New and simple synthesis of acid azides, ureas and carbamates from carboxylic acids: application of peptide coupling agents EDC and HBTU
作者:Vommina V. Sureshbabu、H. S. Lalithamba、N. Narendra、H. P. Hemantha
DOI:10.1039/b920290k
日期:——
Conversion of carboxylic acids into acid azides using peptide coupling agents, EDC and HBTU is described. The procedure is efficient, practical and applicable to a diverse range of carboxylic acids including N-protected amino acids. Using the same reagents, one-pot synthesis of ureas, dipeptidyl urea esters and carbamates from acids has also been achieved.
Modified Borohydride Agents; Efficient Reduction of Azides with (1,4-Diazabicyclo[2.2.2]octane) (Tetrahydroborato)zinc Complex [Zn(BH<sub>4</sub>)<sub>2</sub>(dabco)] and Methyltriphenylphosphonium Tetrahydroborate [MePh<sub>3</sub>P<sup>+</sup>BH<sub>4</sub><sup>−</sup>]
作者:H. Firouzabadi、M. Adibi、B. Zeynizadeh
DOI:10.1080/00397919808005968
日期:1998.4
Abstract (1,4-Diazabicyclo[2.2.2]octane)(tetrahydroborato)zinc complex and methyltriphenylphosphonium tetrahydroborate are stable modified borohydrides which are used for the efficient reduction of aryl, alkyl, and aroyl azides with excellent yields in THF or CH2Cl2 at room temperature or under reflux conditions.
cascade reaction of azides with isonitrile and amines is presented; it offers an alternative facile approach toward N-sulfonyl-, N-phosphoryl-, and N-acyl-functionalized guanidines in excellent yield. These series of substituted guanidines exhibit potential biological and pharmacological activities. In addition, the less reactive intermediate benzoyl carbodiimide could be isolated by silica gel column flash
Visible light C–H amidation of heteroarenes with benzoyl azides
作者:E. Brachet、T. Ghosh、I. Ghosh、B. König
DOI:10.1039/c4sc02365j
日期:——
direct and atom economic C–Hamidation of electron rich heteroarenes in the presence of phosphoric acid, a photocatalyst and visible light. Hetero-aromatic amides are obtained in good yields at very mild reaction conditions with dinitrogen as the only by-product. The reaction allows the use of aryl-, heteroaryl- or alkenyl acyl azides and has a wide scope for heteroarenes, including pyrroles, indole
developed methodology rendered the use of carboxylic acids as a direct surrogate of primary amines, for the synthesis of primary ureas, secondary/tertiaryureas, O/S-carbamates, benzoyl ureas, amides, and N-formyls, exploiting the Curtius reaction. This approach has a potential to provide a diversified library of N-containing compounds, starting from a single carboxylic acid, based on the selection of the