First Systematic Investigations

At that time, hydrocarbons occurring in essential oils with the molecular formula C,oH g were known, which had been named by Kekule terpenes because of their occurrence in turpentine oil. Constituents with the molecular formulas CigHigO and C,oH,gO were also known at that time under the generic name camphor and were obviously related to terpenes. The prototype of this group was camphor itself, which was known since antiquity. In 1891, Wallach characterized the terpenes pinene, camphene, limonene, dipentene, phellandrene, terpinolene, fenchene, and sylvestrene, which has later been recognized to be an artifact. 

During 1884-1914, Wallach wrote about 180 articles that are summarized in his book Terpene und Campher (Wallach, 1914) compiling all the knowledge on terpenes at that time, and already in 1887, he suggested that the terpenes must be constructed from isoprene units. In 1910, he was honored with the Nobel Prize for Chemistry in recognition of his outstanding research in organic chemistry and especially in the eld of alicyclic compounds (Laylin, 1993). 

More recent investigations of J. Read, W. Hiickel, H. Schmidt, W. Treibs, and V. Prelog were mainly devoted to disentangle the stereochemical structures of menthols, carvomenthols, borneols, fenchols, and pinocampheols, as well as the related ketones (see Gildemeister and Hoffmann, 1956). 

The application of ultraviolet (UV) spectroscopy in the elucidation of the structure of terpenes and other natural products was extensively used by R.B. Woodward in the early forties of the last century. On the basis of his large collection of empirical data, he developed a series of rules (later called the Woodward rules), which could be applied to nding out the structures of new natural substances by correlations between the position of UV maximum absorption and the substitution pattern of a diene or an a,p-unsaturated ketone (Woodward, 1941). He was awarded the Nobel Prize in Chemistry in 1965. However, it was not until the introduction of chromatographic separation methods and nuclear magnetic resonance (NMI spectroscopy into organic chemistry that a lot of further structures of terpenes were elucidated. The almost exponential growth in our knowledge in that eld and other essential oil constituents is essentially due to the considerable advances in analytical methods in the course of the last half century. 

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The first systematic investigations of the catalytic Friedel-Crafts-type reaction with alcohols and olefines were performed by Yamamoto and colleagues. After reporting the development of a Pd-catalyzed method for the allylation of different naphthol derivatives [24], the authors used Mo(CO)g for the Friedel-Crafts-type alkylation of electron-rich arenes with allyl acetates [25], The same molybdenum catalyst was additionally used for a Friedel-Crafts-type alkylation of arenes using 1-phenylethanol and styrene as alkylating reagents [26], However, Mo(CO)g is toxic and must be handled under strictly inert conditions. Thus, more stable Lewis acids were necessary. 

Patterson and Holm [95] carried out the first systematic investigation on the influence of the structure of coordinated... 

Phase Relationships. The first systematic investigation of the two-phase behavior of polymer/polymer/solvent systems was probably made by Dobry and Boyer-Kawenoki (2) for a variety of polymer pairs, and more recently this work was extended by Kern and Slocombe (3) and Paxton (35) to a number of other systems including several vinyl polymers. Typically, the three-component phase behavior is as shown in Figure 19 for the polystyrene/polybutadiene/benzene system (2), where a one-phase (polystyrene/polybutadiene/benzene) region is separated by a phase boundary from a two-phase (polystyrene-rich/benzene and polybutadiene-rich/benzene) mixture. As with any three-component system of this type, a critical point exists somewhere near the maximum of the phase boundary, and appropriate tie lines give the compositions and amounts of the respective phases in the two-phase region. 

Until the fabrication of the first conductive LB film by Ruaudel-Teixier et al. [20], LB films had been considered as insulators or at most as semiconductors with very low conductivities. This is understandable since the typical film-forming molecules are long-chain fatty acids, which can act only as insulators. It is no wonder that the first systematic investigations of the electrical properties of LB films were carried out for insulating LB films [21-30]. Mott s variable-range-hopping model [31] is employed to explain the results [21,24]. 

The first systematic investigations of the adsorption of gases on dehydroxylated silicas were made by Kiselev and his co-workers (Kiselev, 1957,1958). In a study of the adsorption of argon and nitrogen, Aristov and Kiselev (1965) found that, in contrast to nitrogen, the reduced argon isotherm did not appear to depend on the degree of surface hydroxylation. 

Billon, using acetonitrile as a solvent, carried out the first systematic investigations on the anodic oxidation of phenothiazine... 

The first systematic investigation of the binding of a metal ion by lysozyme is probably that by Fiess and Klotz (1952), who found the affinity of five proteins for Cu(ll) at pH 6.5 to be in the order bovine a-casein > /3-casein > serum albumin > /8-lactoglobulin > hen egg-white lysozyme. Soon afterward Carr (1953), using membrane electrodes, found that —0.7 mol of Ca(ll) was bound per mole of hen egg-white lysozyme at pH 7.4, compared with 6.7 mol of Ca(ll) per mole of bovine serum albumin. 

