Synthesis and characterization of new phenyl esters
column containing neutral alumina. The organic solvent was removed in vacuum to
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give a white crystalline solid 5a (0.14 g, 50 %). H NMR (CDCl3): 0.94 (s, 3H);
1.11 (s, 3H); 2.29 (s, 3H); 4.89 (m, 1H); 5.45 (t, 1H, J = 5.0 Hz); 6.72 (t, 1H,
J = 1.7 Hz); 8.20 (m, 2H), 8.23 (m, 2H). 13C NMR (CDCl3): 15.7 (C(18)); 20.7
(C(19)); 22.7 (C(21)); 38.1; 56.4; 75.7 (C(3)); 122.5 (C(6)); 123.5; 130.7; 136.2;
139.8 (C(16)); 144.5 (C(17)); 150.5; 155.3 (C(5)); 164.0 (ester C=O); 196.8 (C(20)).
IR (KBr): m (cm-1) 1,700 (s), 1,609 (s), 1,525 (m), 1,349 (m), 1,278 (s), 841 (m).
MS: m/z (%) 296 (59), 145 (41), 105 (55), 91 (69), 79 (32), 43 (100).
16-DHP (1.0 g, 3.2 mmol) and p-nitrobenzoyl chloride (2.4 g, 12.9 mmol) were
added to a flask containing anhydrous pyridine (12 mL) at 0 °C. The mixture was
heated to 90 °C and stirred for 6 h. After reaction, the resulting mixture was allowed
to cool to room temperature and filtered. The precipitate was washed with water and
dried, then dissolved in ethyl acetate and purified by column chromatography to
give a white crystalline solid 5a (0.89 g, 61 %).
Other steroidal compounds 5b–h were prepared from 16-DHP and corresponding
substituted benzoic acids in a similar procedure, and the physical data of the new
steroids were as follows:
3b-(o-Nitrobenzoyloxy)pregna-5,16-diene-20-one (5b)
White powder. Yield 51 %. M.p. 142–144 °C. Rf 0.54 (petroleum ether/ethyl
acetate, 6:1, v/v). H NMR (CDCl3): 0.93 (s, 3H); 1.07 (s, 3H); 2.27 (s, 3H); 4.89
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(m, 1H); 5.48 (t, 1H, J = 5.2 Hz); 6.75 (t, 1H, J = 1.8 Hz); 7.68 (m, 2H); 7.76 (m,
1H); 7.95 (m, 1H). 13C NMR (CDCl3): 15.7 (C(18)); 20.7 (C(19)); 22.7 (C(21));
76.3 (C(3)); 122.5 (C(6)); 139.9 (C(16)); 144.4 (C(17)); 155.4 (C(5)), 164.9 (ester
C=O); 196.9 (C(20)).
3b-(m-Nitrobenzoyloxy)pregna-5,16-diene-20-one (5c)
White powder. Yield 47 %. M.p. 164–166 °C. Rf 0.68 (petroleum ether/ethyl
acetate, 5:1, v/v). H NMR (CDCl3): 0.94 (s, 3H); 1.08 (s, 3H); 2.28 (s, 3H); 4.94
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(m, 1H); 5.48 (t, 1H, J = 5.0 Hz); 6.75 (t, 1H, J = 1.9 Hz); 7.68 (m, 1H); 8.43 (m,
2H); 8.88 (m, 1H). 13C NMR (CDCl3): 14.1 (C(18)); 20.7 (C(19)); 22.7 (C(21));
75.7 (C(3)); 122.5 (C(6)); 139.9 (C(16)); 144.4 (C(17)); 155.4 (C(5)); 163.9 (ester
C=O); 196.9 (C(20)).
3b-(3,5-Dinitrobenzoyloxy)pregna-5,16-diene-20-one (5d)
White powder. Yield 40 %. M.p. 148–150 °C. Rf 0.62 (petroleum ether/ethyl
acetate, 6:1, v/v). H NMR (CDCl3): 0.95 (s, 3H); 1.11 (s, 3H); 2.27 (s, 3H); 4.99
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(m, 1H); 5.50 (t, 1H, J = 5.2 Hz); 6.75 (t, 1H, J = 2.0 Hz); 9.18 (m, 2H); 9.25 (m,
1H). 13C NMR (CDCl3): 16.4 (C(18)); 18.0 (C(19)); 21.6 (C(21)); 74.7 (C(3));
124.5 (C(6)); 141.9 (C(16)); 146.7 (C(17)); 164.2 (C(5)); 175.6 (ester C=O); 199.2
(C(20)).
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