Syntheses of Nitrogen Heterocycles from Pyridines Christopher D. Vanderwal, Department of Chemistry, University of California–Irvine substituted indoles with propenal group at C3
Suzuki coupling
R1
R
R1
CHO
BrCN, EtOH/H2O
X
R
63–87% yield NH2
X
N H
N
H2O R1
R = 4-OMe, 5-OMe, 4-CF3, 5-CF3, 4-F, 5-Cl, 6-Br R1 = H, Me X = CH, N
BrCN
R
N R X
N H
R1
R1
CN
R1
X R H2N
N
X Br
N H
CN
R
N
X
CN
N H
N
CN
6π retro electrocyclization, or expulsion of the electron-deficient cyanamide followed by tautomerization R1O
CONR2
H
Cl NO2
NO2
NHBz
N
n-BuOH, 100 °C
HN
NHBz
Me2NH (4 equiv.) EtOH, 50 °C N Ar
Cl
then NaOH/H2O 57% yield, 2 steps
CHO N Bz
dihydropyrrole core of porothramycins
N
X O Y
porothramycin A : R=Me, R1=H, X=OMe, Y=H porothramycin B : R=Me, R1=Me, X=OMe, Y=H anthramycin : R=H, R1=Me, X=OH, Y=Me