US3927125A - Method of preparing 2,4,6-triiodoresorcinol - Google Patents

Abstract

The method of preparing 2,4,6-triiodoresorcinol consists in that resorcinol is iodinated with iodine chloride in a medium of dilute hydrochloric acid at a temperature to 50*C.

Description

United States Patent [191 Grinev et a1.

[ METHOD OF PREPARING 2,4,6-TRIIODORESORCINOL {761, Inventors: Alexei Nikolaevich Grinev, ulitsa Volgina, 1S, korpus 2, kv. 57; Vasily lvanovich Shvedov,'ulitsa M. Ulyanovoi, 9, korpus 3, kv. 11; Evgenia Nikolaevna Sytina, 5 Parkovaya ulitsa, 4, korpus 2, kv. 93; Nadezhda Sergeevna Bogdanova, ulitsa 26 Bakinskikh komissarov, l, korpus l, kv. 26', Irina Sergeevna Nikolaeva, Matveevskaya uiitsa, 1, kv, 179; Grigory Nikolaevieh Pershin, Novopeschanaya ulitsa, 19/10, kv. 75; Tatyana Anatolievna Guskova, ulitsa Usievicha, 25, korpus 3, kv. 396, all of Moscow,

U.S.S.R.

[22] Filed: June 3, 1974 [21] Appl. No.: 476,043

[52] US. Cl. 260/623 H [51] Int. Cl. C07C 39/27 [58] Field of Search 260/623 H, 623 R, 625

[11] 3,927,125 51 Dec. 16,1975

[56] References Cited FOREIGN PATENTS OR APPLICATIONS l,l34,084 8/1962 Germany 260/623.

OTHER PUBLICATIONS Primary Examiner-James 0. Thomas, Jr. Assistant Examiner-W. B. bone Attorney, Agent, or Firm-Steinberg & Blake 57 ABSTRACT The method of preparing 2,4,l5-triiodoresorcinol consists in that resorcinol is iodina'ted with iodine chloride in a medium of dilute hydrochloric acid at a temperature to 50C.

4 Claims, 190 Drawings METHOD OF PREPARING 2,4,6-TRIIODORESORCINOL This invention relates to a method of preparing 2,4,6- triiodoresorcinol which is used in medicine as a preparation for treating mycoses, viral diseases of the eye, skin, mucosa, and acute respiratory diseases.

Known in the prior art are methods of preparing 2,4,6-triiodoresorcinol by iodination of resorcinol with various iodinating agents, for example, by iodinating resorcinol with iodine in the presence of potassium iodine. This process is carried out in dilute aqueous solutions of the components, the process continuing for sixteen hours at a temperature of 24C. Resorcinol is also iodinated with mixtures of potassium iodide and chlorinated lime, and of potassium iodide and chloramine-T. In both cases the reaction is carried out in dilute aqueous solutions of the starting components with a great excess of potassium iodide.

The yield of the end product does not exceed 50 per cent by weight.

The disadvantage of this method is the high requirement of potassium iodide and the low yield of the end product.

Known also is the method of preparing 2,4,6-triiodoresorcinol in which an aqueous solution of resorcinol is treated with iodine chloride. The triiororesorcinol in this case is formed in a mixture with other products of resorcinol iodination, and pure 2,4,6-triiodoresorcinol can only be crystallized by sublimation from the mixture of the reaction products at a temperature of 190C.

The disadvantage of this method is the complexity of the process and also the low yield.

Still another process is known by which 2,4,6-triiodoresorcinol can be prepared. In this method resorcinol is treated with potassium iodide and dichlorourea in the presence of sulphuric or acetic acid, utilizing 3 moles of potassium iodide and 1.5 mole of dichlorourea per mole of resorcinol. (Likhosherstov, M. V. Tsimbal ist, B. I., lSOKh, 3, 177, 1933). The disadvantage of this method is that it is fraught with danger due to the tendency of dichlorourea to explode during decomposition.

The object of this invention is to remove these disadvantages.

The specific object of the invention is to modify the process in order to increase the yield of the end product and to improve its quality so that the final product could be used for medical purposes.

The object has been accomplished in that in a method of preparing 2,4,6-triiodoresorcinol by iodination of resorcinol with iodine chloride, with subsequent isolation of the end product, according to the invention, the process is carried out in a medium of dilute hydrochloric acid at temperatures to 60C.

