Some Mercuriated Derivatives of Thymol and Carvacrol*

JOURNAL O F T H E

112

Vol. XXV.

No. 2

DISCUSSION OF RESULTS.

The results thus far obtained indicate that packing from the top is somewhat better than packing in sections. When the drug is packed from the top more of the alkaloid is in the reserve and less in the weak percolate than when packed in sections. As far as present results are concerned, the method of packing has no appreciable effect on the rate of extraction of total extractive. When maceration both before and after packing was omitted and the rate of flow doubled, the extraction of alkaloids was slower but there was no appreciable effect on the efficiency of extraction of total extractive. SUM,UARY.

By percolation experiments using SOO-Gm. portions of belladonna root it has been found that extraction of alkaloids is more efficient when all the drug is placed in the percolator and packed from the top than when the drug is introduced in the percolator in portions and each portion packed before the next is added. The method of packing has no appreciable effect on the efficiency of extraction of total extractive. When maceration before and after packing is omitted and the rate of percolation is doubled the extraction of alkaloids is slower but there is no appreciable effect on the efficiency of extraction of total extractive.

SOME MERCURIATED DERIVATIVES O F THYMOL AND CARVACROL. * BY JOSEPH B. BURT.’

According to the anonymous author (1) of a paper on mercury compounds of the aromatic series, a number of such derivatives of mercury have been suggested for use as antisyphilitics. Among others, “Thymol Mercury” was suggested by Bambclon in 1888. This preparation was described as a basic salt having a violetgreen color, which was regarded as unsuitable for therapeutic use because of its lack of stability. The author also mentions a series of thymol mercury derivatives of a different type prepared by E. IMerck, which were thought to be double salts containing an organic or inorganic acid radical as a constituent of the molecule. Three examples of such compounds are listed by Merck (2), Viz., mercuric thymol acetate, mercuric thymol nitrate and mercuric thymol sulphate. The only one of these for which a definite formula is given is thymol mercuric acetate, which is shown as Hg~CH~COOj~-Hg(CH3COO-Cl~Hl~O). In addition, Merck also lists mercuric thymol salicylate as well as mercury thymolate, probably the same as the “Thymol Mercury” previously mentioned. The latter is described as a “basic salt of variable composition, but usually HgCloH130H” (sfc), “a reddish yellow powder, insoluble in water.” Another reference to mercury derivatives of thymol is the report of Dimroth (3) on the formation of chlormercuri thymol, CsH2(CH3)-(C3H7)0H-HgC1,and diacetoxymercuri thymol, CaH(CH,)(C3H7)0H-(HgOCOCH3)2. The author does not indicate the positions of the substituted groups, but the formulas indicate that he ~

* Scientific Section, A. PH. A.. Portland meeting, 193.5. I

College of Pharmacy, University of Nebraska

I’eb. 19.78

AMERICAN PHARMACEUTICAL ASSOCIATION

113

considers the hydrogens of the nucleus replaced, rather than the phenol hydrogen. Whitmore (4), in his review of Dimroth’s report, suggests that the first compound may be considered as the para derivative, for he assigns to it the name (p. 112)-chlormercuri thymol. He calls the second compound diacetoxymercuri thymol, without suggesting the possible positions of the substituted groups. C

C

I /\

I

C

C

/\

CHaCOOHgC CHgOOCCHa

I I/

C

HOHgC

I /I

COH

C

I

C

c/\c

c c

Sodium 2,H-dihydroxymercuri thymolate. DirnercurihydroxyThymolnatrium. (Rupp.)

C

c

I

I

C

C

/\

HONgC

CONa

\/

NC/ I C A

2,F-Diacctoxyrnercuri thymol. Thymolquecksilbcracetat. (Rupp.)

CHgOH

CHg

I ! > y

c c o C

/\

c c Mono-anhydride of 2,6-dihydroxymercuri thymol. Monoanhydridodirnercurihydroxy-Thymol. (Rupp.)

c

/\

ClHgC CHgCl

i COH I

C

NC/ i C A

c c 2’6-dichlormercuri thymol. DimercurichloridThymol. (Rupp.)

C

I C /\

!

C

IHgC CHgI

I I1 y

C

COH

I

C

A

c c 2.6-diiodomcrcuri thymol. Dimcrcurijodid-Thymol. (Rupp.)

