Media Reviews

James Gurney, The World of Dinosaurs, text by Michael Brett-Surman and Thomas Holtz Jr. Greenwich Workshop Press, Shelton, Conn. 48 pages; 1998; $19.95 (hardbound).     

Improved compressed sensing reconstruction for $$^{19}$$ F magnetic resonance imaging

Magnetic Resonance Materials in Physics, Biology and Medicine - In magnetic resonance imaging (MRI), compressed sensing (CS) enables the reconstruction of undersampled sparse data sets. Thus,...     

Synthesis of 5-substituted 2'-deoxyuridines

A series of thymidylate synthetase inhibitors was synthesized, some of which were potential irreversible inhibitors. 5-Formyl-2'-deoxyuridine (9) and its dithiolane derivative 11 were prepared by condensation of the bis(trimethylsilyl) derivative of 5-formyluracil dimethyl acetal and the protected chloro sugar followed by saponification of the protective groups. 5-Acetyl-2'-deoxyuridine (15) was prepared in the same way from 5-acetyluracil. Treatment of the diester of 5-allyl-2'-deoxyuridine (17 or 22) with m-chloroperbenzoic acid gave the corresponding epoxide. Dimethylamine removed the ester groups and opened the epoxide to give the amino alcohol 24. The diester of 5-chloromethyl-2'-deoxyuridine (27) treated with methanol or sodium azide gave 5-methoxymethyl- (29) and 5-azidomethyl- (31) 2'-deoxyuridines. Compound 27 also was converted to 5-iodoacetamidomethyl-2'-deoxyuridine by treatment with ammonia, chloroacetyl chloride, base saponification, and finally sodium iodide.     

Am Limit? – Einschätzungen zur Grundwasserbewirtschaftung im Großraum Grünstadt (Rheinland-Pfalz)

Grundwasser - Im Großraum Grünstadt erfolgt die Wasserversorgung weitgehend dezentral aus Grundwasserleitern des Buntsandsteins. Dieser ist aufgrund der geologisch-tektonischen...     

Aryl Halide Radical Clocks as Probes of Stannylene/Aryl Halide C–H Activation Rates

Using the radical cyclization induced by the reaction of (1) with 1-(but-3-en-1-yloxy)-2-iodobenzene, we have determined the rate of allylic and propargylic C–H activation to be 1.1 ± 0.2 × 10⁸ M^?1 s^?1. The rate of oxidative addition of aryl halide with 1 was estimated to be 10⁷–10⁸ M^?1 s^?1. The radical cyclization involving 1 and 1-(allyloxy)-2-iodobenzene proceeds quantitatively, indicating that the rate of cyclization (9.6 × 10⁹ s^?1) is faster than the rate of hydrocarbon/alkene/alkyne C–H abstraction.