A Mild Two-Step Synthesis of Structurally Valuable Indole-Fused Derivatives

Abstract

A mild two-step synthetic approach for the preparation of structurally valuable indolo­[3′,2′:4,5]­pyrrolo­[3,2,1-kl]­phenothiazines has been developed. In this work, cyclohexanone was used as the key bridge to connect the indole and phenothiazine frameworks to construct a structurally valuable indole-fused derivative. The present protocol achieved the cascade construction of multiple C–hetero bonds, affording a convenient approach access to hexacyclic-fused system that contained both indole and phenothiazine, two privileged skeletons.

Sodium Periodate (NaIO4) in Organic Synthesis

“…To synthesize structurally valuable indolo[3′,2′:4,5]pyrrolo[3,2,1- kl ]phenothiazines, Deng and his group further devised a mild two-step synthesis approach (Table 1 , E). 11 This chemical system was compatible with a wide range of functional groups, yielding a fair diversity of indolo[3′,2′:4,5]pyrrolo[3,2,1- kl ]phenothiazines. By achieving the cascade synthesis of numerous C–heteroatom bonds, the current methodology provides a straightforward method of accessing a hexacyclic-fused system that contains the two favored skeletons, phenothiazine and indole.…”

Divergent Construction of Thiochromanes and N-Arylbutanamides via Arylthiodifluoromethyl Radical-Triggered Cascade of Alkenes

“…On the other hand, sulfur-containing heterocycles are an important class of structural motifs found in bioactive compounds and natural products. − For example, the thiochromanes shown in Scheme a were thio analogues of the naturally occurring chromanes and flavonoid compounds, displaying a variety of bioactivities such as anti-HIV activity, finity to 5HT A1 receptors in human and rat brains, antagonistic and antibacterial activity, etc. − In view of its good application value, many research groups are working on the synthesis of sulfur-containing heterocycles through photochemistry-promoted, metal- or organic-catalyzed cascade reactions. − Conventional approaches for straightforward access to thiochromanes involve a transition-metal-catalyzed C–S cross-coupling reaction. A novel work to access thiochromanes was reported by the Kurahashi and Matsubara’ group through Ni-catalyzed intermolecular cycloadditions of thiophthalic anhydrides with alkynes (Scheme b) .…”

Brønsted Acid Promoted Facile Synthesis of Benzoacridines from Aromatic Aldehydes and N‐Phenyl Naphthylamines

“…Inspired by the Bernthsen Acridine Synthesis and our ongoing interest in the construction of nitrogen‐containing polyaromatic hydrocarbons (NPAHs), [27–36] we envision that N ‐phenyl naphthylamines can react with aldehydes to produce benzo[ a ]acridines via electrophilic annulation process. After continuous attempts, herein we describe a Brønsted acid promoted facile synthesis of benzoacridines from aromatic aldehydes and N ‐phenyl naphthylamines ( Scheme 1, e ).…”