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Semi-syntheses

The entire biosynthesis pathway of artemisinin has not been elucidated yet. The first committed step is conversion of FPP to amorphadiene via the cyclization catalyzed by ADS [102] followed by further oxidations of amorphadiene to artemisinic acid. Artemisinic acid can be used as a precursor for semi-synthesis of artemisinin and related chemicals [88]. [Pg.276]

A fine example of such a semi-synthesis is the preparation of the anti-cancer drug paclitaxel (Taxol ), a relatively scarce compound from Taxus brevifolia. Here, the natural and better accessible 10-deacetylbaccatin III, isolated from the leaves of Taxus baccata, provides the complicated ring system of paclitaxel, including all substituents with the right stereostructure (Scheme 5.1). In just four reaction steps [5] paclitaxel is obtained from 10-deacetylbaccatin III. [Pg.102]

Linalool is an important fragrance and fragrance precursor (esters) with an annual production of over 15 000 t. Some 50% is made by semi-synthesis from a- and / -pinene, the other part is made synthetically starting from isobutene via 6-methylhept-5-en-2-one (9). Addition of an acetylene fragment followed by partial hydrogenation (Pd) leads to linalool. [Pg.106]

Another large volume monoterpene is (—)-menthol, a compound that belongs to a family of eight stereoisomers. Only (—)-menthol (1 R,2S,3R-configuration) possesses the characteristic peppermint odor and exerts the unique cooling sensation on the skin. Most (—)-menthol is obtained by freezing peppermint or cornmint oil, followed by recrystallization. Besides this natural menthol some 20% or 3000 t a-1 is made by (semi)-synthesis. [Pg.107]

Catalytic methods, chemo- as well as bio-catalysis, are of vital importance in the conversion of natural products into derivatives (semi-synthesis). In chemo-catalysis conventional catalysts, such as mineral acids, are being replaced by recyclable solid catalysts. Further progress is also expected in cascade processes in which synthesis steps are combined to one pot methods. [Pg.117]

K. Morihara, T. Oka, H. Tsuzuki, Semi-Synthesis of Human Insulin by Trypsin-Catalyzed Replacement of AlaB30 by Thr in Porcine Insulin , Nature 1979, 280, 412-413. [Pg.91]

Scheme 3.2 Solid-phase semi synthesis of Vancomycin (48) based on a new selenium linker [123, 124]. Scheme 3.2 Solid-phase semi synthesis of Vancomycin (48) based on a new selenium linker [123, 124].
Recently, the semi-synthesis of Vancomycin (48) on solid supports was accomplished using an allylic linker (Scheme 3.2) [123, 124]. Polymer-bound chiral electrophilic selenium reagents have been developed and applied to stereoselective se-lenylation reactions of various alkenes (Tab. 3.9) [125]. [Pg.149]

Combinatorial Derivatization for Immobilized Natural Product Skeletons and Combinatorial Semi-synthesis... [Pg.176]

Scheme 3.30 Derivatives of natural product skeletons and combinatorial semi-synthesis products. Scheme 3.30 Derivatives of natural product skeletons and combinatorial semi-synthesis products.
Opium is a cmde exudate obtained from the opium poppy Papaver somniferum, and it provides several medicinally useful alkaloids. One of these is codeine, which is widely used as a moderate analgesic. Opium contains only relatively small amounts of codeine (1-2%), however, and most of the codeine for dmg use is obtained by semi-synthesis from morphine, which is the major component (12-20%) in opium. Conversion of morphine into... [Pg.186]

The same type of reasoning allows production of pholcodine, an effective cough suppressant, from morphine. In this semi-synthesis, the electrophile is Ai-(chloroethyl)morpholine, and the leaving group is chloride. [Pg.187]

Amides and iS-lactams semi-synthesis and hydrolysis of penicillins and cephalosporins... [Pg.265]

