Structural studies of natural products by new nmr techniques. The structure of a new polyether antibiotic,portmicin

The structure of a new polyether antibiotic portmicin has been determined as shown in Fig. 1 by using new NMR tecnniques, HMBC and HOHAHA.     

Studies on the analytical chemistry of iodonium compounds. Part III

Summary A procedure is described for the determination of the diphenyliodonium cation in the range 1.0 to 4.0 mg, by extraction from solution buffered at p_H 9.5 into chloroform as the diethyldithiocarbamate followed by conversion into the copper(II) complex. Absorbance measurements are made on the chloroform solution of the copper(II) diethyldithio-carbamate at 435 nm, and a linear relation exists between absorbance and cation content within the range specified. The optimum conditions for the extraction are discussed.

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Zusammenfassung Ein Verfahren zur Bestimmung von Diphenyliodoniumkationen in der Größenordnung von 1,0 bis 4,0 mg wurde beschrieben. Es beruht auf deren Extraktion aus gepufferter Lösung (p_H=9,5) mit Chloroform als Diäthyldithiocarbamat und dessen Überführung in einen Kupfer(II)-komplex. Die Absorption des Kupfer(II)-diäthyldithiocarbamats in Chloroformlösung wurde bei 435 nm gemessen. Sie steht in linearem Verhältnis zur Kationenkonzentration. Die optimalen Bedingungen für die Extraktion werden erörtert.

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Résumé On décrit un procédé pour le dosage du cation diphényliodonium dans le domaine de 1,0 à 4,0 mg, en l'extrayant d'une solution tamponnée à p_H 9,5 par le chloroforme, à l'état de diethyldithiocarbamate puis en le transformant en complexe du cuivre-II. On effectue les mesures de densité optique sur la solution dans le chloroforme du diéthyldithiocarbamate de cuivre-II à 435 nm; il existe une relation linéaire entre la densité optique et la teneur en cation dans le domaine spécifié. On discute les conditions optimales pour effectuer l'extraction.

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Part II. Mikrochim. Acta [Wien]1966, 539.     

The structure of a new antibiotic,hygrolidin

The structure of a new antibiotic, hygrolidin has been determined as shown in fig. 3.     

The structure of a new antibiotic,chromoxymycin

Based on ¹H- and ¹³C-NMR spectral data, the planar structure of chromoxymycin, a new antitumor antibiotic, has been determined as shown in Fig. 1.     

Studies on ABX6 Compounds. III. The SnZrCl6 structure type

The compound SnZrCl₆ crystallizes in an ordered substitution variant of the MnF₃ type. The synthesis of this compound and special features of its crystal structure are described.     

The structure of a new isotetracenone antibiotic,capoamycin

Based on ¹H and ¹³C NMR spectral data and chemical degradation, the structure of capoamycin, a new isotetracenone antibiotic has been determined as shown in Fig. 1.     

Studies on the bacterial activity of cobalt(III) complexes. Part II. Cobalt(III) aminoacidato-complexes

Summary Cobalt(III) complexes of the typetrans-[Co(AA)₂(ox)] (where AA = aminoacidato, gly = glycinato, sar = sarcosinato, DL-ala = DL-alaninato, L-ala = L-alaninato; ox = oxalate); [Co(L-val)₂CO₃] and DL-[Co(en)₂sar]I₂ where L-val = L-valinato, en = ethylenediamine) have been investigated for their bacterial activity againstEscherichia coli B using well-cultured techniques on EMB agar and in minimal glucose media. The activities decrease in the order:trans-(N)(+)K[Co(sar)₂(ox)] >trans-(N)(+)K[Co(L-ala)₂(ox)] >trans-(N)(–)K[Co (gly)₂(ox)] >trans-(N)(+)K[Co(DL-ala)₂(ox)] >trans-(N)(+)K[Co(gly)₂(ox)] >trans(+)K[Co(DL-ala)₂(ox)] >trans-K[Co(L-val)₂CO₃].     

The structure of grifolin, an antibiotic from a basidiomycete

Structure of grifolin was deduced as 2-trans,trans-farnesyl-5-methylresorcinol (I).     

The structure of tetramycin,a new polyene macrolide antibiotic

The structure of the tetraene antifungal antibiotic tetramycin has been established by detailed studies of mass, ¹H and ¹³C NMR spectra as well as by chemical degradation. A newly developed mass analysis has been introduced for determining the carbon skeleton of the aglycone.