From Other Carbodiimides

In the reaction of carbodiimides with EtOCONCS the [2-1-2] cycloadduct 39 is obtained, which undergoes a reverse reaction to produce the estercarbodiimide 40.  

The reaction of bis-silyl- or stannylcarbodiimides 41 with carboxylic acid halides or anhydrides,affords carbonylcarbodiimides 42 having one silyl or stannyl substituent. 

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CaM was purified from porcine brain. The purity of proteins was examined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and isoelectric focusing. CaM and PDE were cross-linked with l-ethyl-3(3-dimethylamino-propyl) carbodiimide (EDC) or N-succinimidyl 3-(2-pyridyldithio)propionate (SPDP) in a buffer solution of 0.1 M HEPES (pH 7.1) in the presence of 1 mM CaCl2. After a buffer solution containing 2 mM EGTA added into the reaction solution, the CaM-PDE hybrid was separated from other ingredients by gel chromatography on a Sepharose CL-6B solumn. 

It may be mentioned that bis(imino)thiazetidines (68), which are prepared by the reaction of carbodiimides with isothiocyanates, react with hydrazoic acid to give an aminothiatriazole. Although this reaction may be of interest from other points of view, it has no general synthetic application (equation 41) (81BSB63). 

Many other carbodiimides with two different substituents are conveniently synthesized from isocyanates and iminophosphoranes. For example, carbodiimides 67 with a phosphorous substituent in the a-position are obtained from the isocyanate 65 and the iminophos-phorane 66 (R = i-Pr or Ph). °... 

Using peptides of the gastrin hormone family as model antigens these uncontrolled effects were fully confirmed in our laboratory (48,52). In fact, gastrin/BSA conjugates prepared in conventional manner by the water-soluble carbodiimide led in animal-dependent manner to antibodies of differentiated specificity in full agreement with results from other laboratories where immunization experiments were usually performed on a larger number of animals to obtain in a "trial and error" manner antisera of the desired specificity (53-55). 

Triphenylphosphine dibromide is a versatile dehydrating agent for amides. Depending on the starting material, nitriles, carbodiimides, isonitriles, or keteneimines may be obtained. Silicon tetrachloride is a useful coupling agent for amide formation, since it is converted to silica, easily separable from other reaction products. ... 

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

Other Reactions. 2-Dioxolaniniines, 2-oxathiolaniniines, and 2-oxa2o1idinimines result from the reaction of propylene oxide with isocyanates, isothiocyanates, and carbodiimides, respectively (103,104). 

A (pentamethylcyclopentadienyl)iridium chelating guanidinate complex has been conveniently prepared by treatment of [Cp IrCl2]2 with N,N, N"-th-p-tolylguanidine and base in THF at room temperature followed by recrystallization of the green product from toluene and pentane (Scheme 154). Insertion reactions of the product with heterocumulenes (diaryl carbodiimides, aryl isocyanates) have been investigated. It was found that the complex serves as highly active catalyst for the metathesis of diaryl carbodiimides with each other and for the more difficult metathesis of diaryl carbodiimides with aryl isocyanates (cf. Section V.C). ... 

The aldehyde 38 was obtained from 35, by way of 36 and 37, by the carbodiimide—dimethyl sulfoxide oxidation procedure52 in the presence of 3-(3-dimethylaminopropyl)-l-ethylcarbodiimide hydrochloride (EDAC)53 and dichloroacetic acid. It was isolated in the form of its crystalline 1,3-diphenylimidazolidine derivative (39) by trapping the freshly prepared aldehyde 38 with N,N -diphen-ylethylenediamine. (This reagent was developed by Wanzlick and Lochel54 for the selective derivatization of aldehydes, and has been exploited for the isolation of nucleoside 5 -aldehydes55 and other aldehydo derivatives of carbohydrates by Moffatt and coworkers.52(b))... 

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