Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Pharmaceuticals synthons

The synthetic utihty of the above transformations stems from the fact that many monoesters obtained as a result of hydrolysis may be converted to pharmaceutically important intermediates. For example, the optically active glycerol derivative (27) is a key intermediate in the production of P-blockers. Akyl derivative (25) may be converted into (5)-paraconic acid [4694-66-0] ((5)-5-oxo-3-tetrahydrofurancarboxyhc acid) that is a starting material for the synthesis of (3R)-A-factor. The unsaturated chiral cycHc monoacetate (31) is an optically active synthon for prostaglandins, and the monoester (29) is used for the synthesis of platelet activating factor (PAF) antagonists. [Pg.336]

The usefulness of the carbonyl reductase from Candida magnoliae as an enzyme catalyst in the synthesis of chiral alcohol intermediates has been demonstrated by carrying out the reduction of several ketones on a preparative scale [56]. The isolated yields and enantiomeric excess of the product alcohols are summarized in Table 7.1, from which it can be seen that these chiral alcohols were obtained in essentially optically pure forms in excellent yields. These chiral alcohols are important intermediates in the synthesis of pharmaceuticals and agrichemicals. For example, optically active 2-hydroxy-3-methylbutyrate is an important chiral synthon... [Pg.147]

An efficient and high-yielding enzymatic protocol for regioselective alkoxycarbonylation of the diol precursor of lo ,25-dihydroxyvitamin D3 has been accomplished. The procedure provided a convenient synthesis of the A-ring vinyl carbonate derivative, which is a useful synthon of vitamin D3 analogues for pharmaceutical research. ... [Pg.172]

J )-Mandelic acid 3 is a useful chiral synthon for the production of pharmaceuticals such as semi-synthetic penecillins, cephalosporins and antiobesity agents and many methods have been reported for the preparation of the optically pure material. A method to deracemize the racemate which is readily available on a large scale was developed by Ohta et al. using a combination of two biotransformations. The method consists of enantioselective oxidation of (S)-... [Pg.60]

Synthon Pharmaceuticals Inc., Research Triangle Park, North Carolina, U.S.A. [Pg.267]

Chiral amines are valuable synthons that dominate agrochemicals and pharmaceutical drug pipelines. Current methods for the preparation of amines are largely based upon resolution, and this is an excellent example of an industrial success. BASF makes a range of chiral amines by acylating racemic amines with proprietary esters, whereby one enantiomer is acylated to the amide, which can be easily separated from the unreacted amine [7]. For example, the resolution of racemic 15 in... [Pg.174]

With the recognition that many substances may cocrystallize in a single continuous lattice structure, scientists have more recently initiated intense studies of the mixed molecular crystal systems that have become known as cocrystals [10]. This particular area of solid-state research has led pharmaceutical scientists into the areas of crystal engineering and assembly of appropriate supramolecular synthons, with particular emphasis on understanding the origins of the molecular self-assembly that takes place in the formation of cocrystal systems. [Pg.374]

Despite their low cost and abundant availability, the applications of monoterpenes as chiral synthons or building blocks for synthesis of chiral fine chemicals on an industrial scale have lagged far behind amino acids and carbohydrates. Most of the work in this area is related to multi-step total synthesis of complex natural products in laboratory scale. With the structures of new drug candidates in the research and development pipeline of pharmaceutical companies getting bigger and more complicated, the application of more sophisticated chiral building blocks such as the terpenes will... [Pg.68]

All the optically active terpenes mentioned in this chapter are commercially available in bulk (>kg) quantities and are fairly inexpensive. Although many of them are isolated from natural sources, they can also be produced economically by synthetic methods. Actually, two thirds of these monoterpenes sold in the market today are manufactured by synthetic or semi-synthetic routes. These optically active molecules usually possess simple carbocyclic rings with one or two stereo-genic centers and have modest functionality for convenient structural manipulations. These unique features render them attractive as chiral pool materials for synthesis of optically active fine chemicals or pharmaceuticals. Industrial applications of these terpenes as chiral auxiliaries, chiral synthons, and chiral reagents have increased significantly in recent years. The expansion of the chiral pool into terpenes will continue with the increase in complexity and chirality of new drug candidates in the research and development pipeline of pharmaceutical companies. [Pg.72]

