N-Thiocyanatosaccharin (R) was readily prepared from the sweet additive Saccharin in two steps with a 71% overall yield. By applying this new reagent to diverse nucleophiles such as benzothiophenes, indoles, oxindoles, aromatic amines, phenols, β-keto carbonyl compounds, and aromatic ketones, a novel electrophilic thiocyanation reaction was achieved with high yields (up to 99%). The potential recycling of Saccharin, the wide scope of substrates, and the mild reaction conditions made this protocol much more practical.
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http://dx.doi.org/10.1021/acs.joc.7b02850 | DOI Listing |
Molecules
November 2024
Department of Chemistry, Faculty of Science, Sohag University, Sohag 82524, Egypt.
A series of new quinazolin-2,4-dione derivatives incorporating amide/eight-membered nitrogen-heterocycles -, in addition, acylthiourea/amide/dithiolan-4-one and/or phenylthiazolidin-4-one - and -. The starting compound was prepared by reaction of 4-(2,4-dioxo-1,4-dihydro-2-quinazolin-3-yl)-benzoyl chloride with ammonium thiocyanate and cyanoacetic acid hydrazide. The reaction of with strong electrophiles, namely, -aminophenol, -amino thiophenol, and/or -phenylene diamine, resulted in corresponding quinazolin-2,4-dione derivatives incorporating eight-membered nitrogen-heterocycles -.
View Article and Find Full Text PDFBeilstein J Org Chem
June 2024
Tianjin Key Laboratory for Modern Drug Delivery & High-Efficiency, School of Pharmaceutical Science and Technology, Tianjin University, Tianjin 300072, China.
A series of 4-thio/seleno-cyanated pyrazoles was conveniently synthesized from 4-unsubstituted pyrazoles using NHSCN/KSeCN as thio/selenocyanogen sources and PhICl as the hypervalent iodine oxidant. This metal-free approach was postulated to involve the in situ generation of reactive thio/selenocyanogen chloride (Cl-SCN/SeCN) from the reaction of PhICl and NHSCN/KSeCN, followed by an electrophilic thio/selenocyanation of the pyrazole skeleton.
View Article and Find Full Text PDFOrg Biomol Chem
May 2024
School of Chemistry & Chemical Engineering, Beijing Institute of Technology (Liangxiang Campus), Beijing 102488, China.
A Lewis acid-promoted electrophilic thiocyanation/cyclization of -alkynylanilines for the synthesis of indole derivatives has been developed. The reaction utilizes MeSiBr as the Lewis acid and -thiocyanatosuccinimide as the thiocyanation reagent. A series of 2-aryl-3-thiocyanato indoles were prepared in moderate to high yields under mild conditions without metals and oxidants.
View Article and Find Full Text PDFChem Asian J
February 2024
Physical and Materials Chemistry Division, CSIR-National Chemical Laboratory, Dr.Homi Bhabha Road, Pune, 411008, Maharashtra, India.
The presence of an aromatic additive has been seen to enhance, often significantly, the enantioselectivity and yield in asymmetric organocatalysis. Considering their success across a dizzying range of organocatalysts and organic transformations, it would seem unlikely that a common principle exists for their functioning. However, the current investigations with DFT suggest a general principle: the phenolic additive sandwiches itself, through hydrogen bonding and π⋅⋅⋅π stacking, between the organocatalyst coordinated electrophile and nucleophile.
View Article and Find Full Text PDFChem Rec
March 2024
College of Chemistry and Chemical Engineering, Chemical Synthesis and Pollution Control Key Laboratory of Sichuan Province, China West Normal University, Nanchong, 637000, China.
The process of thiocyanation is a notable chemical conversion owing to the extensive range of applications associated with thiocyanate compounds in the field of organic chemistry. In past centuries, the thiocyanation reaction incorporated metal thiocyanates or thiocyanate salts as sources of thiocyanate, which are environmentally detrimental and undesirable. In recent literature, there have been numerous instances where combined or indirect alternative sources of thiocyanate have been employed as agents for thiocyanation, showcasing their noteworthy applications.
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