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.     

Synthesis of 2-O-ethyl analogues of 3′-azido- and 3′-fluoro-2′,3′-dideoxyuridines and evaluation of their biological activity against HIV

Summary 2-O-Ethyluracil and 2-O-ethylthymine were silylated with 1,1,1,3,3,3-hexamethyldisilazane and condensed in the presence ofTMS triflate with 2,3-dideoxy-3-fluoro-D-erythro-pentofuranoside, 3-azido-2,3-dideoxy-D-erythro-pentofuranoside, and 2,3-dideoxy-3-phthalimido--D-erythro-pentofuranose derivatives to give the corresponding 2-O-ethyl nucleosides. Deprotection with saturated methanolic ammonia afforded the 2,3-dideoxy-3-fluoro-2-O-ethyluridines, whereas 3-azido-2,3-dideoxy-3-O-ethyluridine was obtained by deprotection with tetrabutylammonium fluoride in tetrahydrofuran. 3-Amino-2,3-dideoxy-3-O-ethyluridine could be obtained only by treatment of the corresponding 3-azido nucleoside with triphenylphosphine in pyridine. 3-Deoxy-2-O-ethyl-3-fluorothymidine (6b) showed moderate activity against HIV-1.

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Synthese von 2-O-Ethyl-Analogen von 3-Azido- und 3-Fluor-23-dideoxyuridinen und Bestimmung ihrer biologischen Aktivität gegenüber HIV

Zusammenfassung 2-O-Ethyluracil und 2-O-Ethylthymin wurden mit 1,1,1,3,3,3-Hexamethyldisilazan silyliert und in Gegenwart vonTMS-triflat mit 2,3-Dideoxy-3-fluoro-D-erythro-pentofuranosid, 3-Azido-2,3-dideoxy-D-erythro-pentofuranosid und 2,3-Dideoxy-3-phthalimido--D-erythro-pentofuranosederivaten zu den entsprechenden 2-O-Ethyl-Nucleosiden umgesetzt. Entfernung der Schutzgruppe mit gesättigter methanolischer Ammoniaklösung lieferte 2,3-Dideoxy-3-fluor-2-O-ethyluridin; 3-Azido-2,3-dideoxy-3-O-ethyl-uridin wurde durch Entschützung mit Tetrabutylammoniumfluorid in Tetrahydrofuran erhalten. 3-Amino-2,3-dideoxy-3-O-ethyl-uridin konnte nur durch Behandeln des entsprechenden 3-Azido-Nucleosids mit Triphenylphosphin in Pyridin hergestellt werden. 3-Deoxy-2-O-ethyl-3-fluor-thymidin (6b) zeigt geringe Aktivität gegenüber HIV-1.

     

Photochemical dehydrogenation of 3-acetyl-3,4-dihydrocoumarin

Summary The ultraviolet irradiation of air-saturated alcoholic solutions of 3-acetyl-3,4-dihydrocoumarin (1) leads to the formation of 3-acetylcoumarin (2) and 3,3-diacetyl-3,3,4,4-tetrahydro-4,4-biscoumarin (3). The presence of molecular oxygen is an indispensable condition for the occurrence of a photodehydrogenation process, which is quantitatively when effected on silica gel.

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Photochemische Dehydrierung von 3-Acetyl-3,4-dihydrocumarin (Kurze Mitt.)

Zusammenfassung Bei UV-Bestrahlung von alkoholischen Lösungen von 3-Acetyl-3,4-dihydrocumarin (1) unter O₂ werden 3-Acetylcumarin (2) und 3,3-Diacetyl-3,3,4,4-biscumarin (3) gebildet. Die Anwesenheit von molekularem O₂ ist für die Photodehydrierung erforderlich, wobei die Umsetzung an Silikagel quantitativ verläuft.

     

Diazabicycloalkanes with nitrogen atoms in bridgehead positions. 16. Synthesis and properties of benzo[b]-1,4-diazabicyclo[2.2.2]octene and dibenzo[b,e]-1,4-diazabicyclo[2.2.2]octadiene,containing primary aromatic amino acids

4-Aminobenzo[1,2-b]-1,4-diazabicyclo[2.2.2]octene and 4-aminodibenzo[1,2-b, e]-1,4-diazabicyclo[2.2.2]octadiene have been prepared by cyclization reactions of N--chloroethyl derivatives of 1,2,4-triaminobenzene and aminophenazine, and subsequent catalytic hydrogenation of the corresponding 4-nitrobenzo[1,2-b]-1,4-diazabicyclo[2.2.2]octene and 4-benzylaminodibenzo[1,2-b,e]-1,4-diazabicyclo[2.2.2]-octadiene. Using the conversion of these compounds to azides as an example, we have demonstrated the feasibility of applying these primary aromatic amines for the synthesis of derivatives of these heterocycles.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 831–837, June, 1988.     

Investigations in the field of oxygen-containing heterocycles

2-(4-Chloro-2-methyl-2-butenyl)tetrahydropyran and 2-(4-chloro2, 3-dimethyl-2-butenyl)tetrahydropyran react with organomagnesium compounds and also with sodium amalgam with the formation of mixtures of the 2-(2-alkenyl)tetrahydropyrans corresponding to the initial chlorides and the 2-(3-alkenyl)tetrahydropyrans corresponding to the allyl isomers of the initial chlorides. The structure and composition of the products have been established by IR and NMR spectroscopy and by gas-liquid chromatography.For part V, see [1].     

