19244-11-2Relevant academic research and scientific papers
Synthesis of 1,2,4-oxadiazolidines via [3+2] cycloaddition of nitrones with carbodiimides
Chen, Yuan,Fuyue, Liuting,Wang, Gangqiang,Wang, Hang,Lu, Chun,Guo, Haibing,St. Amant, Chiara,Sun, Shaofa,Xing, Yalan
supporting information, p. 4329 - 4332 (2019/03/19)
An efficient [3+2] cycloaddition of nitrones and carbodiimides has been developed. This 1,3-dipolar cycloaddition features high regioselectivity, mild and metal-free conditions, excellent functional group compatibility, and a broad substrate scope. The X-ray structures of two regio-isomers confirmed the regioselectivity of this transformation.
Tandem regioselective synthesis of tetrazoles and related heterocycles using iodine
Yella, Ramesh,Khatun, Nilufa,Rout, Saroj Kumar,Patel, Bhisma K.
, p. 3235 - 3245 (2011/06/20)
A one-pot, tandem process has been developed for the synthesis of a library of tetrazoles from aryl isothiocyanates. Condensation of aryl isothiocyanates with ammonia, and aryl amines (R-NH2) provided mono, 1,3-disubstituted symmetrical and unsymmetrical thioureas, which on desulfurization with molecular iodine (I2) led to formation of the corresponding heterocumulene (cyanamides or carbodiimides). The in situ generated heterocumulene on subsequent treatment with sodium azide at room temperature gave corresponding tetrazoles. The product regioselectivity for unsymmetrical 1,3-disubstituted thioureas was found to be correlated with the basicities (pKa's) of the parent amines attached to the thiourea. Aryl-sec-alkyl unsymmetrical thioureas gave thioamido guanidino products rather than the 5-aminotetrazoles produced by HgCl2 mediation of the reaction. Bis-thioureas derived from aryl isothiocyanates and hydrazine gave thiadiazoles exclusively.
O-Iodoxybenzoic acid mediated oxidative desulfurization of 1,3-disubstituted thioureas to carbodiimides
Chaudhari, Pramod S.,Dangate, Prasad S.,Akamanchi, Krishnacharya G.
supporting information; experimental part, p. 3065 - 3067 (2011/02/25)
An efficient and mild oxidative desulfurization procedure using o-iodoxybenzoic acid has been developed for the synthesis of carbodiimides starting from easily synthesizable 1,3-disubstituted thioureas.
A greener synthetic protocol for the preparation of carbodiimide
Ali, Abdur Rezzak,Ghosh, Harisadhan,Patel, Bhisma K.
experimental part, p. 1019 - 1021 (2010/04/02)
A new and facile preparation of symmetrical and unsymmetrical 1,3-diaryl and aryl-alkyl carbodiimides via a dehydrosulfurisation of their corresponding thioureas is described. Herein, the classical method of oxidative desulfurisation of thiourea to carbodiimide involving toxic heavy metal oxides (HgO) has been replaced with an easily available, cost-effective and environmentally benign reagent, iodine. Simple reaction conditions, easy purification of the products and high yields are important attributes of the present methodology and perhaps the best alternative from a green chemistry perspective. The only limitation to this method however, is in the preparation of 1,3-dialkyl substituted carbodiimide.
