3-Amino-1,2,4-triazines are considered versatile compounds for its significance as building
blocks in synthetic and pharmaceutical chemistry. The synthesis, chemical reactivity, and applications
of substituted 1,2,4-triazines bearing an amino group were described in this review. The presence
of the amino group at position 3 exhibited unique reactivities towards carbonitrile, carbonyl and
isothiocyanate reagents. The reactions were divided into several categories, depending on the other
substituents on the 1,2,4-triazine ring. In this review, relevant and appropriate applications of the
synthesized, isolated, and condensed heterocycles derivatives were reported.