DANS-amides

Primary and secondary amines, amino acids and phenols react In the case of long-wavelength UV light (A = 365 nm) the DANS amides fluoresce yellow-green, while amines that have reacted at a phenolic OH group have an intense yellow to yellow-orange fluorescence The detection hmit for DANS amides is ca 10 mol [86]... 

The DANS amides show yellow-green fluorescence in long wave UV light (365 nm), whereas that of the amines, the phenol group of which reacted, is intensely yellow or yellow-orange about 10 mole of amide can be thus detected. 

Fig. 161a and b. Two-dimensional thin-layer chromatogram of DANS-amides [36] a) Ethyl acetate-cyclohexane (60 + 40) (Run 1) benzene-methanol-cyclohexane (85 + 5 + 10) (Run 2) b) ethyl acetate-cyqlohexane (60 + 40) (Run 1) benzene-triethylamine (83 + 17) (Run 2). 

N-(2-Pyridylmethy Dan nine Sodium amide 2-Piperidinoethyl chloride... 

Fig. 21.18. Synthesis of a polyimide from an aromatic dianhydride (DAN) and an aromatic diaminoether (DA). The DA is synthesized by the second (lower) two-step reaction. All reactions were performed in the solvent, demethylacet-amide (DMAC).

Figure 1.1 Location of protein backbone amide hydrogens in Factor Vila (PDB I DAN [I]). HX of the protein backbone amides (gray circles) occur spontaneously in a solution containing DJD. The rates of exchange are highly dependent on hydrogen bonding and to a lesser extent solvent accessibility and thus report on protein conformation, dynamics, and intermolecular interactions. Adapted from Ref [2], (See insert for color representation of the figure.)...

Successful separations of the red 4 -nitroazobenz-(4)-amides on silica gel G layers using chloroform, have been accomplished by Netj-EATH and Doeek [20]. Multiple development and/or two-dimensional TLC with the same solvent, improved separation further. As with the benzamides mentioned above, the hi /-values increased with increasing number of C atoms in the amine. Seilee and Wiechmann [36] separate primary and secondary amines after reaction with 1-dimethylamino-naphthalene-5-sulphonyl chloride (= DANS, Firm 60). They used the solvents I. ethyl acetate-cyclohexane (60 + 40) II. benzene-methanol-cyclohexane (85 + 5+10) or III benzene-triethylamine (83 + 17) in one- and/or two-dimensional procedures (Fig. 161). 

L. Oienitcheva (31) a etabli la presence d aminoferases des amides dans tous les germes de plantes soumis h I etude. Dans les extraits des plantules, la transamination de I asparagine et de la glutamine avec plusieurs cetoacides s eifectuait plus rapidement que celle des acides aminodicarboxyliques libres. La function specifique des amides. 

Yoshida et aL recendy reported the direct synthesis of branched alkenylbo-rons via a-selective hydroboration of terminal alkynes employing (pin)B-B(dan) (where dan = 1,8-diaminonaphthalene) in the presence of 2 mol% [(SIPr)CuCl] 212,6 mol% KOt-Bu and MeOH (3 equiv.). Given that the scope of the alkynes is broad, the method was extended to the synthesis of Bexarotene and LG100268, which are used to treat T-cell lymphoma and as retinoid X receptor. In a different study by the same group, 208 catalyzed the selective addition of alkyl hydrob-oranes to imidazofyl-o,p-unsaturated ketones at the Imposition. Interestingly, the 2-acylimidazole moiety could be replaced by esters or amides. ... 

Amidation. A number of other various amidation reactions have been conducted using BOP. Such preparations include A) O-dimethyl hydroxamates of amino acids and peptides (precursors of chiral peptidyl aldehydes), heterocyclic amide fragments in the synthesis of macrolide and porphyrin models, dan-sylglycine anhydride as a mixed sulfonic-carboxylic imide by dehydration-cyclization of dansylglycine, and selective monoacylation of heterocyclic diamine in carbohydrate series (eq 9). ... 

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