Diamide and

Diamides and triamides have been obtained from the action of an aqueous saturated solution of ammonia on the corresponding ester (Scheme 18) (88). Amides can also be obtained by the Curtius (16) or Hofmann reactions (80). Thus the Curtius reaction with 2-substituted 4-thiazolecarboxylic acids gives the 4-acetamido compounds (16). 

Derivatives similar to those mentioned for the monofunctional fluorinated carboxyflc acids have been prepared tetrahydrodiols, tetrahydrodiamines, diamides, and diesters. 

Its manufacture begins with the formation of dodecanedioic acid produced from the trimeri2ation of butadiene in a process identical to that used in the manufacture of nylon-6,12. The other starting material, 1,12-dodecanediamine, is prepared in a two-step process that first converts the dodecanedioic acid to a diamide, and then continues to dehydrate the diamide to the dinitrile. In the second step, the dinitrile is then hydrogenated to the diamine with hydrogen in the presence of a suitable catalyst. 

Perfluorosuccinamide-Lithium Aluminum Hydride (Danger of Explosion). In an attempt to reduce perfluorosuccinamide to the corresponding diamine, it was added to an ether soln of lithium aluminum hydride in a nitrogen atm. Hydrolysis was then attempted, but as a second drop of w was added, a violent expln and ether fire resulted. It was shown that the diamide and the lithium aluminum hydride reacted to give an unstable complex which detonated at room temp Ref T.S. Reid G.H. Smith, C EN 29,3042 (1951) CA 46, 3279 (1952)... 

Among the recent applications of the Hofmann reaction has been the preparation of relatively unstable geminal diamides and carbinolamides. For example, 1,1-diacetamidocyclohexane can be prepared in this way.277... 

In the 7r-bonding model, diamides and triamides are expected to show longer M—N distances than their monoamido counterparts, as there are two or three nitrogen lone pairs competing for just one empty p-orbital... 

Hofmann amine separation org chem A technique to separate a mixture of primary, secondary, and tertiary amines they are heated with ethyl oxalate there is no reaction with tertiary amines, primary amines form a diamide, and the secondary amines form a monoamide when the reaction mixture is distilled, the mixture is separated into components. haf-mon am,en, sep-3,ra-sh3n ... 

Enantiomer separation on optically active amino acid, dipeptide, diamide and amide phases by association via hydrogen bonding. " ... 

Tris(dialkyl)stibines react with sulfur dioxide (equation 33), affording tetraalkylsulfurous diamides and an unidentified antimony/nitrogen compound.101... 

The filtrate contains guanidine nitrate along with a small amount of ammonium nitrate and very small amounts of dicyano-diamide and biguanide nitrate (Note 6). The solution is concentrated to about 1 1. and the guanidine nitrate which crystallizes on cooling is filtered off. A second crop is obtained by... 

A diamide and malonyl chloride gave a compound with two dioxo-tetrahydro-l,3-oxazine rings.116 Diacylamines were also used to produce tetrahydro-1,3-oxazine-4,6-dione.117... 

Azido-iso-succinic Acid Diamide. See under Succinic Acid Diamide and Beil 2, (272)... 

Churchill MEA, Tullius TD, Kallenbach NR, Seeman NC (1988) A Holliday recombination intermediate is twofold symmetric. Proc Natl Acad Sci USA 85 4653-4656 Clark EP, Michaels HB, Peterson EC, Epp ER (1983) Irradiation of mammalian cells in the presence of diamide and low concentrations of oxygen at conventional and at ultrahigh dose rates. Radiat Res 93 479-491... 

Alyapyshev, M.Yu., Babain, V.A., Smirnov, I.V. 2004. Extractive properties of synergistic mixtures of dipicolinic acid diamides and chlorinated cobalt dicarbollide. Radiochemistry 46 (3) 270-271. 

Mowafy, E.A., Aly, H.F. 2007. Synthesis of some A/A//V ,AF-tetraalkyl-3-oxa-pentane-1,5-diamide and their application in solvent extraction. Solvent Extraction and Ion Exchange 25(2) 205-224. 

FIGURE 8.18 Sensitization effect of n-dodecane on the radiolysis of the glycolamide TODGA, a malonamide (MAr-dioclyl-/V,iV -dimethyl-2(3 -oxapentadecyl)-propane-l,3-diamide) and a monoamide DOHA. Conditions gamma-irradiation from 60Co source (125 C kg-1 h 1) in air, at room temperature. The solid lines indicate the experimental G-value with an error of about 10%. The dotted lines indicate the theoretical G-value based on the direct effect on the radiolyis. (Redrawn from Sugo, Y., Sasaki, Y., Tachimori, S., Radiochim. Acta, 90, 161-165, 2002. With permission.)... 

Figure 1. Zig-zag formula of (R,R)-tartaric acid and its derivatives. X = NH2 for the diamide and X =N(CH3)2 for theN,N,N ,N -tetramethyldiamide.

Conformations of primary, secondary, and tertiary amides of (R,R)-tartaric acid, both symmetrically and asymmetrically substituted, have been studied ciys-tallographically [22, 24, 29, 30-40] Moreover, ab initio studies up to MP2 / 6-31G //RHF/6-31G level [41] for both the diamide and N,N,N ,N -tctramcthyl-diamide of (/ ,/ [-tartaric acid have been carried out [20, 22]. X-ray results have shown that primary and secondary amides of (R,R [-tartaric acid tend to adopt a conformation with the extended carbon chain - the Taa structure. In this Taa conformation both the a-hydroxy-amide moieties form planes and the structure gains stabilization from hydrogen bonding between donors, the NH, and acceptors, the proximal OH groups. Moreover, the Taa structure is favorably stabilized by the attraction of antiparallel local dipoles formed along distal C H and Csp2=0 bonds [18, 21, 22],... 

Tables 3 and 4 present results of SM5.4 calculations with PM3 hamiltonian for molecules in water solution of (R,R )-tartaric acid diamide and N,N,N ,N -tetra-methyldiamide, respectively.

In water solution, as shown by AMSOL calculations, the conformational preferences of the studied amides show up. Gibbs free energies ofhydratation calculated with the SM5.4 model and PM3 hamiltonian for structures optimized at the RHF/6-3 1G level indicated that those most favored by hydratation are the T- and G-conformers for the diamide and A, A,A ,A -tetramethyldiamide of (R, R (-tartaric acid, respectively. 

There have been many reported chiral stationary phases for use in both packed and capillary gas chromatography. Most of these phases are of the carbonyl-bis-L-valine isopropyl ester, diamide, and peptide phase types. The most common phase is Chirasil-Val from Alltech Applied Science Laboratories (State College, PA). This phase is ideal for the separation of a variety of enantiomers including amino acids, sugars, amines, and peptides. The phase is composed of L-valine-tert-butylamide linked through a car-oxamide group to a polysiloxane backbone every seven dimethylsiloxane units apart. 

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