Naproxen in heterocyclic chemistry: Novel syntheses of triazoles,triazolothiadiazines, triazolothiadiazoles,and triazolothiadiazepine bearing an asymmetric carbon atom and radiostability of the biologically active compounds

Several s‐triazoles 2, 7a, 10, 12 ; s‐triazolo[3,4‐b][1,3,4]thiadiazines ( 3–5 ); s‐triazolo[3,4‐b][1,3,4]thiadiazoles ( 6, 8, 11, 15 ); and s‐triazolo[3,4‐b][1,3,4]thiadiazepine ( 14 ) were synthesized starting from 2‐(6‐methoxy‐2‐naphthyl)propanoic acid ( 1 ) (Naproxen). The structures of the synthesized compounds were elucidated by elemental analyses and spectral data. Compounds 2, 5, 11, 12, 14 , and 15 exhibited a remarkable antifungal activity compared with the standard fungicide Mycostatine. Radiosterilization of the biologically active compounds 2, 5, 11 , and 14 in the dry state may prove to be applicable (retaining their structures unchanged up to 40 kGy). © 2002 Wiley Periodicals, Inc. Heteroatom Chem 13:199–206, 2002; Published online in Wiley Interscience (www.interscience.wiley.com). DOI 10.1002/hc.10019     

Compatibilization of PA6/rubber blends by using an oxazoline functionalized rubber

The compatibilization of blends of polyamide 6 with a nitrile butadiene rubber has been investigated. The procedure consists of two steps: modification of the nitrile groups of the rubber into oxazoline in the melt through condensation of ethanolamine with formation of a molecule of ammonia, followed by use of the modified rubber as a compatibilizing precursor which is melt mixed with the polyamide to produce the compatibilized blend. The modification reaction has been detected by NMR analysis and a rheological, mechanical and thermomechanical characterization has been carried out on the all the blends. The results indicate that the modification reaction occurs but the conversion of nitrile into oxazoline is relatively low. Use of the modified rubber in the preparation of binary polyamide/rubber blends, leads to an increase in viscosity, which is typical of compatibilized systems, and to enhanced tensile, impact and thermomechanical properties. These phenomena can be explained by the formation of in situ rubber/polyamide copolymers that act as compatibilizers, due to the reaction between oxazoline and the end groups of the polyamide. The presence of residual low molecular compounds, from the modification or from the purification of the rubber worsens all of the properties and inhibits the compatibilizing effect of the modified rubber.