bluuebunny/crossref_metadata_2025_split huggingface dataset:
Kombinierte Elektronenbeugungs- und „electron probe x-ray microanalysis“-Untersuchungen an Frühstadien der Zahnsteinbildung
Authors: Höhling H. J. , Hall T. A. , Mutschelknauss R. , Niem J. 
Published: March 2015

1) From new calculus-formations, deposited on Mylar foils within 4 - 12 days, ultrathinsections were taken after alcohol-fixation. In the electronmicroscopical microanalyzer of Duncumb (5) we carried out Ca/P-measurements as well as relative-quantitative Ca- und P-determinations in microareas of mineralized and unmineralized tissue.
2) From the same person, 1 - 12 days after cleaning of the teeth, we also took the calculusformations, transfered them on Nylon foils, evaporated them with Al and carried out full quantitative Ca- und P-measurements in a normal microprobe.
Concerning 1) our Ca/P values of partly mineralized microareas of the 4 days-foil are in the range of 0.95 - 1,3 and are far below the Ca/P molar ratio of apatite (1,67). Also the Ca/P ratios of mineralized microareas of older formations (e.g. 12 days) were found to ly normally below apatitic.
The Ca/P-ratios of the neighbouring unmineralized microareas normally were even below those of the mineralized ones and increased with increasing Ca- and P-enrichment in the tissue. From this we conclude that Ca-enrichment in the tissue is the important step leading to nucleation which causes a further P-enrichment above the normal P-level in the tissue (probably by binding of HPO4-groups). This conclusion is supported by most of the results of 2).
Immunologische Studien am Omentum
Authors: Malchow H. , Ax W. , Fischer H. 
Published: March 2015

Es wird über Experimente berichtet, die zum Ziel haben, die Reaktionen des Omentum majus der Maus auf einen primären antigenen Stimulus zu untersuchen. Dazu werden Tiere mit korpuskulären und löslichen Antigenen intraperitoneal immunisiert. In weiteren Versuchen wird das System in vitro nachgeahmt.
Nach Immunisierung werden die Omenten in Zeitabständen für eine Stde. mit 3H-Thymidin inkubiert. In allen Experimenten findet sich eine mitotische Aktivität der Mesothelzellen, die bei den Kontrollen und einer 20-proz. Glucoselösung nicht gefunden werden. Die Aktivität hat ein Maximum nach 24-48 Stunden. Dieser Teilungsbereitschaft geht die Phagozytose voraus. Die Beteiligung des Mesothels an der Immunantwort ist unseres Wissens neu und wirft verschiedene Fragen auf, die diskutiert werden.
Nach Abklingen der Teilungsaktivität am vierten Tag ist das Omentum zellreicher und enthält eine Vielzahl von „blastähnlichen“ Zellen. Diese „Immunoblasten“ treten in kleinen Gruppen auf. und sie werden nur bei den in vivo-Experimenten gefunden.
Unterschiedliche Wirkung von Licht auf die Aufnahme von Chlorid und Sulfat in Limnophila-Blätter. Abhängigkeit der Lichtwirkung von der Konzentration der Anionen
Authors: Penth Bernhard , Weigl Josef 
Published: March 2015

