Circular dichroism of steroids with a lactone ring B. Brassinosteroids and compounds related to them

The circular dichroism spectra of steroids having the lactone group in ring B that is characteristic for brassinosteroids, and their isomers, have been studied. It has been shown that in the spectra of the isomeric B-homo-7-oxa-6-ketosteroids and B-homo-6-oxa-7-ketosteroids differences are observed in the sign of the Cotton effect of the n-* transition of the carboxy group, which can be used for proving their structures.Institute of Bioorganic Chemistry, Belorussian Academy of Sciences, Minsk. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 76–82, January–February, 1992.     

Circular dichroism of some carotanes

The circular dichroism method has been used to study the stereochemistry of the carotanes. An analysis of the results obtained has shown that an -oriented ester group at C₆ corresponds to a positive Cotton effect (CE) in the 240–260-nm region. A link has been established between the position of the carbonyl group in the ring B and the sign of a CE in the 340-nm region. Hydrolysis of an ester group at C₆ takes place more readily in an alkaline medium than in an acid medium, and in the case of carbonyl-containing carotanes dehydration takes place as well as hydrolysis.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 45–48, January–February, 1984.     

Synthesis and chirooptical properties of some tertiary amines containing a pyridine ring

Tertiary amines of the pyridine series containing an -phenylethylamine residue have been synthesized. The IR spectra and circular dichroisms of these amines have been measured in the 400–200 nm interval, and an assignment of the bands has been made. It is suggested that the long-wave absorption band in the 315 nm region for N-methyl-N-[2-(pyridin-2-yl) ethyl]--phenylethylamine and the Cotton effect corresponding to it are due to an intramolecular CTC.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 92–96, January, 1984.     

Optically active 2-cymantrenyloxazolines: synthesis and regioselective metallation

Three optically active oxazolines with a cymantrenyl substituent at position 2 of the heterocycle have been prepared. Metallation of these compounds withn-BuLi proceeds only at the two diastereotopic - and '-positions of the Cp-ring to an equal extent. The dependence of the sign of Cotton effect in the region of 300–350 nm upon the absolute configuration of chiral centers remote from the Cp-ring has been demonstrated.Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 1, pp. 182–183, January, 1993.     

Circular dichroism of the alkaloids ofPetilium raddeanum

The circular dichroism (CD) method has been used for studying the stereochemistry of steroid alkaloids containing an azomethine ring — petiline and petisine. In the CD spectrum of petiline a Cotton effect (CE) is observed in the 235 nm region which is due to a n * transition in the azomethine chromophore. The negative sign of this CE shows the 25S configuration in petiline. An analysis of CD spectra has shown that the 25S configuration is retained when petiline is oxidized to petisine.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 345–347, May–June, 1986.     

Synthesis and chiral-optical properties of some benzolactams

Five- and seven-membered benzolactarns — (–)-S-2, 3-dimethyl-2, 3-dihydroisoindolone and (+)-S-5-methyl-2, 3, 4, 5-tetrahydrobenz[c]azepin-1-one — were synthesized. A study of their chiral-optical properties and comparison with the previously studied six-membered lactam (–)-S-4-methyl-3, 4-dihydroisoquinol-1-one showed that their circular dichroism spectra are similar: The spectra contain dichroic absorption bands due to ^* transitions in the aromatic chromophore (270 and 220 nm) and a band of charge transfer in the benzamide chromophore at 240–250 nm. The magnitude of the Cotton effect due to the charge-transfer band increases as the lactam ring becomes larger (five-membered < six-membered < sevenmembered benzolactam). The change in the magnitude of the Cotton effect is explained by the development of a strictly dissymetric chromophore.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 656–662, May, 1978.     

Correlation between stereochemistry and sign of cotton effects for degenerate transitions in spectra of binuclear clusters of molybdenum(II)

A correlation between the stereochemistry and sign of the Cotton effect for ^* transition in the spectra of dimolybdenum tetracarboxylates and related compounds has been accomplished by constructing, within the framework of a one-electron model of optical activity, a 32-sector rule based on data from x-ray structure analysis and circular dichroism for dimolybdenum tetra-(R)-mandelate. It has been shown that a positive value of the pseudoscalar function xyz(x²–y²)(a²-z²) corresponds to a negative Cotton effect for the ^* transition in the case in which the dominant contribution to this effect comes from R_x components of the rotator strength of the transition.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 8, pp. 1783–1785, August, 1990.     

