The selective esterification of the 5′-hydroxyl of thymidine

Zusammenfassung Ein einfacher Weg zur selektiven Esterbildung mit der 5-Hydroxylgruppe von Thymidin wird beschrieben. Beispiele: Thymidin-5-phosphat, Thymidin-5-sulfat und Thymidin-5-trichloracetat.     

Synthesis of dinucleoside phosphates by reaction of 5′-chloro-5′-deoxynucleosides with nucleotide anions

Zusammenfassung Uridylyl-(3–5)-adenosin und Uridylyl-(3-5)-ionosin wurden durch Umsetzung eines passenden 5-chloro-5-deoxy-2, 3-O-isopropylidene-Nukleosids mit Uridin-3-phosphat synthetisiert.     

A new synthetic method of coumestan derivatives

Zusammenfassung Die Synthese von 7-Hydroxy-5,6-dimethoxybenzofurano[3,2:3,4]coumarin aus 7,2-Dihydroxy-oder 7-Benzyloxy-2-hydroxy-4,5-dimethoxyisoflavon wird beschrieben.     

Microbiological transformation of biflavone

Summary Incubation of 5,5-7,7-tetramethoxy-8,8-biflavone withAspergillus niger results in the formation of 4,4-dihydroxy-5,5-7,7-tetramethoxy-8,8-biflavan.Part of this work was done at Allahabad University, Chemical Laboratories.     

The synthesis of a natural dinucleoside phosphate derivative with the aid of a purine cyclonucleoside

Zusammenfassung Die Behandlung von 8-5-Anhydro-8-mercapto-2-o-mesylguanosin mit (1,2 Äquivalent) Tributylammonium-uridylat in siedendem DMF lieferte das Dinucleosidphosphat Uridyl-(3-5)-8-mercapto-2-o-mesylguanosin. Weitere Behandlung mit Raney Ni führte zum Uridyl-(3-5)-2-o-mesylguanosin.     

The syntheses of axillarin and its related compounds

Zusammenfassung Axillarin (5, 7, 3, 4-Tetrahydroxy-3,6-dimethoxyflavon). 5,3,4-Trihydroxy-3,6,7-trimethoxyflavon und 5,7,3,4-Tetrahydroxy-3,8-dimethoxyflavon wurden synthetisiert.     

Über das Vorkommen verschieden substituierter Chalkone während der Mikrosporogenese beiTulipa

Summary During the development of anthers inTulipa cv. Apeldoorn the following chalcones were isolated: 2, 3, 4, 4, 6-pentahydroxychalcone as the main component and 2, 4, 4, 6-tetrahydroxy-3-methoxychalcone as well as 2, 4, 4, 6-tetrahydroxychalcone in a very small amount.

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Die Untersuchungen wurden mit Mitteln der Deutschen Forschungsgemeinschaft unterstützt.     

Peroxides of diisopropylether

Zusammenfassung Stellt man 2,2-Dihydroperoxy-2, 2-Diisopropyläther nachIvanov et al. aus Isopropyläther her, so entsteht nebenbei auch noch 2, 2-Dihydroperoxy-2, 2-Diisopropyl-Peroxid. Beide Peroxide kann man papier- und dünnschichtchromatographisch nachweisen und mit präparativer Dünnschichtchromatographie rein isolieren.     

The effect of cyclic N-2-O-dibutyryl-adenosine-3′, 5′-monophosphate on neuromuscular transmission and concentration of glycogen in the isolated phrenic nerve-diaphragm preparation of the rat

Résumé Le dérivé dibutyrique du 3, 5-AMP cyclique potentialise les contractions du diaphragme provoquées par stimulation électrique indirecte, alors que l'application du 3,5-AMP cyclique n'a pas un tel effet. D'autre part, ce dérivé diminue le taux de glycogène du diaphragme, ce qui n'est pas le cas pour le 3,5-AMP cyclique.     

Hotspots of homologous recombination

Homologous recombination occurs at higher than average frequency at and near hotspots. Hotspots are special nucleotide sequences recognized by proteins that promote, directly or indirectly, a rate limiting step of recombination. This review focuses on two well-studied examples, the Chi sites of the bacteriumEscherichia coli and the M26 site of the fission yeastSchizosaccharomyces pombe. Chi, 5 G-C-T-G-G-T-G-G 3, is recognized by the RecBCD enzyme, which nicks the DNA near Chi and produces a 3-ended single-stranded DNA tail; this tail is a potent substrate for homologous pairing by RecA and single-stranded DNA binding proteins. M26, 5 A-T-G-A-C-G-T 3, is recognized by a heterodimeric protein and stimulates, by an as-yet-unknown mechanism, meiotic recombination at and near theade6 gene. Additional hotspots in bacteria, fungi, and mammals enhance recombination directly or indirectly via a variety of mechanisms. Although hotspots are widespread among organisms, the biological role of their localized enhancement of recombination remains a matter of speculation.     

