Benzoic anhydride → 10-benzoyl-10deacetylbaccatin III

Beteiligte Stoffe

Reaktionsschritte

To a solution of 50 mg (91.9 μmol) of 10-deacetylbaccatin III and 13 μL (1.5 eq.) of benzoic anhydride in 2.0 mL of freshly distilled tetrahydrofuran 100 μL of a solution of 5.8 mg of commercial ytterbium trifluoromethanesulfonate hydrate in 1.0 mL of tetrahydrofuran was added. The reaction mixture was stirred at room temperature for 48 hours. Usual workup and isolation of the product by means of preparative TLC (Silica 60, CH2Cl2/MeOH 10:1) afforded 11 mg unreacted 10-deacetylbaccatin III (22%) along with 29 mg of 10-benzoyl-10deacetylbaccatin III (62%), m.p. 154°-156° C. C36H40O11 calculated C 66.66% H 6.22% measured C 66.50% H 6.23%. 1H-NMR (300 MHz, CDCl3) δ (ppm)=1.18 (s, 3H), 1.25 (s, 3H), 1.69 (s, 3H), 1.80-1.93 (m, 1H), 2.09 (s, 3H), 2.16-2.23 (m, 2H), 2.29 (s, 3H), 2.53-2.61 (m, 1H), 3.95 (d, 1H, J=6.9), 4.17 (d, 1H, J=8.3), 4.32 (d, 1H, J=8.3), 4.55 (dd, 1H, J=6.6, 10.6), 4.91 (br t, 1H, J=7.9), 5.00 (d, 1H, J=9.2), 5.67 (d, 1H, J=6.9), 6.59 (s, 1H), 7.40-7.52 (m, 4H), 7.54-7.61 (m, 2H), 8.04-8.14 (m, 4H).

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