Practical considerations may also arise. Supramolecular functionality introduced to control crystal architecture must be added without degrading the fundamental molecular properties of primary interest. Co-crystals offer an alternative approach for controlling crystal architecture without necessarily modifying the primary molecule of interest. In addition, we must recognize the role of the solvent from which the crystal grows. The occurrence of solvates and polymorphs, particularly relevant in the pharmaceutical industry, is still a relatively poorly understood aspect of crystal chemistry. The manner in which synthons are modified from normal geometries in non-crystalline organic structures is also yet to be explored fully. [Pg.436]

N-Aryl and N-heteroaryl derivatives of aminomethylene malonates are also very useful and fruitful synthons for formation of 4-aminoquinolines used as antimalarials (equation 215), of the anticoccidial 6,7-dialkoxy-4-hydroxyquinoline-3-carboxylates and of antibacterial nalidixic acid derivatives (equation 216). Each of these is an important group of pharmaceuticals, developed in the last twenty years. Because of its medicinal interest this route is widely used for synthesis of quinolines and pyridinofused heterocycles. The chemistry has been comprehensively reviewed in a recent monograph292. Hence, no further details are given here. [Pg.606]

Another reaction of heteroatom oxidation is that of S-oxidation, which leads to the synthesis of sulfoxides, a reaction not very common in the plant cell biochemical factory. Enantiomerically pure sulfoxides are important chiral synthons in asymmetric synthesis, in particular in enantio-selective carbon-carbon bond formation [77]. The sulfoxide functional group is involved in different biological activities, and optically pure sulfoxides are of great pharmaceutical interest [82]. However, plant peroxidases, such as horseradish peroxidase, catalyze the enantio-selective sulfoxidation of alkyl aryl sulfides ... [Pg.752]

Zaworotko has recently demonstrated the ability of the drug carbamazepine to form a crystalline homodimer.43 The structure was sustained by an amide dimer synthon (Fig. 23). The dimer possessed two pendant NH groups that participated in hydrogen bonds with solvent molecules (e.g. acetone). The solids were generated to develop new solid compositions of the drug. Such compositions are anticipated to lead to pharmaceutical materials that exhibit properties (e.g. bioavailability) not realized by previous crystalline forms of the drug molecule. [Pg.31]

In 2001, Deng and coworkers found that nucleophilic catalysts such as (DHQD)2AQN (11) can also affect the parallel kinetic resolution of racemic anhydrides by alcoholysis, that is, the two substrate enantiomers are converted into regioisomeric esters. A variety of monosubstituted racemic succinic anhydrides were converted in the presence of (DHQD)2AQN (11, 15-20 mol%) and allyl alcohol as a nucleophile to both regioisomeric hemiesters 49 and 50 with synthetically reliable ee values (up to 98% ee) and yields (Scheme 11.26) [41]. The obtained regioisomeric 2-or 3- aryl succinates could be converted to the P- and a-aryl-y-butylolactones, which constitute valuable synthons for various pharmaceuticals. [Pg.346]

Asymmetric sulfinyl transfer reactions are of significant interest, since they can be applied to the synthesis of chiral sulfur-containing compounds, which are valuable synthons for pharmaceuticals and natural products [46]. Moreover, chiral sulfoxides are versatile chiral auxiliaries for asymmetric organic synthesis. A number of studies... [Pg.351]

Hydrolases catalyze the addition of water to a substrate by means of a nucleophilic substitution reaction. Hydrolases (hydrolytic enzymes) are the biocatalysts most commonly used in organic synthesis. They have been used to produce intermediates for pharmaceuticals and pesticides, and chiral synthons for asymmetric synthesis. Of particular interest among hydrolases are amidases, proteases, esterases, and lipases. These enzymes catalyze the hydrolysis and formation of ester and amide bonds. [Pg.107]


See other pages where Pharmaceuticals synthons is mentioned: [Pg.451]    [Pg.451]    [Pg.515]    [Pg.482]    [Pg.1166]    [Pg.278]    [Pg.78]    [Pg.245]    [Pg.27]    [Pg.169]    [Pg.277]    [Pg.482]    [Pg.180]    [Pg.385]    [Pg.385]    [Pg.530]    [Pg.85]    [Pg.240]    [Pg.591]    [Pg.197]    [Pg.359]    [Pg.219]    [Pg.369]    [Pg.615]    [Pg.615]    [Pg.617]    [Pg.3000]    [Pg.284]    [Pg.169]    [Pg.95]    [Pg.100]    [Pg.173]    [Pg.906]   
See also in sourсe #XX -- [ Pg.117 ]




SEARCH



Optically pure synthons, biocatalytic pharmaceutical industry

Pharmaceutical industry, biocatalytic pure synthons

Synthon

Synthons

© 2024 chempedia.info