I

C

/\

c c 2,F-dinitratemercuri thymol. L)imercurinitrat-Thymol. (Rupp.)

114

JOURNAL OF THE

Vol. XXV, No. 2

A more comprehensive study of the mercury derivatives of thymol is that of Rupp ( 5 ) , a publication that appears to have been omitted in Whitmore’s compilation. Rupp confined his study to the di-mercuric derivatives of thymol, and reported the preparation of six compounds, the compositionsof which were determined by analysis, and he also established the position of the substituted hydrogens as 2, 6. The compounds which he obtained are shown on page 113. Rupp’s results are not in accord with the earlier view that the diacetoxymercuri thymoI could be obtained in the form of the sodium thymolate by dissolving in sodium hydroxide solution and crystallizing from this solution, for they indicate that the product resulting from this treatment is the sodium dihydroxymercuri thymolate instead of the sodium diacetoxymercuri thymolate. He also points out the fact that these compounds, by dissolving in solutions of fixed alkalies, preclude the possibility of a double salt containing one molecule of mercuric acetate associated with one molecule of the substituted thymol, as suggested by Merck, since in this case the alkali would precipitate mercuric oxide instead of forming a solution. The fact that these compounds retain their phenolic character and at the same time contain a rather high percentage of mercury suggests that they may be of some importance as antiseptics and fungicides. In as much as carvacrol, the phenol isomeric with thymol, has recently been employed in the treatment of dermaphytosis, and no report of the application of the reaction of mercuric salts to carvacrol has been found in the literature, it seemed desirable to investigate this possibility. Accordingly, a study of these products has been undertaken, which is still in progress. This discussion represents but a preliminary report on a few derivatives of carvacrol which have been obtained thus far. EXPERIMENTAL.

Mono-chlormercuri Camacrol and Di-chlormercuri Carvacro1.-Thirty grams (30.72 cc., one mol.) of carvacrol, obtained from the volatile oil of Monarda @ectinate, Nutt., were dissolved in alcohol and boiled, under a reflux condenser, with an alcoholic solution of 63.66 Gm. (one mol.) of mercuric acetate, to which 12 cc. of glacial acetic acid had been added, for about three hours. Upon cooling and standing a few hours, a bulky deposit of needle-shaped crystals was formed, apparently the acetoxymercuri carvacrol. This compound was not isolated, but the reaction mixture was again heated, whereupon the crystalline material dissolved, except for slight traces of flocculent material (not needle-shaped crystals) which were removed by filtering while hot. The solution was then poured with stirring into an aqueous saturated solution of sodium chloride, precipitating the chlormercuri carvacrol. This was filtered out with suction, washed with water and dried. The weight was 62.0 Gm., corresponding to a yield of 80.72 per cent of the theoretical, based upon the mono-derivative. The substance was found to be, however, a mixture of the mono- and the di-derivatives. Thirty-six and one-half grams of the crude product were recrystallized from hot 50 per cent alcohol. After repeated extraction, a white residue remained, which was insoluble in the solvent, and which appeared to be much heavier than the main portion of the product. After drying, the insoluble portion weighed 3.95 Gm. After hydrolysis by boiling with dilute hydrochloric acid (yielding carvacrol and mercuric chloride), the mercury was determined by precipitation as sulphide. Two

