Ring analysis

The most important displayable field for ring analysis is the field Ring System Data (RSD). The following example of azacubane shows this RSD DISPLAY field s potential (Fig. 94). 

Elemental Elemental Size of Ring System Ring RID Analysis j Sequence jthe Ringsj Formula jIcjentifierjOccurrence EA I ES I SZ I RF I RID Count 

5 REFERENCES IN FILE CA (1967 TO DATE) Fig. 94. Ring System Data for the azacubane 

The field EA contains the ring formulae (chemical elements) of the smallest rings. When regarding the above formula as a cube, 5 rings will be seen, 3 of them composed of C3N and 2 of them C4 rings. 

Size of the smallest rings. The example above shows 5 four-membered rings. 

The authors would like to acknowledge the support provided by Gordon Bundy, Mary Torkelson, Dick Thomas, Chic Spilman, Bob Manning, Mario Varasi, and Michael Clare. 

Martin, Y.C. Diverse viewpoints on computational aspects of molecular diversity./. Comb. Chem. 2001, 3, 231-250. 

Willett, P. Similarity and Clustering in Chemical Information Systems. Research Studies Press, Letchworth, 1987. Johnson, M.A. and Maggioea, G.M. (Eds). Concepts and Applications of Molecular Similarity. John Wiley, Sons, New York, 1990. 

Molecular Similarity in Drug Design. Chapman, Hall, Glasgow, 1994. 

Maggioea, G.M. and Shanmugasundaeam, V. Molecular similarity measures. In Chemometrics Methods and Protocols, Bajoeath, J. (Ed.). Humana Press, Totowa, NJ, 2003, 1-50. Willett, P., Barnard, J.P., and Downs, G.M. Chemical similarity searching. 

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FGA and carbonyl strategy the synthesis of long chain fatty acids such as (16) can be achieved in a few steps by suitable FGA. Adding a carbonyl group in a 1,6 relationship allows reconnection to (17) and hence the disconnection of the six carbon atoms in the ring. Analysis... 

Hence there are multiple solutions for the final set of 10000 compounds. The final selection can be diversity driven using for example cluster analysis based on multiple fingerprints [63], hole filling strategies by using scaffold/ring analysis (LeadScope [66], SARVision [66]) or pharmacophore analysis [67, 68]. For a review of computational approaches to diversity and similarity-based selections, see the paper of Mason and Hermsmeier [69] and the references therein. 

RING ANALYSIS AND CARBON-TYPE ANALYSIS OF MINERAL OIL FRACTIONS a. Analytical hydrogenation of mineral oils... 

Fig. 3. Ring analysis diagram according to Vlugter, Waterman and Van Westen.

A diagram has been constructed from which it is possible to determine the number of rings of saturated mineral oil fractions if the specific refraction and the molecular weight are known (Fig. 3). The diagram is called the ring analysis diagram. 

Recently another ring analysis diagram (Fig. 5) has been introduced by Geelen, Waterman and Westerdijk8. It has been constructed by means of the equation... 

Besides constructing lines for equal ring-number or equal %Cr values in the ring analysis diagram, it is also possible to construct lines of equal values of the aniline point3 and the density3. This is shown in Figs. 9 and to respectively. 

It should be pointed out that this method for ring analysis and branching analysis is based exclusively on reliable data of n, d, M and a of pure individual hydrocarbons, and holds, within the limits of accuracy of the determination, for widely differing types of branched as well as non-branched saturated hydrocarbon mixtures. It is particularly recommended for the structural analysis of saturated polymers, where other statistical methods (w- -M-method, v-n-d-method, etc.) fail because they have been developed for mineral oils, and are based on correlations of physical data of mineral oil fractions that always show approximately the same small degree of branching 1-2 branchings per molecular weight = 100. 

Table IV contains data on hydrogenated polymers of propylene, isobutene and cyclohexene obtained by polymerization under various conditions38. The Direct Method (ultimate analysis and molecular weight) shows that the polymers of propylene and isobutene are paraffinic for the estimation of cp the appropriate formulas were used. In the case of the highly cyclic saturated cyclohexene-polymers the formulas for hydrogenated mineral oil fractions were applied. In the table are also given values of q> and Rt determined with the ring analysis diagrams of Figs. 59 and 60 (p. 64-65).

Thus the contributions of these compounds to the specific refraction r of the fractions cancel out [cf. eqn. (71)] this is the reason that diagrams for the ring analysis of saturated mineral oil fractions based on specific refraction and molecular weight are also valid for the estimation of naphthenic rings in aromatic fractions cf. p. 24). 

Fig. 80. Ring analysis of hydrocarbons obtained from polymerized fatty acid esters.

The author s classical work on the ring analysis of mineral oils has been developed into a complete new system of investigation methods which have a specific character and are suitable for general application. The research field has become a very extensive one, and comes into contact with many branches of chemical industry. 

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