When solutions of salicylic aldehydes and o-hydroxyphenyl ketones in acetic anhydride and/or glacial acetic acid are mixed with a solution of boric acid in acetic anhydride and allowed to stand, they give fluorescence. The fluorescent compounds produced were assumed to be complexes of ligand-boron (molar ratio 1 : 1) from the result of continuous variation method. This reaction was successfully applied to fluorometric determination of salicy1ic aldehydes and o-hydroxyphenyl ketones. Conditions for their determination are summarized in Table II.
In order to clarify the characteristics of the reactivity of thiamine derivatives of disulfide type, the exchange reaction rate between bis[2-(N-phenethyl formamido)propenyl] disulfide and cysteine was compared with the reactions between thiamine derivatives of disulfide type and cysteine, Following results were obtained : 1) The reaction was carried out to form 4-methyl-3-alkyl thiazolium. 2) The reverse reaction was not observable below neutral pH. The rate constant k1 was calculated from the formation of 4-methyl-3-alkyl thiazolium below pH 7 ; the rate constant k1 was : 3.88×104 liter mole-1 min-1 and 11.1 kcal mole-1 was the activation energy. 3) The reverse reaction was observed above neutral pH. 4) It was concluded that the exchange reactions between cysteine and thiazolium derivatives of disulfide type including thiamine derivatives of disulfide type depend on the ring opening-closing reaction of thiazolium nucleus and can be expressed as follows : At pH«pKa of thiazolium ThiaSSThia+CyS-→ThiaSSCy+ThiaS- ThiaSSCy+CyS-→cystine+ThiaS- ThiaS-→thiazolium At pH»pKa of thiazolium ThiaSSThia+CyS-⇄ThiaSSCy+ThiaS- ThiaSSCy+CyS-⇄cystine+ThiaS-
For the purpose of clarifying the chemiluminescence mechanism of cypridina luciferin (I), 3, 7-dihydroimidazo[1, 2-α]pyrazin-3-one (VIIa) as the simplest, but rather unstable analog of I and its 2-methyl (VIIb), 2-phenyl (VIIc), and 6-phenyl (VIId) derivatives were synthesized. 2-Aminopyrazines or 2-chloropyrazines were converted into pyrazyl-glycine and its α-substituted derivatives (V), their amides (IV), or their esters (VI), either of which could be cyclized to the corresponding imidazopyrazinones (VII). Cyclization of esters by means of sodium alkoxide was found to be preferable to the acidic condition (by HCl) reported by McCapra, et al.
3, 7-Dihydro-2-methylimidazo[1, 2-α]pyrazin-3-one(II)was assigned to IIa, one of three possible tautomers (IIa, b, c) on the basis of Mass, UV, and NMR spectra of II and its methyl derivative (III). In contrast, 3-amino-2-methylimidazo[1, 2-α]pyrazine (V) was found to have the structure Vb as suggested from the comparison of UV and NMR spectra of V with those of 3-benzylamino derivative (VI). Acetylation of II gave 7-acetyl derivative (VIIa), while the treatment of II with phosphorus oxychloride led to 3-chloroimidazo[1, 2-α]pyrazine (VIIIb), the chlorine atom in it being very inactive.
Condensation of 2-aminopyridine with benzaldehyde sodium bisulfite adduct and NaCN by the method of Ohta, et al. gave, instead of the nitrile as previously suggested, 3-amino-2-phenylimidazo[1, 2-α]pyridine (VI), which in turn was converted by treatment with conc. hydrochloric acid into 3-hydroxy-2-phenyl derivative (X). 3-Amino (IV) and 3-amino-2-methyl derivative (V) by the same treatment, however, gave the corresponding carboxylic acids (XI and XII). Instead of the unsuccessful cyclization of XI and XII, the ethyl ester of XII (XIV) was smoothly converted, on being heated in vacuo, to pure 3-hydroxy-2-methyl derivative (IX). It is interesting to note that the chemiluminescence activity is observed with 3-hydroxy compounds (VIII, IX and X), but not with 2-hydroxy-3-methyl derivative (III), which is synthesized from I and α-chloropropionyl chloride and exists in a tautomeric mixture of 2-hydroxy type (IIIb) and 2-keto type (IIIc) in a DMSO solution.
Instead of the reported synthesis of 3-hydroxyimidazo[1, 2-α]pyridines and 3, 7-dihydroimidazo[1, 2-α]pyrazin-3-ones, the model compounds of Cypridina luciferin, from 2- aminopyridine and aminopyrazines (Xa-c) by several steps, an improved one-step synthesis of the desired compounds was described. Heating of 2-aminopyridine or aminopyrazines (Xa-c) with glyoxal derivatives (IV or V) in aqueous acid solutions afforded the corresponding 3-hydroxyimidazopyridines (I and VI) and 3, 7-dihydroimidazopyrazinones (XIa-e) in good yields.
In order to find if a hypocalcemic factor is present in the thymus gland, ground bovine thymus glands components were extracted with water or a physiological saline solution at pH 8.0. Several active fractions were obtained from the extracts by precipitation with CaCl2, and by addition of acetone to the mother liquid of CaCl2-precipitate, or by adjusting the pH of the liquid to the isoelectric point. It is concluded that the active principles may be substances of a non-nucleoprotein nature.
