The synthesis of 2,3-dinorprostacyclin metabolites—a new approach to spirolactone hemiacetals

Palladium-Catalyzed Hydrocarbonylative Spirolactonization for Expedite Construction of Oxaspirolactones

A novel palladium-catalyzed cascade hydrocarbonylation of the alkene moiety followed by intramolecular spirolactonization of 2-vinylaryl hydroxyalkyl ketones has been developed, which offers efficient and expedited access to furnishing oxaspirolactones in high yields with high chemoselectivities. This new method is compatible with an array of functional groups and proceeds under mild reaction conditions with commercially available catalyst components.

Catalytic Carbonylative Spirolactonization of Hydroxycyclopropanols

A palladium-catalyzed cascade carbonylative spirolactonization of hydroxycyclopropanols has been developed to efficiently synthesize oxaspirolactones common to many complex natural products of important therapeutic value. The mild reaction conditions, high atom economy, broad substrate scope, and scalability of this new method were highlighted in expedient total syntheses of the Turkish tobacco natural products α-levantanolide and α-levantenolide in two and four steps, respectively. The hydroxycyclopropanol substrates are readily available in one step via a Kulinkovich reaction of the corresponding lactones. Mechanistic studies utilizing high-resolution electrospray ionization mass spectrometry (ESI-MS) identified several key intermediates in the catalytic cycle, as well as those related to catalyst decomposition and competitive pathways.

Stereoselective synthesis of 1,6-dioxaspirolactones from spiro-cyclopropanecarboxylated sugars: total synthesis of dihydro-pyrenolide D

A one-pot protocol for the stereoselective construction of γ-spiroketal γ-lactone frameworks from sugar derived spiro-cyclopropanecarboxylic acids involving a ring enlargement and cyclization reaction is revealed.

Simultaneous determination of 6-oxo-prostaglandin F1 alpha and 2,3-dinor-6-oxo-prostaglandin F1 alpha in biological fluids by stable isotope dilution and negative ion chemical ionization mass spectrometry

A stable isotope dilution assay for the simultaneous determination of two metabolites of prostacyclin (1), 6-oxo-prostaglandin F1 alpha (2a) and 2,3-dinor-6-oxo-prostaglandin F1 alpha (3a), in human seminal fluid and human urine is described. A new chemical total synthesis of deuterated internal standard, 18,18,19,19-(2H4)-2,3-dinor-6-oxo-PGF1 alpha (3b), is presented and enables specific and sensitive quantification based on negative ion chemical ionization mass spectrometry. 2a and 3a were analysed as their methoxime pentafluorobenzyl ester tris(trimethylsilyl) ether derivatives in the selected ion monitoring mode registrating the [M-181]- fragments with a detection limit for both prostanoids of 10 pg per injection. The two metabolites occur in human seminal fluid in very low concentrations (2a: 2.8 ng ml-1; 3a: 1.7 ng ml-1) and cannot contribute significantly to the urinary metabolite levels which are in the range of 108-265 ng/24 h for 3a and 124-574 ng/24 h for 2a.

Development of a gas chromatographic-mass spectrometric method using a stable isotope internal standard for quantitation of thromboxane B2

Tetradeuterated 19, 19',20,20'-2H4-thromboxane B2 was synthesized and used as a stable isotope internal standard for the development of a gas chromatographic/mass spectrometric (GC/MS) method to quantitate thromboxane B2. Quantitation was based on the detection of fragment ions at m/z 301 for thromboxane B2 and m/z 305 for the corresponding tetradeuterated internal standard. At m/z 301/305 a response equivalent to a protium/deuterium ratio of 0.2% thromboxane B2 could be measured with a standard deviation of 15% when 100 nanograms of the tetradeuterated internal standard was analyzed. For measurement of cellular biosynthesis of thromboxane B2 in whole blood or platelet rich plasma, the internal standard and naturally occurring thromboxane B2 were i) isolated by solvent extraction, or sequestration to XAD-2 columns; ii) purified by reversed phase high performance liquid chromatography; and iii) converted to methoxime methyl ester trimethylsilyl ethers prior to analysis. A limited comparison was made using both radioimmunological and mass spectrometric quantitation of thromboxane B2.

Development of a GC-MS method for quantitation of 2,3-dinor-6-keto-PGF1∝ and determination of the urinary excretion rates in healthy humans under normal conditions and following drugs

Tetradeuterated 2,3-dinor-6-keto-PGF1 alpha was used as internal standard in the development of a method for quantitation of 2,3-dinor-6-keto-PGF1 alpha in human urine based on gas chromatography - mass spectrometry. The urinary excretion rates of 2,3-dinor-6-keto-PGF1 alpha in twenty normal healthy males and females were 9.7 +/- 4.6 and 8.8 +/- 8.5 (mean +/- SD) ng/h respectively. A considerable inter- and intra-individual variation was found under normal conditions. It was also found that the urinary excretion of 2,3-dinor-6-keto-PGF1 alpha was increased about fivefold during and shortly after 30 min of strenuous jogging. Any data about the effect of nonsteroidal antiinflammatory drugs on the excretion rate of 2,3-dinor-6-keto-PGF1 alpha are difficult to interpret when considering the above findings. However, oral administration of 500 mg of aspirin did not seem to reduce the excretion rate of 2,3-dinor-6-keto-PGF1 alpha.