Diols diamines

To incorporate a labile azo group as the essential active site to MAI, a series of azo compounds such as 2,2 azobisisobutyronitrile (AIBN), 4,4 -azobis(4-cyanopen-tanoyl chloride) (ACPC), 2,2 azobis (2-cyanopropanol) (ACPO), 2,2 azobis [2-methyl-N-(2-hydroxyethyl)prop-ionamide] (AHPA), etc., were used as starting materials for polycondensation with various diols, diamines, diacids, or diisocyanates. 

On the other hand, the enantioselective 1,4-addition of carbanions such as enolates to linear enones is an interesting challenge, since relatively few efficient methods exist for these transformations. The Michael reaction of p-dicarbonyl compounds with a,p-unsaturated ketones can be catalysed by a number of transition-metal compounds. The asymmetric version of this reaction has been performed using chiral diol, diamine, and diphosphine ligands. In the past few years, bidentate and polydentate thioethers have begun to be considered as chiral ligands for this reaction. As an example, Christoffers et al. have developed the synthesis of several S/O-bidentate and S/O/S-tridentate thioether... 

In the single-stage production of polyurethanes, di-, tri-, or polyisocyanates are mixed directly with molecules containing two or more reactive hydrogen atoms, such as diols, diamines, and dicarboxylic acids. We typically increase the reaction rate by adding amine or organotin based catalysts. The reaction normally occurs rapidly, evolving much heat. In order to ensure... 

Statistical copolymers containing repeating units each with a different functional group can be obtained using appropriate mixture of monomers. For example, a polyestermide can be synthesized from a ternary mixture of a diol, diamine, and diacid or a binary mixture of a diacd and amine-alcohol [East et al., 1989]. 

The chemical transformation must not affect the stereogenic centers. Suitable acyclic candidates are compounds with easily convertible functional groups, such as diols, diamines, amino alcohols, dicarboxylic acids and so on. A number of procedures known before 1973 have been compiled, including conversion of diols and amino alcohols into sulfites or 1,3-dioxolanes by thionyl chloride, or acetalization with ketones31,1"319, as well as the conversions of dinitriles into imides320, dicarboxylic acids into cyclic anhydrides or imides321, and hydroxy acids into oxazolidones 322. 

This reaction can be carried out in good yield with a wide variety of alcohols, phenols and, according to Hettche also with secondary and primary amines. Diols, diamines, or aminoalcohols lead to l,l-spiro-X -phosphorins. 

Polyurethanes are manufactured by the reaction of diisocyanates with diols, diamines, or other organic compounds containing two or more active hydrogens. The reaction rate between a diisocyanate and alcohols catalyzed with dibutyltin dilaurate yielding urethanes was studied by G. Borkent and J. J. Van Aartsen. 

Instead of starting with racemic starting material it is also possible to use symmetric substrates [25]. The hydrolase selectively catalyses the hydrolysis of just one of the two esters, amides or nitriles, generating an enantiopure product in 100% yield (Scheme 6.7). No recycling is necessary, nor need catalysts be combined, as in the dynamic kinetic resolutions, and no follow-up steps are required, as in the kinetic resolutions plus inversion sequences. Consequently this approach is popular in organic synthesis. Moreover, symmetric diols, diamines and (activated) diacids can be converted selectively into chiral mono-esters and mono-amides if the reaction is performed in dry organic solvents. This application of the reversed hydrolysis reaction expands the scope of this approach even further [22, 24, 27]. 

This review covers the chemical literature on epoxides and aziridines for the year 2007. As in previous years, this review is not comprehensive but rather covers a selection of synthetically useful and interesting reactions. Three-membered ring systems, epoxides and aziridines in particular, are excellent synthetic intermediates. This is largely due to their ability to be converted into other functional groups such as diols, diamines, and amino alcohols to name but a few. The chapter has been divided into two sections, one covering epoxides and the other covering aziridines. Each of these sections has been further divided into two additional sections, one on the synthesis of the heterocycle and one on the reactions of the heterocycle. There is some overlap between methods for the synthesis of epoxides and aziridines and any overlap has been noted in the text. 

The reactants are dissolved in a pair of immiscible liquids, usually water and a hydrocarbon or chlorinated hydrocarbon. The aqueous phase contains the diol, diamine, dimercaptan, or other active hydrogen compound, an acid acceptor like... 

Both (31)(Fig. 10.9b) and (32) (Fig. 10.11) bind to the HIV-P active site asymmetrically. However, after the X-ray studies of crystalline HIV-P apoenzyme revealed it to be a symmetrical dimer, C2 symmetric inhibitors were designed to take advantage of this structural feature (Fig. 10.12). Both alcohol diamines and diol diamines were examined. For example, the C2 symmetric compound (33) (A-77003) was synthesized at Abbott and entered clinical trials as an antiviral agent for intravenous treatment of AIDS (100). 

