JP2952609B2 - Fingerprint detection reagent and its manufacturing method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a novel O-alkyl derivative of ninhydrin, a method for producing the same, and a fingerprint detection reagent using the same.

[Related Art] Ninhydrin has been conventionally used as a fingerprint detection reagent from papers, but since it is soluble only in polar solvents such as ketones and alcohols, when performing fingerprint detection from papers, This polar solvent dissolves the characters written on the paper, and in the case of thermal paper, discolors the thermal paper itself, so that not only clear fingerprints cannot be detected, but also the evidence value is lost. It was generally known to have

Therefore, conventionally, in the detection of fingerprints from thermal paper or the like,
In order to dissolve the thermal paper or the like in an aliphatic hydrocarbon solvent such as hexane that does not change, a method of adding an auxiliary polar solvent such as ethanol (referred to as method A) has been used. However, in this method, it is considered that the added polar solvent cannot completely eliminate changes in written characters and thermal paper.

A method of directly detecting a fingerprint by sandwiching papers with fingerprints between Japanese paper impregnated with ninhydrin and applying pressure (called a method B) has been considered. Are considered to be generally thin and difficult to analyze, and have problems such as a long time required for detection.

[Problems to be Solved by the Invention] Ninhydrin does not dissolve in an aliphatic hydrocarbon solvent such as hexane because the molecular structure of ninhydrin has a hydroxyl group or a carbonyl group which is a polar group. It is considered that the conventional method in which the polar group is dissolved in the aliphatic hydrocarbon solvent while leaving the polar group is naturally limited. The carbon atom to which the hydroxyl group of ninhydrin is bonded is
It is generally known that the reactivity is enhanced by two adjacent carbonyl groups, and the site is directly involved in the reaction with the amino acid in the fingerprint. Therefore, if a substituent is introduced into this site, the reactivity with the amino acid is reduced, and there is a possibility that fingerprint detection performance may not be obtained. For this reason, it appears that no attempt has been made to introduce a substituent at this site in ninhydrin.

The present invention has a fingerprint detection performance, by dissolving in an aliphatic hydrocarbon-based solvent such as hexane without adding a polar solvent, without blurring written characters, and from an article which is easily changed by a polar solvent. However, an object of the present invention is to provide a ninhydrin derivative capable of detecting a clear fingerprint. It is a further object of the present invention to provide a method for producing the compound.

[Means for Solving the Problems] In order to achieve the above object, various ninhydrin O-
As a result of synthesizing an alkyl derivative and testing its solubility in hexane and fingerprint detection performance, [Wherein R represents an alkyl group] An O-alkyl derivative of ninhydrin represented by the formula: ## STR1 ## that is, a derivative obtained by alkylating only one of the two hydroxyl groups of ninhydrin has fingerprint detection performance, and hexane and the like. It was found to be soluble in aliphatic hydrocarbon solvents. Incidentally, among the compounds represented by the formula [I], the compound represented by the formula [I '] is a novel compound.

As R in the formula [I], all alkyl groups are conceivable, and in particular, an alkyl group having 1 to 9 carbon atoms, for example,
Methyl, ethyl, 1-propyl, 1-butyl, 1-pentyl, 1-hexyl, 1-heptyl, 1-octyl, 3
-Methyl-1-butyl, 2-methyl-1-pentyl, 2,
2-diethylethyl, 3,5,5-trimethyl-1-hexyl group and the like. As R ′ in the general formula [I ′],
For example, 1-pentyl, 1-hexyl, 1-heptyl,
1-octyl, 3-methyl-1-butyl, 2-methyl-
1-pentyl, 2,2-diethylethyl, 3,5,5-trimethyl-1-hexyl group and the like.

