Class "Y” compounds

Fig. 2a. Pulmonary and lymph node burdens of inhaled radioactive particles for Class W and Class Y compounds (no radioactive decay) as projected from the TGLD clearance model.

Class Y - compounds of this type are retained strongly with clearance half-times in excess of 100 days. 

It may be regarded as the parent of a number of important classes of compounds derived from the y-pyrone skeleton (e.g. flavone, xan-thone) and the important chroman derivatives called the tocopherols (vitamin E). 

Class D substances and with a 10 h half-time for Class W and Class Y substances. Absorption of material directly into blood is predicted to occur with a 15 min half-time for all compounds. Direct absorption is predicted for 0.5 of the Class D material, for 0.1 of the Class W material, and for 0.01 of the Class Y material. Cuddihy and Ozog (1973) studied direct absorption of 144CeCl3 solutions deposited in the nasal region of Syrian hamsters. About 0.04 of the deposited radiocerium was absorbed through the nasal membranes into the blood. This is about one-half of that predicted by the Task Group Model for nasal absorption of Class W compounds in humans. 

Fig. 8. Summary of pulmonary retention of l44Ce in Beagle dogs after inhalation of labeled chloride, oxide, and aluminosilicate particles (heavy lines) as compared to Class W and Y compounds of l44Ce (light lines). These include radioactive decay.

Table 13—Time integrated, uCe activity in lung, liver, and skeleton after inhalation of class D, W, and Y compounds and after inhalation of chloride, oxide and fused aluminosilicate particles, FAP, by beagles 1...

A set of n = 209 polycyclic aromatic compounds (PAC) was used in this example. The chemical structures have been drawn manually by a structure editor software approximate 3D-structures including all H-atoms have been made by software Corina (Corina 2004), and software Dragon, version 5.3 (Dragon 2004), has been applied to compute 1630 molecular descriptors. These descriptors cover a great diversity of chemical structures and therefore many descriptors are irrelevant for a selected class of compounds as the PACs in this example. By a simple variable selection, descriptors which are constant or almost constant (all but a maximum of five values constant), and descriptors with a correlation coefficient >0.95 to another descriptor have been eliminated. The resulting m = 467 descriptors have been used as x-variables. The y-variable to be modeled is the Lee retention index (Lee et al. 1979) which is based on the reference values 200, 300, 400, and 500 for the compounds naphthalene, phenanthrene, chrysene, and picene, respectively. 

Recently, a cell-permeable inhibitor of the human Gcn5 named MB-3 8 was discovered (Figure 11.3). This compound is structurally related to the a-methylene-y-butyrolactone class of compounds, a common structural element in a plethora of natural products. MB-3 was developed by appropriate derivatization of the basic y-butyrolactone motif without the arbitrary screening of large compound libraries. Interestingly, the length of the aliphatic side-chain is crucial for biological activity [17, 18]. 

What other types of material would have a set of properties in the range of the desired properties For instance, which class of compounds smells even better than musk, and where would we find a cure of lung cancer This is symbolically written as. v = g(y). 

FIGURE 1.3 HPLC profile for 28 different polyphenols on a Cis column. Classes of compound are shown in the upper part of the chromatogram. (From Sakakibara, H., Honda, Y., Nakagawa, S., Ashida, H., and Kanazawa, K., J. Agric. Food Chem., 51, 571, 2003. With permission.)... 

Figure 20. Simultaneous enantiomer separation of various classes of compounds ( Schurig test mixture 184) on CP-Cyclodextrin-/3-2,3,6-M-19 (permethylatcd /3-cyclodextrin in OV-1701) [25 m x 0.25 mm (i.d.) column, 70°C for 5 min followed by 3cC/miu, 0.65 bar hydrogen]143. 1+2 2,6,6-trimethylbicy-clo[3.1.1]hept-2-ene (x-pinene), 3 ( + )-(lJR)-//ms-2,6,6-trimethylbicyclo[3.1. l]heptane (pinane), 4 (-)-(lS )-fra/M-pinanc. 5 (-)-(lS)-fw-pinane, 6 ( + )-(l/J)-cw-pinane, 7 + 8 2,3-butancdiol. 9 meso-2,3-butanediol, 10 + 11 tetrahydro-5-methyl-2-furanone (y-valerolactone). 12 + 13 1-phenylethanaminc. 14 + 15 1-phenylethanol, 16 + 17 2-ethylhexanoic acid.

Approximately 75 volatile compounds have been identified in juices prepared from plums Prunus domestica) [35]. Lactones from Ce to C12 are the major class of compound in plums [78]. The distribution of plum lactones differs from that found in peaches in that the C12 y-lactones are found in higher concentrations than the corresponding Cio y-lactones and d-decalactone (Fig. 7.2) [78]. GC sniffing has uncovered benzaldehyde, linalool, ethyl nonanoate, methyl cin-namate, y-decalactone and d-decalactone as volatile compounds contributing to plum juice aroma (Table 7.2, Figs. 7.1, 7.2, 7.4, 7.5) [35]. 

Methods for their analysis have been published (Schulz, 1997b, 2001). So far, representatives of this class of compounds have been found in the Linyphiidae (Schulz and Toft, 1993a), the Tetragnathidae (Schulz, 2001), and the Theridiidae (M. D. Papke, S. Schulz, and Y. Lubin, unpublished results). Although the families share some alkanes, each uses different groups of these ethers. For example, specific... 

A new class of compounds is reported to have dual inhibitory properties. They have a y-sultam skeleton and show potent inhibitory effects towards both COX-2 and 5-lipoxygenase as well as production of IL-1 in in vitro assays. These compounds have also proved to be effective in several animal arthritic models without any ulcerogenic activity. Among these compounds S-2474 ((E)-(5)-(3,5-di-fe/t.-butyl-4-hydroxy-benzylidene)-2-ethyl-1,2-isothiazolidine-1,1-dioxide) was selected as an anti-arthritic drug candidate and is now under clinical investigations (Inagaki et al., 2000). 

Just like the common amino acids, the enantiomeric purity of y-amino-P-hydroxy acids is established by formation of diastereomeric derivatives and their analysis by HPLC or NMR spectrometric techniques. In addition to derivatization of the y-amino group, the P-hydroxy moiety of this class of compounds may also possibly be derivatized. 

Ring synthesis by y- closure is a somewhat more versatile entry into this class of compound, though even then it is restricted to suitably activated precursors such as (142) (equation 101) (72T5197). Thiochromones and thioxanthones are probably most frequently prepared by this mode of closure, usually via an intramolecular Friedel-Crafts condensation of a carboxylic acid with an aromatic ring (equation 102) (71GEP2006196). 

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