Over the last several years there has been a huge increase in the development and applications of new efficient organocatalysts for enantioselective pericyclic reactions, which represent one of the most powerful types of organic transformations. Among these processes are cycloaddition reactions (e.g., [3+2]; formal [3+3]; [4+2]; vinylogous [4+2] and 1,3-dipolar cycloadditions), which belong to ...

Of the non-protein constituents of blood, some, such as potassium,’ phosphoric acid,‘, 3 lecithin,3 free cholestero13* 406 and amino-acids,S * 7, 8 are localized to a greater or smaller extent within the corpuscles; some, such as sodium,l calcium,l chlorine,’ cholesterol esters,s glucose,g and adrenalin,‘O are more abundant in, or even entirely confined to the plasma; some, finally, with urea6*...

Nuclease activity was dissociated from proteolytic activity when Sachs confirmed the observations of Milroy that an agent which attacked nucleic acid to liberate inorganic phosphoric acid could not liquefy gelatin and that proteolytic enzymes liquefied gelatin but could not attack nucleic acid (1). Henceforth the rate of separation of inorganic phosphoric acid from nucleic acid became the exclu...

5(4H)-Oxazolones can be formed through the activation of acylated α-amino acids or of peptide C termini. They constitute potentially activated intermediates in the abiotic chemistry of peptides that preceded the origin of life or early stages of biology and are capable of yielding mixed carboxylic-phosphoric anhydrides upon reaction with phosphate esters and nucleotides. Here, we present the re...