Investigation of the circular dichroism spectra of bromine-substituted nucleic acid fragments I. Circular dichroism spectra of 8-bromine-substituted purine nucleotides

Summary The CD spectra of 8-bromo-AMP, 8-bromo-dAMP, 8-bromo-GMP, and 8-bromo-dGMP in acid, neutral, and alkaline media and, in some cases, in methanol have been obtained. In the 200–300 nm region three Cotton effects have been recorded which correspond to -* in the B_2u, B_1u, and E_1ua bands (280–265, 240–250, and 200–220 nm, respectively). The CD spectra obtained differ from the spectra known in the literature for unbrominated compounds of this class. It has been shown that in ribonucleotides the syn conformation is stabilized by the formation of an intramolecular hydrogen bond with the participation of the ribose 2-hydroxyl and the N₃ atom of the purine base. The 5-phosphate group in the molecule of a purine nucloside of the syn type changes the CD profile, particularly in the short-wave region of the spectrum, as compared with the CD spectra of the unbrominated analogs given in the literature.Institute of Molecular Genetics, Academy of Sciences of the USSR, Moscow. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 199–204, March–April, 1979.     

Berberis alkaloids XXXV. The structure of nummularine

The new N-benzyltetrahydroisoquinoline alkaloid nummularine has been isolated from the leaves ofBerberis nummularia. On the basis of a study of its spectral characteristics (PMR, IR, and mass spectra), the structure of nummularine has been established as 6-hydroxy-N-(3-hydroxy-4-methoxybenzyl)-7-methoxy-1-methyltetrahydroisoquinoline.Translated from Khimiya Prirodnykh Soedinenii, Vol. 33, No. 1, pp. 91–93, January–February, 1997.     

Isoflavones of the roots of Lupinus luteus

Summary On the basis of mass and IR spectra it has been established that the substance with mp 169°C known in the literature as the acetyl derivative of gossypetin 3,3,4,5,8-pentamethyl ether is in actual fact gossypetin hexamethyl ether.Thus, yet another case of the migration of a methoxy group from partially etherified compounds in an alkylationprocess has been described.Scientific-Research Institute of the Chemistry and Technology of Cotton Cellulose, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 170–172, March–April, 1972.     

Triterpene glycosides ofAstragalus and their genins. XVII. Cycloasgenin B fromAstragalus tashkendicus

The roots ofAstragalus tashkendicus Bge. have yielded a new triterpenoid — cycloasgenin B – the structure of which has been established on the basis of chemical transformations and spectral characteristics as (24R)-6,11,16,24,25-pentahydroxycycloartan-3-one.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 732–735, November–December, 1984.     

Sesquiterpene lactones ofPyrethrum pyrethroides. II. Pyrethroidin

A new sesquiterpene lactone, pyrethroidin, and a known one — 8-deoxycumambrin B — have been isolated from the epigeal part of the plantPyrethrum pyrethroides. The structure of 4,10-dihydroxy-1,5,7(H),6(H)-guaia-2,11(13)-dien-6,12-olide has been suggested for pyrethroidin.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 199–201, March–April, 1985.     

Alkaloids ofPetilium raddeana. III. Structure of petisidinine

From a mixture of bases from the epigeal part and the bulbs ofPetilium raddeana (Rgl.) Vved. ex Pazij, a new base petisidinine has been isolated with mp 290–292°C (decomp.), composition C₂₇H₃₉NO₃ (I). On the basis of the physicochemical properties of the alkaloid and a correlation with petisine, the structure and configuration of petisidinine have been established as those of 3-hydroxy-20-(5-hydroxy-3-methylpyridin-6-yl)-5-pregnan-6-one.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Trashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 747–749, November–December, 1983.     

Flavonol glycosides of the flowers of a thin-leaved cotton plant of the species Gossypium barbadense

Summary The flowers of the thin-leaved cotton plant of variety 5904-I(Gossypium barbadense) contained more than 5% of combined flavonols consisting of quercimeritrin, hisutrin, quercetin 3-glucoside, and a flavonol with mp 228–229°C. The latter has the structure of gossypetin 7--D-glucopyranoside.Scientific-Research Institute for the Chemistry and Technology of Cotton Cellulose, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 142–146, March, 1971.     

