property.