The first enantioselective synthesis of the anti-Helicobacter pylori agent (+)-spirolaxine methyl ether has been carried out in a convergent fashion by heterocycle-activated Julia olefination of a spiroacetal-containing sulfone fragment with a phthalide-containing aldehyde fragment. The total synthesis of (+)-spirolaxine methyl ether establishes the absolute stereochemistry of the natural produ...

BACKGROUND Crawford Williamson Long (1815 to 1878) was the first to use ether as an inhaled anesthetic for surgical operations. By not publishing his discovery for 7 yr, his pioneering work was largely overshadowed by that of Horace Wells (1815 to 1848), Charles Thomas Jackson (1805 to 1880), and William Thomas Green Morton (1819 to 1868). As a result, sites commemorating Long's discovery are n...

The convergent total synthesis of gambierol (1) is described. The octacyclic ether framework of 1 was constructed via the intramolecular allylation of alpha-chloroacetoxy ether followed by ring-closing metathesis. A modified Stille coupling was successfully applied to the synthesis of the triene side chain.

in the present study, a heterogeneous and homogeneous gas flow dispersion model for simulation and optimization of a large-scale catalytic slurry reactor for the direct synthesis of dimethyl ether (dme) from synthesis gas (syngas) and co2, using a churn-turbulent regime was developed. in the heterogeneous flow model, the gas phase was distributed into two bubble phases including small and large...

The direct synthesis process of dimethyl ether (DME) from syngas in slurry reactors is considered to be promising because of its advantages in caloric transfer. In this paper, the influences of operating conditions (temperature, pressure and weight hourly space velocity) on the conversion of CO, selectivity of DME and methanol were studied in a stirred autoclave over Cu-Zn-Al-Zr slurry catalyst...

A method has been developed for the synthesis of semicrystalline poly(arylene ether ether sulfide) materials by first preparing a soluble, amorphous sulfoxide containing precursor, then rapidly reducing the sulfoxide moiety to sulfide. The sulfoxide polymers are synthesized using conventional nucleophilic aromatic substitution reactions between difluorodiphenyl sulfoxide and diphenols. Reductio...