A highly chemoselective heteroannulation protocol for the synthesis of unreported polysubstituted heterocyclic [3.3.3]propellanes has been developed by sequential four-component reaction of ninhydrin, malononitrile, primary amines, and dialkyl acetylenedicarboxylates under mild conditions in water. To the best of our knowledge, there are no previous reports for the synthesis of these classes of heterocyclic [3.3.3]propellanes. The merit of this sequential Knoevenagel condensation/enamine formation/Michael addition/cyclization sequence is highlighted by its high atom-economy, excellent yields, the use of water as reaction media, and the efficiency of production without the use of any activator or metal promoters. This synthesis serves as a nice addition to group-assistant-purification (GAP) chemistry in which purification via chromatography and recrystallization can be avoided, and the pure products were obtained simply by washing the crude products with 95% ethanol.

A practical and efficient procedure for the synthesis of polysubstituted azirines and in some cases benzamides was developed through reaction of phenacyl bromides and N,N-dialkylcarbodiimides, in the presence of catalytic amount of isoquinoline in dry acetonitrile under mild conditions at ambient temperature. The salient features of this process include operational simplicity, high yields, and easily accessible starting materials.

An easy, highly efficient, and simple one-pot approach for the synthesis of dihyroindeno[1,2-b]pyrroles and indeno[2¢,1¢:4,5]pyrrolo[1,2-a]-fused 1,3-diazaheterocycles under mild conditions is reported. The reaction of a primary amine or 1,n-diamine with 1,1-bis(methylthio)-2-nitroethene in the presence of ninhydrin in aqueous media afforded the title compounds in good yields.

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The one-pot synthesis of highly functionalized pyrrole derivatives from the reaction of an enaminone, which can be derived from the reaction between two primary amines and diketene, in the presence of nitrostyrene is described. The reaction occurred under neutral conditions and in excellent yields.

An effective route to novel 4‐(alkylamino)‐1‐(arylsulfonyl)‐3‐benzoyl‐1,5‐dihydro‐5‐hydroxy‐5‐phenyl‐2H‐pyrrol‐2‐ones 10 is described (Scheme 2). This involves the reaction of an enamine, derived from the addition of a primary amine 5 to 1,4‐diphenylbut‐2‐yne‐1,4‐dione, with an arenesulfonyl isocyanate 7. Some of these pyrrolones 10 exhibit a dynamic NMR behavior in solution because of restricted rotation around the CN bond resulting from conjugation of the side‐chain N‐atom with the adjacent α,β‐unsaturated ketone group, and two rotamers are in equilibrium with each other in solution (10 ⇌ 11; Scheme 3). The structures of the highly functionalized compounds 10 were corroborated spectroscopically (IR, 1H‐ and 13C‐NMR, and EI‐MS), by elemental analyses, and, in the case of 10a, by X‐ray crystallography. A plausible mechanism for the reaction is proposed (Scheme 4).

in Wiley Online Library (wileyonlinelibrary.com).An efficient, facile, and useful synthetic method was developed for the production of spiro[indoline-3,4 0pyrano-pyrazole] carbonitrile derivatives through a one-pot, four-component reaction involving hydrazine hydrate, diketene, substituted isatins, and malononitrile or ethyl cyanoacetate in the presence of iodine as the efficient catalyst in ethanol at room temperature. Significantly, this remarkable method provides novel spiropyranopyrazole derivatives in good to high yields. The significant aspects of this protocol are facile work-up approach and a greener process because the use of toxic and hazardous solvents are avoided. 6 0 -Amino-5-chloro-3 0 -methyl-2-oxo-1 0 H-spiro[indoline-3,4 0pyrano[2,3-c]pyrazole]-5 0 -carbonitrile (2e).White powder, mp = 295-294°C, 0.28 g, yield: 85%. IR (KBr) (ν max , cm À1 ): 3386 and 3347 (NH 2 ), 3137 (2NH), 2182 (CN), December 2018One-Pot Four-Component Synthesis of Spiro[indoline-3,4 0 -pyrano-pyrazole] Derivatives 2777

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