Synthesis of 2,3,7,8-tetramethyldibenzofuran

3,4,3,4-Tetramethyldiphenyl ether readily forms 2,2-dihalo derivatives on bromination and iodination. Heating 2,2-diiodo-4,5,4,5-tetramethyldiphenyl ether with copper powder or oxidation, of 2,2-dilithio-4,5,4,5-tetramethyldiphenyl ether gives 2,3,7,8-tetramethyldibenzofuran, the structure of which was proved by alternative synthesis from 2,2-dinitroand 2,2-diamino-4,5,4,5-tetramethyldiphenyls.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1597–1599, December, 1972.     

Triterpene glycosides from Pulsatilla chinensis

Four triterpene glycosides were isolated from the roots of Pulsatilla chinensis (Bunge) Regel (Ranunculaceae). Two new glycosides, chinensiosides A (1a) and B (2), were identified as 3-O-[-L-rhamnopyranosyl-(12)--L-arabinopyranosyl]-28-O-[-L-rhamnopyranosyl-(14)--D-glucopyranosyl-(16)--D-glucopyranosyl]-3,23-dihydroxylup-20(29)-en-28-oic acid and 3-O-{-L-rhamnopyranosyl-(12)-[-D-glucopyranosyl-(14)]--L-arabinopyranosyl}-28-O-[-L-rhamnopyranosyl-(14)--D-glucopyranosyl-(16)--D-glucopyranosyl]-3,23-dihydroxylup-20(29)-en-28-oic acid. The other two glycosides were identified as previously known hederasaponin C (3) from Hedera helix and glycoside III (4) from Pulsatilla cernua.     

Steroid glycosides XXI. The structure of polygonatoside E′ and protopolygonatoside E′ from the leaves ofPolygonatum latifolium

Summary The chemical structures of two new steroid glycosides from the leaves ofPolygonatum latifolium have been shown. Polygonatoside E is 3-[0--D-glucopyranosyl-(1 3)-0--D-glucopyranosyl-(1 4)-0--d-galactopyranosyl-(1 3)--D-glucopyranosyloxy]-(25R)-spirost-5-ene, and protopolygonatoside E is 26--D-galactopyranosyl-(1 3)--D-glucopyranosyloxy]-(25R)-furost-5-en-22-ol.Institute of Chemistry, Academy of Sciences of the Moldavian SSR, Kishenev. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 350–354, May–June, 1978.     

1,2-bis(2',6'-dimethyl-i',3'-dioxa-6'-aza-2'-silacyclooctyl-2')ethane and the corresponding ethylene and acetylene derivatives

Conclusions The reaction of 1,2-bis(methyldimethoxysilyl)ethane and the corresponding ethylene and acetylene derivatives with bis(2-hydroxyethyl)methylamine gives 1,2-bis(2,6-dimethyl-1,3-dioxa-6-aza-2-silacyclooctyl-2)ethane and the corresponding ethylene and acetylene derivatives. Analogously, 1,2-bis(vinyldimethoxysilyl)acetylene gave 1,2-bis(2-vinyl-6-methyl-1,3-dioxa-6-aza-2-silacyclooctyl-2)acetylene.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 6, pp. 1420–1421, June, 1988.     

Structure of psolusoside a — The main triterpene glycoside from the holothurianPsolus fabricii

The structure of psolusoside A — the main component of the glycosidic fraction from the holothurianPsolus fabricii Duben et Koren — has been determined as 3-0-[0-(3-0-methyl-6-0-sulfato--D-glucopyranosyl)-(1 3)-0-(6-0-sulfato--D-glucopyranosyl)-(1 4)-0--D-quinovopyranosyl-(1 2)--D-xylopyranosyloxy]holosta-9(11),25-dien-16-one.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. 212–217, March–April, 1985.     

