First Evidence of 1,3-Bis-indolylallenes: Generation by a Sequential Double Nucleophilic Process from Ynones

<div><p></p><p>The first examples of 1,3-bis-indol-3-ylallenes (1,3-BIAs) are described. They have been generated by addition of a 3-lithioindole reactant to tetramethylsilane-protected mono- and di-alkynyl ketones. The one-pot preparation of 1,3-BIAs is enabled by both the double electrophilic character of the ynone substrates and the double nucleophilic character of the lithio-enamine function of the indolyl moiety, leading to a transient azafulvenium intermediate.</p> </div

High Throughput Synthesis of Extended Pyrazolo[3,4-<i>d</i>]dihydropyrimidines

Thirteen 5-hetarylaminopyrazoles were synthesized in 62–93% yield through the arylation of 1-isopropyl- and 1-phenyl-5-aminopyrazoles with electrophilic hetarylhalides under optimized conditions. Condensation of 5-hetarylaminopyrazoles with carbonyl compounds facilitated by AcOH or Me₃SiCl furnished 23 pyrazolo­[3,4-<i>d</i>]­dihydropyrimidines in 69–86% yield. The target compounds were isolated through simple crystallization. The scope and limitation of the method are discussed