Pyrimidine as an Aryl C-H Activating Group.

The Pd-catalyzed regioselective C-H activation/arylation, /iodination, and/acetoxylation reactions of 4-arylpyrimidines using aryl iodides, N-iodosuccinimide, and (diacetoxyiodo)benzene respectively as coupling partners are described. Suzuki-Miyaura coupling and Sonogashira reactions of the resulting aryl iodides are demonstrated. The scalability of the C-H activation/functionalization starting with readily accessible 4-aryl pyrimidines is also reported.

Development of a novel Pd-catalyzed N-acyl vinylogous carbamate synthesis for the key intermediate of ICE inhibitor VX-765.

A novel Pd-catalyzed coupling of Cbz-protected proline amide with 4-bromo-5-ethoxyfuran-2(5H)-one was developed for the synthesis of the P1-P2 unit (5) of VX-765. The process afforded quantitative coupling in the presence of water, providing a 1:1 mixture of 5 and its ethoxy epimer epi-5. Compound 5 was isolated as a single diastereomer via fractional crystallization, which was stereoselectively converted to 17 via hydrogenation, and subsequently transformed to VX-765.

Biological actions of formoterol isomers.

Racemic beta(2) agonists, composed of equal amounts of (R)- and (S)-isomers, can display anomalous actions that compromise their effectiveness as asthma therapies. Loss of efficacy during regular use is characteristic of isoprenaline, albuterol and terbutaline and has in part been attributed to the biological effects of the (S)-isomer. This hypothesis was applied to the (R,R)- and (S,S)-isomers of formoterol.

Potent inhibition of human neuronal nitric oxide synthase by N(G)-nitro-L-arginine methyl ester results from contaminating N(G)-nitro-L-arginine.

N(G)-Nitro-L-arginine methyl ester (L-NAME), inhibits the three isozymes of nitric oxide synthase (NOS) in vitro and in vivo. The mechanism of NOS inhibition by L-NAME is uncertain. L-NAME was a time-dependent inhibitor of neuronal NOS (nNOS).

Enzymatic elimination of fluoride from alpha-fluoro-beta-alanine.

Rat liver homogenates catalyzed the elimination of fluoride from (R,S)-alpha-fluoro-beta-alanine. The substrate specificity and physical properties of the defluorinating enzyme were similar to those of mitochondrial L-alanine-glyoxylate aminotransferase II (EC 2.6.