Structure of haplosidine

A new glycoalkaloid, haplosidine, has been isolated from the epigeal part of the plantHaplophyllum perforatum, and its structure has been established as 7-[O--D-glucopyranosyl-(1 3)-2-O-acetyl--L-rhamnopyranosyloxy]-4,8-dimethoxyfuranoquinoline.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 94–97, January–February, 1988.     

PMR spectra of 2-substituted pyrazines and the corresponding pyrazine N-oxides and N,N′-dioxides

The PMR spectra of pyrazine, its 2-substituted derivatives, and the corresponding N-oxides and N,N-dioxides were investigated. The character of the change in the chemical shifts in the N-oxides and N,N-dioxides of unsubstituted pyrazine indicates the electron-donor effect of the NO group. An additive effect of the NO groups on the chemical shifts of the ring protons is observed in pyrazine N,N-dioxide. An appreciable interaction of the substituent with the N₍₁₎O group and a weak interaction with the N₍₄₎O group occur in N-oxides and N,N-dioxides of 2-substituted pyrazines. A significant increase in the ortho and meta spin-spin coupling constants of the ring protons is noted when the nitrogen atoms are oxidized. The sign of the spin-spin coupling constant (J₃₅) through the NO group was determined.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 266–273, February, 1972.     

Simple and effective method for the synthesis of 3′,5′-substituted 1-β-D-arabinofuranosyluracil

3,5-Substituted arabinofuranosyluracil is a starting compound in 2-modifications. A convenient and effective method is proposed for the synthesis of 1-(3,5-di-o-trityl--D-arabinofuranosyl)uracil by successive reactions of 2,2-cyclization of uridine, 3,5-tritylation of the 2,2-anhydrouridine, and hydrolytic cleavage of the 2,2-anhydro bond.Institute of Organic Synthesis, Riga LV-1006. Odense Universitet, Kemisk Institut, Odense, Denmark. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 975–977, July, 1996. Original article submitted April 25, 1996.     

Study of furan compounds

Research on synthesis of polycyclic spirans of the 1, 6-dioxaspiro-[4, 4]nonane group is continued. Electrolysis of methanol solutions of 2-furylcyclopentanol, 2-(5-methyl-furfuryl)cyclopentanol, and 2-furfuryl-1-indanol, gives, by intramolecular alkoxylation, spiro{perhydrocyclopenta[b]furan-2, 2-(5dihydrofuran)}, spiro{perhydrocyclopenta[b]furan-2, 2-(5-methoxy-5-methyl-2, 5-dihydrofuran)}, and spiro{2, 3, 3a, 8b-tetrahydro-4H-indeno[1, 2-b]furan-2, 2-(5-methoxy-2, 5-dihydrofuran)}, hitherto undescribed in the literature. Depending on the conditions, catalytic hydrogenation of these gives: spiro{perhydiocyclopenta[b]furan-2, 2-(5-methoxytetrahydrofuran)}, spiro{2, 3a, 8b-tetrahydro-4H-indeno[1, 2-b]furan-2, 2-(5-methoxytetrahydrofuran)}, spiro{perhydrocyclopenta[b]furan-2, 2-tetrahydrofuran}, and spiro{2, 3, 3a, 8b-tetrahydro-4H-indeno[1, 2-b]furan-2, 2-tetrahydrofuran}.For Part XXXI see [1].     

Flavonoids ofHaplophyllum perforatum. New glycosides of limocitrin

Two new glycosides of limocitrin have been isolated from the epigeal part ofHaplophyllum perforatum (M. B.) Kar. et Kir. On the basis of chemical transformations and spectral characteristics the structures of the substances isolated have been established as 7-(6-acetyl--D-glucopyranosyloxy)-3,4,5-trihydroxy-3,8-dimethoxyflavone and 7-[0--L-rhamnopyranosyl-(1 2)--D-glucopyranosyloxy]-3,4,5-trihydroxy-3,8-dimethoxyflavone.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 192–196, March–April, 1985.