One-pot efficient synthesis of 13(R),14(R)-epoxy-17β-methyl-20(S)-hydroxyl-18-nor-pregna-4-en-3-one via a tandem epoxidation-rearrangement-epoxidation reaction sequence

Discovery of Ingenane Diterpenoids from Euphorbia hylonoma as Antiadipogenic Agents

“…Biogenetically, the assignment of the stereochemistry of 1 and 2 was in agreement with that of a common precursor, the co-isolated new ingenane (6) (Scheme S1). 26,27 O-bearing tertiary carbons (δ C 71.2 and 70.1) delineated an epoxy between C-9 and C-10, 28 which thereby outlined a 9,10epoxy tigliane skeleton for 3. The relative configuration of 3 was assigned utilizing a NOESY analysis (Figure 2) and gaugeindependent atomic orbital (GIAO) calculation of the NMR shifts (Supporting Information).…”

“…As one additional ring was still required in the structure, two relatively upfield-shifted Table 1. 1 H (500 MHz) and 13 C (125 MHz) NMR Data of 1−3 O-bearing tertiary carbons (δ C 71.2 and 70.1) delineated an epoxy between C-9 and C-10, 28 which thereby outlined a 9,10epoxy tigliane skeleton for 3. The relative configuration of 3 was assigned utilizing a NOESY analysis (Figure 2) and gaugeindependent atomic orbital (GIAO) calculation of the NMR shifts (Supporting Information).…”

“…Furthermore, the HMBCs from both H 2 -16 and H 3 -17 to C-13, C-14, and C-15 constructed a cyclopentane fragment, attaching a hydroxymethyl (16-CH 2 OH) and a methyl (Me-17) group at C-15. As one additional ring was still required in the structure, two relatively upfield-shifted O -bearing tertiary carbons (δ C 71.2 and 70.1) delineated an epoxy between C-9 and C-10, which thereby outlined a 9,10-epoxy tigliane skeleton for 3 . The relative configuration of 3 was assigned utilizing a NOESY analysis (Figure ) and gauge-independent atomic orbital (GIAO) calculation of the NMR shifts (Supporting Information).…”

Guggulsterone – a potent bioactive phytosteroid: synthesis, structural modification, and its improved bioactivities

“…Additionally, Feng and Zhang developed a novel one-pot system for 18-norsteroid compound under peracetic acid (PAA)/acetic acid condition. 95 The reaction consisted of three steps: epoxidation, stereoselective 1,2-migration, and a chemo-selective epoxidation reaction (Fig. 17).…”

“…derivatives has been reported by several groups [27][28][29]94,95 and compound 30a is one of the hit structurally modified GS molecules showing potent anticancer activity. Therefore, those currently working on this molecule should pay more attention to the area of structural modification and to the aspects of green chemistry and late-stage diversification, especially through C-H bond activation.…”