Search for "medium size heterocycles" in Full Text gives 3 result(s) in Beilstein Journal of Organic Chemistry.
Beilstein J. Org. Chem. 2020, 16, 32–38, doi:10.3762/bjoc.16.5
Beilstein J. Org. Chem. 2016, 12, 2026–2031, doi:10.3762/bjoc.12.190
Beilstein J. Org. Chem. 2010, 6, No. 48, doi:10.3762/bjoc.6.48