The ionization constants (pKa) of 1-hydroxy-, 4-hydroxy-, 7-hydroxy-10-chloro- and 7-chloro-10-hydroxy-indo1o[2, 3-b]quinoxaline (I, II, III and IV), and the stability constants of some of the transition metal complexes were determined spectrophotometrically. The difference of pKa the UV spectrum between I and II were found to be very slight and we did not observe any significant differences of the stability constants. The prepared complexes were much different from that of oxine in solubilities, stabilities and shifts of absorption maximum in the complex formation and they were found to be less stable in aqueous solution. Because of the poor solubility of III and IV in 50% dioxane, the stability constants of their metal complexes could not be determined under the same conditions as I and II, and they have been measured in alcohol for III and in 50% alcohol for IV : they are less stable than those of I and II.
The phenolic constituents of the root of Sophora subprostrata CHUN et T. CHEN [Chinese drug : Shan Dou Gen ( ?? ?? ?? )] were studied, and a new phenolic compound (I), mp 115°, C31H52O4, was isolated, together with l-maackiain and genistein. I was hydrolysed with alkali to give caffeic acid and an aliphatie alcohol, CnH2n+1OH. Gas chromatography of the alcohol and of the methyl ester of the acid derived from it by oxidation, established the chain-length to be constituted of C20, 21, 22, (main), 23, 24, 25, and 26(Fig.3). From these results and the NMR spectra of I and its derivatives, I was formulated as Fig.1. In addition, di-O-acetyl-trans-caffeic acid docosyl ester (IIa) was synthesized, together with the cis-isomer (IIb), and the spectra (IR, UV, and NMR) of the former were also found to be superimposable with those of diacetate of I (II).
From the root of Sophora angustifolia SIEB. et ZUCC., two kinds of new natural flavonoids, named isoanhydroicaritin (I), mp 275°, C21H26O6, and "nor-anhydroicaritin" (IX), mp 226°, C20H18O6, were isolated, together with xanthohumol and isoxanthohumol. The structures of I and IX were elucidated as 8-isopentenyl-rhamnocitrin and 8-isopentenyl-kaempferol, respectively, by the spectral properties of them and their derivatives and by the procedure shown in Chart 2. Although "nor-anhydroicaritin" had previously been derived from nor-icariin (XI) by acid-hydrolysis and subsequent degradation with alkali and given the name by Akai, et al.14), its direct isolation from a natural source has never been reported.
New absorption bands were observed in the visible region of spectra for ethylene dichloride solution of styrene-maleic anhydride copolymer (SMA) containing antipyrine, aminopyrine, 4-[2-(dimethylamino)propionamido]antipyrine(aminopropylone) or chlorpromazine, indicating occurrence of interaction. The degree of binding of SMA with antipyrine, aminopyrine, aminopropylone, chlorpromazine, promethazine, levomepromazine, propericiazine, prochlorperazine and thioproperazine was evaluated by the equilibrium distribution method. It was shown that all the compounds investigated were reversibly bound with SMA, and that the binding equilibria fit a Langmuir-type equation. The degree of binding of pyrazolone derivatives with SMA appeared to be dependent upon the nature of the substituent at the 4-position of pyrazolone rings ; substitution by basic groups increased the binding constants. Except for the case of chlorpromazine, an increase in the aliphatic character of phenothiazine derivatives resulted in a decrease in the binding constants. The maximum amount (ym) of each compounds bound to SMA indicated that one guest molecule was bound by over than 10 monomeric units of the copolymer chain. In relation to a possible binding mechanism, the significance of these results are discussed.
The triterpenoid fraction of Hoelen ( ?? ?? ), sclerotium of Poria cocos (SCHW.) WOLF., was found to contain pachymic acid (IIIa), tumulosic acid (IVa), and a new triterpene carboxylic acid, 3β-hydroxylanosta-7, 9(11), 24-trien-21-oic acid (Va). Hoelens from various districts were comparatively examined by thin-layer and gas-liquid chromatography. The culture of the fungus was also analysed.
The effects of several benzoquinone and naphthoquinone derivatives on the incorporation of acetate-1-14C into cholesterol have been examined in rat liver homogenates. Within the test compounds, vitamin K3, tauranin, acetylmaesaquinone, 2-methyl-3, 6-dibromo- 1, 4-benzoquinone, ubiquinone-0 (UQ-0) showed potent inhibitory action. Furthermore, the inhibition by 2-methyl-3, 6-dibromo-1, 4-benzoquinone was not affected in the presence of cysteine (5×10-5-5×10-3M) or ATP (10-4-10<-3>M). In the case of ubiquinone-0 (UQ-0), the inhibition was not affected by ATP addition, but it was restored considerably by cysteine. On the basis of the present experiments, structure activity relationship between quinone derivatives and their effects on the incorporation of acetate-1-14C into cholesterol as well as mechanisms of the inhibition are discussed.
