The use of derivative polarographic titration and dead-stop titration, generally applied for oxidoreduction titration, for the titration of acids and bases with antimony electrodes was attempted. Theoretical and practical considerations on the said titrations were made by carrying out Potentiometric polarography with antimony electrodes.
Derivative polarographic and dead-stop titrations for neutralization titration, using antimony electrodes, was found to be applicable with platinum electrodes by the addition of a special additive. Theoretical and practical considerations were made on such application by carrying out potentiometric polarography.
Polarographic behavior of several derivatives of camphor was examined. Of the halocamphors examined, only the 3-halocamphor showed reduction wave, while 8-bromo-dl-camphor, 6-bromo-8-chloro-l-camphor, and 10-bromo-d-camphor did not. 3-Bromo-d-camphor indicated a two-electron reduction wave and its half-wave potential (E1/2) was -0.66 v. vs. N. C. E., irrespective of pH. 3-Oxocamphor showed a reduction wave at pH 1-8 of E1/2=-0.34-0.058 pH, and diffusion current constant of 2.94, in which 2 electrons and 2 protons take part. At pH 8-12, the reduction wave E1/2=-0.57-0.03 pH appears, in which 2 electrons and 1 proton take part. Isoketopinic acid and ketopinic acid showed a hydrogen wave in acid, non-buffered solution. Almost all the camphor derivatives decreased the condenser current at definite potential range and showed a small two-step wave (called a camphor wave). 5-Oxocamphor did not show any reduction wave up to -1.8 v., and showed a camphor wave, a tensammetric wave by A. C. polarograph.
8-Oxocamphor is reduced to 8-hydroxycamphor at the dropping mercury electrode and its half-wave potential is indicated by E1/2=-1.15-0.06 pH (pH >9.5), E1/2=-1.73 (pH 6.8-9.5), E1/2=-1.07-0.09 pH (pH 1-4), its diffusion current constant being 2.67 and temperature coefficient 1.6%. 8-Oxocamphor shows the maximum wave in a solution containing CoCl2 or [Co(NH3)6]Cl, NH4Cl, and gelatin, and the height of its peak is related to the surface area of electrode alone, irrespective of the direction of applied voltage, velocity, and mercury head of the electrode, the peak voltage being indicated by Em=-1.76-iR. Inverse number of the height of the peak and inverse number of the concentration of 8-oxocamphor and cobaltic chloride are in linear relationship, there being an inflexion at the point of [8-oxocamphor]:[CoCl2]=1:2. It is also related to the concentration of the ammonium salt and gelatin, and becomes lower with the rise of temperature.
10-Oxocamphor shows a two-electron reduction wave and its half-wave potential is indicated by -1.31-0.043pH, at pH 9-12.5 and -1.7v. vs. N. C. E. at pH 6.5-9. In alkaline medium, 10-oxocamphor is inactivated by the Cannizzaro reaction. 3-Bromo- and 3-chloro-8-oxocamphor show two steps of two-electron reduction wave due to the halogen and aldehyde. The compounds which show maximum wave similar to that of 8-oxocamphor in a solution containing CoCl2, NH4Cl, NH3, and gelatin are camphor aldehydes such as 3-bromo- and 3-chloro-8-oxocamphors and 10-oxocamphor, whereas ketone, alcohol, and carboxylic acid derivatives of camphor, and benzaldehyde not showing such a wave. Considerations were made on the electrode reaction of this maximum wave.
6-Oxocamphor shows a reduction wave with a half-wave potential of E1/2=-1.4-0.034 pH in a solution of pH 5-9 and with a diffusion current. constant of 2.40 (μA⋅mM-1⋅mg-2/3⋅sec1/2). This reduction wave is assumed to be that due to the reduction of 6-oxocamphor to 6-hydroxy-dl-camphor. 6-Oxocamphor (I) is hydrolyzed to form rac-3-carboxymethyl-4, 4, 5-trimethylcyclopentanone (II, III) and this decomposition reaction was examined kinetically with a polarograph. The decomposition velocity, v, of (I) is represented by k′OH [OH-] [I]+k′H [OH3+] [I] and k′OH and k′H at 100° were respectively 46700 and 0.355 L⋅mol-1⋅min.-1 being the most stable. (at pH 3.5) The activation energy calculated from the Arrhenius equation was 18kcal./mole and activation entropy, -9 to -24cal./deg. From the foregoing facts, the reaction mechanism was considered and it was assumed that the attack of OH- or OH3+ on C=O first occurs and that the lability of (I) was due to the mutual action of the strain of camphane ring and of β-diketone.