The effect of light on anion uptake by detached leaves of Limnophila gratioloides was investigated using different external concentrations of chloride and sulfate. The results show that the effect of light may be dependent not only on the plant species 1-4,8,9 and more or less imponderable conditions like the nutritional and developmental state of the plant but also on the external ion concentration and the duration of the uptake period. Chloride uptake by Limnophila leaves from solutions of 0.1 - 1.0 mM/I was not affected by light (4000 Lux), uptake from 1.0 - 10.0 mM/l, by contrast, was stimulated by light in an initial uptake period (4 h), i. e. the km of this system was decreased by light leaving vmax unaltered. Sulfate uptake was inhibited by light if the external sulfate concentration was within the range of 0.01 -7.0 mM/l. Applying external sulfate concentrations from 7.0 - 50.0 mM/l results in stimulation of uptake by light.
A workable approximation to these observations may still be that the primary metabolic anion uptake, particularly chloride uptake, into leaf cells is mediated by transport systems which are remote from the mitochondria and chloroplasts and which are supported by a cofactor produced either in oxydative phosphorylation, in cyclic plus noncyclic photophosphorylation or in cyclic photophosphorylation alone 1-4, 9. Since kinetic data are equal in light and in dark, direct coupling of chloride uptake to electron flow in mitochondria or chloroplasts is unlikely. The hypothesis is developed that light may exert a dual influence on ion uptake:
1. Metabolic uptake may be influenced by a change in the availability of ATP to transport systems.
2. Passive fluxes and counterfluxes of ions across cell membranes may be affected by production or translocation of intracellular ions. Since chloroplasts represent important intracellular compartments, light-induced translocations of ions22 (including Ca2⨁
23!) across the chloroplast membranes may exert a marked influence on the overall ion uptake by stimulation of the passive influx of ions across the plasmalemma 15.
In line with this views is the observation that in Limnophila leaves, which contain approximately equal ATP levels in light and in dark, there is no stimulation of chloride uptake by light at low external concentrations of KCl while at high external concentrations, at which passive fluxes of ions across the plasmalemma become effective, both ion uptake and ion loss is stimulated by light.
The susceptibility to the external ion concentration of the influence of light suggests that effects of light on ion transport ought to be studied at various external ion concentrations.
The applicability of imidazole as uncoupler of photophosphorylation in vivo is discussed.
Die Temperaturabhängigkeit der Aminoacylierungsgeschwindigkeit von Phenylalanin- und Serin-spezifischer Transfer-Ribonucleinsäure aus Brauerhefe
Authors: Schlimme E. , Haar F. V. D. , Cramer F. 
Published: March 2015

It is known that several physical properties in tRNA * are changed between 35°C and 45°C. These changes have been attributed to unfolding of tertiary structure. In this paper the correlation between these changes and the rate of aminoacylation is studied.
With purified tRNASer
yeast and tRNAPhe
yeast and purified aminoacyl synthetases, aminoacylation reaches a plateau within 20 min. (Fig. 2). The rate of charging was determined in the linear region (5 min.) at varying temperatures. With tRNASer
yeast there is a sharp drop in the rate of charging at 39° (Fig. 3 a) corresponding to the first melting of Ser
yeast (Fig. 6 a). By changing the Mg2⊕ concentration, rate of aminoacylation and first melting are shifted in the same direction. With tRNAPhe
yeast no stepwise decrease of aminoacylation with temperature is observed (Fig. 3 b). At the same time this molecule does not exhibit a two step melting profile (Fig. 6 b). The effects observed cannot be due to a change or irreversible inactivation of the enzyme since the thermal inactivation of the enzyme follows a normal pattern above 43°C and 38.5°C respectively (Figs. 4 a and 4 b). Likewise the amino acid activation reaction is not responsible for these effects. This reaction has been measured by the pyrophosphate formation to have a normal temperature profile up to 50°C. Only at this temperature the enzyme begins to become denatured (Fig. 5). The results indicate that the observed changes in aminoacylation are caused by a change in physical properties of the tRNA. This change yields a molecule having a conformation that can no longer be aminoacylated. Since at the higher temperature still the same plateau is reached, however, at a slower rate, an equilibrium between the two forms must exist. This equilibrium could be of the following manner:
Chemilumineszenz von Redoxreaktionen mit molekularem Sauerstoff / Chemiluminescence of Redox Reactions with O2
Authors: Stauff J. , Nimmerfall F. 
Published: March 2015

The autoxidation of NaSH and Cysteine in the presence of heavy metal ions is accompanied by chemiluminescence due to the formation of O2
⊖ or adequate compounds as intermediates. The observation of the luminescence intensity and its time dependence has been used as analytical indication of the occurrence of electron transfer reactions from - SH to O2.
This enabled the study of the influence of different catalytic promoters. The efficiency of different metal ions could easily be demonstrated by their enhancement of light production during the reaction of NaSH with molecular oxygen. Cu (II) as one of the most efficient catalysts was also applied in the form of different complexes. Because it would catalyse the oxidation of cysteine, glutathione and other electron donors of biological interest, the influence of the nature of the ligands of the complexes was investigated. In the case of cysteine only complexes with stability constants of medium strength and planar configuration acted as effective catalysts. Therefore it has to be assumed that for an effective electron transport to the loosely bound oxygen the cysteine molecule has to enter the inner sphere of the complex. The much longer time of luminescence of this reaction (4 -10 min) compared to the short time luminescence caused by free O2H. OH and H2O2 indicates that these intermediates are stabilized by binding to the Cu (II) -complex as in compounds (I), (II) and (III) of oxidizing enzymes.
Zur Wirkung von Zn2⊕ auf die nucleare RNA- und Proteinbiosynthese der Rattenleber / Effect of Zn2⊕ on Nuclear RNA- and Protein-Biosynthesis in Rat Liver
Authors: Weser U. , Seeber S. , Warnecke P. 
Published: March 2015

