A synthon approach to spiro compounds

The diterpenoid alkaloids, with an intriguing chemistry and numerous varied bioactivities, constitute the largest and most complicated group of terpenoid alkaloids. Among them, the C19-diterpenoid alkaloids have attracted extensive and lasting attention from researchers. This chapter with 1075 references systematically summarizes the past 30 years of studies on the C19-diterpenoid alkaloids, covering the classification and distribution, biogenesis and biosynthesis, applications in the phytochemotaxonomy of Chinese Aconitum L., spectral properties (1H and 13C NMR, MS), X-ray crystallographic analysis, chemical reactions and chemical conversions (as a continuation of Volume 42 of this treatise), and pharmacological activity of this important group of alkaloids. This review on the C19-diterpenoid alkaloids, in combination with two previous reviews in this treatise (C20-diterpenoid alkaloids, Volume 59, and C18-diterpenoid alkaloids, Volume 67), will present readers with a complete and updated profile of the diterpenoid alkaloids. The only exception is the description of the total syntheses of the diterpenoid alkaloids, which will be summarized in a subsequent individual chapter.

The C19-diterpenoid alkaloids.

Molecular diversity of cycloaddition reactions of the functionalized pyridinium salts with 3-phenacylideneoxindoles

Unexpected formation of a spiro acridine and fused ring system from the reaction between an N-acridinylmethyl-substituted thiourea and bromoacetonitrile under basic conditions.

A fast and convenient protocol for the synthesis of novel spiro[dihydropyridine-oxindole] derivatives in satisfactory yields was developed by the three-component reactions of arylamine, isatin and cyclopentane-1,3-dione in acetic acid at room temperature. On the other hand the condensation of isatin with two equivalents of cyclopentane-1,3-dione gave 3,3-bis(2-hydroxy-5-oxo-cyclopent-1-enyl)oxindole in high yields. The reaction mechanism and substrate scope of this novel reaction is briefly discussed.

https://www.beilstein-journals.org/bjoc/content/pdf/1860-5397-9-2.pdf

Synthesis of spiro[dihydropyridine-oxindoles] via three-component reaction of arylamine, isatin and cyclopentane-1,3-dione

Synthesis and mass fragmentation pattern of fluorinated spiro [3H-indole-3.9′-[9H] xanthene]-1′,2,8′ (1H,2′H,5′H)-triones

Studies in Spiroheterocycles: Part X: Reactions of Diazomethane with 3-Aroylmethylene-indole-2-ones and Synthesis of Some Novel Fluorine Containing Spiro[cyclopropane-1,3'(3H)indol]2'(1'H)-ones

S. Arora

Papers

Synthesis and mass fragmentation pattern of fluorinated spiro [3H-indole-3.9′-[9H] xanthene]-1′,2,8′ (1H,2′H,5′H)-triones

Studies in Spiroheterocycles: Part X: Reactions of Diazomethane with 3-Aroylmethylene-indole-2-ones and Synthesis of Some Novel Fluorine Containing Spiro[cyclopropane-1,3'(3H)indol]2'(1'H)-ones

Ring transformation of some indole derivatives using phase transfer catalysis

Ring Transformation of Some Indole Derivatives Using Phase Transfer Catalysis.

Investigation of the reaction of indole-2,3-diones with benzamidine hydrochloride