Skeletons from

As mentioned above, it is usually most convenient to employ as parent structure a skeleton from which all functional substituents have been removed. However, there are many substituted parent names in common use, either with or without implied stereochemistry (see examples 102-106). 

Saul, J.M. and Saul, F.P. 1997 The Preclassio skeletons from Cuello. In Whittington, S.L. and Reed, D.M., eds., Bones of the Maya Studies of Ancient Skeletons. Washington, DC, Smithsonian Institution Press 28-50. 

Martin, A. 1969 Content and distribution of stable strontium and Ra in human skeletons from Wisconsin descendants 1957-1961. BritishJoumal ofRadiology 42 295-298. 

Figure 9.2. Amino acid content (mol %) in collagen extract (dark columns) and serum proteins (light columns) from a skeleton from coastal Peru. Due to a prevalence of degraded and soluble collagen, the nonmineral-bound protein fraction shows a collagen amino acid profile.

Figure 28-9. Conversion of homocysteine and serine to homoserine and cysteine. The sulfur of cysteine derives from methionine and the carbon skeleton from serine.

In general, carotenoids in foods are C40 tetraterpenoids comprised of eight C5 isoprenoid (ip) units (Figure 2.2.2) whose order is inverted at the molecule center, joined head to tail, except at the center where a tail-to-tail linkage reverses the order, resulting in a symmetrical molecule. This produces the parent C40 carbon skeleton from which all the individual variations are derived. ... 

Nevertheless, the placement of two Cl atoms on the C and C carbon atoms of the NHC skeleton, the presence of the strong SO Ar electron-withdrawing group on the aryl A-substituents, or the modification of the NHC skeleton from an imidazol-to a triazol-type, have allowed to fill the gap between the TEP of phosphines and NHCs, see Pig. 1.14. 

Other than a nutritional role linked to mineralization processes, humic compounds have been hypothesized to directly affect plant nutrition, since it has been suggested that roots may take up low-molecular-weight humic molecules (21). Interestingly, plants have been ob.served to express carriers for amino acids (22) and small peptides (23) at the root level. Certain components of the humic fraction have been found inside root cells and were, moreover, translocated to the shoots (24,25). Recent experiments performed on rice cells in suspension culture seem to suggest that they may use carbon skeletons from humic molecules to synthesize proteins and DNA (26). 

Schwarcz HP, Simpson JJ, Stringer CB (1998) Neanderthal skeleton from Tabun U-series data by ganuna-ray spectrometry. J Human Evol 35 635-645... 

Polyene cyclizations are of substantial value in the synthesis of polycyclic terpene natural products. These syntheses resemble the processes by which the polycyclic compounds are assembled in nature. The most dramatic example of biosynthesis of a polycyclic skeleton from a polyene intermediate is the conversion of squalene oxide to the steroid lanosterol. In the biological reaction, an enzyme not only to induces the cationic cyclization but also holds the substrate in a conformation corresponding to stereochemistry of the polycyclic product.17 In this case, the cyclization is terminated by a series of rearrangements. 

Schaller, F. Rahalison, L. Islam, N. Potterat, O. Hostettmann, K. Stoeckli-Evans, H. Mavi, S. A new potent antifungal quinone methide diterpene with a cassane skeleton from Bobgunnia madagascariensis. Helv. Chim. Acta 2000, 83, 407-413. 

Step 3. We first remove the two 7r-orbitals 7Ta and jtb (located in positions 2,3 and 5,6 of the norbornadiene skeleton) from the set of LMOs, and form their linear combinations... 

Burleigh, R., On the Dating of a Human Skeleton from Otavalo, Ecuador, Journal of Human Evolution, 1980, 9, 153. 

Very recently, Ma has reported a rhodium-catalyzed route to 18,19-norsteroid skeletons from bis-allenes, involving a cyclometallation-carbometallation-reductive elimination-Diels-Alder reaction cascade process.410... 

Detailed kinetic studies of the reaction of Fe(II) in cyclophane hemes with 02 and with CO probed polarity and steric effects the effects of deformation of the porphyrin skeleton from planarity were assessed for one compound (121). Volume profiles have been established for reactions of a lacunar Fe(II) complex with CO (122 for myoglobin with 02 and with CO and for hemerythrin with 02 (123). 

Fluoride, Fluoride Is contained In water and In the diet (22,23) Also, fluoride stabilizes the bone crystal (24) and has been shown to decrease bone resorption (25), For these reasons, fluoride has been recommended for the treatment for osteoporosis (26-28), The Importance of the role of fluoride on maintaining the normal bone structure Is also Indicated by a survey which showed that the Incidence of osteoporosis was lower In naturally high fluoride areas than In areas where the fluoride content of the drinking water was low (29) This observation would Indicate that the Intake of certain amounts of fluoride throughout life may be necessary for the maintenance of the normal skeleton, and that fluoride may protect the skeleton from the development of bone loss which leads to osteoporosis with advancing age, particularly In females. 

FIGURE 8.6. Effect of litter size (live fetuses per litter) on incidence of supernumerary rib in 1379 control rat litters. Between 1978 and 1988, fetal skeletons from 1379 litters of control rats were stained with alizarin red and examined for supernumerary rib. 

Table 17 lists a number of commercially available pigments, along with their chemical structures, in order to illustrate the different structural types of Naphthol AS pigments. Fastness to solvents and migration resistance improve from top to bottom, i.e., with increasing number of CONH groups in the molecule. The first example, a simple (3-naphthol pigment, is the skeleton from which all other species are derived. 

Various synthetic pathways have been proposed to prepare the benzimidazolone skeleton, from which all pigments in this series are derived. The 5-amino derivative should be mentioned in particular. It is prepared advantageously from 4-ni-tro-l,2-diaminobenzene as a starting material, which reacts with phosgene or with urea in the melt to form 5-nitrobenzimidazolone. Subsequent reduction yields 5-aminobenzimidazolone ... 

For example, opening of the cluster skeleton from closo to nido to arachno will accompany the addition of electron pairs, whether by reduction reactions or by addition of Lewis base molecules that do not dislodge other Lewis bases. Cluster closing is expected to accompany the removal of electron pairs, whether by oxidation or by loss of a substituent together with the electron pair by which it was formally bound to the cluster ... 

The nonessential amino acids can be synthesized by the body using carbon skeletons from metabolic intermediates or by modification of other amino acids. 

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