Intensity amides

The amide 1 peak is relatively weak in the Raman spectrum, and the amide II peak is not observed. At the low-frequency side of the amide I peak, weak features of DNA and RNA may be observed for the nuclei and nucleoli. All cellular regions show distinct methyl and methylene deformation vibrations at about 1450cm" , and broad, intense amide 111 vibrations between 1350 and 1220cm" . At around 1000 cm" , the symmetric ring breathing mode of the aromatic phenyl alanine side... 

Approximate positions (cm ) of the most intense amide I and III bands in Raman spectra for various polypeptide conformations... 

Solid state ca 1640 Amide I is generally more intense than amide... 

Acids generally absorb more strongly than esters, and esters more strongly than ketones or aldehydes. Amide absorption is usually similar in intensity to that of ketones but is subject to much greater variations. 

Alitame (trade name Adame) is a water-soluble, crystalline powder of high sweetness potency (2000X, 10% sucrose solution sweetness equivalence). The sweet taste is clean, and the time—intensity profile is similar to that of aspartame. Because it is a stericaHy hindered amide rather than an ester, ahtame is expected to be more stable than aspartame. At pH 2 to 4, the half-life of aUtame in solution is reported to be twice that of aspartame. The main decomposition pathways (Fig. 6) include conversion to the unsweet P-aspartic isomer (17) and hydrolysis to aspartic acid and alanine amide (96). No cyclization to diketopiperazine or hydrolysis of the alanine amide bond has been reported. AUtame-sweetened beverages, particularly colas, that have a pH below 4.0 can develop an off-flavor which can be avoided or minimized by the addition of edetic acid (EDTA) [60-00-4] (97). 

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]... 

Europium and Yb display further similarity with the alkaline earth metals in dissolving in liquid ammonia to give intense blue solutions, characteristic of solvated electrons and presumably also containing [Ln(NH3)x]. The solutions are strongly reducing and decompose on standing with the precipitation of orange Eu(NH2)2 and brown Yb(NH2)2 (always contaminated with Yb(NH2)3) which are isostructural with the Ca and Sr amides. 

In summary, if the unknown mass spectrum has an intense peak at m/z 59 and an abundant m/z 72 with an odd molecular ion, this suggests a primary amide. 

Dantrolene should be repeated after 5—8 hr. Bicarbonate, procaine amide, and other drugs should be repeated as needed. Treatment of disseminated intravascular coagulation is symptomatic. Early diagnosis and treatment ofMH is essential. After effective treatment, the patient should be watched closely in the intensive care unit for recurrence of MH, myoglobinuric renal failure, disseminated intravascular coagulation, muscle weakness, and electrolyte imbalance. 

Primary and secondary amines and amides are first chlorinated at nitrogen by the chlorine released by the gradually decomposing calcium hypochlorite. Excess chlorine gas is then selectively reduced in the TLC layer by gaseous formaldehyde. The reactive chloramines produced in the chromatogram zones then oxidize iodide to iodine, which reacts with the starch to yield an intense blue iodine-starch inclusion complex. 

Firstly there is nucleophilic attack of the nitrile carbon atom by hydroxylamine. An amide oxime is produced this then forms an intensely colored complex with the iron(III) chloride. 

Note Primary amines yield fluorescent chromatogram zones even before the application of reagent 3. Secondary amines do not yield fluorescent derivatives until they have been treated with reagent 3. Hence, the reagent sequence allows the stepwise detection of primary and secondary amines. Taurine is preferred as the essential component of reagent 3 over the multiplicity of other possibilities because it produces intense fluorescence it is also not very volatile and is readily available. Amides and substances with peptide linkages, eg. hippuric acid, are not detected, neither are secondary amines that are volatile at high temperatures. 

Although the n-n and tz-tz electronic transitions of the urea chromophore have not been studied as extensively as amides, the contribution of the backbone is expected to dominate the far UV spectra of oligoureas in a fashion similar to that which is observed for peptides. The CD spectra recorded in MeOH of oligoureas 177 and 178 show an intense maximum near 204 nm (Figure 2.48). This is in contrast to helical y" -peptides that do not exhibit any characteristic CD signature. 

However, workers do not agree as to the shape of the c.d. spectrum for these sugars at shorter wavelengths, as Fig. 15 demonstrates. The correct spectrum still remains an open question, but the intense c.d. band expected at 190 nm for the amide mr c.d. bands are of opposite sign for the two anomers and nearly cancel in the equilibrium mixture. Thus, differences in the anomeric mixtures could explain differences in the c.d. spectra. The amide irir c.d. band is obvious for the anomeric mixture from 2-acetamido-... 

Buffington and Stevens measured the c.d. of 2-acetamido-2-deoxy-D-glucose as a film cast from HFIP. The spectrum is considerably more intense than that observed by Dickinson and coworkers for a solution in HFIP, but shows the same general features shifted somewhat towards the red. This vacuum-u.v. c.d. spectrum (see Fig. 18) has, at 218 nm, an intense, positive band due to the mr, an intense negative band due to the amide tttt at 200 nm, and a shoulder at 180 nm, but no other significant features down to 145 nm. 

---