Feb. 1936

AMERICAN PHARMACEUTICAL ASSOCIATION

115

samples gave 64.,58 and 64.62 per cent, respectively, of mercury. The calculated percentage of mercury in di-chlormercuri carvacrol, CloH120Hg2C12,is 64.69 per cent. The compound decomposes with partial fusion at 207-206' C. It gives a positive test for halogens when heated on a copper wire. I t is a fine powder, characterized by the tenacity with which it adheres to everygurface with which it comes in contact, and appears to become electrified upon rubbing. The hot 50 per cent alcoholic solution was allowed to cool, and the material which separated (18.2 Gm.) was filtered out. A second crop (8.75 Gm.) was obtained by partial spontaneous evaporation of the mother liquor. The first crop (18.2 Gm.) was again recrystallized from hot 50 per cent alcohol, in which it was completely soluble. Two crops were obtained as before. These were combined and again recrystallized from the same solvent. Two crops (6.80 Gm. upon cooling, and 7.20 Gm. upon partial evaporation) were obtained. A sample of the first crop appeared to decompose without complete fusion at 163164' C. When assayed for mercury after hydrolysis with dilute hydrochloric acid, by precipitation as sulphide, two samples gave 52.73 and 52.83 per cent, respectively, of mercury. The calculated value for monochlormercuri carvacrol is 52.08 per cent of mercury. Thus it appears that the product, after three recrystallizations from hot 50 per cent alcohol, is still contaminated with traces of the di-derivative. The somewhat impure mono-chlormercuri carvacrol is very soluble in acetone, and in dioxan, from both of which it may be reprecipitated by pouring into water. It is difficultly soluble in alcohol, ether and chloroform, and practically insoluble in petroleum ether and water. A solution in acetone, another in dioxan and a suspension in water, all gave, upon continued treatment with hydrogen sulphide, precipitates of mercuric sulphide, but somewhat less promptly than if previously hydrolyzed. A saturated chloroformic solution, when boiled with solid sodium hydroxide, failed to give a Flueckiger test, indicating the absence of free carvacrol. The substance is finely crystalline, appearing under the microscope as long needles. The second crop formed larger needles, visible to the naked eye. When heated on a copper wire, a positive test for halogens is given. The compound dissolves readily in 5 per cent solution of sodium hydroxide, probably forming the sddium mono-hydroxymercuri carvacrolate. If the solution is acidified with dilute hydrochloric acid, the original mono-chlormercuri carvacrol is reprecipitated. If, however, the alkaline solution is treated with carbon dioxide, a bulky white precipitate is slowly formed, which is, without doubt, the mono-hydroxymercuri carvacrol. 'This product has not, as yet, been examined. Mono-acetoxymercuri Carvacrol.-Equimolecular portions of carvacrol and mercuric acetate (30 Gm. carvacrol, 63.66 Gm. mercuric acetate) were boiled together in alcoholic solution containing 12 cc. of glacial acetic acid, under a reflux condenser, for three hours. The hot reaction mixture was filtered free from a trace of flocculent material which was formed, and, upon cooling, a mass of needle-shaped crystals was deposited. These were filtered out and additional crops were obtained from the alcoholic mother liquor by fractional crystallization. Four crops were obtained, weighing 31.5 Gm., 9.95 Gm., 8.50 Gm. and 10.10 Gm., or a total of 60.05 Gm., corresponding to a yield of 73.59 per cent of the theoretical, based upon the mono-derivative. Three samples of the first crop, without further purification,

116

JOURNAL O F THE

VOl.

xxv. No. 2

gave, upon hydrolysis and precipitation as mercuric sulphide, 49.66,49.75 and 49.76 per cent, respectively, of mercury. The calculated percentage of mercury for the mono-acetoxymercuri carvacrol is 49.08 per cent. I t is evident that the first crop is somewhat impure, being contaminated with traces of the di-acetoxymercuri carvacrol. A sample of the first fraction partially fused and decomposed, rising out of the melting-point tube due t o gas formation, a t 173 -174' C. Mono-chlormercuri Thymol Methyl Ether.-The ease with which the monochlormcrcuri carvacrol and the mono-acetoxymercuri carvacrol dissolve in fixed alkali indicates that the phenol hydrogen is not involved in the reaction. Accordingly, the methyl ether of thymol or of carvacrol should react with mercuric acetate. This reaction was carried out on the methyl ether of thymol on a small scale, the product being precipitated by pouring the alcoholic solution into an aqueous solution of sodium chloride. A grayish white product, appearing almost white when dry, was obtained in a quantity corresponding t o a yield of 90.h7 per cent, based upon the mono-derivative. Although equimolecular proportions were used, it is probable that the product is a mixture of the mono- and di-derivatives, with the mono-derivative predominating. N o attempt has been made to separate the compounds, nor has it been analyzed for mercury. I t gives a positive test for halogens, and a precipitate of mercuric sulphide upon suspending in water and treating with hydrogen sulphide. It is fairly soluble in acetone and dioxan, somewhat less soluble in ether and glacial acetic acid, difficultly soluble in chloroform and alcohol and practically insoluble in petroleum ether. I t is insoluble in a 5 per cent solution of sodium hydroxide, even upon boiling, but turns somewhat grayish under this treatment. Mono-chlormercuri CarvacroI Methyl Ether.-In a procedure similar to that followed in the reaction with the methyl ether of thymol, the methyl ether of carvacrol yielded a product corresponding t o 83.34 per cent of the theoretical, calculated for the mono-derivative. This product was also grayish white in appearance, being somewhat darker when moist. It also gave a positive test for halogens, and is acted upon, in aqueous suspension, by hydrogen sulphide to form mercuric sulphide. It has properties similar t o those of the corresponding derivative of the methyl ether of thymol, except that it is relatively more soluble in glacial acetic acid, and notably less soluble in acetone. I t is likewise insoluble in a 5 per cent solution of sodium hydroxide. SUMMARY AND DISCUSSION.

