Phylloxanthobilins are Abundant Linear Tetrapyrroles from Chlorophyll Breakdown with Activities Against Cancer Cells

Linear tetrapyrroles, called phyllobilins, are obtained as major catabolites upon chlorophyll degradation. Primarily, colorless phylloleucobilins featuring four deconjugated pyrrole units were identified. Their yellow counterparts, phylloxanthobilins, were discovered more recently. Although the two catabolites differ only by one double bond, physicochemical...

8m

Silver‐Catalyzed Diastereoselective Synthesis of Spirocyclic Pyrrolidine‐Lactones by 1,3‐Dipolar Cycloaddition

The preparation of two enantiomerically enriched amino lactones as chiral starting substrates for asymmetric 1,3‐dipolar cycloadditions is described. They act as precursors of the chiral imino lactones, which form in situ the corresponding azomethine ylides. They react with with electrophilic alkenes under silver catalysis to afford spirolactone‐pyrrolidines...

8m

A Simple Strategy for the Preparation of P‐Chirogenic Trost Ligands with Different Absolute Configurations

P ‐chirogenic compounds are useful ligands and organocatalysts in asymmetric synthesis. However, the lack of preparative methods and their configurational instability have significantly hampered their development. Herein, we report a simple strategy for the preparation of enantiomerically pure P , C ‐chirogenic diphosphines. Amidation of the borane...

8m

Rhodium‐Catalyzed Reductive Esterification Using Carbon Monoxide as a Reducing Agent

A rhodium‐catalyzed reductive esterification of carboxylic acids with carbonyl compounds was developed. This protocol fits a variety of carboxylic acids and aldehydes, opening the short way from industrial bulk compounds to valuable esters. Carbon monoxide used to have a limited number of applications in organic chemistry, but it gradually...

8m

Facile Synthetic Route to [3.n]Thiacyclophanes through Ring‐Closing Metathesis and their Structural Studies

Here, we are reporting a simple synthetic strategy for the synthesis of thiacyclophanes by using the Grignard reaction and ring‐closing metathesis as key steps. The structures are confirmed by single‐crystal XRD diffraction studies and compared with computationally optimized structures. We report a useful synthetic strategy to assemble constrained...

8m

Metal‐Catalyzed Regiospecific (4+3) Cyclization of 2‐Indolylmethanols with ortho‐Quinone Methides

The first metal‐catalyzed C3‐nucleophilic (4+3) cyclization of 2‐indolylmethanols with stable ortho‐quinone methides has been established, which was used to construct indole‐based seven‐membered heterocycles in high yields (up to 98 %) with regiospecificity. The first metal‐catalyzed C3‐nucleophilic (4+3) cyclization of 2‐indolylmethanols...

8m

From Rare Reagents to Rare Products: Regiospecific Silver‐Catalyzed [3+2] Cycloaddition of Aryl‐, Alkyl‐ and Aminosulfonyl Diazomethanes with Arenediazonium Tosylates

A AgI‐catalyzed [3+2] cycloaddition between diazomethyl sulfones and sulfonamides with arenediazonium tosylates provides regiospecific access to novel tetrazoles. The reaction products can be obtained in moderate to good yields. The scope of silver nitrate‐catalyzed cycloaddition of arenediazonium salts has been expanded to include aryl‐ and...

8m

Solid Phase Synthesis of Sulfonimidamide Pseudopeptides and Library Generation

In this work the sulfonimidamide functionality has been combined with peptides forming sulfonimidamide pseudopeptides as potential new modalities in drug discovery. Three alternative synthetic methods to generate the pseudopeptides have been developed, all harmonized with classical solid‐phase peptide synthesis (SPPS), including both on‐ and off‐resin...

8m

Construction of 6‐aminopyridazine derivatives by the reaction of malononitrile with dichlorosubstituted diazadienes

The reactions of 4,4‐dichloro‐1,2‐diazabuta‐1,3‐dienes with malononitrile resulted in efficient approach to highly functionalized 6‐aminopyridazine derivatives isolated in up to 98%. The process was found to provide straightforward access to the interesting type of nitrogen‐containing heterocycles with an exocyclic double bond. Furthermore, the possibility...

1d

From natural compounds to bioactive molecules by way of NMR and in silico methodologies

Marine and terrestrial organisms are an unlimited source of active secondary metabolites. They, indeed, are well recognized to be characterized by high chemical diversity, biochemical specificity, and other molecular features that make them a validated starting point for lead generation in the drug discovery process. Considering the complex structural...

1d