Both morphine and codeine are valuable analgesics. Morphine is extracted from opium, the dried latex of the opium poppy, and codeine is usually obtained from morphine by semi-synthesis (see Box 6.2), since the amounts in opium are rather small. Thebaine is a valuable raw material for semi-synthesis of a wide range of morphine-like drugs. [Pg.343]

Taxol has received considerable competitive challenge from taxotere, officially named docetaxel, a patented taxol analog developed by Rh6ne-Poulenc, based on the 1981 first successful semi-synthesis by Gueritte-Voegelein from 10-DAB. In 1987, Rh6ne-Poulenc selected taxotere for clinical development, and it is now used clinically in the United States. [Pg.45]

Antibiotics obtained by direct extraction from native producer, or by semi-synthesis No Yes No... [Pg.4]

Today, well over 100 drugs (accounting for 25% of all prescriptions issued in the USA), were initially isolated from vascular plants. While some are still extracted from their native source, most are now obtained more cheaply and easily by direct chemical synthesis or semi-synthesis. [Pg.53]

Robin, J.-P. Dhal, R. Dujardin, G. Girodier, L. Mevellec, L. Poutot, S. (2000) The first semi-synthesis of enantiopure homoharringtonine via anhydrohomoharringtonine from a preformed chiral acyl moiety. Tetrahedron Lett., 40,2931-4. [Pg.334]

The synthesis of peptide dendrimers covers a broad range of chemistry, from conventional schemes of peptide synthesis, to formation of amide bonds in organic solvents, to protein chemistry that includes conjugation, ligation, and semi-synthesis to form regiospecific amide or non-amide bonds in aqueous solutions. [Pg.140]

Moreau P, Gaillard N, Marminon C, Anizon F, Dias N, Baldeyrou B, Bailly C, Pierre A, Hickman J, Pfeiffer B, Renard P, Prudhomme M (2003) Semi-Synthesis, Topoisomerase I and Kinase Inhibitory Properties, and Antiproliferative Activities of New Rebeccamycin Derivatives. Bioorg Med Chem 11 4871... [Pg.446]

Enzymatic processes also advance in the area of large-scale pharma intermediates /flactam antibiotics can now be produced in a fully biotechnological process, including the semi-synthesis from the /flactam core to the penicillin or cephalosporin. A precursor to ephedrine, long produced by a whole-cell process in yeast, can be obtained from benzaldehyde and acetaldehyde with the help of pyruvate dehydrogenase acting as a carboligase. [Pg.160]


See other pages where Semi-syntheses is mentioned: [Pg.286]    [Pg.150]    [Pg.279]    [Pg.401]    [Pg.634]    [Pg.639]    [Pg.640]    [Pg.681]    [Pg.107]    [Pg.8]    [Pg.45]    [Pg.32]    [Pg.366]    [Pg.120]    [Pg.168]    [Pg.6]    [Pg.354]    [Pg.355]    [Pg.3]    [Pg.815]   
See also in sourсe #XX -- [ Pg.634 , Pg.639 , Pg.640 ]

See also in sourсe #XX -- [ Pg.17 , Pg.29 , Pg.363 , Pg.642 ]




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Alkaloids semi-synthesis

Carbohydrate semi-synthesis

Cephalosporins semi-synthesis

Corticosteroids, semi-synthesis

Gestogens semi-synthesis

Heterocyclic compound semi-synthesis

Leukotrienes semi-synthesis

Lipid semi-synthesis

Morphine semi-synthesis

Penicillins semi-synthesis

Peptides semi-synthesis

Polymer semi-synthesis

Prostaglandins semi-synthesis

Pyranose semi-synthesis

Semi-Syntheses of Estrone

Semi-Synthesis of Corticosteroids

Semi-continuous synthesis

Semi-controlled dendritic structure synthesis

Semi-synthesis, taxol

Steroids semi-synthesis

Syntheses with complete conversion the semi-batch reactor

Vitamins semi-synthesis

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