The reaction mixture (solution or suspension) was stirred at 5 ℃ for 2 hrs and then kept at room temperature (or ambient temperature) for another 2 hrs (or overnight)
The reaction mixture (solution or suspension) was refluxed (or heated to reflux) for 2 hrs (or overnight)
The reaction mixture (solution or suspension) was heated at 60 ℃ for 2 hrs (or overnight)
The reaction mixture (solution or suspension) was allowed to reflux (or heat to reflux) for 2 hrs (or overnight)
After 1 h, TLC analysis (CH2Cl2/hexanes 3:1) showed the complete consumption of compound 15.
The reaction was complete (incomplete or messy) detected by TLC (Petroleum ether/EtOAc 4:1), LC-MS, HPLC or NMR.
The mixture was left standing overnight.
The mixture was allowed to stand at room temperature for 1 day.
The mixture was allowed to stand in a freezer at -15 ℃.
Compound 4A (1.97 g, 6.63 mmol) was coevaporated with toluene five times to remove H2O.
The residue was subjected to toluene azeotrope to give the corresponding acid chloride as a brown oil.
A mixture of compound 1 (190 g, 0.88 mol) and Raney Ni (20 g) in ethanol (1500 mL) and ethyl acetate (500 mL) was stirred under 1 atm of H2 at room temperature for 1 hour.
A mixture of TsOH.H2O (56.91 g, 0.30 mol) and toluene (400 mL) was heated to reflux to remove water by Dean-Stark trap.
The reaction was exothermic.
The sealed vial was irradiated in the microwave on a Biotage Smith Synthesizer at 150 ℃ for 10 min.
After the mixture was heated under microwave irradiation at 130 ℃ for 15 min, Boc2O (33 mg, 157 μmol) and triethylamine (16 μl, 117 μmol) were added.
The mixture was degassed for 10 min and refilled with N2.
The device for absorbing the evolved hydrogen bromide was attached to the reaction flask. [care!! The reaction evolves HBr and is best connected to a HBr gas trap (bubbler containing 1 M NaOH solution)].
To the solution which is protected from light was added dropwise Br2 (3.45 g, 22 mmol) in CH2Cl2 (10 mL) over 5 min and the mixture was stirred for 1 h.
A mixture of compound 8 (213 mg, 0.186 mmol) and compound 9 (220 mg, 0.279 mmol) was refluxed for 20 h under dark in a nitrogen atmosphere.
---有机化学网