Carbodiimides - N, N'-Dicyclohexylcarbodiimide, 1-Ethyl-3-(3-Dimethylaminopropyl)Carbodiimide, N, N'-Diisopropylcarbodiimide (Paperback)

Chapters: N, n'-Dicyclohexylcarbodiimide, 1-Ethyl-3-(3-Dimethylaminopropyl)carbodiimide, N, n'-Diisopropylcarbodiimide. Source: Wikipedia. Pages: 20. Not illustrated. Free updates online. Purchase includes a free trial membership in the publisher's book club where you can select from more than a million books without charge. Excerpt: 34 C, 307 K, 93 F Dicyclohexylcarbodiimide (DCC) is an organic compound with chemical formula C13H22N2 whose primary use is to couple amino acids during artificial peptide synthesis. Under standard conditions, DCC exists in the form of white crystals with a heavy, sweet odor. The low melting point of this material allows it to be melted for easy handling. DCC is highly soluble in dichloromethane, tetrahydrofuran, acetonitrile and dimethylformamide, but insoluble in water. The C-N=C=N-C core of carbodiimides is nonplanar, being related to the structure of allene. Three principal resonance structures describe carbodiimides: RN=C=NR RNC-NR RN-CNRThe N=C=N moiety gives characteristic IR spectroscopic signature at 2117 cm. The N NMR spectrum shows a characteristic shift of 275.0 ppm upfield of nitric acid and the C NMR spectrum features a peak at about 139 ppm downfield from TMS. Of the several syntheses of DCC, Pri-Bara et al. use palladium acetate, iodine, and oxygen to couple cyclohexyl amine and cyclohexyl isocyanide. Yields of up to 67% have been achieved using this route: C6H11NC + C6H11NH2 + O2 (C6H11N)2C + H2OTang et al. condense two isocyanates using the catalyst OP(MeNCH2CH2)3N in yields of 92%: DCC has also been prepared from dicyclohexylurea using a phase transfer catalyst by Jaszay et al. The disubstituted urea, arenesulfonyl chloride, and potassium carbonate react in toluene in the presence of benzyl trimethylammonium chloride to give DCC in 50% yield. DCC is a dehydrating agent for the preparation of amides, ketones, nitriles. In these reactions, DCC hydrates to form dicyclohexylurea ...More: http: //booksllc.net/?id=197275