Stilbene, Tolane

In making di-phenyl methane benzyl chloride reacts with phenyl chloride in the presence of sodium. 

however, benzyl chloride alone is treated with sodium we obtain a compound known as di-benzyl. 

Di-benzyl is therefore symmetrical di-phenyl ethane as is also proven by its preparation from symmetrical di-chlor ethane, by the Friedel-Craft reaction, with benzene as follows  

The reaction of benzyl chloride with sodium also takes place with benzal chloride and sodium yielding an ethylene unsaturated compound corresponding to di-benzyl. 

This compound which is sym. di-phenyl ethene is known as stil-bene. Two other syntheses of stilbene are interesting. When ben-zaldehyde is distilled over sodium two molecules lose oxygen and the benzal radicals unite. 

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Bridging units azomethine, azo, N-oxide, stilbene, tolane, aliphatic chains, alkyl ethers,. .. and derivatives... 

TABLE 6. Mesomorphic properties of azomethine/stilbene/tolane liquid crystals... 

Die Reduktion von cis- und frarcs-a,/3-Diacetoxy-stilben in DMF/Tetrabutylammo-niumjodid an Quecksilber (-1,5 V vs. Ag/AgJ) fiihrt zu Tolan und bei —1,8 Volt zu trans-Stilben2. 2-Oxo-4-methyl-l,3-dioxolan wird an Graphit mit Lithiumperchlorat als Leitsalz unter C-O-Spaltung zu Propen reduziert3 ... 

B. Liquid Crystals Containing Azo-, Azomethine, Stilbene or Tolane Units... 

FIGURE 9. Structures of stilbene and tolane derived azomethine liquid crystals... 

TABLE 7. Structural anisotropy of stilbene and tolane based azomethines ... 

Increasing stilbene units against tolane units... 

Fig. 51 Diagram showing the evolution of the mesophase stability from tolane-rich (left side) to stilbene rich (right side) octopus LCDs (R = = OC12H25, R = H)...

H.C.CgHj known as Iso-stilbene, is a yel oil, ft p 1° and bp 145° at 13mm, d 1.0143at 20° n 1.6234 at 13° can be obtd by exposing the trans- form to UV light, or from tolane (diphenylacetylene) thru electrolyti c reduction at the Ni cathode in alcoholic sulfuric acid, and by other methods (Refs 2 3)... 

Unsaturated groups containing a double bond or a triple bond such as stilbene, azoy, schiff base, tolane or acetylene, and diacetylene. 

Tolane (9.5 g) was mixed under nitrogen with diisobutylhydridoaluminum (17 g) and warmed at 45-50° for 12 h. The red product was then cooled in ice, treated cautiously with methanol and dilute sulfuric acid, and extracted with ether. The extract was washed with water and sodium hydrogen carbonate solution, dried over calcium chloride, and evaporated, yielding a residue whence distillation in a vacuum afforded m-stilbene (7 g, 73 %) of b.p. 147-148°/15 mm. 

Reductions. The complex (dme)3Dyl2 is a reducing agent whose reactivity lies between Birch reducing agents and Sm(II) and Tm(II) salts. It can be used to convert tolane to (Z)-stilbene and naphthalene to the 1,4-dihydro derivative. 

New reactions of isoquinoline derivatives include the following 3,4-di-hydroisoquinoline N-oxide with 2-acetylcycloalkane-l,3-diones, Reissert compounds with stilbene and tolan derivatives, isoquinoline with pyrrole derivatives and with 2-methylfuran " (both in the presence of benzyl chloride), and the chromium trioxide oxidation of the benzo[a]quinolizidine (49) to give (50). Compound (49) was prepared by the condensation of 3,4-dihydroiso-quinoline with the 5-lactone (51). Further examples of a classical benzo[a]-... 

Tolane, CeHsC CCeHB (m.p. 60°), is formed by boiling stilbene, bromide with alcoholic potash —... 

PMMA samples with dopant molecules were prepared by polymerizing MMA doped with either stilbene or tolan. The composition of the initiator and chain-transfer agent and the condition of polymerization were almost the same as the above copolymerization. 

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