Asymmetric Michael additions to .alpha.,.beta.-unsaturated oxazolines. An efficient preparation of chiral .beta.,.beta.-disubstituted propionaldehydes

1991 ◽  
Vol 56 (25) ◽  
pp. 7098-7102 ◽  
Author(s):  
A. I. Meyers ◽  
Michael Shipman
Keyword(s):  
Michael Additions ◽  
Alpha Beta

Phase Transformations in Ti-7w/oMo-3w/oMe Alloy

1974 ◽  
Vol 32 ◽  
pp. 514-515
Author(s):  
S. Fujishiro
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Transmission Electron Microscopy ◽  
Tensile Strength ◽  
Mechanical Processing ◽  
Ray Method ◽  
X Ray ◽  
Transmission Electron ◽  
Water Quench ◽  
Alpha Beta

The mechanical properties of three titanium alloys (Ti-7Mo-3Al, Ti-7Mo- 3Cu and Ti-7Mo-3Ta) were evaluated as function of: 1) Solutionizing in the beta field and aging, 2) Thermal Mechanical Processing in the beta field and aging, 3) Solutionizing in the alpha + beta field and aging. The samples were isothermally aged in the temperature range 300° to 700*C for 4 to 24 hours, followed by a water quench. Transmission electron microscopy and X-ray method were used to identify the phase formed. All three alloys solutionized at 1050°C (beta field) transformed to martensitic alpha (alpha prime) upon being water quenched. Despite this heavily strained alpha prime, which is characterized by microtwins the tensile strength of the as-quenched alloys is relatively low and the elongation is as high as 30%.

Bioavailability of naringenin chalcone in humans after ingestion of cherry tomatoes

2020 ◽  
Vol 90 (5-6) ◽  
pp. 411-416 ◽  
Author(s):  
Carina Kolot ◽  
Ana Rodriguez-Mateos ◽  
Rodrigo Feliciano ◽  
Katharina Bottermann ◽  
Wilhelm Stahl
Keyword(s):  
Plasma Levels ◽  
Average Concentration ◽  
Biologically Active ◽  
Thiol Groups ◽  
Structural Element ◽  
Active Molecule ◽  
Reactive Center ◽  
Average Maximum ◽  
Alpha Beta ◽  
Cherry Tomatoes

Abstract. Chalcones are a type of flavonoids characterized by an α-β unsaturated structural element which may react with thiol groups to activate pathways such as the Nrf2-Keap-1 system. Naringenin chalcone is abundant in the diet but little is known about its bioavailability. In this work, the bioavailability of naringenin chalcone from tomatoes was investigated in a group of healthy men (n=10). After ingestion of 600 grams of tomatoes providing a single dose of 17.3 mg naringenin chalcone, 0.2 mg of naringenin, and 195 mg naringin plasma levels of free and conjugated naringenin and naringenin chalcone (glucuronide and sulfate) were analyzed by UHPLC-QTOF-MS at 0.5, 1, 3, and 6 h post-consumption. Plasma levels of conjugated naringenin increased to about 12 nmol/L with a maximum at about 3 h. Concentrations of free naringenin hardly elevated above baseline. Plasma levels of free and conjugated naringenin chalcone significantly increased. A maximum of the conjugated chalcone was reached at about 3 h after ingestion with an average concentration of about 0.5 nmol/L. No free chalcone was detectable at baseline but low amounts of the unconjugated compound could be detected with an average maximum of 0.8 nmol/L at about 1 h after ingestion. The data demonstrate that naringenin chalcone is bioavailable in humans from cherry tomatoes as a dietary source. However, availability is poor and intramolecular cyclisation as well as extended metabolism likely contribute to the inactivation of the reactive alpha-beta unsaturated reactive center as well as the excretion of the biologically active molecule, respectively.

Particular HLA-DQ alpha beta heterodimer associated with IDDM susceptibility in both DR4-DQw4 Japanese and DR4-DQw8/DRw8-DQw4 whites

Diabetes ◽  
1991 ◽  
Vol 40 (6) ◽  
pp. 759-763 ◽  
Author(s):  
K. S. Ronningen ◽  
H. A. Gjertsen ◽  
T. Iwe ◽  
A. Spurkland ◽  
T. Hansen ◽  
...  
Keyword(s):  
Hla Dq ◽  
Alpha Beta

Total Synthesis of (+)-Granatumine A and Related Bislactone Limonoid Alkaloids via a Pyran to Pyridine Interconversion

2019 ◽  
Author(s):  
Timothy Newhouse ◽  
Alexander Schuppe ◽  
Yizhou Zhao ◽  
Yannan Liu
Keyword(s):  
Total Synthesis ◽  
Inhibitory Activity ◽  
Knoevenagel Condensation ◽  
Cost Effective ◽  
Effective Procedure ◽  
Direct Transformation ◽  
Structural Revision ◽  
Alpha Beta ◽  
Ptp 1B

We report the first total synthesis of (+)-granatumine A, a limonoid alkaloid with PTP-1B inhibitory activity, in 10 steps. Over the course of this study, two key methodological advances were made: a cost effective procedure for ketone alpha,beta-dehydrogenation using allyl-Pd catalysis, and a Pd-catalyzed protocol to convert epoxyketones to 1,3-diketones. The central tetrasubstituted pyridine is formed by a convergent Knoevenagel condensation and carbonyl-selective electrocyclization cascade, which was followed by a direct transformation of a 2<i>H</i>-pyran to a pyridine. These studies have led to the structural revision of two members of this family.

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