[bmIm]OH: an efficient basic catalyst for the synthesis of 4H-benzo[d][1,3-]oxazin-4-one derivatives in solvent-free conditions

Reusable [bmIm]OH was found to be a highly efficient renewable homogenous catalyst for the rapid and convenient synthesis of benzoxazine-4-one derivatives from o-iodobenzoic-acid and benzonitrile at 75 °C in moderate to good yields. This methodology provides a facile and straightforward path to construct other related heterocycles in an eco-compatible fashion.     

Basic Ionic Liquid Promoted Domino Knoevenagel–Thia‐Michael Reaction: An Efficient and Multicomponent Strategy for Synthesis of 1,3‐Thiazines

An efficient, three‐component strategy for synthesis of 1,3‐thiazines with high atom economy in one‐pot mediated by room temperature basic ionic liquid is described here. The strategy involves basic ionic liquid, [bmim]OH‐catalyzed Knoevenagel condensation between ethyl cyanoacetate and aromatic aldehyde and subsequent thia‐Michael addition with substituted thioureas. The reaction sequence is smooth and quantitative under ambient temperature. [bmim]OH was recovered and reused four times without any appreciable decrease in its reactivity and product yield.     

An Efficient One‐Pot Regioselective Approach Towards the Synthesis of Thiopyrano[2,3‐d]thiazole‐2‐thiones Catalyzed by Basic Ionic Liquid under Microwave Irradiation

A green, regioselective protocol for the synthesis of thiopyrano[2,3‐d]thiazole‐2‐thiones catalyzed by basic ionic liquid [bmIm]OH has been developed. The reaction proceeds smoothly under microwave irradiation, and high yields of the products are obtained in very short reaction times (5–11 min). The ionic liquid plays a dual solvent‐catalyst role.     

Novel ionic liquid–mediated approach for the synthesis of tetracyclic[6,5,5,5]indole ring

A novel acidic ionic liquid–catalyzed protocol for the synthesis of diversely substituted tetracyclic indole core has been devised. The application of ionic liquid provides this methodology with various merits over conventional methods regarding reaction time, yield, and ease of handling. Acidic ionic liquid has been employed as a catalytic agent in this protocol.     

Catalyst‐Free Convergent Approach for the Synthesis of Spiro[imidazo[2,1‐b][1,3]oxazine‐7,3′‐indoline

Strategies to address mounting environmental concerns with current approaches include an operationally simple and highly efficient one‐pot three‐component approach for the synthesis of spiro[imidazo[2,1‐b][1,3]oxazine‐7,3′‐indoline derivatives, which has been developed via Huisgen zwitter ion intermediate. The significant advantages of this protocol are short reaction time, excellent yields, and facile formation of three new bonds in one operation from easily available starting materials.     

Visible light promoted formation of N─S bond by photocatalyst Eosin Y

A novel efficient protocol for the synthesis of 5-imino-1,2,4-thiadiazole motif in open air and visible light has been reported. The reaction involves Eosin Y as photocatalyst which is a cost-effective organic dye. The designed protocol represents a novel, mild, metal free, green strategy for the construction of 1,2,4-thiadiazole nucleus by intramolecular cyclization via N─S bond formation. The reaction has been carried out under visible light exposure in ethanol: water (4:1) mixture using 2-aminopyridine and isocyanate as reactants.