Thionation of Optically Pure N-C Axially Chiral Quinazolin-4-one Derivatives with Lawesson’s Reagent

Niijima, Erina; Imai, Tomomi; Suzuki, Hayate; Fujimoto, Yuuki; Kitagawa, Osamu

doi:10.1021/acs.joc.0c02319

Cited by 10 publications

(11 citation statements)

References 24 publications

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“…Racemic and optically pure forms of 3-(2-bromophenyl)-2-methylquinazoline-4(3 H )-thione ( 2a ) and 3-(2-chlorophenyl)-2-methylquinazoline-4(3 H )-thione ( 2b ) were prepared in accordance with the synthetic procedure that we previously reported [ 15 , 16 , 35 ].…”

Section: Methodsmentioning

confidence: 99%

“…These data can be obtained free of charge via , accessed on 3 February 2022. The structural information of CCDC1561609 ( rac - 1a ), 1897963 ( rac - 1b ), and 2032428 [( P )- 2a ] was used [ 16 , 35 ].…”

Section: Methodsmentioning

confidence: 99%

“…Quite recently, we found that optically pure mebroqualone 1a and mecloqualone 1b can be converted to the corresponding thione analogues, i.e. 3-(2-bromophenyl)-2-methylquinazoline-4-thione ( 2a ) and 3-(2-chlorophenyl)-2-methylquinazoline-4-thione ( 2b ), respectively, without a decrease in enantiomeric excess through the reaction with Lawesson’s reagent ( Scheme 1 ) [ 35 ]. The obtained thione derivatives 2a and 2b have higher rotational barriers than the corresponding quinazolinones 1a and 1b .…”

Section: Introductionmentioning

confidence: 99%

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Intermolecular Halogen Bond Detected in Racemic and Optically Pure N-C Axially Chiral 3-(2-Halophenyl)quinazoline-4-thione Derivatives

et al. 2022

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The halogen bond has been widely used as an important supramolecular tool in various research areas. However, there are relatively few studies on halogen bonding related to molecular chirality. 3-(2-Halophenyl)quinazoline-4-thione derivatives have stable atropisomeric structures due to the rotational restriction around an N-C single bond. In X-ray single crystal structures of the racemic and optically pure N-C axially chiral quinazoline-4-thiones, we found that different types of intermolecular halogen bonds (C=S⋯X) are formed. That is, in the racemic crystals, the intermolecular halogen bond between the ortho-halogen atom and sulfur atom was found to be oriented in a periplanar conformation toward the thiocarbonyl plane, leading to a syndiotactic zig-zag array. On the other hand, the halogen bond in the enantiomerically pure crystals was oriented orthogonally toward the thiocarbonyl plane, resulting in the formation of a homochiral dimer. These results indicate that the corresponding racemic and optically pure forms in chiral molecules are expected to display different halogen bonding properties, respectively, and should be separately studied as different chemical entities.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Intermolecular Halogen Bond Detected in Racemic and Optically Pure N-C Axially Chiral 3-(2-Halophenyl)quinazoline-4-thione Derivatives

et al. 2022

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“…Under these extreme conditions, quinazolinone's thionation also decreases optical purity due to rotation around a chiral axis. The above drawbacks were overcome using LR, which is more reactive than P2S5, as demonstrated by Niijima et al [27]. Under xylene reflux conditions, the mebroqualone ( 16) reaction with 1.0 equiv of LR was completed in 3 h to give thioketones in 87% yields, but a decrease in enantiomeric excess (ee; 94%) was observed.…”

Section: Synthesis Of Some Biologically Essential Thioketonesmentioning

confidence: 99%

“…To a solution of oligoamides (0.78 mmol) (27) in dry toluene (20 mL), LR (1.86 mmol) was added to give oligothioamides (28) (Scheme 10). Scheme 10.…”

Section: Synthesis Of Biologically Active Thioamidesmentioning

confidence: 99%

A Focused Review of Synthetic Applications of Lawesson’s Reagent in Organic Synthesis

Khatoon

Abdulmalek

2021

Molecules

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Lawesson’s reagent (LR) is a well-known classic example of a compound with unique construction and unusual chemical behavior, with a wide range of applications in synthetic organic chemistry. Its main functions were rounded for the thionation of various carbonyl groups in the early days, with exemplary results. However, the role of Lawesson’s reagent in synthesis has changed drastically, and now its use can help the chemistry community to understand innovative ideas. These include constructing biologically valuable heterocycles, coupling reactions, and the thionation of natural compounds. The ease of availability and the convenient usage of LR as a thionating agent made us compile a review on the new diverse applications on some common functional groups, such as ketones, esters, amides, alcohols, and carboxylic acids, with biological applications. Since the applications of LR are now diverse, we have also included some new classes of heterocycles such as thiazepines, phosphine sulfides, thiophenes, and organothiophosphorus compounds. Thionation of some biologically essential steroids and terpenoids has also been compiled. This review discusses the recent insights into and synthetic applications of this famous reagent from 2009 to January 2021.

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Six-membered ring systems: diazines and benzo derivatives

Rinderspacher

2023

Progress in Heterocyclic Chemistry

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Thionation of Optically Pure N-C Axially Chiral Quinazolin-4-one Derivatives with Lawesson’s Reagent

Cited by 10 publications

References 24 publications

Intermolecular Halogen Bond Detected in Racemic and Optically Pure N-C Axially Chiral 3-(2-Halophenyl)quinazoline-4-thione Derivatives

Intermolecular Halogen Bond Detected in Racemic and Optically Pure N-C Axially Chiral 3-(2-Halophenyl)quinazoline-4-thione Derivatives

A Focused Review of Synthetic Applications of Lawesson’s Reagent in Organic Synthesis

Six-membered ring systems: diazines and benzo derivatives

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