Antideuteron production in 158 AGeV/c Pb + Pb collisions

The invariant cross section as a function of transverse momentum for antideuterons produced in 158 A GeV/c per nucleon Pb+Pb central collisions has been measured by the NA44 experiment at CERN. This measurement, together with a measurement of antiprotons, allows for the determination of the antideuteron coalescence parameter. The extracted coalescence radius is found to agree with the deuteron coalescence radius and radii determined from two particle correlations. (27 refs)

Some Mercuration Reactions of Substituted Pyrroles

Mercuration of N-unsubstituted pyrroles with mercury(II) acetate results in immediate precipitation of the N-mercurated derivative, which is insoluble in virtually all organic solvents. If the pyrrole N atom is protected (e.g. with Me, CH2OCH2Ph, or CO2t-Bu) then mercuration takes place efficiently at unsubstituted pyrrole carbons. Subsequent palladium/olefin (Heck-type) reactions afford the corresponding pyrrole acrylate when, for example, the olefin is methyl acrylate; deprotection (when the N-substituent is CH2OCH2Ph or CO2t-Bu) then affords the required carbon-substituted pyrrole. Attempts to deprotect the N-methylpyrroles were unsuccessful. © 1989, American Chemical Society. All rights reserved