Polarographic behavior of camphor derivatives reported in preceding papers were considered collectively. Of the camphor derivatives examined, 3-, 6-, 8-, and 10-oxocamphor, 3-bromocamphor, 3-bromo-8-oxocamphor, and 3-chloro-8-oxocamphor showed a reduction wave. These oxocamphors or 3-halocamphors are reduced to the corresponding hydroxycamphors or camphor and halogen ion respectively by a two-electron reduction. Their half-wave potential (E1/2) differs according to the +I effect of the carbonyl and halogen and -I effect of the alkyl and is more pronounced with proximity of the substituent radical. 3-Oxo- and 3-halocamphors show a more positive half-wave potential by the +E effect. From these results, biochemical reduction of camphor derivatives was discussed. Polarographic method was considered to be useful in the analysis of camphor derivatives and 6-, 10-, and 8-oxocamphors, possessing similar half-wave potentials, could be separatory determined by the use of their different stability to alkalis.
3-acetyl-3-mercaptopropyl acetate (RSH) shows an anodic wave due to the electrode reaction of RSH+Hg→RSHg+H++e (pH<6) or RS-+Hg→RSHg+e (pH>6), its diffusion current constant KD is 1.34 (μA⋅mM-1⋅mg-2/3⋅sec1/2), and its half-wave potential is -0.41 V. at pH>6 and (-0.03-0.06 pH) at pH<6. Its oxidation product (RSSR) shows a reduction wave of KD=2.6 and its electrode reaction could probably be indicated by RSSR+H++e→RS⋅+RSH, RS⋅+H++e→RSH. Thiochrome shows a two-electron, two-proton reduction wave of KD=2.8, and E1/2=-0.90-0.074 pH. Thiamine-thiothiazolone shows a reduction wave of KD=4.5 and four electrons take part in its electrode reduction, the pyrimidine portion being considered to be reduced as evidenced by ultraviolet absorption spectra, microcoulometry, and controlled potential electrolysis. Thiamine-thiazolone also shows a similar reduction wave. The height of such reduction waves or anodic waves is proportional to the square root of the mercury head and the concentration, and can be used for the determination of these compounds, but the half-wave potentials of thiochrome, thiamine-thiothiazolone, and-thiamine thiazolone are in close proximity and cannot be used for the separatory determination of their mixture.
When alkaline aqueous solution of thiamine (I) is allowed to stand in contact with air at 25°, oxidation of the thiol-type thiamine (III) chiefly occurs. Thiamine disulfide (IV), bis (1-acetyl-3-hydroxypropyl) disulfide (X), and 3-mercaptopropanol (XI) formed in this case were followed by polarography and the formation of thiothiazolone compound (VI) was measured by the optical density at 320mμ (cf. Tables I and II). For example, percentage composition of the sample solution after 146 hours was as follows: At pH 9.3: (I) 15, (IV) 65, (VI) 10, (XI) 1.3; at pH 104 (I) 14, (IV) 35, (VI) 11, (XI) 8.3; at pH 12.0: (I) 25, (IV) 13, (VI) 11.5, (XI) 17. When the same solution is allowed to stand in nitrogen atmosphere at 25° or heated to 100°, hydrolysis of the thiazole portion of thiamine chiefly occurs, forming (X), (XI), (VI), and 3-acetyl-3-mercaptopropanol, and this was similarly measured. For example, the percentage composition of the sample solution left in nitrogen atmosphere at 25° for 146 hours was as follows: at pH 9.3: (I) 48, (IX) 13, (VI) 11; at pH 10.4: (I) 20; (IX) 20, (VI) 20; at pH 12: (I) 49, (IX) 4.7, (VI) 15, (XI) 3.6.
The nature of thiamine diphosphate (TDP) and thiamine monophosphate (TMP) in aqueous solution was examined by absorption spectra, potential titration, and polarography. TDP monohydrochloride is present as an amphoteric ion (I) in the aqueous solution and pK of pyrophosphoric acid is <2, 7, >12, that of NH3+ is about 5, and that of thiazolium chloride, >12. Above pH 7, TDP changes reversibly to the thiol type (III) and pK of its SH is 9.7. Even at pH 7, 0.01% of TDP is present in a thiol type. Stability of TDP was examined by the thiochrome reaction using ion exchange resin and Takadiastase. At pH 3-5, TDP decomposes chiefly into TMP and phosphoric acid and in alkaline range, the thiazole portion undergoes decomposition to form a substance giving negative thiochrome reaction. The velocity of TDP reduction is taken as the first order reaction and the velocity constant increases with the increase of pH, differing with the kind of buffer solution used.
