Noncyclic intermediate in the synthesis of pyrazolidinylpyrazoles

Hydroxypyrazolidine 1 reacts with 5-aminopyrazoles 2 to form selectively the products of substitution to 4 or 5-aminogroup positions; the isolated intermediate of interaction of noncyclic tautomer 1 with two molecules of aminopyrazole carried out the cyclization into 4-pyrazolidinyl-5-aminopyrazole eliminating one molecule of aminopyrazole