Benzene, />-diiodo

Synthesis of l,3-dihydro-2,2-bis(trifluoroacetoxy)-benzo[c]tellurophenef A mixture of 2,2-diiodo-l,3-dihydrobenzo[c]tellurophene (4.86 g, 10 mmol) and silver trifluoroacetate (4.42 g, 20 mmol) in benzene (200 mL) was stirred at room temperature for 2 h. After filtration, the fdtrate was concentrated to give l,3-dihydro-2,2-bis(trifluoroacetoxy)-benzo[c]tellnrophene (4.17 g, 91%), m. p. 160°C (dec.). 

The present procedure is the most convenient method for preparation of mono- or diiodo derivatives from various poly-alkylbenzenes in high yields.1 2 Thus 5-i-butyl-1,3-dimethyl-benzene gives 4-<-butyl-2,6-dimethyliodobenzene in 90% yield and 4 - - buty I -1,2 - d imet hy 1 benzene gives 5-<-butyl-2,3-dimethyl-iodobenzene in 81% yield. 5- -Butyl-l,2,3-trimethylbenzene,... 

BF IrCuH, Iridium (III), (1,2-diiodo-benzene)dihydridobis(triphenylphos-phine)-tetrafluoroborate(l -), 26 125 BF4lr02P2C36H)6, Iridium(III),... 

Catalytic amounts of [Pd(PPh3)4] (chiffres ) and Cul were added to a solution of dithienophosphole 80 (1.73 g, 1.5 mmol) and l,4-diiodo-2,5-bis(octyloxy)benzene (0.88 g, 1.5 mmol) in N-methylpyrrolidinone (80 mL). The light-yellow reaction mixture was then stirred for 48 h at 200 °C, after which time the color changed to orange-red. The solution was then cooled to room temperature, the solvent evaporated under vacuum and the resulting amorphous solid taken up in a small amount of THF (ca. 5 mL). The suspension was filtered, precipitated into hexane and the residue dried under vacuum to yield 80 as a reddish brown pow-... 

Octaphenyl-l,2,3,4,5-telluratetragerinolane3 A red, elhanolic solution of sodium hydrogen telluride is added dropwise to a solution of 1.0 g (0.86 mmol) of 1,4-diiodo-l, 1,2,2,3,3,4,4-octaphenyltetra-germane in 15 m/ of benzene under an argon atmosphere until the red color just persists. The mixture is filtered, the filtrate is concentrated, and the residue is dissolved in benzene. Diethyl ether is added to the benzene solution until the product crystallizes. The product is filtered and stored under argon. The colorless crystals decompose on contact with air and at 50° when heated under argon. 

The reaction has been successfully extended to 2,3-diiodo-5-nitrothiophene (Scheme 62). However, irradiation of 2,4-diiodo-5-nitrothiophene in the presence of benzene gave a mixture of the expected product and a rearranged one (Equation 101). 

Cyanophenol, which is first transferee into 4-cyano-2,6-diiodo-phenol, can be photolysed with benzene to give 4-cyano-2,6-diphenylphenol in 71 % yield 58). The latter is identical with the compound prepared from 2,6-diphenyl-4-nitrophenol59). 

Iodo-4-penten-l-yl 11-Methoxycarbonylundecyl Tellurium (Sodium Borohydride Reduction) Into an argon-purged, 100-m/ flask are placed a magnetic stirrer, 343 mg (0.5 mmol) of bis[ll-methoxycarbonylundecyl] dilellurium and 20 ml of methanol. Excess sodium borohydride is added and the mixture is stirred until it becomes colorless. 354mg (1.1 mmol) of l,5-diiodo-4-pentene are added, the mixture is stirred for 0.5 h, diluted with water, and extracted twice with diethyl ether. The combined diethyl ether extract is washed with water, dried with anhydrous sodium sulfate, and the solvent is evaporated. The residue is dissolved in 2 ml of benzene and chromatographed on a silicic acid column (1 x 20 cm) slurried in petroleum ether. The column is eluted with 200 ml of petroleum ether and then with 400 ml of benzene. Fractions of 20 ml are collected and fractions 16-19 are combined and evaporated yield 130 mg (22%) light yellow oil. 

H2BF4l,IrC4 Hu, Iridium(III), (1,2-diiodo-benzene)dihydridobis(triphenylphos-phine). tetrafIuoroborate l -), 26 125 H2BF4lrO P C ,H.i4, Iridium(III), diaquadi-hydridobis(triphenylphosphine)-, tetrafluoroborate( I -), 26 124 H2BF4lr02P C4 H42, Iridium(III), bis(ace-tone)dihydridobis(tri phenyl phosphine)-, tetrafluoroborate( 1 -),... 

The metallacyclic compounds react with protic reagents to yield the corresponding substituted 1,3-butadienes and the iodination reactions give the 1,4-diiodo 1,3-butadiene derivatives (Scheme 122). Reactions with different unsaturated organic molecules have also been investigated. They catalyze the cyclotrimerization of a range of alkynes. Terminal alkynes with small substituents produce the 1,2,4-trisubstituted benzene, preferentially, in an exothermic reaction. The more bulky substrates BuTl CH and Me3SiC=CH react more slowly and only the symmetrical 1,3,5-isomer is produced (Scheme 122).174... 

Our best approach to PPTe (19) involves reaction of p-diiodo-benzene with Na2Te in DMF at 110-120° to give a tan solid, m.p. 162-170°(dec) in 70-75% yield, found by analysis to have the composition c6H4.6Te1.35. OSS The Percentage of iodine, as... 

Synthesis of PPSe (yellow) and PPTe p-dibromo- and p-diiodo-benzene in DMF (5-8 ml/gm) were reacted with Ife Se and l Te, prepared analogously to Na2Te2 (15), respectively, at 110-120° (PPTe) or 120-140° (PPSe) for twenty hours. After cooling to room temperature, the reaction mixtures were poured into brine, and the polymers were isolated by suction filtration. PPSe was washed with Na2S solution, followed by water and methanol. Both crude polymers were extracted with THF and vacuum dried at 100° before further study. 

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