US2063865A - Salts of acridinium bases and a process of preparing them - Google Patents

Description

Patented Dec. 8, 1933 UNITED STATES PATENT OFFICE SALTS OF ACRIDINIUM BASES AND A PROCESS OF PREPARING THEM No Drawing. Application March 28, 1935, Serial No. 13,579. In Germany May 26, 1932 8 Claims.

The present invention relates to salts of acridinium bases and to a process of preparing them.

As is known the quaternary acridinium salts are prepared by addition of halogen compounds, sulfuric acid esters or aromatic sulfonic acid esters to the corresponding acridines; If it is intended to produce theacridinium salts with the aid of other anions, for instance with those of acetic acid, tartaric acid, lactic acid or the like, it is necessary to cause the corresponding chlorides, sulfates, etc. toreact with salts of the acids the quaternary salts of which are to be obtained. There are, for instance, caused to react the sulfates of the quaternary compounds with barium acetate and the chlorides with silver acetate. This known method is complicated and expensive since the by-products obtained, such as barium sulfate and silver chloride, have to be removed and the excess of barium salts and silver salts must be carefully eliminated. The direct reaction of the acridinium chlorides etc. with alkali metal salts of the corresponding acids, such as sodium acetate, sodium tartrate, etc. proceeds in most cases in an incomplete manner so that it has hitherto been necessary to take the indirect way above referred to.

This invention is based on the observation that the acridinium compounds and the salts thereof mayeasily be converted into their bicarbonates which generally are but slightly soluble in water and may, therefore, readily be precipitated from solutions of the quaternary compounds. These bicarbonates may be caused to react with any acids so as to yield the salts of these acids. The process is, for instance, carried out by dissolving the chlorides, bromides, sulfates, nitrates or other salts of the acridinium bases, especially salts with strong mineral acids, in cold or warm water and then adding an excess of an alkali metal bicarbonate, for instance, sodium bicarbonate, potassium bicarbonate or lithium bicarbonate, the resultant bicarbonates being precipitated after a short time; if desired, the solutions obtained are cautiously evaporated under reduced pressure until the bicarbonates begin to separate. It is, of course, also possible to mix the, solutions of the salts used as parent materials with a caustic alkali or sodium carbonate and then to introduce carbon dioxide. For the most part the resultant bicarbonates of the acridinium bases may readily be redissolved. On boiling their aqueous solutions they lose carbon dioxide and are transformed into the neutral carbonates and finally into the free acridinium bases. They very readily dissolve in acids with evolution of carbon dioxide gas and formation of the acridinium salts of the acid added.

The process of this invention, therefore, affords a very simple method of making from easily accessible salts of the acridinium bases, by way of the bicarbonates, any desired salts of the acridinium bases. It furthermore involves the advantage that the precipitation of the acridinium bases in the form of their bicarbonates is at the same time a purification in so far as all or part of the by-products which do not form diflicultly soluble bicarbonates remain in solution.

As alkyl acridinium compounds there may, for instance, be used the compounds which are substituted in l-position, i. e. at the nitrogen, by methyl, ethyl, propyl, beta-hydroxypropyl or butyl and which may be substituted in the nuclei at any position by amino groups, methyl groups, ethyl groups, propyl groups, methoxy groups or ethoxy groups. Carboxylic acids, in which'the bicarbonates may be dissolved are, for instance, formic acid, acetic acid, prcpionic acid, butyric acid, lactic acid, tartaric acid, benzoic acid, orthotoluic acid, meta-toluic acid, para-toluic acid, glycolic acid, citric acid, gluconic acid, and quinic acid.

The following examples serve to illustrate the invention, but they are not intended to limit it thereto:

(1) 20 grams of 3,6-diamino-IO-methylacridinium chloride of the following formula:

HaN-

and grams of sodium bicarbonate are dissolved in 200 cc. of hot water and the hot liquid is poured into 300 cc. of a solution of. sodium bicarbonate of 8 per cent strength. On cooling the solution the bicarbonate of 3,6-diamino-10-methylacridinium hydroxide crystallizes. The compound may be recrystallized from hot water on addition of sodium bicarbonate. Its melting point is 240 C. with decomposition. 2.2 grams of the product are mixed with a solution of 0.5 gram of glacial acetic acid and 10 cc. of water; the bicarbonate passes into solution with evolution of carbon dioxide gas. The solution is mixed with acetone until it begins to become turbid and the whole is. placed into ice. The acetate then precipitates in a crystalline form and is isolated in the usual manner.