The compound represented by the formula [I] of the present invention has the formula Can be easily produced by reacting a compound represented by the formula R-OH [III] with a ninhydrin represented by the formula: It is considered that this reaction proceeds reversibly using triketoindane [IV] as an intermediate, and one molecule of compound [III] is bonded to one molecule of ninhydrin [II] as shown in the following reaction formula. That is, ninhydrin [I
I] is more stable in terms of molecular structure, and in the same way that ninhydrin [II] is generated by adding only one water molecule to triketoindane [IV], one water molecule is generated from ninhydrin [II]. It has been found that the compound [I] can be synthesized relatively easily by adding one compound [III] to the triketoindane [IV] formed by singulation.

[Wherein R represents an alkyl group] According to the method of the present invention, compound [II] is reacted with 1.5 to 5 equivalents of compound [III] at an appropriate temperature of 80 to 130 ° C for 30 minutes to 2 hours. , The equivalent of water formed and excess compound [II
Compound [I] is obtained by distilling off [I].

Since the compound [I] is obtained as a crystal or an oil by the above method, a purified product with higher purity can be obtained by performing a recrystallization operation.

The obtained compound [I] has the property of slowly decomposing into ninhydrin and alcohol in air or an organic solvent, but there is almost no practical problem in fingerprint detection. In addition, ninhydrin does not have, and compound [I] has characteristics such as solubility in aliphatic hydrocarbon solvents such as hexane, and its infrared absorption spectrum and nuclear magnetic resonance spectrum. And the presence of a peak derived from an alkyl group.

[Action] Using this compound [I], for example, a fingerprint is detected as follows.

0.5 g of the compound [I] (R = 3,5,5-trimethyl-1-hexyl group) and 100 ml of hexane are placed in a container such as a beaker, and stirred at room temperature for 15 to 30 minutes using a magnetic stirrer or the like. , Dissolve. By filtering this solution, a hexane solution of a compound [I] (R = 3,5,5-trimethyl-1-hexyl group), which is a fingerprint detection solution, is obtained. The effectiveness of this fingerprint detection liquid lasts for 9 days or more.

An article whose fingerprint is to be detected, for example, thermal paper, is immersed in this detection liquid, or this detection liquid is applied to an article whose fingerprint is to be detected, and hexane is dissipated by natural drying. Thereafter, a clear fingerprint that has developed into a blue to reddish purple color is detected simply by leaving the article whose fingerprint is to be detected in the room.

Since the fingerprint detection liquid does not contain any polar solvent, the fingerprint detection liquid is characterized in that it does not contaminate an article whose fingerprint is to be detected or its written characters. Further, the obtained fingerprint itself is as stable as the fingerprint obtained by the conventional ninhydrin method, and can be easily erased with a hydrogen peroxide solution or the like.

[Example] (Example 1) Compound of formula [I] (R = 1-pentyl group)
Preparation of 5 g of ninhydrin and 10 ml of -pentanol are heated and stirred at 100 ° C. for 1 hour. If water and excess 1-pentanol are distilled off, the liquid changes from yellow to green, and the heating is stopped at this point. Upon cooling to room temperature, the O-pentyl derivative of ninhydrin is obtained as an oily crude product. The crude product is purified by recrystallization from hexane to obtain 3 g of an oily purified product.

(Example 2) Production of compound of formula [I] (R = 3,5,5-trimethyl-1-hexyl group) 5 g of ninhydrin and 15 ml of 3,5,5-trimethyl-1-hexanol were added at 130 ° C for 1 hour. Heat and stir. If water and excess 3,5,5-trimethyl-1-hexanol are distilled off, the liquid changes from yellow to green, and the heating is stopped at this point. When cooled to room temperature, ninhydrin O-3,
The 5,5-trimethyl-1-hexyl derivative is obtained as crude crystals. When the crude crystals are purified by recrystallization from hexane, 5 g of purified crystals are obtained.

Example 3 Compound of Formula [I] (R = 3-methyl-1-
Production of butyl group) Ninhydrin 5 g and 3-methyl-butanol were prepared in the same manner as in Example 2 except that 3-methyl-1-butanol was used instead of 3,5,5-trimethyl-1-hexanol in Example 2. The compound [I] (R =
4 g of 3-methyl-1-butyl group) are obtained.

