182
S. D. Shnyder and C. W. Wright
19
N
SO2Ph
N
22
N
R 1
O
R 3
O2N
R 2
1. nBuLi, THF,
—78°C to r.t.
2.
21
N
SO2Ph
R 1
OH
R 3
O2N
R2
20
SO2Ph
R 1
R 2
R 3
PPh3M, MoO2Cl2(dmf)2,
toluene, reflux, 16 h
aq. NaOH, MeOH,
80°C, 3 h
N
H
22
N
R 1
R 2
R 3
CH3I, sulfolane,
55°C, 16 h
N
H
23
N
R 1
R 2
R 3
I
Fig. 5 Synthesis of 1; involving tandem reductive cyclization; adapted from [7]
Fig. 6 Suggested
mechanisms of reductive
cyclization; adapted from [7]
24 (R groups omitted)
N
SO2Ph
OH
O2N
N
26
N
N
27
N
OH
N
SO2Ph
OH
N
N
SO2Ph
OH
:N
25
PR3
PR3=O
H
H
or
route a
route b
22
– H2O
H
SO2Ph
SO2Ph
OH
H
S. D. Shnyder and C. W. Wright
19
N
SO2Ph
N
22
N
R 1
O
R 3
O2N
R 2
1. nBuLi, THF,
—78°C to r.t.
2.
21
N
SO2Ph
R 1
OH
R 3
O2N
R2
20
SO2Ph
R 1
R 2
R 3
PPh3M, MoO2Cl2(dmf)2,
toluene, reflux, 16 h
aq. NaOH, MeOH,
80°C, 3 h
N
H
22
N
R 1
R 2
R 3
CH3I, sulfolane,
55°C, 16 h
N
H
23
N
R 1
R 2
R 3
I
Fig. 5 Synthesis of 1; involving tandem reductive cyclization; adapted from [7]
Fig. 6 Suggested
mechanisms of reductive
cyclization; adapted from [7]
24 (R groups omitted)
N
SO2Ph
OH
O2N
N
26
N
N
27
N
OH
N
SO2Ph
OH
N
N
SO2Ph
OH
:N
25
PR3
PR3=O
H
H
or
route a
route b
22
– H2O
H
SO2Ph
SO2Ph
OH
H