Add time:08/14/2019         Source:sciencedirect.com

Publisher SummaryMinuscule quantities of naturally occurring pyrazines are found in some foodstuffs and are largely responsible for their flavor and aroma. For example, 3-methylpropyl-2-methoxypyrazine occurs in green peas and wine, and a seasoned wine connoisseur can identify a parts per trillion quantity. In addition, 2-methyl-6-vinylpyrazine exists in coffee. Pyrazine is an electron-deficient, 6π-electron heteroaromatic compound, wherein the inductive effects of the nitrogen atoms induce a partially positive charge on the carbon atoms. Consequently, oxidative addition of chloropyrazine takes place more readily than chlorobenzene although the C–Cl bond lengths for both chloropyrazine and chlorobenzene are virtually the same—1.733 and 1.745 Å, respectively. Simple chloropyrazines and their N-oxides undergo a wide range of C–C bond forming reactions under standard palladium-catalyzed reaction conditions. It is worth noting that oxidative addition of chlorobenzene to Pd(0) occurs, using sterically hindered, electron-rich phosphine ligands as reported. This enhanced reactivity may be ascribed to the observation that oxidative addition of an aryl chloride is greatly promoted by electron-rich palladium complexes. The nickel-catalyzed cross-coupling reaction of fluoropyrazine and phenylmagnesium bromide was achieved in high yield using commercially available ligands such as dppe, dppp, and dppf to afford 2-phenylpyrazine 1. The Stille reaction is a Pd-catalyzed cross-coupling between an organostannane andelectrophile, and regarded as one of the versatile methods in organic synthesis.

We also recommend Trading Suppliers and Manufacturers of 2-aMino-3-(Methoxycarbonyl)pyrazine 1-oxide (cas 17149-35-8). Pls Click Website Link as below: cas 17149-35-8 suppliers