(Example 4) Compound of formula [I] (R = 1-octyl group)
Preparation of Compound [I] (R = 1-octyl group) oily from 5 g of ninhydrin and 10 ml of 1-octanol in the same manner as in Example 1 except that 1-octanol was used instead of 1-pentanol in Example 1. 5) is obtained.

Next, a solubility test of the compound of the present invention prepared from ninhydrin and 12 kinds of alcohols in hexane was carried out, and the comparison results are shown in Table 1.

The amount of dissolution shown in this table is the number of grams and the number of moles of each compound dissolved in 100 ml of hexane at room temperature.

As is evident from Table 1, ninhydrin did not dissolve at all, whereas the compound of the present invention dissolved in hexane. In particular, those prepared from alcohols having a large number of carbon atoms showed high solubility.

Next, an example of a test for detecting the fingerprint of the compound of the present invention from thermal paper will be described.

(Fingerprint Detection Test Example 1) Compound [I] of the present invention (R = 3,
0.4 g of 5,5-trimethyl-1-hexyl group) in hexane 100
The resulting solution was stirred and dissolved in ml, and further filtered to obtain a filtrate, which was used as a fingerprint detection solution from thermal paper. Using this detection liquid, detection of fingerprints impressed on three types of commercially available white thermal paper by the immersion natural drying method was attempted. The imprinted fingerprint was divided into three equal parts, and this method was compared with the conventional method (the above-mentioned method A and method B). Table 2 summarizes the detection results.

As is clear from Table 2, remarkable discoloration of the thermal paper was observed in the conventionally used method A, and the fingerprint detected in the method B was faint, whereas the discoloration in the present method using the compound of the present invention was weak. Was not seen at all, and a clear fingerprint could be detected.

(Fingerprint Detection Test Example 2) Compound [I] of the present invention (R = 3,5,5-trimethyl-1) in the same manner as in Fingerprint Detection Test Example 1.
-Hexyl group) to detect fingerprints imprinted on three types of heat-sensitive tickets. The results are shown in Table 3.

As is evident from Table 3, blurring and discoloration of written characters are observed in the conventionally used method A, and fingerprints are hardly detected in the method B, whereas in the method using the compound of the present invention, No blurring or discoloration of the written characters was observed, and a clear fingerprint could be detected.

[Effects of the Invention] The O-alkyl derivative compound of ninhydrin represented by the formula [I], which is the object compound of the present invention, can be described by a conventional reagent even from various objects such as various papers. Fingerprints can be detected clearly without blurring,
Even when applied to articles that discolor or dissolve in polar solvents that have been considered impossible or difficult to detect fingerprints, such as thermosensitive papers, thermosensitive materials such as thermosensitive tickets, clear fingerprints can be applied. Can be detected.

According to the present invention, a novel chemical substance having excellent properties as a fingerprint detection reagent can be provided.

Further, by using ninhydrin represented by the formula [II] as a starting material, the target compound of the present invention represented by the formula [I] could be easily produced.

──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Hiroshi Kageyama 3-332 Nakajyugaoka, Shizen-cho, Miki-shi, Hyogo Examiner Yuji Hondo (56) References JP-A-50-90682 (JP, A) Tetrahedron, 1968, 24 [19], p. 6149-6156 (58) Field surveyed (Int. Cl. ⁶ , DB name) C07C 49/755 C07C 45/64 G01N 31/22 122 CA (STN) REGISTRY (STN)

Claims (3)

(57) [Claims] (1) Expression [In the formula, R ′ represents an alkyl group having 5 to 9 carbon atoms.] An O-alkyl derivative of ninhydrin represented by the formula: (2) A compound represented by the formula: R-OH [III] wherein R represents an alkyl group, is reacted with ninhydrin represented by the formula: (Wherein R represents an alkyl group). 3. The expression [Wherein, R represents an alkyl group].