PTPN1 and metabolic disease: In this study, we hypothesized that by exploring an expanded set of 3-(hydroxymethyl)-4-oxo-1,4-dihydrocinnoline analogs 1–4 (Figure 1), we might not only obtain yet another set of PTP1B inhibitors but could potentially identify dual inhibitors of PTP1B/TC-PTP, which are sought after in the context of metabolic disease treatments (vide supra).