An environmentally benign and efficient synthesis of substituted benzothiazole-2-thiols, benzoxazole-2-thiols, and benzimidazoline-2-thiones in water

Abstract

An efficient and practical method for the one-step synthesis of benzothiazole-2-thiols, benzoxazole-2-thiols and benzimidazoline-2-thiones in water was described.

Three-Component Synthesis of 2-Alkylthiobenzoazoles in Aqueous Media

“…To further confirm the structure of the desired product, the product 3p was characterized by X-ray crystallography (Figure 2). 20 According to the above results and our previous work on C-S formation, 18 we propose a possible pathway as shown in Scheme 5. TMTD A reacts with aniline B to generate intermediate thiourea C, the XH (X = O, S, NH) undergoes intramolecular nucleophilic addition giving intermediate D.…”

“…17 Recently, from the green and environmental point of view, we reported that tetramethylthiuram disulfide (TMTD) was a very useful sulfur reagent for organic synthesis. 18 As part of our efforts in organosulfur chemistry and our progress in metalfree synthesis, 19 here we would like to demonstrate a convenient and efficient protocol for the synthesis of 2-alkylsubstituted thiobenzoxazoles in a one-pot manner. The further survey on alkane halides (this work) could illustrate its good substrate adaptability, providing an easy, green, and high-efficient way to establish molecular libraries for the pharmaceutical industry.…”

A Review on Domino Condensation/Cyclization Reactions for the Synthesis of 2‐Substituted 1,3‐Benzothiazole Derivatives

“…Recently, our group reported an efficient green synthesis of benzothiazole‐2‐thiols, benzoxazole‐2‐thiols and benzimidazoline‐2‐thiones by cyclization of 2‐aminothiophenols, 2‐aminophenols, and 1,2‐phenylenediamines with tetramethylthiuram disulfide (TMTD) as thiocarbonylation trigger in water [Eq. (43)].…”

Metal-free C–H mercaptalization of benzothiazoles and benzoxazoles using 1,3-propanedithiol as thiol source

“…Conventional methods for the synthesis of 2-mercaptobenzoxazoles and 2-mercaptobenzothiazoles include the interaction of 2-aminophenol or 2-haloanilines with carbon disulfide [14–16], or potassium ethyl xanthate [17–18] (Scheme 1). In 2017, the Dong group reported a new method for the synthesis of 2-mercaptobenzoxazoles and 2-mercaptobenzothiazoles by cyclization of 2-aminothiophenols or 2-aminophenols with tetramethylthiuram disulfide in water [19]. Very recently, the Liu group developed a novel protocol for the synthesis of 2-mercaptobenzothiazoles via a three-component reaction of o -iodoanilines and K 2 S in DMSO [20].…”