Aniline consumes 3 moles of periodic acid, when its amount is sufficient, under the conditions (for the general determination of α-glycol) of aniline concentration of 10-3M solution and at ordinary temperature, in critical time (Fig. 1). When the molar ratio of aniline to periodic acid is made constant, the amount of periodic acid consumed by aniline during a definite period after the critical time is small when the concentration is greater but constant, irrespective of its concentration above a certain concentration (Fig. 2). The substances which reduce periodic acid after critical time are primary oxidation products sparingly soluble in water. From the periodic acid oxidation products of aniline in higher concentrations, 2, 5-dianilino-and 2, 5-dianilino-N-phenyl-p-benzoquinone imine, 2, 5-dianilino-N-phenyl-p-benzoquinone diimine, and 2-amino-5-anilino-N-phenyl-p-benzoquinone were isolated and identified. Iodic acid does not react with aniline under the same conditions and periodic acid is therefore considered to be the so-called second oxidation agent for aniline.
Determination of 5-acetamidomethyl-4-amino-2-methylpyrimidine was carried out. Its basicity increases markedly in glacial acetic acid and it was titrated as 1 mole is 1 equivalent with 0.1 N perchloric acid. A mixed indicator was tried as the indicator and a mixture of methyl violet and bromophenol blue was found to show excellent change of color from reddish amber to blue at the equivalent point. Of the impurities included during the course of synthesis of this pyrimidine compound, sodium acetate and 4-amino-5-ethoxymethyl-2-methylpyrimidine quantitatively consumes perchloric acid and constitute the sources of error. The former can be removed by treatment with ion exchange resin and the latter by extraction with chlorobenzene. The determination accuracy was within ±0.2% with reference standard and within ±0.4% by separatory determination of an impure sample.
Hydroxy derivative of N-methyl-15-aza-des-N-morphinan was prepared by the condensation of 4-chloro-5, 6, 7, 8-tetrahydroquinoline and anisyl cyanide or veratryl cyanide in toluene, in the presence of sodium amide, by the process similar to that in preparing the benzyl derivative. It was reaffirmed by this synthesis that in the octahydro compound, the enamine converted to ketimine in acid medium and underwent cyclization.
Optical resolution of N-methyl-15-aza-des-N-morphinan and its 3-hydroxy compound was carried out and their pharmacological activity was examined but none showed any analgesic action. Optical resolution of 1-methyl-4-benzyioctahydro-quinoline with d-tartaric acid was attempted and it was again found that the enamine underwent conversion even with tartaric acid to ketimine to undergo cyclization to a hydrophenanthrene.
A new steroidal sapogenin having three hydroxyl groups, m.p. 273-274°, was isolated from Metanarthecium luteo-viride MAXIM. and was named metagenin (I). From the infrared spectrum of its triacetate (II), it was assumed that it possessed an iso-type side chain and a C5-normal form 2, 3-diol structure, similar to that of samogenin acetate (III) and markogenin acetate (IV). This is further supported by the formation of an acetonide (V) and of monoketodicarboxylic acid (VI) by oxidation with chromium trioxide at room temperature. The infrared spectrum of its dimethyl ester (VII) indicates the absorption of a six-membered ring carbonyl and the third hydroxyl is limited to C6, C7, or C11 position.
By the reaction of ammonia and hydrazine hydrate with diesters (III, V) of α-kainic acid (I) and α-dihydrokainic acid (II), and their N-acyl derivatives (VIII to XII), corresponding diamides and dihydrazides (XIII to XX) were prepared. The reaction of (I) and diazomethane in hydrous methanol affords a monoester which can be derived further to a monoamide compound. These were proved from the measurement of their pK′ to be γ-derivatives (XXI, XXII). By the reaction of (I) and potassium cyanate, (IV) and alkyl α-haloacylate, and (III) and ethyl acrylate and methyl crotonate, the corresponding N-carbamoyl and N-alkoxycarbonylalkyl derivatives (XXIII to XXVI) were obtained.
By the application of amines, alcohols, and water to N-acylkainic anhydrides (III, IV) and N-acyldihydrokainic anhydrides (VI, VII), obtained from α-kainic acid (I) and α-dihydrokainic acid (II), the corresponding monoamides, monoesters, and N-acylkainic acids (VIII to XXXIII) were prepared. These mono-substituted compounds were proved to be α-substituted derivatives from the measurement of pK′ of N-acetyl-glycine- and N-acylkainic derivatives. Further, (V) and (VIII) were derived to (XXXIV) and (XXXV) through N-acylkainic dichlorides.
