Di functional

Up to now, nine classes of different polyphosphazenes are known and characterized substituted with aliphatic alcohols [40,41,262-281] or phenols [41,95, 277,282-297],with aliphatic [42,298-300] or aromatic [301-304] amino groups, with di-functional spiro hydroxy (e.g. dihydroxybiphenyl [305] or di hydroxy-... 

In total the analysis of protein complexes indicates that methionine is the most likely group to bind to [PtCU]2 and [PtenClfc] probably by a displacement reaction. However a specific attachment to another residue such as histidine or sulphydryl can not be ruled out. Furthermore the antitumour activity is that of cis- [Pt (NH 3) 2CI2] and the di-functional character of this reagent has not been revealed so far by the above studies. In fact no attempt has been made to uncover the difference between [PtCl2(NH3)2] in its cis and fraMS-forms. 

Crosslinked co-polymers of 4-allyloxystyrene can be obtained by the addition of small amounts of divinylethers, di-functional alkoxystyrene monomers or propeny-loxystyrene monomers, such as (2) or (3), in the cationically active composition. The polymers obtained from these mixtures by cationic polymerization are insoluble in organic solvents and generally exhibit good mechanical and adhesive properties. 

A novel ring-contraction reaction which proceeds via an epi-sulfonium ion intermediate has been reported for the simple and regiospeciflc synthesis of mono-and symmetrically di-functionalized tetrathiamacrocycles, starting with the mono- or dichloro-substituted macrocycles that have one or two more ring atoms. 

An analysis of the shift reagent properties of lanthanide 3-diketonato-complexes, (1 R = R = Bu Ln = Eu, R = CF3, R = Bu ), with respect to mono- and di-functional substrates, has been given. The ability of these complexes to form 1 1 and 1 2 adducts with the substrates seemed to be determined by the nature of the substrate and the relative concentrations of the... 

The acylative cleavage of the cyclic ether tetrahydrofuran showed an excellent yield (95%) to 4-iodobutylbenzoate when fully acidic ionic liquid [EMIM]Al2Cl7 was used, but the yield to di-functionalized product (61%) suffered when the mildly acidic halogenoaluminate ionic liquid (which has a mole fraction of AICI3 (x) at a value of 0.52) was used as the solvent. In contrast, for 1,5-dimethyltetrahydrofuran and tetrahydropyran, a good yield to the cleavage products was obtained when the mildly acidic chloroaluminate was used. 

Brookes, P. Lawley, P.D. (1961). The reactions of mono- and di-functional alkylating agents with nucleic acids. Biochem. J. 80,496-503. 

In some cases, the intermediate carbanion can be trapped, e.g. with dimethyl-carbonate or esters etc. This approach has been developed elegantly by Krespan to synthesise di-functional derivatives derived from tetrafluoroethene [95] (Scheme 42). 

Not only 1,2-di-functionalized substrates with heteroatoms but also tertiary alcohols and hemiketals undergo oxidative C-C bond cleavage at the a position on treatment with lead tetraacetate. For example, a y-hydroxy ketone and the corresponding hemiketal have been fragmented by lead tetraacetate into a 9-membered olefinic lactone (Scheme 13.57) [76]. 

Polyfunctional Silane Chemistry—The use of di-functional or trifunctional silanes to create bonded groups with two or three attachment points leading to phases with higher stability in low or high pH, and lower bleed for LC/MS (see Figure 3.14a). Note that polyfunctional silane chemistry is more difficult to control. 

As mentioned above, protecting certain internal nitrogen atoms using the benzoyl moiety is useful for the preparation of mono- or di-functionalized peraza-crowns. The selective removal of the benzoyl group was accomplished... 

Macrocycles can be part of the polymer backbone or attached to the backbone on a side chain. The methods of preparation of these two types of systems are different. Polymers with macrocycles as part of the backbone were prepared by polymerization of macrocycles containing special functional groups or, more often, by copolymerization of di-functionalized macrocycles with other di-functionalized molecules. The preparation of a diaza-crown-containing polymer is an example of this latter process (Yokota et al., 1986). 

Waste of polyesters and polyamides may have suffered from the hydrolytic depolymerization. Thus, it may be necessary to increase the molecular weight by solid-state polycondensation under high vacuum, or by reactive coupling using such di-functional agents as di-glycidyls. Prior to melt processing, the resins should be dried to less than 0.01 wt% of moisture, re-stabilized and (if compounded with immiscible polymers) compati-bilized. 

Fig. 21. Comparison of theoretical PS molecular weight for mono and di-functional initiators...

How to Use the Book to Locate Examples of the Preparation of Di-functional Compounds. The difunctional index on p. xiv gives the section and page corresponding to each difunctional product. Thus Section 327 (alcohol, thiol-ester) contains examples of the preparation of hydroxyes-ters Section 323 (alcohol, thiol-alcohol, thiol) contains examples of the preparation of diols. 

Crosslinking is referred to the copolymerization between the hydroxyl of CD and the di-functional groups or multi-functional groups of a compound for... 

Figure 3.1 shows the ideal molar-mass distribution for a polymer produced by the self-condensation reaction of a pure di-functional monomer. The... 

Previously these mono-functional oligomers have been prepared by the use of functional chain transfer agents, e.g. thioglycolic acid. l In the case of di-functional oligomers the technique referred to as "dead-end polymerization has been used, whereby high concentrations of a functional initiator are used. This approach requires termination to occur exclusively by either combination or primary radical tennination. A satisfactory incorporation of functionality is only obtained with monomers that satisfy this criterion. Mixtures are obtained at best, for example, with polystyrene it is claimed that the degree of functionality f=1.8 rather than the required f=2.0. 

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