New Pyrazolo[3,4-b]pyrazines: Synthesis and Biological Activity. -A variety of new pyrazolopyrazines and related heterocycles are synthesized and evaluated for their antifungal and antiparasitic activities. The key intermediate (IIIa) is obtained via reaction of 5-amino-4-nitrosopyrazole (I) with malononitrile. -(EL-KASHEF, H. S.; EL-EMARY, T. I.; GASQUET, M.; TIMON-DAVID, P.; MALDONADO, J.; VANELLE, P.; Pharmazie 55 (2000) 8, 572-576; Dep. Chem., Fac. Sci., Assiut Univ., Assiut 71516, Egypt; EN)