Yield:5721-91-5 66%

Reaction Conditions:

with immobilized p-toluenesulfonic acid polymer bound macroporous in neat (no solvent) at 100; for 0.0416667 h;Microwave irradiation;Sealed tube;Green chemistry;

Steps:

Tosylic acid-catalyzed synthesis of testosterone esters 2a-e under conventional heating (Method B) and microwave irradiation (Method C).
General procedure: Method C. Testosterone (1, 150 mg, 0.52 mmol), immobilized p-TsOH (6.5 mg, 13 μmol, 0.025 equiv), and the appropriate acyl chloride (3.0 equiv) were placed in a glass microwave vial (10 mL) capped with a Teflon septum, and subjected to microwave irradiation with an initial ramp time of 30 sec. at 35 °C (200 W). The temperature was then increased to 100 °C, using a 200 W MW-source with a holding time of 2.5 or 5 min, respectively (depending on the experiment performed, maximum pressure inside the MW reactor was in the range of 2-4 bars). Afterwards, the reaction was stopped by bringing the content of the vial to room temperature by cooling the jet for 1 min. Next, the crude reaction mixture was dissolved in acetone (3 mL), the immobilized catalyst was removed by filtration under suction, then rinsed with additional portion of acetone (3 mL), and the resulting permeate was evaporated to dryness using rotapovator. The crude oil residues were purified by silica gel column chromatography using gradient of mixture of CHCl3/acetone (99:1, 98:2, 95:5, v/v) to afford the 17β-testosterone esters 2a-e in 23-96% yield, respectively. Physical and spectral data of 2a-e were consistent with the one reported in literature and those obtained via classical route using (Et3N/DMAP)-catalytic system. Attention: The removed p-TsOH catalyst after washing with acetone was dried on standing and used directly in the next charge without additional treatment.

References:

Borowiecki, Pawe?;Kraszewski, Maciej [Arkivoc,2019,vol. 2019,# 6,p. 288 - 305]

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