scholarly journals A selective removal of the secondary hydroxy group from ortho-dithioacetal-substituted diarylmethanols

2018 ◽  
Vol 14 ◽  
pp. 1229-1237
Author(s):  
Anna Czarnecka ◽  
Emilia Kowalska ◽  
Agnieszka Bodzioch ◽  
Joanna Skalik ◽  
Marek Koprowski ◽  
...  
Keyword(s):  
Transition Metal ◽  
Hydroxy Group ◽  
Potential Application ◽  
Selective Removal ◽  
Synthetic Approach ◽  
Secondary Hydroxy Group ◽  
Optoelectronic Materials ◽  
Reaction Proceeds

We present a successful deoxygenation reaction of ortho-1,3-dithianylaryl(aryl)methanols which enables a selective removal of the secondary hydroxy group in presence of the 1,3-dithianyl moiety under reductive conditions. This reaction proceeds well with ZnI2/Na(CN)BH3 in dichloroethane or benzene for both unsubstituted and substituted aryls (by electron-rich groups). This is leading to formyl-protected diarylmethanes with potential application in the synthesis of new pharmaceuticals and optoelectronic materials. This synthetic approach gives an access to a wide variety of functionalized ortho-1,3-dithianylaryl(aryl)methanes in 26–95% yields and is recommended for the substrates containing sulfur atoms, for which transition metal-induced reactions fail.

scholarly journals A Study on the Lipase-catalysed Acylation of 6,7-Dihydroxy-linalool

2016 ◽  
Vol 11 (9) ◽  
pp. 1934578X1601100 ◽  
Author(s):  
Stefano Serra ◽  
Davide De Simeis
Keyword(s):  
Hydroxy Group ◽  
Candida Rugosa ◽  
Secondary Hydroxy Group ◽  
Acylation Reaction ◽  
Novozyme 435 ◽  
Isomeric Purity ◽  
Reaction Proceeds ◽  
Vegetal Species ◽  
Lipase From Candida Rugosa

We here describe a study of the enzyme-mediated acylation reaction of 6,7-dihydroxy-linalool stereoisomers, which are natural triols occurring in different vegetal species. We found that only few lipases are able to catalyze the acylation of the secondary hydroxy group present in these isomers and only lipase from Candida rugosa and novozyme 435 provide either (3 R,6 R)-6-acetoxy-7-hydroxylinalool or (3 R,6 S)-6-acetoxy-7-hydroxylinalool in moderate and very good isomeric purity, respectively Even for these favorable cases the reaction proceeds very sluggishly. Our finding can give a sensible interpretation to the fact that 6-acyl-7-hydroxy-linalool derivatives do not occur in nature, whereas the corresponding glycosides, whose formation is catalyzed by glycosidase, are very common.

A metal-free radical cascade reaction of phosphine oxides with 2-aryloxy phenylacetylenes to assemble diphosphonyl xanthene derivatives

2021 ◽  
Author(s):  
Tao Fan ◽  
Yan Liu ◽  
Caina Jiang ◽  
Yanli Xu ◽  
Yan-Yan Chen
Keyword(s):  
Free Radical ◽  
Transition Metal ◽  
Cascade Reaction ◽  
Phosphine Oxides ◽  
Metal Free ◽  
Mild Conditions ◽  
Xanthene Derivatives ◽  
Reaction Proceeds ◽  
Radical Cascade

A radical cascade reaction of 2-aryloxy phenylacetylene with phosphine oxides promoted by K2S2O8 was developed, provided diphosphonyl xanthenes as products. This reaction proceeds under transition metal-free and mild conditions with...

Diversity-Oriented Synthesis via Catalyst-Free Addition of Ketones to [e]-Fused 1H-Pyrrole-2,3-diones

Synthesis ◽  
2018 ◽  
Vol 50 (24) ◽  
pp. 4897-4904 ◽  
Author(s):  
Ekaterina Stepanova ◽  
Andrey Maslivets ◽  
Svetlana Kasatkina ◽  
Maksim Dmitriev
Keyword(s):  
Intramolecular Cyclization ◽  
Aromatic Hydrocarbons ◽  
Michael Addition ◽  
Aldol Reaction ◽  
Synthetic Approach ◽  
Reaction Conditions ◽  
Diversity Oriented Synthesis ◽  
Catalyst Free ◽  
Solvent Free Conditions ◽  
Reaction Proceeds

A facile synthetic approach towards two distinct pyrrole-based heterocyclic scaffolds has been developed by the interaction of 1H-pyrrole-2,3-diones fused at the [e]-side to a 1,4-benzoxazin-2-one or quinoxalin-2(1H)-one moiety with ketones. The described interaction proceeds either as an aldol reaction or as a Michael addition/intramolecular cyclization depending on the reaction conditions. The disclosed aldol reaction proceeds with good diastereoselectivity under catalyst-free conditions when the reaction is carried out in aromatic hydrocarbons. Products of the cascade Michael addition/intramolecular cyclization reaction are predominantly formed under catalyst-free and solvent-free conditions. The proposed strategy provides facile access to pharmaceutically interesting pyrrole-based polyheterocycles.

scholarly journals Et3N/DMSO-supported one-pot synthesis of highly fluorescent β-carboline-linked benzothiophenones via sulfur insertion and estimation of the photophysical properties

2020 ◽  
Vol 16 ◽  
pp. 1740-1753 ◽  
Author(s):  
Dharmender Singh ◽  
Vipin Kumar ◽  
Virender Singh
Keyword(s):  
Transition Metal ◽  
Elemental Sulfur ◽  
Photophysical Properties ◽  
Quantum Yields ◽  
One Pot ◽  
Light Emitting ◽  
Metal Free ◽  
One Pot Synthesis ◽  
Synthetic Strategy ◽  
Reaction Proceeds

A robust transition-metal-free strategy is presented to access novel β-carboline-tethered benzothiophenone derivatives from 1(3)-formyl-β-carbolines using elemental sulfur activated by Et3N/DMSO. This expeditious catalyst-free reaction proceeds through the formation of β-carboline-based 2-nitrochalcones followed by an incorporation of sulfur to generate multifunctional β-carboline-linked benzothiophenones in good to excellent yields. The synthetic strategy could also be extended towards the synthesis of β-carboline-linked benzothiophenes. Moreover, the afforded products emerged as promising fluorophores and displayed excellent light-emitting properties with quantum yields (ΦF) up to 47%.

Preparation and Conformational Study of B-Ring Substituted Lupane Derivatives

2006 ◽  
Vol 71 (8) ◽  
pp. 1131-1160 ◽  
Author(s):  
Martin Dračínský ◽  
Simona Hybelbauerová ◽  
Jan Sejbal ◽  
Miloš Buděšínský
Keyword(s):  
Double Bond ◽  
Hydroxy Group ◽  
Molecular Modelling ◽  
Nmr Spectra ◽  
Hydroxy Derivative ◽  
Secondary Hydroxy Group ◽  
Conformational Study ◽  
Primary Hydroxy Group ◽  
Type 3 ◽  
C Nmr

New lupane-type triterpenoids with 5(6) double bond were prepared using the method of partial demethylation on carbon C-4. Hydroboration of the double bond led to 6α-hydroxy derivative. By the oxidation and following reduction of 6α-hydroxy derivative the 6-oxo and 6β-hydroxy derivatives were prepared. A new method for selective oxidation of secondary hydroxy group in the presence of primary hydroxy group was performed. The conformation of ring A of new lupane-type 3-oxo derivatives with a substituent on ring B was elucidated on the bases of 1H and 13C NMR spectra and molecular modelling.

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