https://s3-eu-west-1.amazonaws.com/pstorage-acs-6854636/5931213/ol6b02464_si_001.pdf

Copper Nitrate Mediated Regio- and Stereoselective Difunctionalization of Alkynes: A Direct Approach to α-Chloro-β-nitroolefins

The tripeptide Tyr–Gly–Ser and a series of conjugations to coumarin, cinnamic and gallic acid were synthesized in salt form and their antioxidant and antimicrobial activities were investigated. The N-connecting hydroxycoumarin, cinnamic and gallic acid derivatives to peptides and the use of BBr3 as a demethylating agent for peptides was reported. Their activities were investigated based on the conjugated moiety structures. Studies of their activities showed that conjugated tripeptides 7,8-dihydroxycoumarin-peptide (17), caffeic acid-peptide (22) and gallic acid-peptide (28) were found to be superior to ascorbic acid with respect to their antioxidant activity, and 12, 14, 24, and 25 exhibited the most antimicrobial activity in the series compared to amoxicillin. Additionally, the incredible florescence intensity and brightness of 17 in water and DMSO, compared to other synthesized compounds, qualified this peptide as a suitable probe in the human body.

Peptides N -connected to hydroxycoumarin and cinnamic acid derivatives: synthesis and fluorescence spectroscopic, antioxidant and antimicrobial properties

A one-pot reaction was developed for the synthesis of polyfunctionalized 1,1'-(α,ω-alkanediyl)bis(1,2,3,4-tetrahydropyridines) in 28–69% yields on the basis of a three-component reaction between 1,3-dicarbonyl compounds, aqueous 33% solution of formaldehyde, and α,ω-diamines.

Synthesis of polyfunctionalized 1,1'-(α,ω-alkanediyl)bis(1,2,3,4-tetrahydropyridines)

The multicomponent reaction of aldehydes, cyano-containing C-H acids, esters of 3-oxocarboxylic acid and ammonium acetate led to unexpected results. The boiling of starting materials in methanol for one to two hours resulted in the formation of polysubstituted 1,4,5,6-tetrahydropyridines with two or three stereogenic centers. During the 2020 lockdown, we obtained key intermediates of this six-step domino reaction. A number of fast and slow reactions occurred during the prolonged stirring of the reaction mass at rt. Sequence: 1. Knoevenagel condensation; 2. Michael addition; 3. Mannich reaction; 4. cyclization—fast reactions and cyclization of the product polysubstituted 2-hydroxypiperidine—was isolated after 40 min stirring at rt. Further monitoring proved the slow dehydration of 2-hydroxypiperidine to obtain 3,4,5,6-tetrahydropyridine after 7 days. Then, four-month isomerization occurred with 1,4,5,6-tetrahydropyridine formation. All reactions were stereoselective. Key intermediates and products structures were verified by X-ray diffraction analysis. Additionally, we specified conditions for the selective intermediates’ preparation.

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Tetrahydropyridines’ Stereoselective Formation, How Lockdown Assisted in the Identification of the Features of Its Mechanism

The reaction of ethyl benzoylacetate with formaldehyde and primary amines in boiling pyridine or methanol afforded new 1,2,3,4-tetrahydropyridine derivatives and substituted hexahydropyrimidines.

Nan ShiBin

Papers

Novel nitenpyram analogues with tetrahydropyridone-fixed cis-configuration : synthesis, insecticidal activities, and molecular docking studies