Catalyzes the C6-oxidation step in brassinosteroids biosynthesis (By similarity). May convert 6-deoxoteasterone (6-deoxoTE) to 3-dehydro-6-deoxoteasterone (6-deoxo3DT, 6-deoxo3DHT), and teasterone (TE) to 3-dehydroteasterone (3DT, 3-DHT) (By similarity). Involved in the elongation of leaf sheaths and stems (By similarity). 6-deoxoteasterone + O2 + reduced [NADPH--hemoprotein reductase] = 3-dehydro-6-deoxoteasterone + H(+) + 2 H2O + oxidized [NADPH--hemoprotein reductase] Plant hormone biosynthesis; brassinosteroid biosynthesis. Belongs to the cytochrome P450 family.