In order to increase the yield of the end product the process is carried out at temperatures from to C.

The proposed method is realized as follows.

The starting resorcinol is treated with iodine chloride 2 at a temperature from 0 to 60C, preferably at a temperature from 20 to 25C, in a medium of dilute hydrochloric acid. Hydrochloric acid acts as a catalyst in this process.

The yield of 2,4,6-triiodoresorcinol, according to the invention, is 58-93 per cent by weight, depending on the process temperature. The chemistry of the process IS as this follows:

Unlike the known processes, the proposed method of preparing 2,4,6-triiodoresorcinol makes it possible to attain the end product at high yields ranging to 93 per cent by weight.

The method is simple to realize, and can be employed to prepare 2,4,6-triodoresorcinol on an industrial scale.

The advantage of the proposed method of preparing 2,4,6-triiodoresorcinol is that the need is abolished for organic solvents, and that the process is carried out in an aqueous medium, which rules out any side reactions and drastically reduces the volume of effluents.

For a better understanding of the invention, the following examples of its practical embodiment are given by way of illustration.

EXAMPLE 1 A solution of l l g (0.1 mole) of resorcinol in l 10 ml of 2.5 per cent hydrochloric acid is added to a mixture prepared from 48.8 g (0.3 mole) of iodine chloride, 55 ml of concentrated hydrochloric acid, and 200 ml of water, cooled to a temperature of 20C, the addition being gradually, with intense stirring. The resorcinol solution is added at a rate such that the temperature of the reaction mixture does not rise above 25C. Resorcinol solution adding is discontinued in 30-40 minutes. The reaction mixture is kept at a temperature of 20-25C. The precipitate of 2,4,6-triiodoresorcinol is separated by filtration, washed on the filter with water until the washings do not react acid (Congo), and dried at a temperature of 50C to constant weight. The yield of 2,4,6-triiodoresorcinol is 45.7 g (93.6 per cent by weight), m.p., l54-l55C (from carbon tetrachloride).

Found, in per cent by weight: [78.10, 77.78;

C6H I O Calculated, in per cent: I 78.05

White crystals, readily soluble in alcohol, chloroform and carbon tetrachloride; sparingly soluble in water.

EXAMPLE 2 The process is carried out with 48.8 g (0.3 mole) of iodine chloride, 55 ml of concentrated hydrochloric acid, 200 ml of water, ll g (0.1 mole) of resorcinol, and ml of a 2.5 per cent hydrochloric acid. The procedure is the same as in Example 1. The process temperature is 0C. The yield of 2,4,6-triiodoresorcinol is 43.2 g (88.5 per cent by weight).

EXAMPLE 3 The process is carried out with 48.8 g (0.3 mole) of iodine chloride, 55 ml of concentrated hydrochloric acid, 200 ml of water, 11 g (0.1 mole) of resorcinol, and 110 ml of a 2.5 per cent hydrochloric acid. The

whereby the resorcinol is directly iodinated to 2,4,6- triiodoresorcinol.

2. Method according to claim 1, wherein the reaction is carried out at a temperature from 20 to 25C.

3. Method according to claim I, wherein the reaction is carried out at a temperature of 0 25C.

4. Method according to claim 1, wherein resorcinol in hydrochloric acid is added to a solution of iodine chloride in hydrochloric acid.

Claims (4)

1. METHOD OF PRODUCING 2,4,6-TRIIODORESORCINOL, WHICH COMPRISES REACTING RESORCINOL WITH IODINE CHLORIDE IN A MEDIUM CONSISTING ESSENTIALLY OF DILUTE AQUEOUS HYDROCHLORIC ACID AT A TEMPERATURE OF 0 TO 60*C., WHEREBY THE RESORCINOL IS DIRECTLY IODINATED TO 2,4,6-TRIIODORESORCINOL.

2. Method according to claim 1, wherein the reaction is carried out at a temperature from 20* to 25*C.

3. Method according to claim 1, wherein the reaction is carried out at a temperature of 0* - 25*C.

4. Method according to claim 1, wherein resorcinol in hydrochloric acid is added to a solution of iodine chloride in hydrochloric acid.