Cyclic AMP and cyclic GMP in rats paw edema by prostaglandins

Summary Experimental results indicate that rat's paw oedema development by PGs is inhibited by 35 AMP and increased by 35 GMP. This research confirms the opposite effect to that of cyclic nucleotides. The respective behaviour of 35 AMP and 35GMP in their primary oedema-induced activity is discussed.We gratefully acknowledge the technical assistence of Mr.Sauro Pellegrini.     

Polyhydroxylated metabolites oftrans-stilbene in the rat

Zusammenfassung Nach Eingabe vontrans-Stilben bei Ratten wurden die grössten Mengen im Harn als 3,4,4-Trihydroxystilben, 3,4,4-Trihydroxybibenzyl und 3,3, 4,4-Tetrahydroxybibenzyl nachgewiesen. Die Bibenzylderivate werden nachscheinlich nach Ausscheidung in der Galle von Darmbakterien metabolisiert.     

A new synthesis of dehydromunduserone

Zusammenfassung Eine einfache Synthese von Dehydromunduseron aus 7,2,4,5-Tetramethoxy-isoflavon wird beschrieben.     

Arabinose nucleoside triphosphates are no inhibitors for DNA-dependent RNA polymerases

Summary 1--d-arabinofuranosylcytosine-5-triphosphate and 9--d-arabinofuranosyladenosine-5-triphosphate were found to have no inhibitory potency for both mammalian DNA-dependent RNA polymerase II andE. coli DNA-dependent RNA polymerase.     

Occurrence of 3-epi-22-deoxy-20-hydroxyecdysone and its phosphoric ester in diapause eggs of the silkworm,Bombyx mori

Ecdysteroids in diapause eggs of the silkworm,Bombyx mori, were analyzed using high-performance liquid chromatography (HPLC) combined with radioimmunoassay (RIA). A relatively large amount of an unidentified free ecdysteroid and its phosphoric ester (conjugated form) were detected. These two compounds were isolated by a combination of column chromatography on silicic acid, thin-layer chromatography (TLC), and HPLC using a reverse-phase (RP) column. The purified compounds were identified as 3-epi-22-deoxy-20-hydroxyecdysone (22d20E) and 3-epi-22-deoxy-20-hydroxyecdysone 2-phosphate (22d20E2P) by means of mass spectrometry and nuclear magnetic resonance spectroscopy. to our knowledge, this is the first report of 22d20E and 22d20E2P.     

A new chalcone glucoside and cernuoside from the flowers ofAcacia dealbata

Summary A new chalcone glucoside has been isolated from the flowers ofAcacia dealbata and shown to be 4,2,4,6-tetrahydroxy-3-methoxychalcone 2-O--D-glucoside (1) by chemical degradations and spectroscopic methods. Cernuoside (4,6,3,4-tetrahydroxyaurone 4-O--D-glucoside), (2) has also been found in this plant material.Acknowledgments. The author thanks Prof. H. Wagner, Institut für pharmazeutische Arzneimittellehre der Universität München, for a sample of homoeriodictyol, and Prof. J.B. Harborne, University of Reading, for a sample of aureusidin.     

Correlation between 3′,5′, c-AMP levels and thyrotropin in separated rat pituitary thyrotropic cells

Summary The correlation between 3,5, c-AMP levels, TSH content and secretion of separated thyrotropic cells was studied. Incubation of the separated cells with 1, 10 and 100 ng of TRH does not change the 3,5, c-AMP levels, despite the significant rises of the TSH level. Dibutyryl c-AMP causes rise in TSH content, with no indication of its secretion. PGE₂ 10^–5 increased 3, 5, c-AMP levels with no change in the content or secretion of TSH in separated thyrotropic cells.     

Die Induktion lysogener Bakterien durch Nitrosamide

Summary N, N-dinitroso-N, N-dimethyloxamide and N, N-dinitroso-N, N-dimethylterephtal acid amide, both mutagenic for yeast cells, induce phage production by lysogenicEscherichia coli K12 () cells.