Heterocyclic compounds analysis

Retro-Synthetic Analysis (= Antithesis 193 3.1.5 Aromatic and Heterocyclic Compounds... 

The conclusion that the nitration of quinoline in sulphuric acid takes place via the conjugate acid has been confirmed by Moodie et al.50, who measured the rates of nitration of a wide range of heterocyclic compounds in nitric acid-sulphuric acid mixtures at a range of temperatures. A summary of the second-order rate coefficients and Arrhenius parameters is given in Table 4. From an analysis of the shapes of the plots of log k2 versus sulphuric acid acidity (or some function of this), it was concluded that all of the compounds starred in Table 4... 

In this chapter, an attempt has been made to present a total number of 20 QSAR models (12 QSAR models for topo I inhibitors and eight QSAR models for topo II inhibitors) on 11 different heterocyclic compound series (an-thrapyrazoles, benzimidazoles, benzonaphthofurandiones, camptothecins, desoxypodophyllotoxins, isoaurostatins, naphthyridinones, phenanthridines, quinolines, quinolones, and terpenes) as well as on some miscellaneous heterocyclic compounds for their inhibition against topo I and II. They have been found to be well-correlated with a number of physicochemical and structural parameters. The conclusion, from the analysis of these 20 QSAR, has been drawn that the inhibition of topo I is largely dependent on the hydrophobicity of the compounds/substituents. On the other hand, steric parameters (molar refractivity, molar volume, and Verloop s sterimol parameters) are important for topo II inhibition. 

These observations indicated that an intermolecular double condensation to give a bis N-(methylene-4-oxocoumarinyl)-l,4 aromatic diamine had occurred. Data from the elemental analysis indicated that the calculated and observed values were within the acceptable limits ( 0.4%) and in conformity with the assigned structure. In the addition of molar equivalents of 1,4-aromatic binucleophilic compounds to compound 72 we did not observe any heterocyclic compounds resulting from the further intermolecular nucleophilic attack on the single condensation product. Since the condensation of 3-(dimethylaminomethylene)-chromane-2,4-dione with aromatic binucleophilic compounds is the only route to the new coumarinic compounds, this represents a useful synthetic method. 

For the purpose of polymer/additive analysis most applications refer to vulcanisate analysis. Weber [370] has determined various vulcanisation accelerators (Vulkazit Thiuram/Pextra N/Merkapto/AZ/DM) in rubbers using PC. Similarly, Zijp [371] has described application of PC for identification of various vulcanisation accelerator classes (guanidines, dithiocarbaminates, thiuramsulfides, mercapto-substituted heterocyclic compounds, thioureas, etc.). The same author has also... 

Cyclic voltametric analysis has been utilized to determine material properties of this class of heterocyclic compounds. All the DTPs 23 <2003JOC2921 > exhibited a well-defined irreversible oxidation presumably corresponding to the formation of the radical cation. When scanned to higher positive potentials, it resulted in two consecutive broad oxidations for most of the DTPs. The second oxidation is quite weak, followed by a more intense and well-defined third oxidation. Coupling of thiophene radical cation is usually rapid (r <10-5 s) <1995SM(75)95>. These additional broad waves most likely correspond to the oxidation of coupled products rather than further DTP oxidations. The electrochemical data of the DTP S 23 are given in the Table 10. 

Since in the synthesis of heterocyclic compounds the ring closure usually involves the formation of the carbon-heteroatom bond, in the retrosynthetic analysis the first bond to be disconnected is the carbon-heteroatom bond (Cf. heuristic principle HP-8), either directly or after the pertinent (FGI or FGA) functional group manipulation. For instance, compound 17 -which is the starting material for Stork s synthesis of Aspidosperma alkaloids [30]- may be disconnected as shown in Scheme 6.11. 

See G.F. Riddell, "The Conformational Analysis of Heterocyclic Compounds", pags. 139-140, Academic Press, London, 1980. 

In the first part of this review a critical analysis of various criteria of aromaticity and the indices quantifying aromatic or antiaromatic character is presented in Section II with an emphasis on application to heterocyclic compounds. Special attention is paid to the elucidation of general trends observed in the change of aromatic character on going from the parent... 

B-80MI20401 F. G. Ridell The Conformational Analysis of Heterocyclic Compounds ,... 

Applications of Linear Free Energy Relationships to Polycyclic Arenes and to Heterocyclic Compounds , M. Charton, in Recent Advances in Correlation Analysis in Chemistry , ed. N. B. Chapman and J. Shorter, Plenum, New York, 1978, pp. 175-268. Applications of the Hammett Equation to Heterocyclic Compounds P. Tomasik and C. D. 

Conformational Analysis of Five- and Six-Membered Rings and Related Non-Bridged Systems (Saturated Heterocyclic) , F. G. Riddell, in Aliphatic, Alicyclic and Saturated Heterocyclic Compounds , ed. W. Parker, Royal Society of Chemistry, London, 1974, vol. 1, pt. 3, pp. 69-91. 

Conformational Analysis in Saturated Heterocyclic Compounds E. L. Eliel, Acc. Chem. Res., 1970, 3, 1-8. 

W.A.Schroeder et al, IEC 43, 941-3(1951) 8) W.C.Sumpter F.M.Miller, Heterocyclic Compounds with Indole and Carbazole Systems , Interscience, NY(1954), 71 2 9)Organic Analysis, Interscience. NY, yols 1,2,3 Sr 4-net found Addnl Refs a)B. 1.Ardashev, ZhPriklKhim 10, 1032-41X1041 in Fr)(i 937) CA 32, 1612(1938) RusP 52893(1938) CA 34, 5378(1948)(Detn of carbazole by titrating its AcOH soln with bromide-bromate reagent until the blue coloration of I-starch paper remains for lOmins) c)M.Tl inskii R.B.Roshal, DoklAkadN 17, 117-20(1937)(in... 

Section 3.2.1 covers a similar area of synthesis planning as S. Warren s (1978) book Designing Organic Synthesis . This book contains many examples of antitheses of achiral carbo-and heterocyclic compounds that are largely ignored in this chapter (but see sections 2.5,4.6, and 4.7 for heterocycles). Warren s much more elaborate introduction into the "synthon approach to rerro-synthetic analysis is based on E.J. Corey s work (1967A, 1971) and is highly recommended for further study. 

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