Female rats have been employed for a study of the reactivity of zinc ions on RNA and protein biosynthesis of liver nuclei. Intraperitoneal injections of 20 μmoles of this metal ion have been found to stimulate RNA biosynthesis up to 80% and a 40% increase of protein synthesis was observed under the same conditions. The precursor for RNA synthesis was [6-14C] -orotic acid and [l-14C]-ᴅʟ-leucine served as a label for nuclear protein. Low Zn2®-concentrations showed no reactivity, even when zinc-deficient rats were used.
DNA-dependent RNA-polymerase activity was progressively diminished when increasing amounts of Zn2⊕-ions were added in vitro to the incubation mixtures. However, RNA-polymerase activity was strongly stimulated following a 10 h pulse of Zn2® prior to the isolation of liver nuclei.
Der Einfluß von Methylcholanthren auf Synthese, Vernetzung und Abbau des Kollagens der Mäusedermis und die mögliche Bedeutung dieses Abbaues für malignes Wachstum
Authors: Seilern-Aspang F. , Mazzucco K. , Christian I. 
Published: March 2015

1. In der Embryogenese und Regeneration wird die Proliferation und Differenzierung der Epidermiszelle von der Dermis, wahrscheinlich mit besonderer Bedeutung des Kollagens gesteuert. Malignes Wachstum der Epidermiszelle wird als ein Primärdefekt der Dermis bzw. ihres Kollagens und den dadurch bedingten Ausfall der Steuerung aufgefaßt. Untersucht wird daher der Einfluß eines in Benzol gelösten Cancerogens auf das Kollagen der Dermis.
2. Unter dem Einfluß von Benzol steigt die Kollagensynthese und es findet sich wesentlich mehr und nach den Vernetzungsverhältnissen jüngeres Kollagen.
3. In Benzol gelöstes Cancerogen scheint die Kollagensynthese stark zu senken. Das Kollagen nimmt in allen Vernetzungsstufen gleichmäßig ab.
4. Verletzte Haut, die mit Cancerogen behandelt wurde, zeigt zusätzlich zu der gesenkten Kollagensynthese einen stärkeren Abbau der höher vernetzten Kollagenanteile. Größere Mengen Hydroxyprolin-hältiger molekularer Bruchstücke sprechen für eine kollagenolytische Aktivität.
5. Die gegen die Induktion von Carcinomen durch Carcinogene resistente Schwanzhaut (resistent nur in sito) zeigt außer der durch Benzol erhöhten Kollagensynthese keine der oben beschriebenen Veränderungen.
6. Es wird angenommen, daß das Carcinogen die Kollagensynthese stört. Dadurch wird die im Wundepithel auftretende Kollagenasesynthese im Ausheilungsprozeß durch Ausfall neu aufgebauter Kollagene nicht blockiert. Es wird im Gegenteil durch weiteren Abbau von Kollagen durch die Kollagenase der Epidermiszellen jeder steuernde Einfluß der Dermis auf die Epidermis aufgehoben. Die Epidermiszelle entgleitet ihrer zwischengeweblichen Kontrolle und wird unter bleibender Kollagenasesynthese maligne.
Substitutionsreaktionen an Phosphor- und Schwefel-Amiden
Authors: Roesky Herbert W. , Böwing Walter Grosse 
Published: March 2015

