Adaptive synthesis

The general biology and metabolism, including such diverse subjects as the biosynthesis, adaptive synthesis, presence or absence in other areas of the body of the fish, and possible biological roles of the smaller inactive proline-containing glycopeptides. 

Therefore, the addition of lactose to E. coli leads to the adaptive synthesis of /3-galactosidase by the mechanism outlined above. 

Synthesis The early stages of this route are a well established method to make benzocyclohexanones the later stages are adapted from Johnson s Conessme synthesis ( J. 

The Gassman method has proven to be adaptable to complex structures, such as the intermediate 7.20B used in the synthesis of the indole diterpenes paspalicine and pasalinine[5]. Table 7.5 gives some other examples. 

The malonic ester synthesis has been adapted to the preparation of cyclo alkanecarboxyhc acids from dihaloalkanes... 

Sections 27 15 through 27 17 describe the chemistry associated with the protection and deprotection of ammo and carboxyl functions along with methods for peptide bond formation The focus m those sections is on solution phase peptide synthesis Section 27 18 shows how these methods are adapted to solid phase synthesis... 

Phosphorothioates. All three synthetic approaches appHcable to unmodified oligonucleotides can be adapted for synthesis of phosphorothioates (11) (33,46). If all of the phosphodiester linkages in an oligonucleotide are to be replaced with phosphorothioates, the ff-phosphonate method for coupling, followed by oxidation with Sg in carbon disulfide and triethylamine in the final step, is the most straightforward method. 

The current paradigm for B syntheses came from the first report in 1957 of a synthesis of pyridines by cycloaddition reactions of oxazoles (36) (Fig. 5). This was adapted for production of pyridoxine shordy thereafter. Intensive research by Ajinomoto, BASF, Daiichi, Merck, Roche, Takeda, and other companies has resulted in numerous pubHcations and patents describing variations. These routes are convergent, shorter, and of reasonably high throughput. 

Only one successful penem synthesis involving a [nitrogen, C-3] ring closure has been described (119). Cyclization of the ketomalonate (79) usiag hydrofluoric acid-pyridine afforded the penams (80) which were converted to the penem (81). Attempts to adapt the versatile diazoketoester-carbapenem cyclization for penem synthesis failed (120). 

The conversion of chlorohydrins into epoxides by the action of base is an adaptation of the Williamson synthesis of ethers. In the presence of hydroxide ion, a small proportion of the alcohol exists as alkoxide, which displaces the chloride ion from the adjacent carbon atom to produce a cycHc ether (2). 

A possible problem of sealing the electrolyte path is found in the Foreman and Veatch cell. This can be avoided by placing the cells in a vessel. The best known example of this is the Beck and Guthke cell shown in Figure 8 (74). The cell consists of a stack of circular bipolar electrodes in which the electrolyte is fed to the center and flows radially out. Synthesis experience using this cell at BASF has been described (76). This cell exhibits problems of current by-pass at the inner and outer edge of the disk cells. Where this has become a serious problem, insulator edges have been fitted. The cell stack has parallel electrolyte flow however, it is not readily adaptable to divided cell operation. 

The checkers used 16.8 g. of Eastman Kodak Company cyanamide (P1995) without further purification. A convenient method of preparing cyanamide from commercial calcium cyan-amide has been described. According to the submitters, an aqueous solution of crude cyanamide is satisfactory in the present synthesis and is obtained by adapting this published procedure as follows. 

The present method is adapted from Fischer employing recently developed modifications of the cyanohydrin synthesis. - ... 

The procedure described for the preparation of 3-hydroxycin-choninic acid is adapted from that reported. This synthesis is successful when bromopyruvic acid or its ethyl ester is substituted for chloropyruvic acid. The reaction of isatin with chloropyruvic acid to produce 3-hydroxycinchoninic acid has been reported however, no details or physical properties were given. This method offers a decided advantage over the method involving diazotization of the difficultly accessible 3-aminocinchoninic acid. ... 

The reaction was adapted to the stereospecific synthesis of trisubstituted olefins in two ways as shown in the following scheme. 

Deuterium labeling of C-18 has also been accomplished by an alternate procedure adapted from the Nagata steroid synthesis. During the course of the total synthesis of pregnanolone, thevC-18 function is introduced in the form of a nitrile group. Reduction of this function in intermediate (247) with lithium aluminum deuteride leads to a deuterated imine (248), which upon Wolff-Kishner reduction and acid-catalyzed hydrolysis... 

Several routes to 2,3-diketones have been reported. The most practical and general method is that of Ruzicka, Plattner and Furrer as adapted by Nace and Nelander for synthesis of the diosphenol corresponding to 5a-pregnane-2,3,20-trione (44) starting from 5a-pregnane-3,20-dione (40). The overall yield of diosphenol (44) by this route is 62% based on... 

This method can be adapted for the synthesis of biologically active compounds the 2,2-difluoro derivative of the antibacterial pleuromutalin a tricyclic terpenoid, was prepared in 31% yield from 2-diazopleuromutahn and dilute fluorine in chloroform in the presence of potassium fluoride at 50 °C [96]... 

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