A modified hammerhead ribozyme (R32S) with a phosphorothioate linkage between G8 and A9, a site that is considered to play a crucial role in catalysis, was examined by high-resolution 1H and 31P nuclear magnetic resonance (NMR) spectroscopy. Signals due to imino protons that corresponded to stem...

A convenient and general method for the synthesis of nucleoside 3′,5′-cyclic phosphorothioates using nucleosides as starting materials is described.A synthesis of nucleoside 3′,5′-cyclic phosphorothioates is described.

The first boron-containing 2′,3′-cyclic phosphate-modified analogue, uridine 2′,3′-cyclic boranophosphate (2′,3′-cyclic-UMPB), was synthesized. 5′-O-Protected uridine was cyclophosphorylated by diphenyl H-phosphonate to yield uridine 2′,3′-cyclic H-phosphonate, which upon silylation fol...

In general, potent non-ketolide versions of erythromycin possessed conformationally constricted two- or three-atom-length sidechains at 3-OH. Novel 14-membered non-ketolides possessing long spacers beyond three-atom length were evaluated for antibacterial activity. The most potent one is 34a, fe...

The (9E)-oxime of erythromycin A (1) was isomerized to the (9Z)-isomer 2 in the presence of strong base. Stereospecific Beckmann rearrangement of the (9Z)-oxime led to a series of novel 8a-aza-8a- homoerythromycin A derivatives. In vitro data is provided that shows the 8a-methyl derivative 10 to...

A new method for the preparation of clarithromycin is described through the highly regioselective O-methylation at C(6)–OH of the novel derivative 9-pyrimidyloxime erythromycin A. The facile synthesis of 6,11-O-dimethyl- and 6,11,12-O-trimethyl erythromycin A is also reported. These compounds a...

Beckmann rearrangement of erythromycin A 9(E)-oxime with toluenesulfonyl chloride in ethyl ether at −45°C generates 9,11-imino ether IV which leads to azithromycin. The 9,11-imino ether can also be readily obtained from isomerization of its isomer 6,9-imino ether III.

A novel series of 3-O-arylalkylcarbamoyl-3-O-descladinosyl-9-O-(2-chlorobenzyl)oxime clarithromycin derivatives, were designed, synthesized and evaluated for their in vitro antibacterial activity. These derivatives were found to have strong activity against susceptible and resistant bacteria str...

Erythromycin was long viewed as a bacteriostatic agent. The erythromycin derivatives, 9-oxime ketolides have a species-specific bactericidal profile. Among them, the 3′-allyl version of the 9-oxime ketolide 1 (Ar = 3-quinolyl; 17a) is bactericidal against Streptococcus pneumoniae and Streptococ...

The synthesis and anti-Helicobacter pylori (H. pylori) activity evaluation of a new series of erythromycin A (E)-9-oxime ether derivatives are described. These compounds exhibited comparable in vitro anti-H. pylori activity and improved acid stability compared to the reference compound clarithro...

Constitutively erythromycin-resistant apathogens are more difficult to address than inducibly resistant and efflux-resistant strains. Three series of the 4th generation 2-fluoro 9-oxime erythromycin ketolides were synthesized and evaluated. Incorporation of substituted heteroaryl groups (a - m),...

The synthesis of novel erythromycin A 9-O-(2-ethenesulfony-ethyl)-oxime and erythromycin A 9-O-(3-oxo-butyl)-oxime from erythromycin A (EA) by the Michael reaction is described and to describe the effects of transformation of ketone in position 9 of EA to an oxime ether. This transformation occu...

A series of erythromycin-A oxime ether as well as esters have been synthesized. Ether derivatives were synthesized through the epoxy ether intermediate of erythromycin-9-oxime, followed by opening of the epoxy linkage through various amines, whereas esters have been prepared through DCC mediated...

Regiospecific monomethyl prostaglandin F2α ethers (at 0–9, 0–11, and 0–15) have been prepared by total synthesis. The 9,15-bis-ether was also prepared. The 11- and 15-monoethers have been converted to the corresponding prostacyclins. Nuclear Magnetic Resonance (NMR) spectral comparisons indi...

We have cloned a receptor, named LSCPR, for vasopressin-related Lys-conopressin in Lymnaea stagnalis. Lys-conopressin evokes Ca2+-dependent Cl− currents in Xenopus oocytes injected with LSCPR cRNA. Expression of LSCPR mRNA was detected in central neurons and peripheral muscles associated with re...

Publisher SummaryThis chapter describes the current insights into the role of Lys-conopressin, an analog of vasopressin and oxytocin, in the control of male sexual behavior in the freshwater snail, Lymnaea stagnalis. The molecular biology of Lys-conopressin and its receptors, the effects of Lys-...

We examined functional aspects of co-localization of neuropeptides involved in the regulation of male copulation behaviour in the simultaneous hermaphrodite snail Lymnaea stagnalis. The copulation behaviour is controlled by several types of peptidergic neurons that include a cluster of neurons i...

D. B. Nielsen, J. Dykert, J. E. Rivier and J. M. McIntosh. Isolation of Lys-conopressin-G from the venom of the worm-hunting snail, Conus imperialis. Toxicon32, 845–848, 1994.—Vasopressin homologs have previously been isolated from the venom of fish-hunting cone snails. We investigated whether...

The presence of a vasopressin (VP)- or vasotocin (VT)-like peptide in the central nervous system of the gastropod mollusc Aplysia has been indicated previously. In the case of Aplysia californica, HPLC and RIA evidence suggested the peptide was VT-like but not identical with the nonmammalian ver...

Lys-conopressin was isolated from the pond snail Lymnaea stagnalis, and consists of nine amino acids containing consensus amino acids of the OXT/VP superfamily peptides: Cys1, Asn5, Cys6, Pro7, Gly9; and C-terminal amidation. The Lys-conopressin gene in the pond snail is composed of three exons ...