Methylthiophosphonsäureamidfluorid, CH3P (S) FNH2, und Äthylthiophosphonsäureamidfluorid, C2H5P(S)FNH2, reagieren mit Trimethylchlorsilan in Gegenwart von Triäthylamin zu den Verbindungen CH3P(S)FNHSi(CH3)3 und C2H5P(S)FNHSi(CH3)3. Mit PCl5 läßt sich Äthylthiophos-phonsäureamidfluorid zum C2H5P(S)FN = PCl3 umsetzen. Durch partielle Ammonolyse von Phenylthiophosphonsäuredifluorid erhält man C6H5P(S) FNH2.
Bei der Reaktion von P3N3F5NH2 mit PF3Cl2 entsteht P3N3F5N = PF3. Die entsprechende Umsetzung mit C3N3F2NH2 ergibt C3N3F2N = PFCl2. Mit FSO2NH2 reagiert PF3Cl., sowohl zum FSO2N = PF3 als auch zum FSO2N = PF2Cl. IR-, 19F- und 1H-KMR-Spektren werden angegeben.
Absorptionsänderungen von Chlorophyll-b im elektrischen Feld / Absorption Changes of Chlorophyll-b in the Electric Feld
Authors: Schmidt S. , Reich R. , Witt H. T. 
Published: March 2015

In order to test recent interpretations of field indicating absorption changes in photosynthesis, the influence of the electric field on the absorption spectrum of chlorophyll-b is measured in vitro.
50 monomolecular layers of chlorophyll-b are built up on quartz slides by the technique of Blodgett and Langmuir. Absorption changes induced by an electric field linearly increasing from −1.8 · 106 V/cm to +1.8 · 106 V/cm are detected by a repetitive photometer. The absorption changes can be separated into one part, which is proportional to the electric field strength, and a second one, which is proportional to the square of it. The linear change of absorption in the region at ~650 nm may be interpreted as a shift of the absorption band of about

.
Die Ausschüttung und Funktion von Häutungshormon während eines Zwischenhäutungs-Intervalls bei der Strandkrabbe Carcinus maenas L.
Authors: Adelung D. 
Published: March 2015

Der Häutungszyklus der Strandkrabbe wird mit Hilfe neuer Kriterien in 21 verschiedene Stadien eingeteilt. Als Charakteristika für die einzelnen Stadien dient neben den bisher angewendeten morphologischen Merkmalen der Entwicklungszustand der Regenerate und die Geschwindigkeit, mit der die Krebse den Häutungszyklus durchschreiten.
Für jedes Stadium wird der Häutungshormongehalt mehrerer Tiere bestimmt und eine Hormontiterkurve für einen Häutungszyklus aufgestellt. Aus den Änderungen des Hormongehaltes und den gleichzeitig stattfindenden morphologischen und physiologischen Veränderungen wird auf die Funktionen des Häutungshormones geschlossen. Vor der Häutung erfolgen zwei Hormonausschüttungen, die eine ca. 6 - 8 Tage, die andere 1 - 2 Tage vor der Häutung. Die erste Hormonausschüttung löst wahrscheinlich die Apolyse aus, die zweite bewirkt eine Erhöhung des osmotischen Wertes der Hämolymphe und führt damit zur Auslösung der Häutung im engeren Sinne. Unmittelbar nach der Häutung wird erneut Hormon ausgeschüttet, das vermutlich die Härtungsprozesse in der Cuticula steuert. Nachdem sämtliche mit der vorangegangenen Häutung zusammenhängenden Prozesse abgeschlossen sind, löst eine weitere kurzfristige Hormonausschüttung die Regeneratentwicklung und vielleicht den nächsten Häutungszyklus aus.
Ein Vergleich des Häutungshormongehaltes der Strandkrabbe während eines Häutungszyklus mit demjenigen von Insekten während der Puppenhäutung ergibt einige Übereinstimmungen, z. B. in der Höhe des Hormongehaltes und einige Unterschiede, die sich aus der unterschiedlichen Lebensweise dieser Tiere erklären.
Untersuchungen zur Anwendung von 32P-markiertem Dimefox
Authors: Koch H. , Abendroth H.-Chr. , Jeske A. 
Published: March 2015

Die Markierungssynthese des 32P-markierten Dimefox [Bis- (dimethylamino) -phosphorylfluorid] ausgehend von rotem Phosphor-32 wird beschrieben.
Es wird über den hydrolytischen Abbau bei saurer sowie bei alkalischer Reaktion berichtet.
Über die Aufnahme des Wirkstoffes nach Blatt- bzw. Wurzelbehandlung an Hopfenpflanzen in Hydrokulturen und unter Freilandbedingungen wird berichtet sowie Betrachtungen über das Verhalten des Wirkstoffes in der Pflanze werden dargelegt. Die Dauer der Wirksamkeit des Insektizides in der Pflanze wird verfolgt.
Notizen: Die Struktur von [(CH3)2Si]2S2N4 / The Structure of [(CH3)2Si]2S2N4
Authors: Ertl Gert , Weiss Johannes 
Published: March 2015