Following the previous report on the reaction of 1-styryl-3, 4-dihydroisoquinoline derivatives, as diene component of a C=C-C=N system, with maleic anhydride, a reaction of 1-cyclohexenyl-3, 4-dihydro-6, 7-dimethoxyisoquinoline, possessing a cyclohexenyl group in place of styryl, with maleic anhydride was carried out under practically identical conditions. A compound (IV), identical in analytical values with that anticipated, was isolated as its picrate. In order to establish its structure, Hofmann degradation of the methiodide of the substance obtained by reduction and saponification of (IV), was carried out. Repeated three degradations resulted in the liberation of trimethylamine to form a neutral substance. Such a fact confirms the benzoquinolizine structure of the product and thereby indicates that this is a regular reaction. It was concluded from the result of the present and the preceding experiments that the diene component of C=C-C=N system including the C=N bond in 1-2 positions of the 3, 4-dihydroisoquinoline compound can take part in the Diels-Alder type reaction.
The process of synthesizing sym-diaryl telluride from diazonium salt leaves much to be desired. The process of Waters was applied to various anilines and numerous sym-diaryltelluronium dichlorides were prepared from their diazonium salts and tellurium powder. Their treatment with sodium sulfide easily afforded sym-diaryl telluride. The compounds prepared by this process were sym-diaryltellurium dichlorides with o-, m-, and p-tolyl, methoxyphenyl, ethoxyphenyl, chlorophenyl, and bromophenyl group, and some of their allied compounds. Antibacterial tests of these compounds gave the results listed in Table I, indicating that they as a whole possessed a comparatively strong antibacterial action, the strongest being bis (p-methoxyphenyl) tellurium dichloride (VII) which gave values of inhibitory concentration of 3 γ/cc. and suppresive concentration of 1 γ/cc. against H37Rv strain tubercle bacilli.
dl-Magnoflorine (N-methylcorytuberine) (IV), a phenolic, quaternary aporphine-type base which is distributed widely in the Menispermaceae, Berberidaceae, Magnoliaceae, Rutaceae, and Ranunculaceae family, was synthesized.
Sulfophthalein series dyes combine with organic bases to form addition products soluble in organic solvents and colorimetric determination of bases by the utilization of this nature is possible. Conditions for this determinination were examined with dl-methylephedrine hydrochloride and ephedrine hydrochloride and it was found that the dyes of halogen derivatives, such as bromothymol blue, bromocresol green, and bromocresol purple, and polar solvents such as ethylene dichloride and chloroform gave good results. Partition coefficients between the aqueous layer of the addition product and the organic solvent layer, under the conditions employed, were measured and a part of the mechanism of this determination method was clarified. Relationship between chemical structure and optical density was examined in several basic compounds, including official and new remedies. It was thereby revealed that pKb, kind of amines used, molecular weight, and the presence or absence of hydrophilic radical affected the optical density.
The application of the determination method for sympathomimetic amines to the determination of preparations often gave difficulties or incorrect values. The colorimetric determination of organic bases with sulfophthalein dyes was applied to the determination of ephedrine and dl-methylephedrine hydrochlorides, using bromocresol green, and good results were obtained. At the same time, effect of chemicals compounded in such preparations was examined. The relationship between chemical structure and optical density of sympathomimetic amines was found to be the same as that described earlier and the effect of the kind of amines and presence of a hydroxyl group was fonnd to be the controlling factor.
2-Salicylidenehydrazono-4-thiazolidone (I) derivatives with methyl, phenyl, and p-methoxyphenyl group in 3-position were prepared and their antituberculor action was tested. The compounds were prepared by deriving methylamine, aniline, and anisidine to 4-substituted thiosemicarbazides, condensed with salicylaldehyde, and further condensed with ethyl chloroacetate. These three kinds of 2-salicylidenehydrazono-3-alkyl (or aryl)-4-thiazolidones possessed much smaller antibacterial action than the original substance (I).
It had earlier been revealed that magnoflorine, the quaternary aporphine-type alkaloid, is contained in the root and rhizome of Epimedium rugosum NAKAI, a Berberiacceae plant. It was found by the present series of experiments that a large amount of the water-soluble quaternary base, magnoflorine, is contained in the root and rhizome of Epimedium grandiflorum MORREN var. Thunbergianum NAKAI in which tertiary base was not found. It was also proved that these root and rhizome contained a flavone glycoside, des-O-methylicariin.
When D-glucose and p-toluidine are dissolved in 50% acetic acid and allowed to stand, N-p-tolyl-D-isoglucosamine is obtained in a good yield. Oxidation of this with 34% hydrogen peroxide in ammonia alkalinity afforded ammonium D-arabonate in a good yield.