(2) 20 grams of 3,6-diamino-IO-methylacridinium chloride and 20 grams of sodium carbonate are dissolved in 500 cc. of hot Water and carbon dioxide is introduced into the liquid until it is saturated. After a short time the bicarbonate crystallizes from the cooled solution; as to its properties it corresponds to the compound described in Example 1. The product is dissolved in a molecular proportion of dilute lactic acid and the lactate obtained is mixed with acetone. After some time the lactate crystallizes.

(3) 10 grams of 3,6-dimethoxy-IO-methylacridinium chloride and 10 grams of sodium bicarbonate are dissolved in 400 cc. of hot water and the solution is rapidly poured into 200 cc. of a solution of sodium bicarbonate of 5 per cent strength. The precipitate which crystallizes still contains a small quantity of chloride; it is dissolved in 300 cc. of water and the solution is mixed with cc. of a solution of sodium bicarbonate of 5 per cent strength. On cooling the bicarbonate of the acridinium compound crystallizes. Its point of decomposition is at about 116 C. On dissolving it in the calculated quantity of dilute acetic acid and adding acetone there is obtained a precipitate of the acetate of 3,G-dimethoxy-IO-methylacridinium hydroxide.

(4) 5 grams of 2-ethoxy-9-amino-10-methylacridinium chloride are dissolved in 300 cc. of hot water, there are added 5 grams of sodium bicarbonate and the whole is allowed to stand in ice where it is cooled. The product which separates may be recrystallized from hot water with addition of a small amount of sodium bicarbonate. Its point of decomposition is at C. By dissolving the product in dilute acids, such as acetic acid, lactic acid, tartaric acid, etc. there is obtained the corresponding acetate, lactate or tartrate.

(5) 10 grams of 3-methoxy-6-hydroxy-10- methylacridinium chloride are dissolved in 600 cc. of water and the solution is mixed with a concentrated solution of sodium bicarbonate. The bicarbonate of the acridinium compound which separates is filtered by suction and washed with a small quantity of water. On dissolving the bicarbonate in the calculated quantity of lactic acid there is obtained the lactate of 3- methoxy-G-hydroxy 10 methylacridinium hydroxide.

(6) 10 grams of 2,7-dimethyl-3,6-diamino-10- methylacridinium chloride are dissolved in 400 cc. of water and the bicarbonate of 2,7-dimethyl- 3,6-diamino-10-methylacridinium hydroxide is precipitated by addition of a concentrated solution of sodium bicarbonate. The point of. de composition lies over 270 C. By dissolving the product in dilute acids, such as lactic acid, tartaric acid, acetic acid, etc. there is obtained the corresponding lactate, tartrate and acetate.

We claim:

1. The bicarbonates of alkylacridinium bases, said salts being difiicultly soluble in water, readily soluble in acids with formation of the salts of these acids.

2. The bicarbonates of methylacridinium bases, said salts being diflicultly soluble in water, readily soluble in acids with formation of the salts of these acids.

3. The bicarbonate of 3,6-diamino-10-methylacridinium hydroxide, said salt being difficultly soluble in water, readily soluble in acids with formation of the salts of these acids.

4. The bicarbonate of 2-ethoxy-9-amino-10- methylacridinium hydroxide, said salt being difficultly soluble in water, readily soluble in acids with formation of the salts of these acids.

5. The bicarbonate of 2,7-dimethyl-3,6-dlamino-IO-methylacridinium hydroxide, said salt being difficultly soluble in water, readily soluble in acids with formation of the salts of these acids.

6. In the method of making alkylacridinium salts, the steps which comprise transforming strong mineral acid salts of alkylacridinium bases into the corresponding bicarbonates.

'7. In the method of making alkylacridinium salts, the steps which comprise dissolving strong mineral acid salts of alkylacridinium bases and an alkali metal carbonate in hot water, saturating the solution with carbon dioxide and separating the bicarbonate of the alkylacridinium base.

8. In the method of making alkylacridinium salts, the steps which comprise treating strong mineral acid salts of alkylacridinium bases with an alkali metal bicarbonate and separating the bicarbonate of the alkylacridinium base.

MAX BocKMiiHL. LEONHARD STEIN.