Schwyzer

The processes used in the manufacture of morphine are believed to be still based on that described by the Scottish chemist Gregory,in 1833, with improvements devised by Anderson. A description has been published by Schwyzer, who also deals with the manufactme of codeine, narcotine, cotarnine, and the commercially important morphine derivatives, diamorphine (diacetylmorphine), and ethylmorphine (morphine ethyl ether). More recently Barbier has given an account of processes, based on long experience in the preparation of alkaloids from opium. Kanewskaja has described a process for morphine, narcotine, codeine, thebaine and papaverine, and the same bases are dealt with by Chemnitius, with the addition of narceine, by Busse and Busse, and by Dott. It is of interest to note that a number of processes for the extraction and separation of opium alkaloids have been protected by patent in Soviet Russia. ... 

Processes for the isolation and purification of yohimbine have been described by Thoms, Feldhoff, Chemnitius, Schwyzer, Raymond-Hamet and others. Some of these processes have been modified to provide for estimation of the yield of yohimbine, usually as the hydrochloride, from the bark, or to facilitate the identification of this alkaloid in commercial yohimbe bark, which is apt to vary both in quality and in botanical origin.According to Witkop (1943) modern technical yohimbine hydrochloride may contain a little isoyohimbine but no allo-yohimbine. 

Preparation. The mother liquors from strychnine manufacture are concentrated and the alkaloids precipitated as neutral oxalates. The precipitate is dried and extracted with dry alcohol in which the strychnine salt is the more soluble. The less soluble salt dissolved in water is decolorised with charcoal, the alkaloid regenerated with ammonia and purified by crystallisation as the sulphate. According to Saunders, pure brucine may be obtained by slow crystallisation from a solution of the pure hydrochloride in alcoholic ammonia. A method of separation depending on the greater solubility in water of strychnine hydriodide was employed by Shenstone, whilst others have made use of the sparing solubility of strychnine chromate for the removal of small quantities of this alkaloid from brucine. For a large scale process see Schwyzer. ... 

Commercial veratrine is a mixture of alkaloids prepared from sabadilla seeds and consists largely of cevadine and veratridine with some cevine. Its manufacture has been described by Schwyzer. Crystalline veratrine was first isolated by G. Merck. Wright and Luff introduced the name cevadine to distinguish this alkaloid from the commercial amorphous mixture known as veratrine. ... 

Sonderer, B., Wild, P., Wyler, R, Fontana, A., Peterhans, E. and Schwyzer, M. (1987). Murine glia cells in culture can be stimulated to generate reactive oxygen. J. Leukocyte Biol. 42, 463-473. 

FIGURE 2.9 Peptide-bond formation from activated esters of /V-alkoxycarbonylamino acids [Wieland, 1951 Schwyzer, 1955 Bodanszky 1955], Some hydroxy compounds have two abbreviations. HONSu conveys the notion of bonding through a nitrogen atom and is consistent with HONPht = /V-hydroxyphthalimide. Su can be interpreted as succinyl/oyl. 

R Schwyzer, M. Feuer, B Iselin. Activated esters. IB. Reactions of activated esters of amino acid and peptide derivatives with amines and amino acid esters. Helv Chim Acta 38, 83, 1955. 

R Schwyzer, W Rittel, H Kappeler, B Iselin. Synthesis of a nonadecapeptide with higher corticotropic activity, pert-butyl removal) Angew Chem 72, 915, 1960. 

R Schwyzer, P Sieber, H Kappeler. On the synthesis of N-f-butyloxycarbonyl-amino acids. Helv Chim Acta 42, 2622, 1959. 

R Schwyzer, B Rittel. Synthesis of intermediates for a corticotropic nonadecapeptide. I. A, -ferf-Butoxycarbonyl-L-lysine, A a(M-/c rt-biitoxycarbonyl-i,-lysyl)-/Vr-/< rt-butoxycarbonyl-L-lysine, M-tert-butoxycarbonyl-L-lysyl-i.-prolyl-i.-valylglycine and derivatives. Helv Chim Acta 44, 159, 1961. 

R Schwyzer, P Sieber. The total synthesis of adrenocorticotrophic hormone. Nature 199, 172, 1963. 

R Riniker, R Schwyzer. Steric homogeneity of synthetic valyl5 hypertension-II-aspar-tyl-B-amide. Helv Chim Acta 44, 658, 1961. 

R Schwyzer, CH Li. A new synthesis of the pentapeptide L-histidinyl-L-phenylalanyl-L-arginyl-L-tryptophyl-glycine and its melanocyte-stimulating activity. (/Moluene-sulfonyl) Nature (London) 182, 1669, 1958. 

BM Iselin, R Schwyzer. Synthese of peptide intermediates for the construction of 3-melanophore-stimulating hormone (P-MSH) of beef. I. Protected peptide sequences 1-6 and 1-7. [imide by saponification of ROCO-Asp(OMe)-] Helv Chim Acta 45, 1499, 1962. 

J-L Fauchere, R Schwyzer. Differential protection and selective protection in peptide synthesis, in The Peptides Analysis, Synthesis, Biology, Vol. 3, pp 203-251, Academic Press, New York, 1981. 

Prague (J Rudinger) Munich (F Weygand) Basel (R Schwyzer)... 

It is obvious why the spectroscopist wants to investigate the structure of integral membrane proteins or enzymes, whose biological action is linked to the presence of phospholipids such as phospholipase, in a membrane-mimicking environment Why such an environment should also be used for other peptides like hormones becomes more clear when we take into account the membrane compartment theory [10-12] as postulated by R. Schwyzer. This theory states that peptides that target membrane-embedded receptors... 

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