Potts method

The present approach to terpyridine is a two-step procedure based on a variation of the Potts strategy.11 In this sequence, the 1,5-enedione formation is accompanied by the loss of dimethyl amine and the ring closure gives terpyridine directly, thus avoiding both drawbacks of the Potts method. The synthesis of the intermediate enaminone (1) has been previously reported.12... 

The development of G-i and W-i (Ahrens 1951 Fairbairn et al.1951 Stevens et al. i960) was the response to this demand with respect to dc arc emission spectrogra-phy. As similar samples are used routinely in calibration for XRF and INAA analyses, many geological samples have been developed as reference materials since that time to support geoanalysis (Potts et al.1992). Just as the change from classical to instmmental methods of analysis changed the nature of demands for reference... 

Zajicek, J.L. Tillitt, D.E. Huckins, J.N. Petty, J.D. Potts, M.E. Nardone, D.A. 1996, Application of Enzyme-Linked Immunosorbent Assay (ELISA) for Measurement of Polychlorinated Biphenyls (PCBs) from Hydrophobic Solutions Extracts of Fish and Dialysates of Semipermeable Membrane Devices (SPMDs). In Environmental Immunochemical Methods, ACS Symposium Series 646 American Chemical Society Washington, D.C. Chapter 26, pp 307-325. 

The traditional synthesis of miinchnones involves the cyclodehydration of N-acylamino acids usually with acetic anhydride or another acid anhydride. Potts and Yao (3) were apparently the first to employ dicyclohexylcarbodiimide (DCC) to generate mesoionic heterocycles, including miinchnones. Subsequently, Anderson and Heider (4) discovered that miinchnones can be formed by the cyclodehydration of N-acylamino acids using Ai-ethyl-Ai -dimethylaminopropylcarbodiimide (EDC) or silicon tetrachloride. The advantage of EDC over DCC is that the urea byproduct is water soluble and easily removed, in contrast to dicyclohexylurea formed from DCC. Although the authors conclude that the traditional Huisgen method of acetic anhydride is still the method of choice, these two newer methods are important alternatives. Some examples from the work of Anderson and Heider are shown. The in situ generated miinchnones (not shown) were trapped either with dimethyl acetylenedicarboxylate (DMAD) or ethyl propiolate. 

In 1775, Pursevil Pott first noted that the compounds associated with soot caused scrotal cancer in British chimney sweeps (] ). Not having modern methods of Instrumental analysis available to him, Pott was unable to specify the chemical structures of these compounds. It remained until 1933 before Cook et al. identified the exact structure of benzo[a]pyrene and demonstrated its carcinogenicity ( ). Thus, polycyclic aromatic hydrocarbons (PAH) are one of the few groups of compounds which are known to be carcinogenic to man. 

In a great research On the method of extracting zinc from its true mineral, calamine, A. S. Marggraf in 1746 reduced calamine from Poland, England, Breslau, and Hungary with carbon in closed retorts, and obtained metallic zinc from all of them (2, 19, 53). He found the ore from Holywell to be especially rich m it. He stated that both J. H. Pott and... 

The chimney-sweeper cancer described by P. Pott in England as early as 1775, which is basically related to soot but not to carbon black, was the starting point of intensive research on analytical test methods for polycyclic aromatic hydrocarbons (PAH) in carbon blacks. Increasingly refined test methods have been developed (e.g., column, thin-layer, and paper chromatography, gas chromatography, UV and fluorescence spectrophotometry, and mass spectroscopy) to detect traces of such substances and to investigate the ability of carbon black surfaces to adsorb and to desorb PAHs. 

B-80MI43600 K. T. Potts Modem Methods of Heterocyclic Chemistry , Rensselaer Polytechnic Institute, Troy, New York, 1980. 974... 

Potts, R. O. and Francoeur, M. L. Physical methods for studying stratum comeum lipids. Seminars in Dermatology 11(2) 179- 3S, 1992. 

The structures of the a and P forms remain somewhat enigmatic (Paulus el al. 1989), at least in the open literature. Leusen (1996) has claimed that computational methods for generating possible structures and subsequent comparison with X-ray powder diffraction patterns have been used to produce all three of the quinacridone structures, in the correct stability order. However, details are still to be published (Leusen et al. 1996). Lincke and Finzel (1996) published a proposed structure of the a-form from a powder pattern that was computed by generating the structure by perturbing the known y structure (Potts et al. 1994). However, the rather high R-factor (20.6 per cent) and the presence of quite a few peaks on the final difference plot, raise some doubts as to the correctness of this proposed structure. 

Potts and co-workers have developed a three-step preparation of tpy which involves first the synthesis of the bisthiomethylpropenone intermediate (3a) from 2-acetylpyridine (2) (Scheme 1). This enone is then cyclized to the 4 -thiomethyltpy (4), which is finally reduced to the parent compound.4 An improved two-step method has been reported, which proceeds through the analogous eneamine intermediate (3b) and produces the desired tpy in 47% overall yield.5... 

Figure 49-13 Schematic representation of PTH immunoassays including first and second generation noncompetitive intact immunoassays and midregion/C-termlnal and N-terminai competitive methods. The approximate location of the peptide regions recognized by the antibodies of the four classes of methods is indicated. (Modified from Jiippner H, Potts JT Jr. immunoassays for the detection of />orofhyro/d hormone.] Rone Miner Res 2002 l7 N8l-86.)...

Nussbaum SR, Lin CS, Potts JT, Rosenthal AS, Rosenblatt M. Development of monoclonal antibodies against parathyroid hormone genetic control of the immune response to human PTH. Methods Enzymoi 1985 109 625-38. 

The classical book on techniques by W. J. Potts (108) is still the book of choice for sample preparation and quantitative methods. Practical aspects of theory, sample handling, and application are well-described by A. L. Smith (109). ASTM E-13 is expected to release a new practice on qualitative analysis in 1985, and its "Manual on Practices in Molecular Spectroscopy" (27) covers nomenclature, instrument testing, microanalysis, internal reflection, and quantitative analysis. 

Infrared Sample Preparation. Details of sample preparation for obtaining infrared spectra are discussed for films, capillary layers, demountable cells, fixed thickness cells, pressed halide pellets, and oil mulls in the above references by Potts and Smith and in ASTM methods (27). Other more specialized techniques are described briefly below. 

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