SOLUBILITIES OF SOME STRYCHNINE BENZOATES CHARLES F. POE, JOHN F. SUCHY,
AND
GEORGE L. BAKER
Department of Chemistry, University of Colorado, Boulder, Colorado Received M a y 9, 1034
During the use of some strychnine benzoates in a series of toxicological and pharmacological experiments (l),it became necessary to determine their solubilities in water at 20°C. It was decided to make like determinations at other temperatures, and the results of this investigation are reported in the present communication. For the determination of the solubilities up to 60"C.,a constant temperature bath, capable of being regulated to f0.05', was used. The strychnine salt was placed in a Pyrex test tube with about 30 cc. of water, and the tube was sealed. For the lower temperatures the mouth of the test tube was closed by sealing in the flame; for the higher temperatures pure gum rubber stoppers were used. A number of tubes were fastened to a frame, which in turn was connected to a mechanical shaker. The tubes were allowed to remain in the bath for from thirty-six to forty-eight hours. For the determination of solubilities a t the higher temperatures, a n excess of the strychnine salt in distilled water was brought to the boiling point and then allowed to cool to the desired temperature. The tube containing the solution was allowed to remain in a constant temperature bath at this temperature for at least thirty minutes. In order to obtain a temperature of 95"C.,since water at this altitude boils below this temperature, a small amount of sodium chloride was added to the water in the water bath. The tubes containing the strychnine salts in water were placed in this boiling solution. The bath used was a large Erlenmeyer flask. Most of the water which evaporated condensed and ran back in the flask. If the thermometer kept in the salt solution indicated that the temperature was greater than 95"C.,a new salt solution was used. In every case the tubes were frequently agitated. After the salts had remained in contact with the water at the desired temperature for the required length of time, the tubes were removed to a constant temperature air oven regulated to the same temperature. With pipettes heated to this same temperature, 25 cc. of the solution was removed from each tube, placed in a weighed platinum dish, and evaporated to dryness on the water bath. The dish was then placed in an air oven and 239
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CHARLES F
. POE.
.
.
JOHN F SUCHT AND GEORGE L BAKER
dried to constant weight at 100°C. The grams of the strychnine compound present in 100 cc . of solution were calculated . The results showing the different solubilities are presented in table 1 From the data in this table it may be noted that a number of the compounds gave rather high solubility values in water As a rule the ortho compounds gave the highest
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TABLE 1 Solubilities of some strvchnine benzoates
. . . . . T = T= TT= T= 40°C. 85°C. 50°C. 60°C. 75oc . .
QRAMB OF SALT P I R STRYCHNINE BALT
T =
Benzoate. . . . . . . . . . . . . . . . . . o-Chlorobeneoate . . . . . . . . . . In-Chlorobenzoate . . . . . . . . . p-Chlorobenzoate . . . . . . . . . . . o-Bromobenzoate . . . . . . . . . . . m-Bromobenzoate . . . . . . . . . . p-Bromobenzoate ........... o-Iodobenzoate . . . . . . . . . . . . . p-Iodobenzoate ............. o-Nitrobenzoate . . . . . . . . . . . . m-Nitrobenzoate . . . . . . . . . . . . p-Nitrobenzoate . . . . . . . . . . . . o-Hydroxybenzoate . . . . . . . . . m-Hydroxybenzoate ........ p-Hydroxybenzoate ......... o-Methylbenzoate ........... m-Methylbenzoate .......... p-Methylbenzoate . . . . . . . . . . o-Aminobenzoate ........... na- Aminobenzoate ........... plAminobenzoate ........... 3,5-Dinitrobenzoate. . . . . . . . 2,4-Dinitrobenzoate . . . . . . . . 2,4,6-Trinitrobenzoate...... 5-Iodosalicylate . . . . . . . . . . . . 3,5-Dinitrosalicylate........ Diiodosalic ylate . . . . . . . . . . . .
T=
20°C. -
30°C
.
0 ,433 1.783 0.176 0.264 1.063 0.092 0.211 0.526 0.167 0.521 0.447 0.183 0.250 0 . 179 0.149 0.519 0.869 0.560 0.297 1.092 0.371 0.136 0.249 0.075 0.037 0.025 0.020
0.578 1.995 0.229 0.302 1.204 0.115 0.244 0.582 0.195 0.621 0.565 0.222 0.297 0.185 0.188 0.634 0.992 0.578 0.378 1.204 0.652 0.163 0.298 0.098 0.045 0.041 0.023
100 CC OF BOLUTION AT T E E GIVEN TmMPERATURES
0.784 2.211 0.344 0.330 1.410 0.141 0.299 0.653 0.229 0.724 0.706 0.266 0.402 0.335 0.241 0.984 1.181 0.625 0.462 1.437 0 . 986 0.197 0 . 389 0.116 0 . 057 0.063 0.031
1.156 2.770 0.509 0.425 1.846 0.201 0.351 0.768 0.341 0.928 0.896 0.328 0.606 0.432 0.339 1.331 1.688 0 . 828 0.710 2.107 1.324 0 . 271 3.557 3.165 1.079 1.088 1.032
1.607 3.410 0 .669 0.551 2 .470 0.402 0.528 1.122 0.475 1.320 1.359 0.467 0.964 0.562 0.517 1.958 2.350 0.931 0.984 2.971 2.046 0.384 0.821 0.273 0.126 0.116 0.046
2.311 4.798 0.944 0.688 3.818 0.576 0.744 1.514 0.606 1.970 2.452 0.698 1.470 0.872 0.875 2.807 3.856 1.250 1.590 4.786 3.586 0.599 1.230 0.450 0.215 0.422 0.071
3.460 0.725 1.376 1.158 6.571 0.835 0.915 2.116 0.840 3.140 4.138 0.970 2.500 1.517 1.432 4.142 7.765 1.808 2.602 7.963 7.136 0.951 1.610 0.717 3 , 374 1.064 0.127
values. but this was not true for the nitro. methyl. and amino compounds . In these three compounds the meta form showed the greatest solubility The compounds with the benzoic acids having more than one substituted group gave. as a rule. very low solubility values . The strychnine diiodosalicylate was almost insoluble in water at all temperatures
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SOLUBILITIES O F SOME STRYCHNINE BENZOATES
241
SUMMARY
The solubilities in water at different temperatures have been determined for twenty-seven strychnine benzoates. REFERENCE (1) POE,CHARLES F., AND SUCHY,JOHN F.: Some Strychnine Benzoates. Chem. SOC. 66, 1640 (1934).
J. Am.
