Synthesis of [1,3]thiazolo[3,2-b][1,2,4]triazol-7-ium and [1,2,4]triazolo[5,1-b][1,3]thiazin-4-ium salts via regioselective electrophilic cyclization of 3-[(2-alken-1-yl)sulfanyl]-4H-1,2,4-triazoles

AbstractA convenient procedure for the regioselective preparation of [1,3]thiazolo[3,2-b][1,2,4]triazol-7-ium 10 and [1,2,4]triazolo[5,1-b][1,3]thiazin-4-ium salts 9 via regioselective electrophilic cyclization of 3-[(2-alken-1-yl)sulfanyl]-4H-1,2,4-triazoles 3 is reported. Direction of electrophilic heterocyclization strongly depends on nature of the alkenyl substitutent.

Download Full-text

Electrophilic cyclization of propargyl thioethers of 3-methyl(phenyl)-2-(prop-2-yn-1-ylthio)-7-(trifluoromethyl)quinazolin-4(3H)-ones by tellurium tetrahalides

Voprosy Khimii i Khimicheskoi Tekhnologii ◽

10.32434/0321-4095-2021-139-6-40-44 ◽

2021 ◽

pp. 40-44

Author(s):

D.Zh. Kut ◽

◽

M.M. Kut ◽

M.Yг. Onysko ◽

V.G. Lendel

Keyword(s):

Intramolecular Cyclization ◽

Room Temperature ◽

Biologically Active ◽

Electrophilic Cyclization ◽

Angular Structure ◽

Cyclization Process ◽

Electrophilic Heterocyclization ◽

Methyl Phenyl ◽

Hydrohalic Acid

The paper presents the results of the study of the process of electrophilic intramolecular cyclization of 3-methyl(phenyl)-2-(prop-2-yn-1-ylthio)-7-(trifluoromethyl)quinazolin-4(3H)-ones by tellurium tetrahalides. 3-Methyl(phenyl)-2-(prop-2-yn-1-ylthio)-7-(trifluoromethyl)quinazolin-4(3H)-ones were prepared by the alkylation of the corresponding thions with propargyl bromide in an alkaline alcohol medium. It is found that the interaction of propargyl thioethers of 3-substituted 2-thioxo-7-(trifluoromethyl)-2,3-dihydroquinazolin-4(1H)-ones with tellurium tetrahalides, which were obtained in situ from tellurium dioxide and six equivalents of corresponding concentrated hydrohalic acid, leads to the formation of halides of angular 4-methyl(phenyl)-5-oxo-1-((trihalotellanyl)methylidene)-8-(trifluoromethyl)-1,2,4,5-tetrahydrothiazolo[3,2-a]quinazolin-10-iums. The most optimal conditions for the tellurium-induced electrophilic heterocyclization of propargyl thioethers with tellurium terahalides are the use of glacial acetic acid as a solvent and stirring of the reaction mixture at room temperature for 24 hours. It is found that the electrophilic cyclization of 3-methyl(phenyl)-2-(prop-2-yn-1-ylthio)-7-(trifluoromethyl)quinazolin-4(3H)-ones by tellurium tetrahalides occurs stereoselectively with the formation of one configurational isomer. The influence of the nature of halogen in the electrophilic reagent and the substituent in position 3 of quinazoline is examined and it is found that these factors do not affect the regioselectivity of the electrophilic intramolecular cyclization process. As a result of the conducted study, potentially biologically active salts of tellurofunctionalized thiazolinoquinazolines of angular structure were received.

Download Full-text

Recent Progress in Chemosensors Using Aldehyde-bearing Fluorophores for the Detection of Specific Analytes and their Bioimaging

Current Medicinal Chemistry ◽

10.2174/0929867325666180117095528 ◽

2019 ◽

Vol 26 (21) ◽

pp. 4003-4028 ◽

Cited By ~ 1

Author(s):

Fangjun Huo ◽

Yaqiong Zhang ◽

Caixia Yin

Keyword(s):

Biomedical Research ◽

Nucleophilic Addition ◽

Recent Progress ◽

Biological Imaging ◽

Tissue Imaging ◽

Fluorescence Probes ◽

Biological Applications ◽

Convenient Procedure ◽

Nucleophilic Mechanism

In recent years, aldehyde-appended fluorescence probes have attracted increasing attention. Fluorescent biological imaging includes many modern applications for cell and tissue imaging in biomedical research. Meanwhile, the nucleophilic mechanism is a very simple and convenient procedure for the preparation of aldehyde-sensing probes. This tutorial review focuses on aldehyde-bearing chemosensors based on nucleophilic addition mechanism with biological applications.

Download Full-text

Synthesis of Novel Bis-pyrazoles via Electrophilic Cyclization

Letters in Organic Chemistry ◽

10.2174/1570178615666181106155555 ◽

2019 ◽

Vol 16 (6) ◽

pp. 511-516

Author(s):

Adnan Cetin

Keyword(s):

13C Nmr ◽

Cyclization Reaction ◽

Electrophilic Cyclization ◽

Pyrazole Derivatives ◽

Spectral Analyses ◽

Mass Spectral ◽

Palladium Catalyzed ◽

Ft Ir ◽

Reaction Compound

Efficient steps towards the synthesis of novel (phenyl)(1'-aryl-1,5,5'-triphenyl[3,3'-bi-1Hpyrazol]- 4-yl)methanones 4a-e were developed. The procedure starts from 1-(4-benzoyl-1,5-diphenyl- 1H-3-pyrazolyl)-3-phenyl-2-propyn-1-one (2) which was synthesized by a palladium catalyzed crosscoupling reaction. Compound 2 reacted with various hydrazines to give (E)-(phenyl)[1,5-diphenyl-3- [3-phenyl-1-(2-arylhydrazono)-2-propyn-1-yl]-1H-4-pyrazolyl]methanones E-3a-e. The bis-pyrazole derivatives 4a-e were synthesized from electrophilic cyclization reaction of α,β-acetylenic hydrazones E-3a-e and copper(I) iodide. All synthesized compounds were characterized by FT-IR, 1H, 13C NMR and Mass spectral analyses.

Download Full-text