The present invention provides new amyloidogenesis inhibiting compounds of formula (I): ##STR00001## in which R.sub.1 is a --NR.sub.aR.sub.b group, where R.sub.a and R.sub.b, independently, are a hydrogen atom or a C.sub.1-C.sub.6 alkyl group; --OR.sub.C group, where R.sub.C is a hydrogen atom or a C.sub.1-C.sub.6 alkyl group; a glycosyl; a C.sub.1-C.sub.6 polyhydroxyalkyl; or a --NH--CH(R.sub.d)--COOR.sub.e group, where R.sub.d is a side chain of one of the 20 natural alpha-amino acids in either of their two enantiomerically pure forms L or D, and R.sub.e is a hydrogen atom or a C.sub.1-C.sub.6 alkyl group; and R.sub.2 is a hydrogen atom, a C.sub.1-C.sub.6 alkyl group, a glycosyl; a C.sub.1-C.sub.6 polyhydroxyalkyl; --C(.dbd.O)--R.sub.f group, where R.sub.f is a C.sub.1-C.sub.6 alkyl group; or a --CH.sub.2--COO--R.sub.g group, where R.sub.g is a hydrogen atom or a C.sub.1-C.sub.6 alkyl group; and pharmaceutically acceptable salts thereof, which are useful in the treatment of neurodegenerative diseases, among others.