The X-ray structures of complexes between HIV-P and diol diamine derivatives like (33) showed (101) that, although one of the hydroxyl groups bound between the catalytic aspartyl carboxylates and made contacts with both, the second hydroxyl made only one such... 

A number of organotin polyesters, polyamides, polythiols, polyethers, and polyaminoesters have been synthesized from dialkyltin halides with dicarboxylic acids, diols, diamines, dithiols, urea, thiourea, amino acids, and hydroxyl acids involving polycondensation reactions. These polymers have potential applications as thermostabilizers for PVC. 

On the other hand, a functionality of 1 on each chain end will be related to telechelic compounds (Scheme 1). This includes diols, diamines, and diacides. Of course it also comprises diolefin compounds that usually lead to gels or networks. We can also note that when the G and G functional groups are different at each chain end, the appropriate term becomes heterotelechelic (Table 1). It is also necessary to specify the particular case of macromolecules bearing a well-identified G functionality at one chain end and a thermally reactivated group at the G chain end. These groups can be nitroxides, an iodine atom, xanthate, etc.and are commonly used in living radical polymerizations (LRP). These compounds may be classified as monofunctional oligomers (Table 1). 

In principle, any difunctional chiral compound, such as a diol, diamine, or amino alcohol, can form a cyclic boron derivative by reaction with borane, haloboronic acid or its esters, alkylboronic acids, trihaloboranes or similar compounds. Several syntheses of this type are described in chapters D.1.3.3.3. (together with applications for allylic additions to carbonyl compounds) and D. 1.1.2.1. (with applications of a-haloboronic acids). 

K. M. P. Coppock (1996), Durable wood adhesives from furfural-based diols, diamines, and diisocyanates, Ph.D. Dissertation, University of Wisconsin, Madison (avaUable from Univ. Microfilms Int., Order No. DA9708820, Diss. Abstr. Int., B 1997, 57(12), 7625), 1996, 317 pp. 

Heterochain polymers of the type -(M-X) - contain polar M-X bonds (for reviews see [1,2,12-15]). Such polymers are often prepared by polycondensation of a bifimctional metal halide (M = B, Si, Ge, Sn, Pb, Sb, Ni, Pd, Pt, Ti, Hf) with a bifunctional Lewis base such as a diol, diamine, dihydrazine, dihydrazide, dioxime, diamideoxime, dithiol, diacetylene (Eq. 7-2). Another possibilitiy is the polyaddition of a bifunctional metal hydride to bifunctional alkenes (Eq. 7-3). Mn and mg containing poly(p-xylylenes) of the composition -(-CH2-C6H4-CH2-M-) - were produced by solid-state UV-photopolymerization of a cocondensated mixture of p-xylylene with Mn or mg at 80 K [16]. Prolonged storage of the polymers at ambient temperature under vacuum led to gradual decomposition. 

Entry Diols Diamines polyafitl yield (%) Mip MALTI-... 

The common structural feature of PUs is their block structrrre. These PUs are ealled segmented polyrrrethanes, SPU. The SPU polymer chains consist of alterrrating hard arrd soft blocks (segments) of different polarity. The hard blocks form as a result of diisocyanate reaction with a low molectrlar mass diols, diamines, arrd other low molecular rrrass bifunctional substances. The molectrlar stmctme of soft segmem is determined by the chetttical structure of oligomers used in the SPU synthesis. 

To prepare polymers containing metals (e.g., Sn, Pb, Ni, Pd, Pt, or Ti) in the main chain, use is conunonly made of the linear condensation of metal dihalides and bifunctional Lewis bases [16], such as diols, diamines, dicarboxylic acids, hydrazines, oximes, and dithiols. The preparation of such metal-containing polymers can be represented in Scheme 10.1. 

Figure 3.1 Some bifunctional monomers used in step polymerisation diol, diamine, dicarboxylic add, dicarboxylic acid chloride, diepoxide, diisocyanate, hydroxyacid.

Diamine Diol Diamine Diol Diamine Diol Diamine Diol Route Route Route Route Route Route Route Route... 

Structurally, transparent PUs are —(A—B) — block copolymers containing alternating soft segments (A), with flexible chains of low glass transition temperatures, and hard, polar blocks (B). Linear polyols from the soft segments, diisocyanates the hard blocks and the two are linked or chain-extended, preferably with a linear diol. Diamine chain extenders usually lead to coloured urethanes which darken further on exposure to light. 

The properties of the final PUR are primarily dependent on the chemical nature of the three building blocks (type of diol, diamine, or diisocyanate), and the relative proportions used during the synthesis (Vermette et aL, 2001). Because of these three degrees of freedom, a virtually infinite number of polymers with various physicochemical and mechanical properties can be synthesised (Lamba et aL, 1998). 

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