Effect of electrolytes on the swelling and the electrostatic properties of Sephadex gels was examined by measurements of ζ-potential of gel particles, effective diffusion coefficient (Deff) in xerogels, and water regain (Wr) of the gels which had been swollen with aqueous solution of several potassium salts of lyotropic series. It was revealed that the negative ζ-potential of the gel particles decreased in the order of water>NCS->Cl->OAc->Cit3->SO42-, according to Hofmeister's lyotropic series of the anions, whereas Deff values increased in the order of water<NCS-<C1-<SO42-. The values of water regain of the gels decreased distinctly in the presence of high concentrations of sulfate. In the presence of electrolytes, swelling of Sephadex gels of G-series was assumed to be restricted by the accompanying sealing of the negative charge.
Polarographic determination of free sulfur in anethole-trithione [5-(p-methoxyphenyl)-1, 2-dithiacyclopentene-3-thione] was carried out by the use of pyridine-hydrochloric acid as the supporting electrolyte. Free sulfur gives a reduction wave with E1/2=-0.33V(vs. S.C.E.) in DC polarogram even it the presence of anethole-trithione, and the wave height is proportional to the concentration, The wave height of free sulfur is influenced by the amount of anethole-trithione and dioxan in the electrolytic solution and also by the period of contact time with mercury. Therefore, polarographic condition must be controlled for the determination. The condition shown in Table I is adequately applied for the sample of anethole-trithione containing 0.1-0.7% free sulfur. The amount of free sulfur can be determined by the calibration curve prepared for the concentration of sulfur ranging from 1×10-5M to 1×10<-4>M in the presence of 0.5 to 2×10-3M of anethole-trithione.
Methyl xylenol blue forms a blue complex with cerium(III) in the presence of cetylpyridinium chloride at pH 7.6-9.5, and 0.5-3.5 μg of cerium(III) can be determined from the absorption of this blue complex at 645 mμ. Methyl xylenol blue can also be utilized for direct chelate titration of cerium(III) in the region of hexamine in the same way as methyl thymo1 blue and xylenol orange. In both cases, methyl xylenol blue coloration is comparatively easily affected by coexisting ions.
A new method for the determination of glycyrrhizin in Liquorice root by spectrophotometric measurements has been deviced, after its separation from the other constituents by TLC. 0.05 gram of powdered Liquorice root was extracted with 50% (v/v) ethanol, which was chromatographed on Kieselgel plate using as developer a mixture of butanol-3N NH4OH-ethanol (=5 : 2 : 1). (Fig.1). The g1ycyrrhizin portion was scratched out of the chromatogram and extracted with 50% (v/v) ethanol. The absorption was measured through the filter 252 mμ and the glycyrrhizin content was determined according to the calibration curve (Fig.2) previously prepared. This manipu1ation took about 12 hours and the recovery rate was found to be more than 95% in average (Table II). Considering that the separation of g1ycyrrhizin from the other accessary components is complete, this method can be considered to be superior to the previously described ones.
Investigations on the relations between retention value and molecular structure, which have been described in one of our previous paper, have been extended as follows. The retention indices of ω-phenylalkyl derivatives were measured on APIEZON-L, SQUALANE, D.N.P., SE-30 and EMULPHOR-O as stationary phases. It was revealed on the basis of experimemtal results that there was additive property in retention index regard to the molecular structure of ω-phenylalkyl derivative and the following empirical was obtained. [chemical formula] Comparison of the experimental results with the calculated results is approximately satisfactory.
The metabolites in the human urine after the administration of trans-π-oxocamphor (I) were examined by changing the administration formula. Main metabolites in the urine after oral administration of I were trans-π-hydroxycamphor glucuronide (II-G) (70%), trans-π-apocamphor-7-carboxylic acid (III) (5%), and its glucuronide (III-G) (25%), while those after subcutaneous a dministration were II-G (trace), III (30%), and III-G (70%). The absorption of I through oral cavity membrane was also examined.
Reaction of β-aminocrotonamide (I) and carboxylic acid ester afforded 2-substituted 6-methyl-4(3H)-pyrimidone (III). Refluxing of I and ethyl acetate in ethanol, in the presence of sodium ethoxide, gave 2, 6-dimethyl-4(3H*)-pyrimidone (IIIa). Under a similar condition, reaction of I with ethyl propionate, ethyl butyrate, ethyl isobutyrute, methyl benzoate, ethyl p-toluate, ethyl p-nitrobenzoate, ethyl phenylacetate, and ethyl lactate produced corresponding substituted pyrimidones ; i.e., 2-ethyl (IIIb), 2-propyl (IIIc), 2-isopropyl (IIId), 2-phenyl (IIIe), 2-(p-tolyl) (IIIf), 2-(p-nitrophenyl) (IIIg), 2 -benzyl (IIIh), and 2-(α-hydroxyethyl) (IIIi) compounds. The same reaction with diethyl acetone-dicarboxylate gave ethyl γ-(2-oxo-6-methyl-(3H)-pyrimidinyl)acetoacetate (IIIj) which was considered to have an enolic structure.
Amentoflavone and podocarpusflavone A were isolated from the leaves of Juniperus rigida. This result is different from the other Cupressaceae plants which usually contain hinokiflavone and its methyl ethers.