The structure of [(CH3)2Si]2S2N4 has been determined from threedimensional diffractometer data and refined by least squares methods to R = 0.07. The unit cell is orthorhombic with four molecules per unit cell and a = 599,5 pm, b = 2300.9 pm, c = 841.9 pm.
Wie von ROESKY und WIEZER1 gezeigt werden konnte, lassen sich im achtgliedrigen Ringsystem des S4N4 2 Schwefelatome durch Si(CH3)2-Gruppen ersetzen. Die Struktur dieser Verbindung haben wir röntgenographisch bestimmt.
Notizen: Schwingungsspektren der Gold(I)-halogenide AuX (X = Cl, Br und I); Strukturprognosen für AuCl und AuBr / Vibrational Spectra of the Aurous Halides AuX (X= Cl, Br and I); Structural Prognoses for AuCl and AuBr
Authors: Breitinger Dietrich , Leuchtenstern Heiko 
Published: March 2015

Chain structure, Force constants
From vibrational spectra chain structures are predicted for AuCl and AuBr; bond angles, bond lengths and force constants have been estimated for these aurous halides.
Darstellung und Komplexierungsverhalten von 2.4.6-Tri(4-pyridyl)-s-triazin / Preparation and Complex Behaviour of 2,4,6-Tri(4-pyridyl)-s-triazine
Authors: Biedermann Hans-G. , Wichmann Klaus 
Published: March 2015

2,4,6-Tri(4-pyridyl)-s-triazine is prepared from 4-cyanopyridine by a cationic and anionic mechanism. It forms with transition metal chlorides in toluene or benzene the complexes: (FeCl3)3(TPyT)2, and (MeCl2)3(TPyT)2 with Me = Ni, Co, Cu.
The IR spectra, magnetic and electrical conductivity measurements are discussed.
Zur Existenz neuer Verbindungen zwischen Alkalimetallen / On the Existence of New Compounds Between Alkali Metals
Authors: Simon Arndt , Ebbinghaus Gebhard 
Published: March 2015

Compound formation is found in the systems Na/K (Na2K), Na/Cs (Na2Cs) and K/Cs (K2Cs, K7Cs6).
Due to modified GUiNIER-photographs Na2Cs crystallizes with the hexagonal LAVES-type structure (a0 = 7.861 ± 0.001, c0 = 13.062 ± 0.002 Å at —50°C). The structure is discussed in terms of VEC- and geometrical arguments.
Radiation Chemistry of Carbohydrates, VI: γ-Radiolysis of Glucose in Deoxygenated N2O Saturated Aqueous Solution
Authors: Dizdaroglu Miral , Henneberg Dieter , Schomburg Gerhard , Sonntag Clemens von 
Published: March 2015

In the γ-radiolysis of deoxygenated N2O-saturated aqueous solutions of D-glucose (10-2 M, 1 · 1019 - 4 · 1019 eV/g, dose rate 4.3 · 1018 eV/g · h at 25°C), the following products have been identified: Gluconic acid (1), 2-deoxy-gluconic acid (2), arabinose (3), 2-deoxy-ribose (4), 5-deoxy-gluconic acid (5), glucosone (6), 3-deoxy-glucosone (7), 3-keto-glucose (8), [2-deoxy-3-keto-glucose (9), 4-deoxy-3-keto-glucose (10)]3, 4-ketoglucose (11), 3-deoxy-4-keto-glucose (12), 5-deoxy-4-keto-glucose (13), 5-keto-glucose (14), 2-deoxy-5-keto-glucose (15), 4-deoxy-5-keto-glucose (16), 6-deoxy-5-keto-glucose (17), gluco-hexodialdose (18), 5-deoxy-xylo-hexodialdose (19), ribose (20), xylose (21), erythrose (22), threose (23), 3-deoxy-pentulose (24), 2-butanone-(1,4)-diol (25), and dihydroxyacetone (26). G-values were also determined.
In the primary processes OH radicals and H atoms from the radiolysis of the solvent water abstract carbon bound hydrogen atoms from D-glucose to give all six possible primary glucosyl radicals. The observed products are formed in disproportionation reactions of the primary glucosyl radicals (1, 6, 8, 11, 14, 18) or of sugar radicals which originate from the primary glucosyl radicals by water elimination (2, 4, 7, 9, 10, 12, 13, 15, 16, 17, 19), rearrangements (5, 14, 15), or loss of carbon monoxide (3, 4, 20).
Products 1-5 and probably 20 have primary glucosyl radicals with the odd electron at C-1 as precursors. Radicals with the free spin at C-2 give rise to the products 6 and 7. Attack at C-3 yield products 8-10, at C-4 products 11-13, at C-5 products 14-17, and an attack at C-6 products 18 and 19. Products 21-26 are formed in very low yields and hence are of minor importance. Their mechanism of formation has not been investigated.
Radiation Chemistry of DNA-Model Compounds, VIII Dephosphorylation Products from Reactions of OH Radicals with Ribose-5-phosphate in Aqueous Solution. The Effect of Oxygen
Authors: Stelter Lothar , von Sonntag Clemens , Schulte-Frohlinde Dietrich 
Published: March 2015

