Bifunctional derivatives

Intramolecular variations of a series of bifunctional derivatives lead to the formation of cyclic nitrones. Many pyrroline /V-oxide derivatives were obtained in the course of intramolecular interaction in situ between carbonyl and hydrox-ylamine groups, resulting from the reduction of a y-nitro group (Scheme 2.31) (Fig. 2.8) (238-253). 

Recently, additional radical capturing polymers have been proposed, in which, similar in substances to be discussed later, bifunctional derivatives of the active component are incorporated into polymeric chains directly by polycondensation. Substance 35, one of three polymers tested by Berlin (1 03), has been found to be the most active one inhibiting most effectively the development of leucosis. 

The basic route to the synthesis of epoxides and, in general, vicinal bifunctional derivatives is a non-isohypsic (oxidative) transformation of alkenes (to be discussed below), Epoxides can also be formed directly as a result of certain C-C bond-forming reactions such as the Darzens reaction (modification of a classical aldol-like reaction with a-chloro esters 130 as a methylene component)... 

Commercially available cyclooligomers, such as the butadiene dimer 473, can be easily transformed via partial ozonolysis into bifunctional derivatives such as 474. These derivatives, with a rigorously defined location and configuration of the double bond, serve as valuable precursors to the preparation of natural products such as pheromones. The selectivity of the monooxidation of these reactions is ensured by a careful metering of one equivalent of ozone. ... 

Hydrocarboxylation of the Ce-Cs a-olefins with cobaltcarbonyl/pyridine catalysts at 200 °C and 20 MPa gives predominantly the linear carboxylic acids. The acids and their esters are used as additives for lubricants. The Ce-Cio a-olefins are hydroformylated to odd-numbered linear primary alcohols, which are converted to polyvinylchloride (PVC) plasticizers with phthalic anhydride. Oligomerization of (preferably) 1 -decene, applying BF3 catalysts, gives oligomers used as synthetic lubricants known as poly-a-olefins (PAO) or synthetic hydrocarbons (SHC) [11, 12]. The C10-C12 a-olefins can be epoxidized by peracids this opens up a route to bifunctional derivatives or ethoxylates as nonionic surfactants [13]. 

Pyridinophanes, synthesis from 3,5-bifunctional derivatives of pyridine 79SOC202. 

Similarly, chiral iminium salts such as 3.244 can be reduced in a diastereoselec-tive fashion by NaBH4 in MeOH at -78°C [PKl] (Figure 3.95). The highest stereoselectivity is observed when the aryl group is 2,6-dichlorophenyl. The bifunctional derivatives can undergo two successive reductions [MR2]. 

Fig. 11 a Chemical structures of mono functional ureidotriazene 17 and ureidopyrimid-inone 18 derivatives and their mode of association into mesogenic dimers, b Bifunctional derivatives 19 and 20 and a schematic representation of their proposed self-assembly into main-chain supramolecular polymeric columns... 

Variable-temperature H NMR studies29 of the monofunctional derivatives 14 and 15, and the bifunctional derivatives 16, revealed intramolecular coordination at low temperatures by the presence of two signals from diastereotopic N-methyl groups. 

Before conducting the quantitative analysis of carboxylic acids, especially of their bifunctional derivatives, as well as high-boiling acids, they are converted into more stable and less adsorptionally active derivatives. Methyl esters are frequently used as derivatives of acids in GC analysis. To obtain methyl esters of carboxylic acids, diazomethane [101, 148, 150, 335], a methanolic solution of hydrochloric acid [164, 336], a methanolic solution of boron trifluoride [f51, 152, 337], pyrolysis of tetramethyl-ammonium salts [166, 338, 339] and other methods [181,340-344] have been used. In a number of instances [345—347] higher esters are used. The sensitivity of detection with an BCD is increased when halogen-containing reagents are used to obtain esters... 

Fedorova, G.B. Dolgopol skii, I.M. Suvorova, M.A. Gubanov, V.A. Gracheva, P.E. Bifunctional derivatives of perfluorocarboxyhc acids. IV. S3mthesis of co-cyano-substituted chlorides of perfluoro carboxylic acids. Zh. Org. Khim. 1973, 9(11), 2211-2214. 

A large number of dibasic acids and anhydrides are used in the preparation of poly(ester amide)s. These include terephthalic acid, phthalic anhydride, isophthalic acid, endic endo-cis bicyclo(2,2,10-5)-heptene-2,3-dicarboxylic] anhydride, hydrogenated endic anhydride, maleic anhydride, fumaric acid, dichloromaleic anhydride, itaconic acid, brassylic acid, dimer acid, adipic acid, sebacic acid, succinic acid, trimeUitic anhydride, pyrromellitic anhydride and ethylenediamine tetraacetic acid (EDTA). However, tri- and poly-functional compounds are used only partially and are combined with bifunctional derivatives, or derivatives of previously prepared multifunctional compounds which are subsequently polymerised with bifunctional compounds. 

A range of synthons such as a, u-bifunctional derivatives and (Z)-and (E)-unsaturated derivatives have been obtained by Wittig and... 

Based on malonic ester synthesis, a bifunctional derivative of 1,4,7,10-tetraazacyclotridecane-N,N, N",N" -tetraacetic acid (TRITA) has been developed as well (Ruser et aL 1990). Again, an intermolecular reaction between a diamine and a diester leads to the macrocycle forming peptide bonds (O Fig. 45.11). The final BFCs have been studied as complexation agents for in and have shown fast chelate formation, high radiochemical yield, and high stability. 

As mentioned before, Copper prefers macrocyclic chelators like cyclam-14 and its derivatives. Cyclam-14 forms thermodynamically stable complexes and its X-ray structure shows a square-plane configuration with four equal Cu-N bonds (Tasker and Sklar 1975). This complex with coordination number four lose less than 0.5% metal when incubated for 24 h in human serum. Open chain chelators do not reach this stability. Its bifunctional derivative CPTA (O Fig. 45.17) coupled to an antibody and labeled with Cu shows a half-life for copper exchange in phosphate buffer >1,000 days (Smith-Jones et al. 1991). 

The isoelectronic ion (rj -CJlJCo CO) reacts with a wide range of nucleophiles, the terminal position of the diene being attacked exclusively. The proton n.m.r. spectrum of the pyridine adduct is consistent with its having Anti-stereochemistry. By adding a second nucleophile to the neutral cobalt allyl it is possible, in some cases, to convert a 1,3-diene into a 1,4-bifunctional derivative in a regio- and stereoselective fashion. 

Examples of bifunctional derivatives formed from fatty acids or their methyl esters that are useful monomers are given in Table 3.3. 

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