ChemicalBook CAS DataBase List Exemestane

Exemestane synthesis

10synthesis methods

Product Name:Exemestane
CAS Number:107868-30-4
Molecular formula:C20H24O2
Molecular Weight:296.4

Exemestane is an irreversible steroid aromatase inhibitor. Its structure is similar to that of aromatase’s natural substrate, androstenedione, and acts as a pseudosubstrate.Exemestane is synthesized by using androstere-4-ene-3, 17-dioneas raw material, 6-methylene androstere-4-ene-3, 17-dione is prepared by condensation with triethyl orthoformate, N-methylaniline and 40% formaldehyde solution. Then oxidize it with 2, 3-dichloro-5, 6-dicyanobenzoquinone (DDQ) to get exemestane.

19457-55-7 Synthesis

19457-55-7
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$46.00/1g

107868-30-4
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$28.00/5mg

Yield:107868-30-4 81.8%

Reaction Conditions:

with N,O-Bis(trimethylsilyl)trifluoroacetamide;chloranil;trifluorormethanesulfonic acid in toluene at 108 - 110; for 0.75 h;Product distribution / selectivity;Heating / reflux;

Steps:

1
EXAMPLE 1 Obtaining 6-methylenandrost-1,4-dien-3,17-dione; [Show Image] A mixture of 1 g of 6-methylenandrost-4-en-3,17-dione (3.5 mmol), 0.91 g of 2,3,5,6-tetrachloro-1,4-benzoquinone (chloranil) (3.7 mmol), 80 ml of toluene, 0.03 ml of trifluoromethanesulfonic acid (0.35 mmol) and 3.74 ml of bis(trimethylsilyl)trifluoroacetamide (BSTFA) (14.1 mmol) is stirred at reflux temperature (about 108-110°C) for 45 minutes. The mixture is then cooled at room temperature (20-22°C) and washed 6 times with a 2% aqueous sodium hydroxide solution (20 ml each time) and 3 times with a 30% aqueous sodium chloride solution. The organic phase is evaporated under reduced pressure, the solvent is substituted with heptane and the suspension is cooled. The product is filtered, washed with cold heptane and dried, obtaining 0.81 g [Yield : 81.8%] of crude 6-methylenandrost-1,4-dien-3,17-dione. The product can be purified by recrystallization in solvents or mixtures of solvents (ethyl acetate, ethyl acetate/heptane, ethanol or ethanol/water). The recrystallized solid has a melting point (m.p.) of 191-194°C and the following spectroscopic characteristics: ¹H-NMR (DMSO-d₆) : 0.83 (3H, s, CH₃ 18), 1.09 (3H, s, CH₃ 19), 1.30-1.80 (10 H), 1.99 (1H, dt, J 9.6; 18.8 Hz, H16), 2.39 (1H, dd, J 8.8; 18.8 Hz, H16), 5.01 (2H, s, H 6a), 5.96 (1H, s, H4), 6.12 (1H, d, J 10.0 Hz, H2), 7.22 (1H, d, J 10.0 Hz, H1). ¹³C-NMR (DMSO-d₆): 14.1 (CH₃ 18), 20.1 (CH₃ 19), 22.0 (CH₂), 22.2 (CH₂), 31.5 (CH₂), 35.3 (CH), 35.9 (CH₂), 39.2 (CH₂), 44.1 (C 13), 47.7 (C 10), 49.9 (CH), 50.3 (CH), 112.8 (C 6 a), 122.4 (C4), 127.6 (C3), 146.1 (C5), 155.8 (C1), 168.2 (C6), 185.7 (C3), 219.7 (C17).