Entry
|
Compound
|
R1
|
R2
|
R3
|
R4
|
Yield% under microwave irradiation†
|
Yield% using traditional conditions‡
|
---|
1
|
7a
|
OH
|
H
|
H
|
H
|
70
|
69
|
2
|
7b
|
H
|
OH
|
H
|
H
|
82
|
66
|
3
|
7c
|
H
|
H
|
OH
|
H
|
71
|
71
|
4
|
7d
|
OH
|
H
|
OH
|
H
|
n/a
|
76
|
5
|
7e
|
OH
|
H
|
H
|
Br
|
78
|
64
|
6
|
7f
|
OH
|
OMe
|
H
|
H
|
72
|
69
|
7
|
9a
|
H
|
-
|
-
|
-
|
92
|
67
|
8
|
9b
|
OH
|
-
|
-
|
-
|
72
|
62
|
- † Isolated yield after microwave dielectric heating in EtOH at 120°C for 10 min (hold time) in a sealed tube using a CEM Discover single-mode microwave synthesizer by moderation of the initial magnetron power (20–150 W), followed by purification by recrystallization (EtOH). ‡ Isolated yield after reaction by traditional conductive heating at reflux in MeOH in the presence of AcOH for 1–4 h and purification by recrystallization (EtOH or EtOH–CHCl3) (see reference 20 for details). n/a Experiment not investigated.