The first sets of experiments carried out on the reduction of benzoic acids gave mixtures of dihydro and tetrahydro derivatives. This is hardly surprising in the light of the Van Bekkum study. The first systematic investigation appears to have been carried out on p-lsopropylbenzoic acid (84 Scheme 15), ° for which it was found that reduction by lithium-ammonia at -70 C followed by the addition of ethanol and then ammonium chloride at 5 min intervals furnished a 2 1 mixture of trans- and c/i-1,4-dihydro derivatives (85). In the absence of ammonium chloride the 3,4-dihydro isomer (86) was obtained and this could be reduced further to a 2.5 1 mixture of the tetrahydro derivatives (87) (ammonium chloride quench) and ( )-phellandric acid (88). 

The first systematic investigation on the gas chromatographic separation of xanthine de-rivatives was published by Reisch and Walker. The naturally occurring xanthines, caffeine, theobromine and theophylline, as well as a number of derivatives, were gas chromatographed on an 1.5 % packed SE-30 column on Chromosorb W. In Table 20.1 the compounds are given and and in Figure 20.1 typical gas chromatograms. 

While reports of Se NMR reach back to the early fifties the first systematic investigations in this field were published between 1965 and 1971. Thereafter, the interest in this nucleus increased steadily when it was noticed that its NMR properties were comparable to those of C making it rather easily accessible under routine pulse Fourier transform recording conditions. At the end of the century, the number of papers reporting Se NMR data exceeded 1200. 

The first systematic investigation toward Lewis acid catalyzed vinylogous Mukaiya ma Mannich reactions was reported by the group of Ojima in 1987 who showed that acyclic vinylketene silyl 0,0 acetals 10 reacted with imines activated by stoichio metric amounts of TiCU to furnish either 5 amino 2 alkenoates 11 or 5,6 dihydro pyridones 12 selectively in excellent yields depending upon the substitution of the silyl dienolate employed (Scheme 5.4) [5]. Although 2 methyl substituted vinylketene acetal 10a gave rise to acyclic 5 amino 2 alkenoates 11 exclusively, 3 methyl substi tuted vinylketene acetal 10b furnished 5,6 dihydropyridones 12 as the sole products. 

Early work on the hydrolysis of starch was reviewed by Rolfe and Defren, who made the first, systematic investigation (following the report by Kirchoffi in 1811 that acid hydrolysis of starch yields a sugarlike sub-... 

Although it had been known for many years that cyclopentane derivatives are nonplanar in solution and that furanose derivatives are non-planar in the solid state, it was not until the investigations of Jardetzky and of Lemieux, that it was obvious that furanoses are also nonplanar in solution. The first systematic investigation of a series of related furanoses was made by Abraham and coworkers. These workers investigated... 

The first systematic investigation of the reaction of an anionic nucleophile with substituted acetaldehydes, using the analytical gradient techniques, was reported recently by Wong and Paddon-Row [143]. The study focused on the addition of cyanide ion to aldehydes. This ion displays characteristics of a stabilized carbanion. 

Almost all the formalism and the approximation schemes of Sections II and III have a natural extension to systems of polarizable dipolar particles, but the precise details of the extension depend on the way polarizability is introduced into the Hamiltonian. We refer to the two quite distinct Hamiltonian models that have been most thoroughly developed in this context as the constant-polarizability model and the fluctuating-polarizability model. The dielectric behavior of the former was first systematically investigated from a statistical mechanical viewpoint by Kirkwood and by Yvon, who considered the model almost exclusively in the absence of permanent dipole moments. (Kirkwood S subsequently pioneered an exact formulation of the statistical mechanics of polar molecules, but largely as a separate enterprise that did not attempt to treat the polarizability exactly.) The general case of polar-polarizable particles remained only very partially developed ... 

The adsorption kinetics of proteins have been first systematically investigated by Graham and Phillips [73] and later by other authors, as reviewed by Wustneck et al. [75]. The typical course... 

Poisoning of Pt by metals, S, N, hydrogenation reactions Linear, exponential First systematic investigation of impurity poisoning effects on noble metals... 

The first systematic investigation of steric interactions in a liquid film sandwiched between two macroscopic liquid bodies was that of Andrews et al. [53], who applied an electric field across the film, leading to a compressional force on the film that consisted of glycerol mono-oleate chains in hydrocarbon oils. The films were formed in a 1 mm hole in a Fluon disk that was mounted between two bulk aqueous electrolyte solutions. Sonntag et al. [54] have studied aqueous films sandwiched between two hydrocarbon layers. The aqueous film containing the nonionic surfactant was formed between two approaching emulsion droplets that were projected in the dispersion medium at the ends of two capillaries. The film thickness and its change were determined by means of an interferometric method. 

The first systematic investigation of Lewis acid-catalyzed additions of indole to enones used Yb(OTf)3. The enones examined included methyl vinyl ketone, pent-3-en-2-one, 4-phenylbut-3-en-2-one and cyclohexenone, all of which gave good yields. The p,p-disubstituted systems 4-methylpent-3-en-2-one and 3-methylcyclo-hex-2-enone gave lower yields [210]. 

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