Amides, hydrogenation

Hagler A T and S Lifson 1974. Energy Functions for Peptides and Proteins. II. The Amide Hydrogen Bond and Calculation of Amide Crystal Properties. Journal of the American Chemical Society 96 5327-5335. 

Chlorine Tolerance Most of the best RO membranes are attacked by oxidants, and they are particularly susceptible to chlorine. A particularly sensitive locus for attack is the amidic hydrogen. Cellu-losic membranes are generally less sensitive, and pass the chlorine into the permeate giving downstream biocidal activity, veiy useful for under-the-sink RO. These factors are largely responsible for CA s survival in RO membranes. Chlorine, whatever its vices, has the virtue of being a known, effective, residual bactericide and a good inhibitor of... 

In a typical a-helix of 12 (or n) residues, there are 8 (or w — 4) hydrogen bonds. As shown in Figure 6.9, the first 4 amide hydrogens and the last 4 carbonyl oxygens cannot participate in helix Fl-bonds. Also, nonpolar residues sit-... 

A number of interesting conclusions could be drawn from the screening. For example, the amide hydrogen atom at the second amino acid residue close to the... 

Figure 5. Schematic representation of four-stranded )9-sheet in RpII. Observed NOEs which were used to identify this secondary structure are shown by dashed lines. Dots indicate slowly exchanging amide hydrogens.

Cieplak, P., Caldwell, J. W., Kollman, P. A., Molecular mechanical models for organic and biological systems going beyond the atom centered two body additive approximation aqueous solution free energies of methanol and IV-methyl acetamide, nucleic acid base, and amide hydrogen bonding and chloroform/water partition coefficients of the nucleic acid bases, J. Comput. Chem. 2001, 22, 1048-1057... 

Equation 44).57 The amide hydrogen is acidic in these compounds and can be deprotonated with standard organometallic bases such as raBuLi to give the imido complex 28 (Equation 44). 

D. J. Tobias and C. L. Brooks, Thermodynamics of amide hydrogen bond formation in... 

Substituted thiazolylindole 66 was formed via the Stille coupling of 6-iodoindole 64 and 5-tributylstannylthiazole 65 [42], Stannane 65 was not stable at temperatures higher than 60 °C and decomposition occurred presumably by amidic hydrogen transfer on the 5-position. Simply blocking NH with a methyl group greatly improved the yield. 

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