US3812146A

US3812146A - Phthalide

Info

Publication number: US3812146A
Application number: US00252785A
Authority: US
Inventors: S Farber; A Wright
Original assignee: Ncr
Current assignee: Takenaka Corp; WTA Inc; NCR Voyix Corp
Priority date: 1972-05-12
Filing date: 1972-05-12
Publication date: 1974-05-21
Anticipated expiration: 1991-05-21
Also published as: FR2184699A1; DE2322497A1; ES414206A1; GB1379712A; FR2184699B1; BE799406A; DE2322497C3; DE2322497B2

Abstract

THE PHTHALIDE, 3 - (1 -ETHYL-2-METHYLINDOL-3-YL)-3-(1BENZYL-2-METHYLLINDOL-3-YL) PHTHALIDE, IS DISCLOSED. THIS PHTHALIDE IS REPRESENTED BY THE STRUCTURE:

3-(1-(C2H5-),2-CH3-INDOL-3-YL),3-(1-(PHENYL-CH2-),2-CH3-

INDOL-3-YL)PHTHALAN-1-ONE

THIS COMPOUND IS USED IN PRESSURE-SENSITIVE RECORD MATERIAL AND IN MARK-FORMING MANIFOLD SYSTEMS.

Description

"United States Patent 3,812,146 PHTHALIDE Sheldon Farber, Appleton, Wis., and Arthur J. Wright, Dayton, Ohio, assignors to The National Cash Register Company, Dayton, Ohio No Drawing. Filed May 12, 1972, Ser. No. 252,785 Int. Cl. C07d /06, 27/56 U.S. Cl. 260326.14 R 1 Claim ABSTRACT OF THE DISCLOSURE The phthalide, 3 (l ethyl-2-methylindol-3-yl)-3-(1- benzyl-2-methylindol-3-yl) phthalide, is disclosed. This phthalide is represented by the structure:

| N CHs This invention relates to colorless, but colorable compounds. More specifically, this invention relates to a certain phthalide compound.

This compound is colorless or substantially colorless when in liquid solution, but is converted to a red-colored form upon reactive contact with an acidic material. In pressure-sensitive mark-forming systems, the unreacted mark-forming components (the colorless, but colorable compound and the acidic material) and a liquid solvent in which each of the mark-forming components is soluble is disposed on or within a sheet support material. The liquid solvent is present in such form that is maintained isolated by a pressure-rupturable barrier at least one of the markforming components until the application of pressure causes a breach of the barrier in the area delineated by the pressure pattern. The application of pressure brings the mark-forming components into reactive contact, thereby producing a distinctive mark.

Various phthalide compounds are known in the art. For example, see U.S. Pat. 3,509,174, which discloses many 3-(indol-3-yl) phthalides.

The phthalide, 3 (1 ethyl-2-rnethylindol-3-yl)-4-( lbenzyl-2-methylindol-3-yl) phthalide now has been invented. Generally, phthalide compounds have adequate solubility properties for use in pressure-sensitive record material and in mark-forming manifold systems. The phthalide of this invention has greatly increased solubility properties.

Accordingly, "an object of this invention is to provide a colorless, but colorable phthalide compound.

Other objects, aspects and advantages of this invention will be apparent to one skilled in the art from the following disclosure and appended claim.

The colorless, but colorable phthalide of this invention is represented by the structure:

The color developed from this compound is red.

In a preferred embodiment of this invention, the phthalide and liquid solvent are encapsulated in microscopic capsules which are coated on base sheet record material. In close contact with the base sheet record material is a sensitized undersheet. The base sheet yields the phthalide under pressure of writing against the sensitized undersheet in a pattern of droplets corresponding to the written matter, in accordance with the disclosure of such a capsule-bearing sheet in U.S. Pat. No. 2,712,507 which issued July 5, 1955, on the application of Barrett K. Green. U.S. Pat. No. 2,712,507 also discloses a preferred method of forming the capsules. Other preferred methods for preparing solvent-containing microscopic capsules are disclosed in US. Pat. No. 2,800,457 which issued on July 23, 1957, on the application of Barrett K. Green and Lowell Schleicher and in U.S. Pat. No. 3,041,289, which issued on June 26, 1962, on the application of Bernard Katchem and Robert E. Miller.

