On water: iodine-mediated direct construction of 1,3-benzothiazines from <i>ortho</i>-alkynylanilines by regioselective 6-<i>exo-dig</i> cyclization

Saini, Kapil Mohan; Saunthwal, Rakesh K.; Kumar, Shiv; Verma, Akhilesh K.

doi:10.1039/c9ob00128j

Cited by 11 publications

(12 citation statements)

References 45 publications

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“…Similar to this mechanism, Verma and co‐workers accomplished an iodine‐mediated cascade synthesis of 1,3‐benzothiazines 14 b via the formation of the iodonium ion 15 b and followed by the 6‐ exo‐dig ring closure at ambient temperature (Scheme 5 b). [28b] …”

Section: Iodine‐promoted C−s Bonds Formationmentioning

confidence: 99%

Recent Advances in Iodine‐Promoted C−S/N−S Bonds Formation

Zhang

Wang

Jiang

et al. 2020

Chemistry A European J

111

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Sulfur-containing scaffold, as aubiquitous structural motif, has been frequently used in natural products, bioactive chemicals and pharmaceuticals, particularly CÀS/NÀS bonds are indispensable in many biological importantc ompounds and pharmaceuticals. Development of mild and general methods for CÀS/NÀSb onds formation hasg reat significance in modern research. Iodine and its derivativesh ave been recognizeda si nexpensive,e nvironmentally benign and easy-handled catalysts or reagents to promote the construction of CÀS/NÀSb onds under mild reactionc onditions, with good regioselectivities andb road substrate scope.E specially based on this, severaln ew strategies, such as oxidation relay strategy,havebeen greatlydeveloped and accelerated the advancement of this field. This review focuses on recent advances in iodine and its derivatives promoted hybridized CÀS/NÀSbonds formation.The features and mechanisms of corresponding reactions are summarized and the results of some cases are compared with those of previous reports. In addition, the future of this domain is discussed.

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Section: Iodine‐promoted C−s Bonds Formationmentioning

confidence: 99%

Recent Advances in Iodine‐Promoted C−S/N−S Bonds Formation

Zhang

Wang

Jiang

et al. 2020

Chemistry A European J

111

View full text Add to dashboard Cite

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“…The 6‐ exo‐dig ring closure of the latter gives 177 which is tautomerized to 1,3‐benzothiazines 178 bearing iodo group (Scheme 54). [118] It is noteworthy to mention that the use of isoselenocyanates instead of isothiocyanates gives the selenaquinoline derivatives [119] …”

Section: ‐Alkynylanilines In the Synthesis Of Six‐membered Heterocycl...mentioning

confidence: 99%

“…The 6-exo-dig ring closure of the latter gives 177 which is tautomerized to 1,3-benzothiazines 178 bearing iodo group (Scheme 54). [118] It is noteworthy to mention that the use of isoselenocyanates instead of isothiocyanates gives the selenaquinoline derivatives. [119] Through annulation of 2-alkynylanilines with carbon disulfide catalyzed by protonated 1,8diazabicyclo[5,4,0]undec-7-ene (DBU) a series of benzo[d] [1,3]thiazine-2(4H)-thiones 179 were synthesized (Scheme 55).…”

Section: Benzothiazine Synthesismentioning

confidence: 99%

Annulation of 2‐Alkynylanilines: The Versatile Chemical Compounds

2022

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2-Alkynylanilines as versatile building blocks have been widely applied for the construction of nitrogen atomcontaining heterocycles in organic synthesis. The focus of this review is on the application of 2-alkynylaniline and its derivatives in the metal-catalyzed or metal-free synthesis of various heterocycles including indoles, oxindoles, indazoles, benzisoxazoles, quinolines, benzoxazines, benzothiazines, quinazolines, cinnolines, and seven-and eight-membered heterocycles.

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“…established cascade synthesis of 1,3‐benzothiazine derivatives 35.3 from alkylnyl aniline derivatives 35.1 and aroyl isothiocyanates 35.2 via iodine promoted regioselective 6‐ exo ‐ dig cyclization in water (Scheme 35). [117] According to the proposed mechanism, reactions between 35.1 and 35.2 forms intermediate thiourea 35.1 a . Then the alkyne bond of thiourea 35.1 a interacts with iodonium cation (I + ) to amplify its electrophilic character by making iodonium species 35.1 b .…”

Section: Oxidative Coupling Reactionsmentioning

confidence: 99%

“…[115,116] In 2019, Verma et al established cascade synthesis of 1,3benzothiazine derivatives 35.3 from alkylnyl aniline derivatives 35.1 and aroyl isothiocyanates 35.2 via iodine promoted regioselective 6-exo-dig cyclization in water (Scheme 35). [117] According to the proposed mechanism, reactions between 35.1…”

Section: Cà S Bond Forming Reactionsmentioning

confidence: 99%

Iodine‐Catalyzed or ‐Mediated Reactions in Aqueous Medium

Samanta¹

2021

Asian J Org Chem

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Transition metal‐catalyzed reactions are the heart of modern organic synthetic chemistry. In most cases, the synthesis of target molecules involved at least one or more transition metals such as palladium, ruthenium, rhodium, platinum, iridium, rhenium, cobalt, copper, iron, etc. But these transition metals are costly, toxic, and sometimes very difficult to separate from the target product. Instead of transition metals, molecular iodine or iodide salts have drawn the attention of modern organic synthetic chemists over a few decades due to their inexpensiveness, tolerance, and environmentally benign nature. So molecular iodine or iodide catalyzed reactions are highly efficient, atom‐economical, easy to control, eco‐ friendly protocol rather than transition metal‐catalyzed reactions. But many iodine‐catalyzed or mediated reactions, toxic solvents like tetrahydrofuran (THF), 1,4 dioxane, dimethylacetamide (DMA), dimethylformamide (DMF), benzene, toluene, chlorobenzene, nitrobenzene, n‐hexane, etc. are used which is a major concern in terms of environmental issues. Therefore, our present endeavour focuses on the recent developments (mainly in the period 2005–2020) of the iodine‐catalyzed or iodine‐mediated various reactions like oxidative additions, condensation reactions, C−C, C−N, C−O, C−S cross‐couplings etc. consciously performed in an aqueous medium to avoid environmental hazardous, which is a thrust area to the young researchers.

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On water: iodine-mediated direct construction of 1,3-benzothiazines from ortho-alkynylanilines by regioselective 6-exo-dig cyclization

Abstract: Herein, we report the 6-exo-dig ring closure of ortho-alkynylanilines with readily available aroyl isothiocyanate.

Cited by 11 publications

References 45 publications

Recent Advances in Iodine‐Promoted C−S/N−S Bonds Formation

Recent Advances in Iodine‐Promoted C−S/N−S Bonds Formation

Annulation of 2‐Alkynylanilines: The Versatile Chemical Compounds

Iodine‐Catalyzed or ‐Mediated Reactions in Aqueous Medium

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