A simple and general procedure for preparation of various phosphotyrosine mimetics from the corresponding phenolic precursors is described. In situ silylation of phenol acids followed by treatment ...with Et
3N/CBr
4/HP(O)(OEt)
2 provides diethyl phosphate intermediates (36–96%), which can be cleanly deprotected in quantitative yields upon treatment with BSTFA/TMSI to afford novel phosphotyrosine mimetics.
in situ silylation of phenol acids
1 followed by treatment with Et
3N/CBr
4/HP(O)(OEt)
2 yields diethyl phosphate intermediates
2, which can be cleanly deprotected with BSTFA/TMSI to afford novel phosphotyrosine mimetics
3.
A strategic analysis of various issues which pertain to the enablement of combinatorial organic synthesis to produce libraries of non-polymeric organic molecules is given. Methods and examples of the ...development of solid-phase organic chemistry and its subsequent application to combinatorial library synthesis for drug discovery is illustrated with successful case studies. The synthetic versatility of resin-bound amino-acid-derived imine intermediates to produces, ?-sultams and pyridines is shown. Use of natural products as key components for creation of combinatorial libraries is presented using Rauwolfia alkaloids and the cephalosporin nucleus as examples.
Semiconductor laser diodes are conventionally based on a relatively thin waveguide structure grown epitaxially on a thick single crystalline substrate, wherein the latter serves as a medium for ...carrier flow and as mechanical support and plays no role in optics. Although earlier attempts to provide the outcoupling of light through a transparent substrate in leaky lasers realized a narrow leaky emission beam, either significant leakage losses led to the deterioration of the laser performance or/and a large fraction of the output optical power was concentrated in a co-existing angularly broad emission peak originating from the narrow active waveguide. Our solution, a tilted wave laser (TWL), includes polishing the back side of the substrate under the stripe providing mirror-like reflection for the leaky mode which can thus exhibit multiple reflection and amplification cycles before exiting the device from the substrate facet. Fulfillment of phase matching conditions allows wavelength-stabilized operation. At a wavelength of 1060 nm TWLs are shown to exhibit a very small thermal shift of the emission wavelength of 0.03 nm/K. A cw output power of 3.3 W for 2 mm long cavities with uncoated facets is obtained, wherein the entire power is concentrated in a single vertical lobe having a full width at half maximum of 0.8°. The scattering of the tilted optical wave by the back substrate surface roughness is modeled and found to be the main mechanism limiting the differential efficiency, wherein the scattering contributes up to 10 cm -1 to the losses for a present roughness of ~30 nm. The free carrier absorption in the n-doped substrate ( ~3 cm -1 for n ~10 18 cm -3 ) dominates for a roughness <; 10 nm.
1-(a-Phosphoroylideneaminoalky1)benzotriazoles reacted with organocerium (III) dichlorides or Grignard reagents to produce N-(sec-alkyl) iminophosphoranes, which were hydrolyzed to sec-alkyl primary ...amines in good overall yields. This sequence provides a convenient two-pot transformation of aldehydes to sec-alkyl primary amines.
Aim. To assess the safety of the application of high-dose atorvastatin and its effect on metabolic parameters, such as the total level of nitric oxide and homocysteine in the blood plasma in patients ...with ischemic heart disease during a coronary artery bypass surgery (CABG).Material and methods. The study included 42 patients with stable effort angina II-IV functional class. A special criterion for selection was the taking atorvastatin at a dose of 20 mg/day for at least 30 days before patient was directed to surgical revascularization of the myocardium. Immediately before the intervention, the dose of atorvastatin was increased to the maximum allowed with subsequent taking of 40 mg/day. Complications after CABG, indicators of lipid metabolism and biochemical safety of statin use were analyzed. The duration of observation of results of the acute atorvastatin recapture therapy was 3 weeks during hospital period. We used modern enzymatic method for nitrogen oxides determination with the application of nitrate reductase. Determination of total homocysteine was performed by high performance liquid chromatography.Results. It was found that atorvastatin 80 mg for 12 hours and 2 hours before CABG in patients previously treated with atorvastatin 20 mg/day is well tolerated and leads to decrease in total levels of nitric oxide by 1.6 (0.18-10.8 ) μmol/l and homocysteine by 0.9 (0.17-2.69) μmol/l (p< 0.05 for both)Conclusion. It is assumed that the metabolic effects of high-dose therapy with atorvastatin may have a positive influence on the immediate postoperative period.
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