Sulfamic Acid: Efficient, Cost-Effective Catalyst for Facile Synthesis of Deazaoxaflavin at Ambient Temperature

<div><p></p><p>A facile, ecofriendly procedure has been developed for the synthesis of substituted 5-deaza-10-oxaflavins by sulfamic acid–catalyzed two-component condensation of salicylaldehyde and barbituric acid at ambient temperature. Mild reaction conditions, short reaction time, ambient temperature, ecofriendly solvent system, wide substrate scope, simple workup procedure, no need for chromatographic separation, and good yields are auxiliary advantages of the present protocol.</p></div

Green Aspect for Multicomponent Synthesis of Spiro[4<i>H</i>-indeno[1,2-b]pyridine-4,3′-[3<i>H</i>]indoles]

<div><p></p><p>An efficient, four-component reaction of isatin, 1,3-indanedione, ethyl acetoacetate, and ammonium acetate in ethanol/water (9:1) system furnished spiro[4<i>H</i>-indeno[1,2-b]pyridine-4,3′-[3<i>H</i>]indoles] at room temperature. Merits of the method are mild reaction conditions, simple workup procedure, and ambient temperature. The synthesized compounds exhibit excellent fluorescence properties.</p></div

Sulfamic Acid: A Mild, Efficient, and Cost-Effective Catalyst for Synthesis of Indoloquinoxalines at Ambient Temperature

<div><p></p><p>A simple, cost-effective method for synthesis of indoloquinoxalines from isatin and <i>o</i>-phenylenediamine employing a catalytic amount of sulfamic acid at ambient temperature is reported. Moreover, the method is applicable for a variety of isatins, ninhydrin, 4-hydroxynaphthaquinone, and 1,2-diketones. The key features of the protocol include rapid reactions with good yields, simple workup procedure, and easy isolation of products.</p> </div