Figure 1. Structure of mansonone F (1).

Scheme 1. Reagents and conditions: (i) RMgX, CeCl₃, Et₂O, −78 °C; (ii) Pd/C, triglyme, reflux; (iii) BBr₃, CH₂Cl₂, −78 °C, 65–87% for three steps; (iv) PhB(OH)₂, (CH₂O)_n, C₂H₅CO₂H, C₆H₆, reflux; (v) Pd/C, H₂, c-HCl, MeOH/THF(1/3), rt, 68–82%; (vi) BrCH₂CO₂Me, NaH, THF, 40 °C, 89–95%; (vii) LiOH, THF/H₂O (3/1); (viii) (COCl)₂, C₆H₆; reflux; then AlCl₃, CH₂Cl₂, 0 °C, 74-87% for two steps; (ix) MeMgI, Et₂O, rt; (x) Cu(NO₃)₂–xH₂O, Ac₂O, 77–83% for two steps; (xi) Pd/C, H₂, MeOH, rt; (xii) Fremy’s salts, 0.06 M NaH₂PO₄, acetone, rt, 64–81% for two steps; (xiii) H₂SO₄/EtOH (1/20), reflux, 34–72%. a; R¹ = CH₂(CH₂)₂CH₃, b; R¹ = CH₂(CH₂)₃CH₃, c; R¹ = CH₂(CH₂)₄CH₃, d; R¹ = OMe, e; R¹ = H.

Scheme 2. Reagents and conditions: (i) TBSCl, imidazole, DMF, rt, 65%; (ii) Et₂AlCl, (CH₂O)_n, CH₂Cl₂, 0 °C; (iii) Pd-C, H₂, MeOH, rt, 52% for two steps; (iv) BrCH₂CO₂Me, NaH, THF, 50 °C, 97%; (v) BBr₃, CH₂Cl₂, −5 °C, 50%; (vi) TBAF, THF, rt; (vii) Tf₂O, pyridine, CH₂Cl₂, 0 °C, 70% for two steps; (viii) MeMgI, Et₂O, rt, 71%; (ix) Pd(0) catalyzed reaction⁷, 80–91%; (x) Cu(NO₃)₂–xH₂O, Ac₂O, 43–78%; (xi) Pd/C, H₂, MeOH, rt; (xii) Fremy’s salts, 0.06M NaH₂PO₄, acetone, rt, 56–81% for two steps; (xiii) H₂SO₄/EtOH(1/20), reflux, 37–52%. a; R = CHCH₂ b; R = CH₂CHCH₂, c; R = CH₂CHC(CH₃)₂, d; R = CH(CH₃)₂, e R = CO₂Me, a; R¹ = CH₂CH₃, b; R¹ = CH₂CH₂CH₃, c; R¹ = CH₂CH₂CH(CH₃)₂, d; R¹ = CH(CH₃)₂ e; R¹ = CO₂Me.

Scheme 3. Reagents and conditions: (i) NBS, t-BuNH₂, CH₂Cl₂, 0 °C, 40%; (ii) BrCH₂CO₂Me, NaH, THF, 40 °C, 94%; (iii) LiOH, THF/H₂O (3/1); (iv) (COCl)₂, C₆H₆; then AlCl₃, CH₂Cl₂, 83% for two steps; (v) MeMgI, THF, rt, 67%; (vi) Pd(0) catalyzed reaction⁸, 60–81%; (vii) Cu(NO₃)₂–xH₂O, Ac₂O, 45–81%; (viii) Pd/C, H₂, MeOH, rt for 18b–18e and Pd/C, HCO₂NH₄, MeOH, rt for 18a and 18f; (ix) Fremy’s salts, 0.06 M NaH₂PO₄, acetone, rt, 41–83% for two steps; (x) H₂SO₄/EtOH (1/20), 32–48%. a; R = Br, b; R = CHCH₂, c; R = CH₂CHCH₂, d; R = C(O)CH₃, e; R = CO₂Me, a; R² = Br, b; R² = CH₂CH₃, c; R² = CH₂CH₂CH₃, d; R² = C(O)CH₃, e; R² = CO₂Me, f; R² = H.

Antibacterial activities of the synthesized mansonone F analogs against MRSAs

The clinical isolates were obtained from Seoul National University Hospitals in Seoul, Korea.

Antibacterial activities of 8a against MRSA and Gram-positive strains

The clinical isolates were obtained from Seoul National University Hospitals in Seoul, Korea.