Solid-liquid phase method

Frank and Hagenmaier suggested an alternative to both solid- and liquid-phase peptide synthesis by creating the solid-liquid-phase method in order to overcome the problem of failure and truncated sequences [105, 106], To this end, poly(ethylene glycol) monoalkyl ethers were used as carboxy protecting poups. The principle of this method is depicted in Scheme 2. 

Scheme 2. Scheme of the alternating solid-liquid-phase method for peptkfe synthesis [105]... 

A brief discussion of solid-liquid phase equihbrium is presented prior to discussing specific ciystaUizatiou methods. Figures 22-1 and 22-2 illustrate the phase diagrams for biuaiy solid-solution and eutec-... 

There are many types of phase diagrams in addition to the two cases presented here these are summarized in detail by Zief and Wilcox (op. cit., p. 21). Solid-liquid phase equilibria must be determined experimentally for most binaiy and multicomponent systems. Predictive methods are based mostly on ideal phase behavior and have limited accuracy near eutectics. A predic tive technique based on extracting liquid-phase activity coefficients from vapor-liquid equilib-... 

Thus, a novel chiral zirconium complex for asymmetric aza Diels-Alder reactions has been developed by efficient catalyst optimization using both solid-phase and liquid-phase approaches. High yields, high selectivity, and low loading of the catalyst have been achieved, and the effectiveness of chiral catalyst optimization using a combination of solid-phase and liquid-phase methods has been demonstrated. 

The column. The actual separation of sample components is effected in the column where the nature of the solid support, type and amount of liquid phase, method of packing, length and temperature are important factors in obtaining the desired resolution. 

This methodology developed to observe water freeze-thaw in concrete materials, may be used quite generally to observe solid-liquid phase transitions in many different materials of industrial and technological interest. The method could be also applied to other problems involving freezing and thawing of water in confined pores. 

With bifunctional alcohols CDI yields polycarbonates.[5] Syntheses of polycarbonates based on the CDI-method in a solid/liquid phase-transfer catalyzed reaction are described in references [261]—[263],... 

Tris(l-pyrazolyl)methane was first prepared by Hiickel and Bretschneider by the reaction of sodium pyrazolate with chloroform.17 Trofimenko prepared the tris(3,5-dimethyl-l-pyrazolyl)methane by a similar method.2 More recent preparations have utilized both liquid-liquid18 and solid-liquid12 phase-transfer catalysis. The preparation of tris(l-pyrazolyl)methane (E) given below is a modification of the solid-liquid phase-transfer procedure.12... 

Treatment of diethyl malonate and related compounds with 1,2-dihaloethane in the presence of base constitutes a classical method of cyclopropane synthesis296"300. The reaction can be conveniently carried out under PTC conditions. An improved method utilizing solid-liquid phase transfer catalysis has been reported298. The reaction of dimethyl or diethyl malonate with 1,2-dibromoalkanes except for 1,2-dibromethane tends to give only low yields of 2-alkylcyclopropane-l, 1-dicarboxylic esters. By the use of di-tm-butyl malonate, their preparations in satisfactory yields are realized (equation 134)297. The 2-alkylcyclopropane derivatives are also obtained from the reaction of dimethyl malonate and cyclic sulfates derived from alkane-1,2-diols (equation 135)301. Asymmetric synthesis... 

A general formulation of the problem of solid-liquid phase equilibrium in quaternary systems was presented and required the evaluation of two thermodynamic quantities, By and Ty. Four methods for calculating Gy from experimental data were suggested. With these methods, reliable values of Gy for most compound semiconductors could be determined. The term Ty involves the deviation of the liquid solution from ideal behavior relative to that in the solid. This term is less important than the individual activity coefficients because of a partial cancellation of the composition and temperature dependence of the individual activity coefficients. The thermodynamic data base available for liquid mixtures is far more extensive than that for solid solutions. Future work aimed at measurement of solid-mixture properties would be helpful in identifying miscibility limits and their relation to LPE as a problem of constrained equilibrium. 

Solid-phase method of Merrifield 9-111 and the liquid-phase method of Mutter 12),... 

Metallocenes can be synthesized by solid-liquid phase-transfer catalysis (74). This mild reaction is most useful for the preparation of 1,1 -disub-stituted ferrocenes. The method does not require alkali metals or anhydrous conditions, and reactions are complete in less than 1 hour. 

Activation with sulfonic acid chlorides is more general, rendering amides with the possible participation of symmetric anhydrides after disproportionation. This method has also found use in the synthesis of modem 3-lactam antibiotics. However, in peptide chemistry this activation method leads to unwanted side reactions, like formation of nitriles in the cases of glutamine and asparagine, and racemization. In a convenient one-pot procedure, the carboxylic acids are activated by sulfonyl chlorides under solid-liquid phase transfer conditions using solid potassium carbonate as base and a lipophilic ammonium salt as catalyst. ... 

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