JPH046224B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to novel naphthalene derivatives that are valuable as dyes and pigments or intermediates thereof.

[Prior art] Conventional vat dyes for textiles are made by converting the dye into leuco bodies using a reducing agent in a bath, and while the fibers are immersed in the bath, the leuco bodies are oxidized in the air to develop color and are adsorbed onto the fibers. It is the type of thing that makes you

For example, indigo, which is a typical vat dye, has the structure of the following formula (), and for dyeing, fibers are immersed in a solution containing indigo, an alkali, and a reducing agent. Indigo becomes a leuco substance of the following formula () under the above conditions, and it is thought that this substance develops color when oxidized in the air, and at the same time dyes the fiber.

In addition, there are other vat dyes such as indasthrene dyes and anthraquinone dyes, which are also thought to be dyed by a similar mechanism.

[Problems to be solved by the invention] However, these leuco bodies are extremely unstable and are immediately oxidized when exposed to air, so it is necessary to coexist a large amount of reducing agent in the bath. This is a harsh condition for fibers. Furthermore, since the reduction was carried out under alkaline conditions, this caused further damage to the fibers.

Helindon Yellow developed by Cassella
R is a naphthoquinone dye having a condensed carbazole ring, and is a yellow vat dye for wool, but it is well known that it was not commercially available because it required a strong alkaline bath for reduction.

On the other hand, the sulfate ester of the leuco form of indigo is too stable and cannot be colored without using a strong oxidizing agent, such as potassium permanganate, which is also not a good condition for fibers. do not have.

In view of the above-mentioned circumstances, the present inventors have conducted intensive research to find out whether it is possible to obtain a leuco compound that has appropriate stability, that is, can be isolated as a leuco compound, and which develops a strong color when oxidized under mild conditions. The invention was completed.

[Means for Solving the Problems] That is, the present invention is a naphthalene derivative represented by the following formula ().

The above naphthalene derivative is 2-benzylamino-
5,8-Dihydroxynaphthoquinone is prepared in water, alcohol, a water-alcohol mixed solution in the presence of an alkali such as potassium hydroxide, sodium hydroxide, or sodium carbonate using a reducing agent such as sodium dithionate, or in an aqueous hydrochloric acid solution in the presence of zinc. It can be obtained by reducing . Suitable reaction conditions are anaerobic reaction at room temperature to reflux temperature for 1 to 5 hours.

When dyeing using the naphthalene derivative of the present invention, the fibers can be dyed even better if 0.7 to 2.0% by weight of ammonia is present in the bath.

[Effect of the invention] As mentioned above, the naphthalene derivative of the present invention has the following properties:
It can be isolated as a leuco form from the reaction system under anaerobic conditions, and can be stored stably.Furthermore, it can be oxidized in a bath without using a special oxidizing agent to develop good color and dye fibers. can.

With conventional vat dyes, sufficient dyeing cannot normally be expected unless the concentration is 5% or higher, but the naphthalene derivative of the present invention exhibits a dyeing power sufficient for practical use at a concentration of about 0.1%.

The naphthalene derivative of the present invention can be used not only as a vat dye for textiles but also as a hair dye for human hair, and when used as a hair dye, it is particularly preferable that it can be used under mild conditions. Recognized as a characteristic.

[Synthesis Example] Hereinafter, the present invention will be explained in more detail by giving a synthesis example of the naphthalene derivative of the present invention.

Synthesis example 1 Naphthazarin in 20 mmol of benzylamine
80 ml of an ethanol solution containing 10 mmol was slowly added and stirred at a temperature of 0 to 2°C for 3.5 hours. After the reaction was completed, the reactant was poured into a dilute aqueous hydrochloric acid solution, and the precipitate was filtered and dried under reduced pressure. The dried product was fractionated and purified by column chromatography using silica gel as a filler and benzene as a solvent to obtain 1.257 g (yield: 42.3%) of the desired crystals, which were further recrystallized from ethanol. This product was confirmed to be 2-benzylamino-5,8-dihydroxynaphthoquinone based on the following analytical values.

