Phase three-component

Fewer procedures have been explored recently for the synthesis of simple six-membered heterocycles by microwave-assisted MCRs. Libraries of 3,5,6-trisubstituted 2-pyridones have been prepared by the rapid solution phase three-component condensation of CH-acidic carbonyl compounds 44, NJ -dimethylformamide dimethyl acetal 45 and methylene active nitriles 47 imder microwave irradiation [77]. In this one-pot, two-step process for the synthesis of simple pyridones, initial condensation between 44 and 45 under solvent-free conditions was facilitated in 5 -10 min at either ambient temperature or 100 ° C by microwave irradiation, depending upon the CH-acidic carbonyl compound 44 used, to give enamine intermediate 46 (Scheme 19). Addition of the nitrile 47 and catalytic piperidine, and irradiation at 100 °C for 5 min, gave a library of 2-pyridones 48 in reasonable overall yield and high individual purities. 

Murphy, N.F., Lastovica, J.E., and Fallis, J.G. Correlation of interfacial tension of two-phase three-component systems, Ind. Eng. CAem.,49(6) 1035-1042, 1957. 

Solid-phase three-component domino-Knoevenagel-hetero-Diels-Alder reaction can also be performed using a resin-linked 1,3-dicarbonyl compound such as 100 with aldehydes and an enol ether to give dihydropyrans 102 via the intermediately formed 1-oxa-l,3-butadiene 101 (Scheme 5.18) [30], The resin can be deaved off after the reaction by solvolysis, for instance using sodium methanolate to give the corresponding methyl ester 103 as a mixture of diastereomers. The overall yield varies from 12 to 37% and the selectivity from 1 1 to 1 5 in favor of the tis-product depending on the applied aldehyde. The crude dihydropyrans thus obtained are reasonably pure (> 90% HPLC). 

Scheme 5.18. Solid-phase three-component domino-Knoevenagel-hetero-Diels—Alder reaction.

Bomah and co-workers [99] developed an efficient procedure for the synthesis of ring-A fused [3,2-h]pyrimidines 53 in a steroidal moiety. The novel steroidal pyrimidines were prepared via a solid phase three-component reaction of a 2-hydro-xymethylene-3-keto steroid, an arylaldehyde and ammonium acetate under micro-wave irradiation. This protocol has been applied successfully to the cyclization of bicyclic, monocyclic and acyclic 2-hydroxymethylene ketones with diversely substituted aromatic aldehydes (Scheme 39). 

In pursuing an accurate thermodynamic description of the three-phase, three-component system, the phase equilibrium compositions can be calculated after pressure and temperature have been fixed, since it is known from the Gibbs phase rule that there are only 2 degrees of freedom. There are five unknown compositions, assuming that the solid is crystalline and pure and that its solubility in the vapor/fluid phase is negligible. Two of these unknown mole fractions are eliminated by the constraints that the mole fractions in each phase sum up to unity. To find these three unknown mole fractions, namely, xi, X3, and y2, only three equilibrium relations are required. 

A similar three-liquid region was observed by Ali and Mulley [28] in a quaternary system containing dodecane, water and two non-ionic surfactants, CjoE and C10E3. The compositions involved were near the face of the tetrahedron representing the four-component system and containing about equal quantities of water and dodecane and 1 to 2.5 % C qE, Addition of 3 to 7.2 % C10E3 to this two-phase, three-component system in the face of the tetrahedron, produced the system with three liquid phases in equilibrium. The lower liquid... 

Tie1996a Tietze, L.F., Hippe, T. and Steinmetz, A., Solid-Phase Three-Component Domino Reactions. Combinatorial Approach to Substituted 3,4-Dihydro-2H-pyrans, Synlett, (1996) 1043-1044. 