Synthetic studies in the field of chlorobium chlorophyll

By the condensation of -halogenomethyl derivatives of pyrroles with -unsubstituted pyrroles the synthesis of the following unsymmetrical dipyrrolylmethanes has been effected: 5-benzyloxycarbonyl-5-ethoxycarbonyl-3, 3-di(-methoxycarbonylethyl)-4,4-dimethyl-2,2-dipyrrolylmethane (IIIa), 5-benzyloxycarbonyl-5-ethoxycarbonyl-3-(-methoxycarbonylethyl)-4, 4-diniethyl-3-n-propyl-2,2-dipyrrolylmethane(IIIb), 3-acetyl-5-benzyloxycarbonyl-4-ethyl-5-methoxycarbonyl-3, 4-dimethyl-2,2-dipyrrolylmethane (IIIc), and 3-bromo-5-benzyloxycarbonyl-4-ethyl-5-methoxycarbonyl-3, 4-dimethyl-2,2-dipyrrolylmethane (IIId). Hydrogenation of the unsymmetrical dipyrrolylmethanes IIIa, b, c, and d has given the corresponding monocarboxylic acids IVa, b, c, and d. The formylation of the dipyrrolylmethanemonocarboxylic acid IVa has given 5-ethoxycarbonyl-5-formyl-3,3-di(-methoxycarbonylethyl)-4, 4-dimethyl-2,2-dipyrrolylmethane (V).For communication II, see [1].Deceased.Translated from Khimiya Geterotsiklicheskikh Soedinenii, Vol. 6, No. 8, pp. 1045–1047, August, 1970.     

Nitration,amination, and halogenation of Di-O-methylphloracetophenone

Chlorination of the title compound gave 5- and 3-chloro-2-hydroxy-4,6-dimethoxyacetophenone. The nitration of its acetate, followed successively by reduction, diazotization, and reaction with cuprous chloride, gave the 3-substituted series, 2-acetoxy-4,6-dimethoxy-3-nitroacetophenone, 3-amino-2-hydroxy-4,6-dimethoxyacetophenone, and 3-chloro-2-hydroxy-4,6-methoxyacetophenone, respectively. The orientation of substituents in the products was proved. The amino and chloro members of the isomeric 5-substituted series were availablevia 2-hydroxy-4,6-dimethoxy-5-phenylazoacetophenone, the product of the reaction of the title compound with benzenediazonium chloride.

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Nitrierung, Aminierung und Halogenierung von Di-O-methylphloracetophenon

Zusammenfassung Chlorierung der Titelverbindung gab 5- und 3-Chlor-2-hydroxy-4,6-dimethoxyacetophenon. Die Nitrierung des Acetats, gefolgt von Reduktion, Diazotierung und Reaktion mit CuCl ergab die 3-substituierte Reihe: 2-Acetoxy-4,6-dimethoxy-3-nitroacetophenon, 3-Amino-2-hydroxy-4,6-dimethoxyacetophenon und 3-Chlor-2-hydroxy-4,6-dimethoxyacetophenon. Die Orientierung der Substituenten wird diskutiert. Die Amino- und Chlorderivate der isomeren 5-substituierten Reihe sind über 2-Hydroxy-4,6-dimethoxy-5-phenylacetophenon zugängig, dem Produkt der Reaktion der Titelverbindung mit Phenyldiazoniumchlorid.

     

Coumarins of Smyrniopsis aucheri

Chemical transformations and spectral characteristics have enabled us to establish the structure and configurations of three coumarins: (+)-2,2-dimethyl-3-hydroxy-3,4-dihydropyrano(5,6:6,7)coumarin (I); (+)-4-hydroxy-5-(1-hydroxy-1-methylethyl)-4,5-dihydrofuro(2,3:6,7)coumarin (II); and (+)-4-hydroxy-5-(1-glucopyranosyloxy-1-methylethyl)-4,5-dihydrofuro(2,3:6,7)-coumarin (III) isolated from the roots ofSmyrnopsis aucheri Karjag. This is the first time that these compounds, which have been called smyrinol, smyrindiol, and smyrindioloside, have been detected in nature.Institute of Chemistry of Plant Substances, Uzbekistan Republic Academy of Sciences, Tashkent. Azerbaidzhan State University, Baku. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 36–40, January–February, 1992.     

Soluble polysaccharides of Rhodotorula flava

Conclusions 1. Xanthalin has been shown to have the structure of 2, 2-dimethyl-3, 4,-diangeloyloxy-3, 4-dihydropyrano-5, 6:6, 7-coumarin on the basis of the preparation of a number of derivatives and cleavage products.2. The following products of the alkaline hydrolysis of xanthalin have been isolated and characterized for the first time: (±)-3, 4-dihydroxy-3, 4-dihydroxanthyletin (isokhellactone), C₁₄H₁₄O₅, with mp 213–215° C and (–)-trans-3-hydroxy-4-methoxy-3, 4-dihydroxanthyletin (isomethylkhellactone, C₁₅H₁₆O₅, with mp 136.5–138° C and [] _D ²⁰ –47.7 (ethanol).Khimiya Prirodnykh Soedinenii, Vol. 6, No. 1, pp. 14–19, 1970