A preliminary study, chiefly of the mono-mercuri derivatives of carvacrol, has been made. The following compounds have been prepared : mono-chlormercuri carvacrol, di-chlormercuri carvacrol, mono-acetoxymercuri carvacrol, monochlormercuri thymol methyl ether and mono-chlormercuri carvacrol methyl ether. The mono-derivatives of carvacrol dissolve readily in dilute alkalies t o form the corresponding phenolates, which may be obtained by crystallization from the solution, or precipitated in the form of the mono-hydroxymercuri carvacrol by treatment of the alkaline solution with carbon dioxide. Although equimoleeular proportions of carvacrol and mercuric acetate were used, the product of the reaction is a mixture of the mono- and di-derivative, in which the mono-derivative predominates.

Feb. 1936

AMERICAN PHARMACEUTICAL ASSOCIATION

117

Ten per cent ointments of the mono-chlormercuri carvacrol and of the monoacetoxymercuri carvacrol have been prepared and submitted to Dr. R. I,. McIntosh, of the State of Wisconsin General Hospital, who has kindly agreed to conduct a series of laboratory and clinical tests of their fungicidal properties. REFERENCES. (1) Neuere Arzneimittel, “Die Quecksilberverbindungen aus der aromatischen Reihe,” Therap. Monatsh., 4, 128-136 (1890). (2) Merck’s Index, 1907. ( 3 ) Dimroth, O., “Ueber die Mercurirung aromatischer Verbindungen,” Ber. d. d. chem., Ges., 35, 2864 (1902). (4) Whitmore, F. C., “Organic Compounds of Mercury,” 278 (1921). ( 5 ) Rupp, E., “Die Konstitution von Hydrargyrum thymolo-aceticum,” Archzv der Pharmazie, 255, 191-197 (1917).

A TOXICOLOGICAL STUDY O F T H E CUTANEOUS SECRETIONS O F T H E SALAMANDER, TRITURUS TOROSUS (RATHKE).* BY ERNST T. STUHR.’

INTRODUCTION.

Interest in the secretions and excretions of various animals has been long manifested. The literature records numerous references to the poisonous skin secretions of toads (1, 2, 3), reptile venoms (4), spider bites (5, ci), insect bites and stings. Noble (7) has indicated that the secretion of the skin glands of certain salamanders is potent, particularly the secretion from the granular glands, due to sevcral alkaloidal-like principles, and that the virulence of the poison differs with the species of salamander. The toxic properties of an aqueous solution of the granular gland secretions of the salamander is here considered.

THEGLANDULAR SECRETIONS. The western newt, Triturus torosus (Rathke), is a common species of salamander in the Oregon country. Profuse cutaneous excretion occurs during the breeding (mating) season, March-April. The glands can be stimulated by subjecting the animals to crowded quarters or b y partial suffocation. The secretion may then be secured by washing the salamanders. The granular cell product is transparent, while the mucous cell product is turbid, possibly indicating partial oxidation and insolubility. The two secretions can be separated by decantation or by the use of a scparatory funnel. ACUTE TOXICITY.

Hypodermic injections (subcutaneously or intraperitoneally) caused animals (frogs, cats, rabbits, guinea-pigs and dogs) to rapidly develop toxic symptoms and . -

- - -- - - -

-~

* Scientific Section, A PH.A , Portland meeting, 1935. Department of Pharmacology and Pharmacognosy, School of Pharmacy, Oregon State College, Corvallis.