Low-molecular-weight metabolies of wheat. I. Components of an ethereal extract of wheat leaves

The chromatographic separation of the components of an ethereal extract of the leaves of Mironovskaya 808 wheat has been performed. The presence in wheat of phthalic acid and its dimethyl, diethyl, and dibutyl esters has been shown for the first time. Substituted benzoic and cinnamic acids, p-hydroxybenzaldehyde, vanillin, 6-methoxybenzoxazolone, tricin, and aconitic and fumaric acids have also been isolated. The structures of the compounds isolated have been confirmed by IR, UV, mass, and NMR spectra.M. M. Shemyakin Institute of Bioorganic Chemistry, Academy of Sciences of the USSR, Moscow. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 783–789, November–December, 1981.     

Induced circular dichroiism spectra of benz[b]anthracene included inβ-cyclodextrin

The assignment of the absorption spectra of benz[b]anthracene (1) is reported by measuring the induced circular dichroism spectra of the -cyclodextrin complex with1. It is concluded from the signs of the induced circular dichroism bands that the first absorption band (20.4–30.9×10³ cm^–1) has the transition dipole moment perpendicular to the long axis and the second absorption band (30.9–37.2×10² cm^–1) has the transition dipole moment parallel to the long axis of1. Our assignments are in complete agreement with earlier assignments. The induced circular dichroism spectra exhibit Cotton splittings at 19.1×10³ and 42.8×10³ cm^–1. It can be concluded from Cotton splittings of the induced circular dichroism spectra that the association of two 1:1 inclusion complexes forms a ground-state dimer.     

Triterpene saponins fromThalictrum minus. IV. The structure of thalicoside A

The predominating saponin, which has been called thalicoside A, has been isolated from low meadow rue (Thalictrum minus). It has been established by chemical and spectral methods that thalicoside A is 3,16,22(S),29-tetrahydroxy-9,19-cyclo-20(S)-lanost-24-ene 3-O--D-galactopyranoside 29-O--D-glucopyranoside.Irkutsk Institute of Organic Chemistry, Siberian Branch, Academy of Sciences of the USSR. Pacific Ocean Institute of Bioorganic Chemistry, Far Eastern Scientific Center, Academy of Sciences of the USSR, Vladivostok. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 213–219, March–April, 1984.     

Proanthocyanidins ofPolygonum coriarium. IV. Structures of proanthocyanidins T3 and T4

Two oligomeric proanthocyanidins have been isolated from the roots ofPolygonum coriarium. By a study of their physical properties and spectral characteristics and analysis of the results of chemical transformations, the chemical structures of these compounds have been established as: (–)-epicatechin-77[O--D-glucopyranosyl]₃ O-⊃-D-glucopyranosyl (m-trigallolyl)-[(4-6)-(–)-epigallocatechin]₂-(4-6)-(–)-epigallocatechin—T3; and (–)-epicatechin-3-O-galloyl-7-[O--D-glucopyranosyl]₃O--D-glucopyranosyl galloyl-[(4-6)-(–)-epicatechin]₄-(4-6)-(–)-epigallocatechin — T4.The materials of this paper were presented at the IInd International Symposium on the Chemistry of Natural Compounds (SCNC), Eskiehir, Turkey, October 22–24, 1966).Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 707–713, September–October, 1997.     

Alkaloids ofHaplophyllum foliosum. III. Structure of folidine

The new alkaloid folidine with mp 148–149°C (acetone-petroleum ether) has been isolated from the epigeal part of the plantHaplophyllum foliosum Vved., and on the basis of spectral characteristics and passage to the known alkaloid folifidine (8-hydroxy-4-methoxy-1-methyl-2-quinoline) its structure has been established as 4-methoxy-1-methyl-8-(2-oxo-3-methylbutoxy)-2-quinolone.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 823–824, November–December, 1985.     

Glycosides ofPatrinia sibirica. II

Conclusions It has been established that two trisaccharide chains are present in sibiroside C, one combined with the 3-hydroxyl and the other with the 28-carboxyl of hederagenin.The first trisaccharide is -D-glucopyranoside-(1–4)--L-arabopyranosido-(1–4)--D-glucopyranose, while the second is D-glycopyranosido-(1–4)-D-glucopyranosido-(1–4)--L-arabopyranose.Khimiya Prirodnykh Soedinenii, Vol. 6, No. 1, pp. 64–69, 1970