Carbodiimides compounds

Behringer and Meier found that treatment of thiourea 105 with yellow mercury(Il) oxide gave traces of N, AT-pentamethylenecarbodiimide (107), the smallest known cyclic carbodiimide. Compound 107 was reported as unstable and able to polymerize readily (larger ring homologs were, ex-... 

On the other hand, covalent agents can also be applied to the unpreated carbon surface directly before DNA immobilization onto activated sites of carbodiimide compounds [21]. 

An antioxidant used in the S5mthesis of a carbodiimide compound. The antioxidant is added during the synthesis. A suitable... 

The inorganic filler allows to adjust the desired acoustical and mechanical properties. The hydrolysis inhibitor comprises at least one member selected from a carbodiimide compound, an isocyanate compound, and an oxazoline compound. 

The hydrolysis inhibitor is added for preventing the acoustic apparatus housing from easily decomposing due to moisture in air during the period of use. Preferred hydrolysis inhibitors are car-bodiimides. A carbodiimide compound can be melt-kneaded with the biodegradable polymer compound. Examples are N,N -dicy-clohexylcarbodiimide or N,N -diisopropylcarbodiimide (22). For definitely obtaining the required mechanical strength a rubber component is added. 

Related to the diphosphazanes of types (7.230) are the carbodiimide compounds formed in... 

The IR spectrum shows a weak, broad new signal at 2200 cm. This may indicate that a small amount of a carbodiimide compound is present. 

Bisa2iridine compounds and A/-(2-chloroethyl)carbodiimides have also been prepared using isocyanide dichlorides and ethyleneimine (178,179). The iodide-cataly2ed rearrangement of the formerly mentioned compounds provides a method for preparing the tetrahydroimida2oimida2ole system ... 

Other six-membered rings with two heteroatoms are also obtained from reaction of diketene with imidates, cyanamides, carbodiimides, isocyanates, oxa2olines, or other multiftmctional compounds. 

By a suitable choice of activating reagents, primary and secondary alcohols can be selectively oxidi2ed to carbonyl compounds in good yields at room temperatures. Typical activating reagents are acetic anhydride, sulfur trioxide—pyridine, dicyclohexyl carbodiimide, and phosphoms pentoxide (40). 

Olefin isomerization can be catalyzed by a number of catalysts such as molybdenum hexacarbonyl [13939-06-5] Mo(CO)g. This compound has also been found to catalyze the photopolymerization of vinyl monomers, the cyclization of olefins, the epoxidation of alkenes and peroxo species, the conversion of isocyanates to carbodiimides, etc. Rhodium carbonylhydrotris(triphenylphosphine) [17185-29-4] RhH(CO)(P(CgH )2)3, is a multifunctional catalyst which accelerates the isomerization and hydroformylation of alkenes. 

Finally, attachment of a rather complex side chain to the para position of the benzene ring on the sulfonamide leads to the very potent, long-acting oral antidiabetic agent, glyburide (215). Preparation of this compound starts with the chlorosul-fonation of the acetamide of 3-phenethylamine (209). The resulting sulfonyl chloride (210) is then converted to the sulfonamide (211) and deacylated (212). Reaction with the salicylic acid derivative, 213, in the presence of carbodiimide affords the amide, 214. Condensation of that with cyclohexylisocyanate affords glyburide (215). ... 

Diazametallacycles of the type Cp2Zr[Bu NC( = NR )NR ] have been prepared according to Scheme 92 from terminal zirconium imides and carbodiimides. A second series of analogous compounds was synthesized starting... 

Closely related mixed amido/imido/guanidinato tantalum complexes of the type Ta(NR R )[(R R2N)C(NR )2]( = NR ) (R R = Me, Et R = Cy, Pr R = Pr", BuO were synthesized by the insertion of carbodiimides into to tantalum-amide bonds in imidotantalum triamide precursors, and the effects of ligand substitution on thermal properties were studied by TGA/DTA measurements. In addition, selected compounds were pyrolyzed at 600 °C and the decomposition products were studied by GC-MS and NMR spectroscopy. ... 

A similar approach, i.e., carbodiimide insertion into M-N bonds was used to prepare unusual zirconacarboranes containing guanidinate ligands. In an alternative approach, these compounds were also synthesized by the route outlined in Scheme... 

Treatment of UCI4 with the lithium complex obtained from dicyclohexylcar-bodiimide followed by crystallization from pyridine afforded a dinuclear uranium(rV) oxalamidinate complex in the form of dark green crystals in 94% yield (Scheme 191). The same compound could also be obtained by first reducing UCI4 to LiUCli (or UQs+LiCl) followed by reductive dimerization of di(cyclo-hexyl)carbodiimide as shown in Scheme 191. The molecular structure of this first oxalamidinato complex of an actinide element is depicted in Figure 31. ° ... 

A full development of the rate law for the bimolecular reaction of MDI to yield carbodiimide and CO indicates that the reaction should truly be 2nd-order in MDI. This would be observed experimentally under conditions in which MDI is at limiting concentrations. This is not the case for these experimements MDI is present in considerable excess (usually 5.5-6 g of MDI (4.7-5.1 ml) are used in an 8.8 ml vessel). So at least at the early stages of reaction, the carbon dioxide evolution would be expected to display pseudo-zero order kinetics. As the amount of MDI is depleted, then 2nd-order kinetics should be observed. In fact, the asymptotic portion of the 225 C Isotherm can be fitted to a 2nd-order rate law. This kinetic analysis is consistent with a more detailed mechanism for the decomposition, in which 2 molecules of MDI form a cyclic intermediate through a thermally allowed [2+2] cycloaddition, which is formed at steady state concentrations and may then decompose to carbodiimide and carbon dioxide. Isocyanates and other related compounds have been reported to participate in [2 + 2] and [4 + 2] cycloaddition reactions (8.91. 

A first terminal imido complex of nickel (121) was prepared according to Equation (3).468 The synthesis goes via the Ni11 amido compound (122) and uses the steric bulk of the arylimido group for stabilization. The Ni11 center in (121) is planar and three-coordinate. Reaction of (121) with CO or benzyl isocyanide leads to formal nitrene transfer with formation of (124) and (125), respectively. Further reaction with CO liberates the isocyanate and carbodiimide (Equation (4)). 69... 

An alternative strategy for the synthesis of these tricyclic compounds involves the reaction of the azidoalkenyl-functionalized furo[3,2-A]pyrrole 30, which reacts with triphenylphosphine to give the corresponding iminophos-phoranes 31 these upon reaction with aryl isocyanates give the pyrrolo[2, 3 4,5]furo[3,2-r-]pyridines 32, via the corresponding carbodiimides which are not isolated < 1994H(37) 1695, 1992M807> (Scheme 9). 

In view of the importance in biochemical processes of pteridines such as folic acid, methotrexate, L-biopterin, and leucettidine <1996CHEC-II(7)679>, synthetic routes to fused pteridines continue to occupy considerable attention. Imidazo-fused pteridines have now been prepared from 3-aminopyrazine-2-carboxamides via carbodiimide intermediates. If the amido-nitrogen in the starting compound is further substituted, as in the scheme, the... 

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