Earl B. Whipple

CP-60,993, a new dianemycin-like ionophore produced byStreptomyces hygroscopicus ATCC 39305: fermentation, isolation and characterization

SummaryCP-60,993, 19-epi-dianemycin, is a novel polycyclic ether antibiotic produced byStreptomyces hygroscopicus ATCC 39305. Fermentation recovery, purification and crystallization were achieved using standard procedures. CP-60,993 was characterized as a monocarboxylic acid. Elemental analysis suggested a molecular formula of C47H78O14 for the free acid and C47H77O14 Na for the sodium salt. Crystalline form CP-60,993 sodium salt shows the following properties: m.p. 193∼205°C, E1 cm1%=157 at 232 nm, [α]D25°C+11.0 (c 1, methanol). The structure, determined by MS, PMR and CMR, differs from dianemycin only in the stereochemistry at position 19. This was confirmed by X-ray crystallography carried out on the rubidium salt of CP-60,993. It exhibited activity in vitro against Gram-positive and anaerobic bacteria, efficacy againstEimeria coccidia in vivo in poultry, and stimulation in vitro of rumen propionic acid production.

Quantitative measurement of deuterium labels by carbon-13 magnetic resonance spectroscopy

Abstract A progressive saturation method is proposed for the quantitative measurement of deuterium-labeled carbon atoms that does not require resolution of signals from corresponding carbons labeled to different extents, and which optimizes the sensitivity versus time limitations that are inherent in CMR. While the theory is generalized to all types of carbon, practical considerations limit the method to those containing a single replaceable proton, which is the most commonly occurring situation where alternative methods of NMR assay are inapplicable. The method is applied to a problem of typical complexity; and the general nature of the theory is verified on the basis of measured relaxation properties.

Multiplet moments of NMR band spectra

Abstract The method of multiplet moments developed by Anderson and McConnell is ideally suited to the analysis of experiments which alter a limited number of parameters in a complex spectrum. While the direct measurement of band moments does not appear to be very practicable, many of the problems are canceled in the moments of difference spectra. A simple method of determining changes in the second moment is by triple integration of the difference spectrum. The application of this method to a spin-decoupling experiment is illustrated.