Domino reaction of arylglyoxals with pyrazol-5-amines: selective access to pyrazolo-fused 1,7-naphthyridines, 1,3-diazocanes, and pyrroles.
New multicomponent domino reactions of arylglyoxals with pyrazol-5-amines have been established, providing selective access to unprecedented pyrazolo-fused 1,7-naphthyridines, 1,3-diazocanes, and pyrroles (up to 52 examples). The unreported dipyrazolo-fused 1,7-naphthyridines were regioselectively synthesized through a special double [3 + 2 + 1] heteroannulation accompanied by direct C-C formation between two electrophilic sites of arylglyoxals. The unusual [3 + 3 + 1 + 1] cyclization resulted in 20 examples of novel dipyrazolo-fused 1,3-diazocanes, whereas pyrrolo[2,3-c]pyrazoles were obtained in good yields by varying arylglyoxals 1 and pyrazol-5-amines 2 in the ratio 1:2. Mechanisms of formation of these three new types of heterocycles are also proposed.
School of Chemistry and Chemical Engineering, Jiangsu Key Laboratory of Green Synthetic Chemistry for Functional Materials, Jiangsu Normal University , Xuzhou 221116, People's Republic of China.
Bo
B
Jiang
Wei
W
Fan
Mu-Yan
MY
Sun
Qin
Q
Ye
Shu-Liang
SL
Wang
Shu-Jiang
SJ
Tu
Guigen
G
Li
D000588:Amines / Q000737:chemistry*; D002384:Catalysis; D006038:Glyoxylates / Q000737:chemistry*; D015394:Molecular Structure; D009287:Naphthyridines / Q000737:chemistry*; D011720:Pyrazoles / Q000737:chemistry*; D011758:Pyrroles / Q000737:chemistry*; D013237:Stereoisomerism
D000588:Amines; D006038:Glyoxylates; D009287:Naphthyridines; D011720:Pyrazoles; D011758:Pyrroles