The encapsulated droplets are released by the rupture of capsules in writing operations. The phthalide liquid droplets are transferred in the pattern of the data configuration to the top of the underlying sheet. The top of the underlying sheet is coated or impregnated with at least one material which is an acid reactant with respect to the phthalide and produces color with any such component that is reactive therewith. Representative acidic coating materials are, on one hand, oil-insoluble minerals or inorganic particulate solid material, represented by kaolin, attapulgite, silica gel, zeolites, and the like, and, on the other hand, organic polymeric acidic materials, such as acid-reacting phenolic resins of oil-soluble characteristics.

The record member consists of a base sheet or web member either of fibrous construction, such as paper, or of continuous structure, such as films of organic polymer material, carrying the color reactant in. an exposed state with respect to applied liquid. The acid reactant, when of particulate nature, is arranged in intimate juxtaposition to form an apparently unbroken liquid receptive surface, yet substantially each particle individually is available for contact with applied liquid. Polymeric materials of sufficient activity in an acid sense and suitable for use in this invention because they are oil-soluble are disclosed in a continuation application for U.S. Letters Patent, Ser. No. 744,601, filed June 17, 1968, based on applications for U.S. Letters Patent Ser. No. 392,404, filed Aug. 27, 1964, by Robert E. Miller and Paul S. Phillips, Jr., both now abandoned.

Among the oil-soluble organic polymeric materials suitable for use in this invention together with appropriate solvents to be used therewith, acid-reaction phenol-aldehyde and phenol-acetylene polymers, maleic acid-rosin resins partially or wholly hydrolyzed styrene-maleic anhydride copolymers and ethylene-maleic anhydride copolymers, carboxy polymethylene (Carbopol 934), and wholly or partially hydrolyzed vinyl methyl ether-maleic anhydride copolymer are specified as typical of the reactive acidic polymeric materials.

Among the phenol-aldehyde polymers found useful are members of the type commonly referred to as novolaks, which are characterized by solubility in common organic sol-vents and which are, in the absence of cross-linking agents, permanently fusible. Another group of useful phenol polymeric materials are alkylphenolacetylene resins, likewise soluble in common organic solvents and possessing permanent fusibility in the absence of being treated by cross-linking materials. Generally, the phenolic polymer materials useful in practicing this invention are characterized by the presence of free hydroxyl groups and by the absence of groups, such as methylol, which tend to promote infusibility or cross-linking of the polymer, and by their solubility in organic solvents and relative insolubility in aqueous media.

A laboratory method useful in the selection of suitable phenolic resins is a determination of the infrared radiation absorption pattern of a candidate material. It has been found that phenolic resins showing an absorption in the 32003500 cm. region (which is indicative of the free hydroxyl groups) and not having an absorption in the 1600-1700 cm.- region are suitable. The latter absorption region is indicative of the desensitization of the hydroxyl groups and consequently makes such groups unavailable for reaction with the chromogenic material to be specified.

The liquid solvent portion of this invention is capable of dissolving the mark-forming components. The solvent can be volatile or nonvolatile, and a single or multiple component solvent which is wholly or partly volatile can be used. Examples of volatile solvents useful with the phthalide and acidic polymer mark-forming components specified are toluene, petroleum distillate, perchloroethylene, and xylene. Examples of nonvolatile solvents are highboiling-point petroleum fractions and chlorinated diphenyls.

Generally, the solvent forming the vehicle to a large extent should be chosen so as to be capable of dissolving at least 1%, on a weight basis, of the phthalide, preferably in excess of 2% and a larger amount of polymeric matterialup to say, or moreto form an efiicient reaction. However, in the preferred system, the solvent should be capable of dissolving an excess of the polymeric material, so as to provide every opportunity for maximum reaction utilization of the benzopyran and thus to assure the maximum coloration at a reaction site.

A further criterion of the selected solvent is that it must not interfere with the mark-forming reaction. In some instances, the presence of the solvent may interfere with the mark-forming reaction or diminish the intensity of the mark, in which case the solvent chosen should be sufficiently vaporizable to assure its leaving the reaction site after having, through solution, brought the markforming components into intimate admixture, so that the mark-forming reaction proceeds.

