Extractive substances ofLarix dahurica

Summary The quantitative determination of quercetin and dihydroquercetin in the total flavonoids ofLatrix dahurica has been effected by the use of thin-layer chromatography on Kapron for separating the mixture with subsequent elution of the spots and colorimetry of the eluates obtained. The methanol-dimethylformamide (1:1) system was used as the eluate. It has been found that the flavonoids of the heartwood ofLatrix dahurica contain a predominating amount, 69% of dihydroquercetin, the amount of quercetin being 11%.Khimiya Prirodnykh Soedinenii, Vol. 3, No. 5, pp. 298–301, 1967     

Formation of negative ions by interaction of electrons with heterocyclic compounds

Curves are derived for the effective yield of negative ions from the interaction of electrons with thiophene, 2-methylthiophene, 2-propylthiophene, 3-methylthiophene, 3-propylthiophene, furan, and selenophene. It is found that there are two quasi-stationary states of the molecular negative ions having lifetimes of about 10^–14 and 4 · 10^–15 sec. The cross sections for formation of these states are estimated, and also the cross sections for resonant elastic scattering of electrons. The states are shown to be related to excited states of the molecule. It is found that alkyl substitution has the following effects on resonant electron capture: a) reduces the probability of ring breakage and b) reduces the energy levels of the quasi-stationary state. Some aspects of dissociative ionization are discussed.     

Arylhydroxyacetic acids and amino acids derived from ethinylphenols

Conclusions A method of synthesis of arylhydroxyacetic acids and ammo acids derived from ethinylphenols has been developed in view of possible physiological activity of these compounds.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, pp. 1170–1172, May, 1970.     

Reactions of amides of arylphosphorous acids with acyl chlorides

Conclusions The reactions of amides of arylphosphorous acids with acyl chlorides take place with replacement of the amide group and formation of amides of carboxylic acids and the corresponding aryl chlorophosphates.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 9, pp. 2131–2133, September, 1968.     

Functional derivatives of thiophenes

2,3-Polymethylene-4-oxo-3,4-dihydrothieno[2,3-d]pyrimidine derivatives were obtained by reaction of esters of α-aminothiophene-β-carboxylic acids with lactame or α-aminothiophene-Β-carboxylic acids with lactims. Desulfuration of the thienopyrimidines obtained in this manner is a convenient method for the synthesis of pyrrolo-, pyrido-, and azepino[1,2-a]pyrimidine derivatives.     

Strukturaufklärung sesquiterpenoider Pflanzeninhaltsstoffe

In the essential oil of Asarum europaeum L. the four sesquiterpene alcohols α-eudesmol, β-eudesmol, selinane-7,11-diol and seline-6(7)en-11-ol have been isolated and identified. For limiting the possibilities of structure the dehydrogenating TAS method (sulphur dehydrogenation) has been employed. Good results have been obtained with unsaturated C₁₅-alcohols. Saturated sesquiterpene alcohols with decalin structure could be better dehydrogenated by the selenium method. UV spectra have been recorded of the naphthalene derivatives formed directly from the thin-layer plate and employed for identification. By this combination of micro methods the basic structure of the alcohols could be determined unequivocally with μg amounts.     

Circular dichroism of some pregnenes substitutes at C-17

The optical properties of pregnenes containing different substituents at C-17 (—SCN, —SAc, —SC(CH₃)₂O—, —Br, —OAc, —N₃) have been investigated with the help of the CD spectra. It is shown that the sign and value of the Cotton effect of the carbonyl chromophore n → π^* transition is determined by the nature of the substituent at C-17.     

Researches on benzodiazines

2-R-Quinazolones have been synthesized (R=Me, Ph,-pyridyl,-furyl), and subsequently the 4-chlorides and the corresponding 2-R-4-hydrazinoquinazolines were obtained. By the reaction of orthoformic ester and nitric acid on the hydrazines, 5-R- [3, 4-c]-s-triazoloquinazolines and 5-R- [1, 5-c] tetrazoloquinazolines were prepared, respectively. The compounds in which R=Me differ considerably from compounds with other groups, both in color and stability of intermediate reaction products. 5-R- [1, 5-c] tetrazoloquinazolines are hydrolyzed by HCl into quinazol-4-ones.For Part IV see [1].     

Investigations in the 1,2,4-triazole series

To select a method for the synthesis of the previously difficulty accessible 5-bromo-1-phenyl-1,2,4-triazole (I) and 1-phenyl-1,2,4-triazoline-5-thione (II), a MO LCAO calculation has been carried out in Huckel's approximation of the energies of the radical, electrophilic, and nucleophilic localization on the various carbon atoms of 1-phenyl-1,2,4-triazole (III). In accordance with this calculation, the required compounds have been obtained in good yields by reactions taking place by a radical mechanism: I by bromination with bromosuccinimide and II by the direct thionation of III. The high reactivity of the bromine atom in position 5 has been noted.For part VIII, see [1].     

Magnetic properties of copper(II) complexes with some hydrazones of substituted salicylaldehydes

A series of novel mono-and binuclear copper(II) complexes with substituted salicylaldehyde acylhydrazones H₂L of the formula CuL · xH2O (x = 0 and 1) and [Cu(HL)](ClO₄)(CH₃OH) were synthesized. The isolated dimeric complexes of copper acetate were found to exist as isomers with different bridging atoms. In dimers showing a superexchange between the paramagnetic centers through bridging phenoxide O atoms, the antiferromagnetic exchange couplings were much stronger than those in complexes with bridging O atoms of the a-oxyazine fragment.