Preparation of diacetylene

In this article, we will describe in detail the preparation of diacetylene (DA) microaystals and their solid-state polymerization behavior and optical properties as a function of crystal size. In addition, we also report OKS response of organic microciystal dispersions. 

A solution of the monosodium salt of diacetylene in 300 ml of liquid ammonia is prepared from 13.8 g (0.6 g-atoms) sodium and 24.6 g (0.2 moles) l,4-dichlorobut-2-yne. To this mixture is added a suspension of 5 g (17.6 mmoles) 3-methoxyestra-l,3,5(10)-trien-17-one in anhydrous tetrahydrofuran at —40° and the reaction mixture is stirred and maintained at this temperature for 2 hr. Ammonium chloride is then added and the ammonia is allowed to evaporate overnight. The residual solids are extracted with methylene dichloride and the extracts washed with water, dried over magnesium sulfate, and evaporated at 70°. The resultant dark gum is... 

A process for the preparation of functionalized pyridines from diacetylene and the ethyl ester of /3-aminocrotonic acid and acetylacetonimine (72ZOR1328 75DIS) has been described. Owing to the lower nucleophilicity of nitrogen in the initial enamine esters and enamine ketone, the reaction with diacetylene occurs in the presence of sodium metal (80°C, dioxane, 3 h, yield of up to 20%). 

A general process for the preparation of pyrimidines from diacetylene and carbamide derivatives RC(X)NH2 (X = NH, O, S R = Ph, OH, NH2) with fixation and subsequent cyclization of primary products has been patented (94GEP4308073). 

I. A. Maretina and B. A. Trofimov (Irkutsk, Russia) have contributed a chapter covering applications of diacetylenes in the preparation of heterocycles. This is another field that has grown immensely in the past decade and one which has been significantly enriched by work from these authors laboratories. 

By using a cocatalyst of Pd-Cu, aryl-alkenyl halides couple efficiently widi alkynes to generate die disubstituted alkynes (Scheme 9.6).8 This coupling reaction has been applied to die synthesis of polyphenyleneethynylenes by Yamamoto et al. in 1984 (Scheme 9.7).9a Due to the ready availability of diacetylenes and the mild coupling condition, this strategy has been widely used for die preparation of many poly(aryleneethynylene)s.9... 

Immobilization of the bilayer membranes as thin solid films is required when the bilayer membranes are used as novel functional materials. Casting method is a simple way to immobilize the bilayer membrane on a solid support from an aqueous solution by drying. Polymer film is easily prepared when the cast film of polymerizable bilayer membrane is polymerized. A free standing polymer film prepared by photo polymerization of the cast film of diacetylene amphiphiles was reported by O Brien and co-workers [34]. Composition with macromolecular materials is another way of polymer film preparation. Bilayer membranes are immobilized as polymer composites by the following physical methods ... 

Liposomes prepared from diacetylene hydrazide 7 undergo chromatic transitions in response to pH changes (Jonas et al. 1999). Liposomes of 7, which form only in... 

Yang Y, Lu Y, Lu M, Huang J, Haddad R, Xomeritakis G, Liu N, Malanoski AP, Sturmayr D, Fan H, Sasaki DY, Assink RA, Shelnutt JA, van Swol F, Lopez GP, Bums AR, Brinker CJ. Functional nanocomposites prepared by self-assembly and polymerization of diacetylene surfactants and silicic acid. J Am Chem Soc 2003 125 1269-1277. 

The preparation of butadiynyl carbinols needs a prior explanation. Especially those carbinols derived from aldehydes have limited thermostability and bath temperatures higher than 100 C should be avoided. Distillation of amounts larger than 15 g involves the risk of explosive decomposition at the last stage. It is therefore essential that the undistilled product is sufficiently pure. If equivalent amounts of BuLi and diacetylene are used in the preparation of the lithium compound, there is a great chance that diols are formed from LiCeCOCLi ... 

In some derivarization reactions with mono-metallaied bmadiyne, considerable amounts of disubstimted diacetylene are farmed. Their presence can hamper the purification of the desired mono-substitution products, particularly when the boiling point is high and the thermal stability limited. The formation of disubstitution products can be effectively suppressed, however, by using a large excess of butadiyne. The preparation of butadiynvl tributyltin is an illustrative example. 

The correct alignment of surfactants in some, but not all, SUVs is an essential requirement for polymerization. Polymerization of diacetylenes is topochemically controlled and only occurs below the phase transition temperature of the surfactant. In contrast, SUVs prepared from styrene-containing surfactants could be polymerized in their fluid states [55]. The degree of polymerization varied from very low (10-20 for SUVs prepared from styrene containing surfactants) to rather high (several hundred for SUVs prepared from diacetylene-containing surfactants). 

Polymerized SUVs prepared from surfactants containing styrene or vinyl moieties retained their phase transition behavior. Conversely, polymerized SUVs prepared from diacetylenic surfactants lost their phase transitions and those of methacrylamide surfactants had lower phase transition temperatures... 

Tubules prepared from diacetylenic phospholipids (21) Copper and nickel films Electron microscopy and X-ray fluorescence measurements indicated 20- to 30-nm metallic coatings on the interiors and exteriors of the tubules 356... 

Whether polymerized model membrane systems are too rigid for showing a phase transition strongly depends on the type of polymerizable lipid used for the preparation of the membrane. Especially in the case of diacetylenic lipids a loss of phase transi tion can be expected due to the formation of the rigid fully conjugated polymer backbone 20) (Scheme 1). This assumption is confirmed by DSC measurements with the diacetylenic sulfolipid (22). Figure 25 illustrates the phase transition behavior of (22) as a function of the polymerization time. The pure monomeric liposomes show a transition temperature of 53 °C, where they turn from the gel state into the liquid-crystalline state 24). During polymerization a decrease in phase transition enthalpy indicates a restricted mobility of the polymerized hydrocarbon core. Moreover, the phase transition eventually disappears after complete polymerization of the monomer 24). 

A similar coupling of alkynyliodonium tosylates 132 with dialkynylcuprates 134 leads to conjugated diynes 135 (Scheme 55) [114,115]. This method can be used for the preparation of unsymmetrical diynes in moderate yield. Recently, this coupling was employed in the synthesis of various liquid-crystalline diaryl-diacetylenes [115]. 

By the same process it is possible to prepare diphenyl-diacetylene from the copper derivative of plienyl-acetylene ... 

These examples serve to highlight that supramolecular self-assembly and topo-chemical diacetylene polymerizations are a perfect match. Topochemical diacetylene polymerizations are an advantageous means of covalent capture for the reasons outlined above. The required order may, on the other hand, be provided by supramolecular self-assembly, which extends the scope beyond singlecrystalline monomers. This aspect becomes particularly important in the case of functional monomers in order to address specific applications. However, in contrast to previous investigations, the targeted preparation of hierarchically structured poly (diace tylene)s with a defined, finite number of strands required the presence of equally well-defined, uniform supramolecular polymers [106] with the propensity to form predictable superstructures, instead of micellar or vesicular ID aggregates. 

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