Sulfur substituted carbodiimides

The remaining chapters are carbodiimides with unsaturated substituents, halogenated carbodiimides, acyl-, thioacyl- and imidoylcarbodiimides, silicon substituted carbodiimides, nitrogen substituted carbodiimides, phosphorous substituted carbodiimides, sulfur substituted carbodiimides, metal substituted carbodiimides, cyclic carbodiimides, polymeric carbodiimides and application of carbodiimides. 

Also, N-trimethylstannyl-N -triisopropylsilylcarbodiimide 23 reacts with bis(diiso-propylamino)-chlorophosphane to give the P, Si substituted carbodiimide, which was oxidized with elemental sulfur, to give the more stable thiophosphoryl carbodiimide... 

The process is satisfactorily rationalized by the mechanism59 shown in Scheme 5, in which the hydrolytic formation of a substituted sulfenic add precedes that of the carbodiimide. Depending on the relative nucleophilidty of the sites in the thiourea, its condensation with carbodiimide will yield either the monosulfide (38d), by attack of sulfur on the carbodiimide (Path A), or the amidinothiourea (39d, Path B attack by nitrogen). The distribution... 

The syntheses of substituted 5-aminotetrazoles 228, using azide ions for assembling the tetrazole scaffold, can be divided into two different approaches. The first approach is the addition of sodium azide to car-bodiimides 222 [156,157] or cyanamides 223 [158-161]. The second approach is the nucleophilic substitution of a chlorine in a-chloroformamidines 224 [162], the nucleophilic substitution of benzotriazole in (benzotria-zolyl)carboximidamides 225 [163], the nucleophilic substitution of the sxflfite anion in aminoiminomethanesulfonic acids 226 [164] and the nucleophilic substitution of sulfur from thioureas 227 in the presence of mercury [165] or lead [ 166-169] salts in the presence of an azide ion (Scheme 43). In this chapter, the main focus is on the addition of azides to carbodiimides 222 to form substituted 5-aminotetrazoles 228. 

In the reactions of 3-2 with different substrates such as ketone, carbodiimide, alkyne, element sulfur, CO, and iodine, the zirconacyclopropene moiety is independently involved and the azasilacyclopentadiene moiety in 3-2 does not participate in these cases. Firstly, ketones were used to substitute the coordinating r-BuCN. Selective insertion of the C=0 double bond into the zirconacyclopropene ring afforded the corresponding oxazirconacyclopentene derivative 3-6 (Scheme 3.4) [19]. The compound 3-6a was isolated in 72 % yield, and its stmcture was determined by single-crystal X-ray stmctural analysis. Although the azasilacyclopentadiene moiety did not participate in this transformation, however, the cooperation... 

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