Mass spectrum M ⁺ = 295 Elemental analysis value C = 69.11 (calculated value 69.15) H = 4.44 (calculated value 4.44) N = 4.68 (calculated value 4.74) Nuclear magnetic resonance spectrum (CDCl ₃ , δ, ppm) ¹ H-NMR, 13.28 (1H, OH, S), 11.83 (1H,
OH, S), 7.35 (5H, aroma., like S), 7.03−
7.26 (2H, aroma., q), 6.39 (1H, NH, broad),
5.72 (1H, quinone, s), 4.36-4.42 (2H, CH ₂
ph, d) ¹³ C-NMR carbonyl group, 187.2, 183.7 Synthesis Example 5 2-benzylamino-5,8- obtained in Synthesis Example 1
400 mg of dihydroxynaphthoquinone was dispersed in 30 ml of water along with 400 mg of sodium carbonate and 1200 mg of sodium dithionate, and the mixture was stirred at reflux temperature for 3 hours under an argon atmosphere. The solution turned yellowish brown, confirming that the reduction had progressed sufficiently, and after cooling to room temperature, it was filtered, and the crystals were thoroughly washed with degassed water. All these operations were performed under an argon atmosphere. The crystals were dried under reduced pressure to obtain 355 mg of the target product (yield
88.8%) was obtained, and further recrystallized from ethanol under an argon atmosphere.

There are several possible tautomers of this substance, but as seen in the analysis values below, ¹³ C-NMR
Since the chemical shift of the carbonyl group in is observed to be significantly lower than that of quinones,
It is thought that a methyl group or methylene group exists adjacent to the carbonyl group, and 6-benzylamino-
It was confirmed to be 2,3-dihydro-5,8-dihydroxynaphthalene-1,4-dione.

Mass spectrum M ⁺ = 297 Elemental analysis value C = 68.50 (calculated value 68.68) H = 5.00 (calculated value 5.09) N = 4.62 (calculated value 4.71) Nuclear magnetic resonance spectrum (CDCl ₃ , δ, ppm) ¹ H-NMR, 12.85 (1H, OH, S), 12.50 (1H,
OH, S), 7.32 (5H, arom., S), 6.22 (1H,
arom., s), 5.71 (1H, NH, broad), 4.38~
4.44 (2H, CH ₂ ph,), 2.93 (4H, -(CH ₂ )-, s) ¹³ C-NMR carbonyl group, 202.9, 197.2 Next, examples of staining using the naphthalene derivative of the present invention will be shown.

Example 1 6-benzylamino-2,3- obtained in Synthesis Example 2
dihydro-5,8-dihydroxynaphthalene
20 mg of 1,4-dione was dissolved in 20 g of water, and a wool muslin test fiber manufactured by Shirozome Co., Ltd. was immersed in the solution at a bath ratio of 1/40 at a temperature of 30°C or 40°C.
Shake dyeing for 45 minutes gave in each case a bright reddish-purple wool muslin.

In addition, at this time, if 0.7 to 2.0% by weight of ammonia is co-present, the dyeing will be performed even better.

Example 2 6-benzylamino-2,3- obtained in Synthesis Example 2
dihydro-5,8-dihydroxynaphthalene
20 mg of 1,4-dione was dissolved in 20 g of water, and 1.0 g of gray hair purchased from Abeille Co., Ltd. was immersed in the solution and dyed by shaking at 30° C. for 45 minutes.
Thereafter, the dyed hair was washed with 200 ml of water at 30°C for 5 minutes to obtain hair without any gray hair.

The obtained dyed hair was washed using a commercially available shampoo and further treated using a rinse, but there was no change in color tone.

Example 3 Test multi-fiber manufactured by Shirozome Co., Ltd. (consisting of 17 types of fibers; acetate is beige, others are white) was dyed according to Example 1, and bright colors were dyed according to the presence or absence of ammonia and its amount. A reddish-purple dyed fiber was obtained.

Claims (1)

[Claims] 1. A naphthalene derivative represented by the following formula ().