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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.Dicyclohexylcarbodiimide (DCC) is used in automated stepwise synthesis of polypeptides to activate the carboxyl group, for example, in the Merrifield method for the synthesis of the polypeptide ribonuclease A, consisting of 124 amino acids. 1 Oligonucleotides are also synthesized using carbodiimides in automated condensation steps. 2 Carbodiimides have been extensively used in organic synthesis as auxiliary reagents in reactions such as Moffatt oxidation of primary alcohols to aldehydes using DCC/ DMSO combination, conversion of alcohols or phenols into hydrocarbons via hydrogenation of acylisoureas derived from the corresponding carbodiimide adducts, and dehydration of aldoximes to nitriles and others. 3 Carbodiimides have also found use as key synthetic intermediates in agricultural chemicals 4 and pharmacologically active compounds viz. substituted indoles, quinolidines, and isoquinolines displaying strong cytostatic antitumor activity. 5 Aromatic carbodiimides have huge industrial applications such as stabilizers for polyester-based polyurethanes. 6Methods available for synthesis of carbodiimides can be broadly classified into three categories:(i) Thermolysis-decarboxylation of isocyanates. 7 Generally, these reactions are carried out at high temperature in the presence of metal catalyst and silicon-based reagents. 7b However, this approach suffers from drawbacks including low yields, use of toxic transition metals such as palladium and nickel, toxic waste generation and formation of dimers or polymers. 7c (ii) Dehydration of ureas. 8 Dehydration is effected using phosgene and alkyl/arylsulfonyl reagents in combination with bases. Although the process generally results in good yields, the major concern is formation of highly reactive side products such as N,N-dimethylcarbamoyl chloride, excessive use of triethylamine 8a as base and possibility of product instability during isolation after aqueous workup.(iii) Desulfurization of thioureas. 9,10 This represents the most general method of synthesis. Desulfurization is effected by reagents such as methanesulfonyl chloride, 9b sulfur dioxide and thionyl chloride, 9g phosgene, 9j mercuric oxide 9k,l and, very recently, molecular iodine. 10 Drawbacks of these methods are use of noxious and toxic reagents and removal of phosphorous byproducts formed during Mitsunobu reaction. 9g,h The molecular-iodinebased method is mild and efficient but suffers from the limitation of not being applicable for the synthesis of bisdialkylcarbodiimides.The rich chemistry exhibited by hypervalent organoiodine(V) reagents such as o-iodoxybenzoic acid (IBX) and Dess-Martin periodinane (DMP) is attributed to the central iodine atom having strong electrophilic character coupled with the leaving ability of the phenyliodino group. The soft electrophilic iodine center can be attacked by a wide r...