The most important developments in nucleoside synthesis in the last few years have been the application of the mercury salt procedure to both purines and pyrimidines, and the isolation of relatively stable, crystalline 2-deoxyribofuranosyl halides; as a result, almost any nucleoside may now be synthesized. Earlier syntheses, based on older methods or on the conversion of one nucleoside to another, played an essentialpart in establishing the structure of the nucleosides (and hence of the nucleic acids).
p-Lactams
, Their Polymerization and Use as Raw Materials for Fibers [*I BY DR. R. GRAF, DR. G. LOHAUS, DR. K. BORNER, DR. ERWIN SCHMIDT AND DR. H. BESTIAN FARBWERKE HOECHST AG., FRANKFURT/MAIN (GERMANY)
/I-Lactams cart be prepared by cyclization of /I-amino acid esters. Recently they have become available also from olefins by addition of N-carbonylsulfamyl chloride (isocyanatosulfonyl chloride) and from aldehydes by reaction with N-carbonylsuljamyl chloride and ketene. Condensative or anionic polymerization results in polyamides the chains of which contain many more amide groups than the chains of polyamides of the nylon-6 type. Hence the new polymers resemble silk more closely. Fibers and films can be prepared from solution.