In the base-acid color system, as stated above, the polymeric mark-forming component(s) chosen must be acidic relative to the phthalide compound and reactive with the phthalide material to effect the distinctive color formation or color change.

Kaolin is generally known and used in the papermaking industry as china clay and is outstandingly preferable as a particulate oil-insoluble and water-insoluble mineral material of acid characteristics necessary to color the phthalide of this invention. A white kaolin is used, and, because of its whiteness, its plate-like particle form, which gives it unparallel coating properties in aqueous slurries, its universal abundance in supply, its historical general usage in the papermaking andpaper-converting industries, and its low cost, it is an ideal material. Other types of particulate and substantially colorless waterand oil-insoluble minerals of the necessary acid properties are deemed equivalents of kaolin, some being bentonites.

Attapulgite can be used in this invention as an efiicient colorless mineral reactant material to color the phthalide of this invention that react on contact in an electrondonor-acceptor reaction, and, by reason of its high oil absorbency, is doubly useful as an absorbent reactant coating on paper to form color with such compounds dissolved in oil as may be applied to it.

Various methods known to the prior art and disclosed in the aforementioned application Serial No. 392,404 to Miller, et al. and US. Pat. No. 3,455,721, issued July 15, 1969, can be employed in coating compositions of the mark-forming materials into their supporting sheets. An example of the compositions which can be coated onto the surface of an underlying sheet of a two-sheet system to react with the capsule coating of the underside of an overlying sheet is as follows:

Coating composition: Percent by weight Phenolic polymer mixture 17 Paper coating kaolin (white) 57 Calcium carbonate 12 Styrene butadiene latex 4 Ethylated starch 8 Gum arabic 2 The advantages of this invention are further illustrated by the following examples. The reactants and the proportions and other specific conditions are presented as being typical and should not be construed to limit the invention unduly.

EXAMPLE I Preparation of 3-(l-benzyl-2-methylindol-3-yl)-3-( lethyl-2-methylindol-3 -yl) -phthalide A mixture of 9.26 g. (0.03 moles) of I-ethyI-Z-methyl- 3-(2-carboxybenzoyl) indole, 6.63 g. (0.03 moles) of 1- benzyl-Z-methyl indole and 90 ml. of acetic anhydride were heated on a steam bath for two and one half hours. The reaction mixture was poured into ice water and made basic with ammonium hydroxide to a pH of 8-9. Additional cooling was necessary. The aqueous solution was extracted with benzene and the benzene washed three times with 5% sodium hydroxide solution and then with water until neutral. The benzene was dried (Na SO concentrated and diluted with petroleum ether. The supernatant was decanted and the oil was washed with petroleum ether and dissolved in acetonitrile. After standing overnight, 4.0 g. (28%) of material was filtered, M.P. -7 C. The material was characterized by elemental analyses after repeated recrystallization. Calcd. for C H N 0 C, 82.33; H, 5.92; N, 5.49. Found: C, 82.13; H, 6.07; N, 5.54. A benzene solution of this compound when applied to paper coated with clay or phenolics gave a red color.

EXAMPLE II The 3-(1-ethy1 2 methylindol-3-yl)-3-(1-benzyl-2- methylindol-3-yl) phthalide prepared in Example I and two other phthalides, 3,3-bis(1-ethy1-2-methylindol-3-yl) phthalide and 3,3-bis (l-benzyl 2 methylindol-3-yl) phthalide, each were individually dissolved in a 2:1 mixture by weight of monoisopropylbiphenyl and magnaflux oil. Each solution was saturated with the respective phthalide. After one Week, the solution of the inventive phthalide contained about 2% of the inventive phthalide and the solutions of the other phthalides contained about 0.2 and 0.1% of the respective phthalide. These results demonstrate that the phthalide of this invention has greatly increased solubility properties over known phthalides.

Although this invention has been described in considerable detail, it must be understood that such detail is for the purposes of illustration only and that many variations and modifications can be made by one skilled in the art without departing from the scope and spirit thereof.

What is claimed is:

1. 3-(1 ethyl-2-methylindol-3-yl)-3-(l-benzyl-Z-methylindol-3-yl) phthalide.

Lin 260326.l4

5 JOSEPH A. NARCAVAGE, Primary Examiner US. Cl. X.R.