The reaction of hydroxyl radicals with ribose-5-phosphate in oxygenated aqueous solution leads to the following phosphate free products (G-values): Erythrodialdose (0.4), formic acid (0.4) and ribodialdose (0.1). In addition, inorganic phosphate (0.6) and some minor phosphate free products (total G≈ 0.08) are formed.
Within the limits of experimental error material balance between dephosphorylation products and inorganic phosphate is obtained. A mechanism is proposed which can account for the main products. The primary steps of the dephosphorylation are H atom abstraction from C-5 of ribose-5-phosphate by OH radicals and subsequent addition of O2. The peroxy radicals formed decompose to ~80% by C-C bond cleavage followed by elimination of inorganic phosphate and only to ~20% by direct dephosphorylation. The relevance of these results with respect to the radiolysis of DNA is discussed.
Notizen: Evidence against OH Radical Formation during Photocatalyzed Reduction of Manganese(III) in K2 [Mn(III)-2-α-hydroxyethyl-isochlorin e4]acetate in Oxygen Free Aqueous Alkaline Solutions
Authors: Vierke Gerhard , Müller Manfred 
Published: March 2015

The hypothesis of GLIKMAN and ZABRODA (Biochemistry [USSR] 84,, 239 [1969]) that the primary electron donor during photoreduction of manganese(III) in Mn(III)-hydroxychlorin compounds in oxygen free aqueous alkaline solutions is the axially bound OH- ion was tested with Mn(III)-2-a-hydroxyethyl-isochlorin e4. It has been shown that
1) the primary generation of OH radicals upon irradiation of the complex is highly improbable,
2) light is not essential for the reduction reaction,
3) the kinetics of photoreduction of the Mn(III)-compound in 2 N NaOH clearly is not compatible with OH radical formation.
Die Kristallstruktur des Spirophosphorans (HOCH2 · C6H3 · CH2O)2PPh.
Authors: Hellwinkel D. , Krapp W. , Schomburg D. , Sheldrick W. S. 
Published: March 2015

The title compound crystallises in the monoclinic space group, Cc, Z = 4, with a = 12.370(1), b = 19.447(1), c = 7.786(1) Å, β = 90.82(1)°.
The structure was solved by direct methods and refined to R = 0.070 for 2163 independent reflections.
Trigonal-bipyramidal geometry is observed at phosphorus with the ring oxygens occupying the axial sites. The plane of the phenyl substituent makes a dihedral angle of 20.2° with the equatorial plane. The molecules are linked into infinite chains in the [010] plane through (CH2)O ••• H—O(CH2) hydrogen bonds of length 2.77 A.
Notizen: Eine neue Totalsyntese von Methionin-Enkephalin.
Authors: Voelteb Wolfgang , Kalbacheb Hubert , Pietrzik Emanuel 
Published: March 2015

A new improved synthesis of methionineenkephalin is described. For methionineenkephalin the structure
L-Tyr-Gly-Gly-L-Phe-L-Met-OH has been suggested most recently. The peptide is synthesized from Boc-Gly-Gly-OH, H-L-Phe-OMe, Boc-L-Tyr(Bzl)-OH and H-L-Met-OMe by means of “classical” methods.