Most LB-forming amphiphiles have hydrophobic tails, leaving a very hydrophobic surface. In order to introduce polarity to the final surface, one needs to incorporate bipolar components that would not normally form LB films on their own. Berg and co-workers have partly surmounted this problem with two- and three-component mixtures of fatty acids, amines, and bipolar alcohols [175, 176]. Interestingly, the type of deposition depends on the contact angle of the substrate, and, thus, when relatively polar monolayers are formed, they are deposited as Z-type multilayers. Phase-separated LB films of hydrocarbon-fluorocarbon mixtures provide selective adsorption sites for macromolecules, due to the formation of a step site at the domain boundary [177]. 

The accompanying sketch qualitatively describes the phase diagram for the system nylon-6,6, water, phenol for T > 70°C.f In this figure the broken lines are the lines whose terminals indicate the concentrations of the three components in the two equilibrium phases. Consult a physical chemistry textbook for the information as to how such concentrations are read. In the two-phase region, both phases contain nylon, but the water-rich phase contains the nylon at a lower concentration. On this phase diagram or a facsimile, draw arrows which trace the following procedure ... 

In a ternaty hqiiid-hqiiid system, such as the acetic acid-water-MIBK system, all three components are present in both liquid phases. At equilibrium the activity A° of any component is the same in both phases by definition [Eq. (15-6)]. 

Composition Uiagrants In its elemental form, a leaching system consists of three components inert, insoluble solids a single non-adsorbed solute, which may be liqmd or solid and a single solvent. Thus, it is a ternaiy system, albeit an unusual one, as already mentioned, by virtue of the total mutual Mnsolubility of two of the phases and the simple nature of equilibrium. 

Three components A, B and C of an alloy dissolve completely when liquid but have no mutual solubility when solid. They do not form any chemical compounds. How many phases, and of what compositions, do you think would appear in the solid state ... 

This type of chromatographic development will only be briefly described as it is rarely used and probably is of academic interest only. This method of development can only be effectively employed in a column distribution system. The sample is fed continuously onto the column, usually as a dilute solution in the mobile phase. This is in contrast to displacement development and elution development, where discrete samples are placed on the system and the separation is subsequently processed. Frontal analysis only separates part of the first compound in a relatively pure state, each subsequent component being mixed with those previously eluted. Consider a three component mixture, containing solutes (A), (B) and (C) as a dilute solution in the mobile phase that is fed continuously onto a column. The first component to elute, (A), will be that solute held least strongly in the stationary phase. Then the... 

Figure 1. Distribution of Three Components of a TLC Mobile Phase After Traveling Some Way Along a TLC Plate...

The state of any particle at any instant is given by its position vector q and its linear momentum vector p, and we say that the state of a particle can be described by giving its location in phase space. For a system of N atoms, this space has 6iV dimensions three components of p and the three components of q for each atom. If we use the symbol F to denote a particular point in this six-dimensional phase space (just as we would use the vector r to denote a point in three-dimensional coordinate space) then the value of a particular property A (such as the mutual potential energy, the pressure and so on) will be a function of r and is often written as A(F). As the system evolves in time then F will change and so will A(F). 

The method of construction of this type of diagram will be illustrated using the general case of the three component system metal-sulphur-oxygen (M-S-O) whose values of AG for the reactions between the various condensed phases are given in Talile 7.37 on page 7 191. 

Microwave and fluorous technologies have been combined in the solution phase parallel synthesis of 3-aminoimidazo[l,2-a]pyridines and -pyrazines [63]. The three-component condensation of a perfluorooctane-sulfonyl (Rfs = CgFiy) substituted benzaldehyde by microwave irradiation in a single-mode instrument at 150 °C for 10 min in CH2CI2 - MeOH in the presence of Sc(OTf)3 gave the imidazo-annulated heterocycles that could be purified by fluorous solid phase extraction (Scheme 9). Subsequent Pd-catalyzed cross-coupling reactions of the fluorous sulfonates with arylboronic acids or thiols gave biaryls or aryl sulfides, respectively, albeit it in relatively low yields. 

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