Benzene in acetonitrile

Iodine pentafluoride reacts quantitatively with perfluoro(trifluorOsilyl)benzene in acetonitrile at 20"C in the absence of pyridine to yield (pentafluorophenyl)iodine tetrafluoride.133 Alk-oxysilanes were used to replace fluorine atoms in iodine pentafluoride with alkoxy groups.135136... 

Figure A. Hydroxylation of benzene in acetonitrile under degassing (0) and under oxygen (Q) ...

Koser isolated the intermediate N-A3-iodanyl carboxyamide 62 as a moderately stable solid by the reaction of a-phenylacetamide with [methoxy(tosy-loxy)iodo]benzene in acetonitrile, and demonstrated that the hydrolytic decomposition of 62 in acetonitrile-water affords an alkylamine with one less carbon atom [105]. 

Although 1,4,7-triazacyclononane was first incorporated into linked macrocyclic systems around three decades ago [7], it was only in 1997 that the corresponding three-ring analogue 1 was synthesised and investigated. The synthesis of 1 [8] (Scheme 1) proceeds from the tricyclic orthoamide derivative of 1,4,7-triazacyclononane 2 [9] and involves reaction with l,3,5-tris(bromomethyl)benzene in acetonitrile in a 3 1 molar ratio followed by base hydrolytic work-up of the product. The addition of excess HBr to the reaction mixture led to isolation of 1 as its nonahydrobromide salt in 76% yield. 

Olefins undergo a two-step oxidative process, with the first step leading to an epoxide that, in the presence of excess oxidant, subsequently is cleaved to afford aldehydes or ketones, dependent on the position of the olefinic bond. Oxidative reactions by peroxovanadates tend to be retarded by protic solvents such as water or methanol. For instance, oxidation of norbomene by picolinatooxomonoperoxo-vanadate in acetonitrile affords 22% of the product epoxide in 9 min. After 120 min in methanol solvent, only 1.8% yield was obtained. In dichloromethane, even cyclohexane is oxidized faster than this, giving 4% cyclohexanol and 9% cyclohexanone in 120 min, whereas benzene in acetonitrile yields 56% of phenol [23],... 

Photolysis of complex 125 (arene = benzene) in acetonitrile gives a quantitative yield of cyclopentadienyl tris(acetonitrile) ruthenium complex... 

The propargyl ether of 3-benzyloxyphenol was cyclised in hot diethylaniline to 7-benzyloxychrom-3-ene which with 3-hydroxy-4-chloromercurimethylenedioxy benzene in acetonitrile containing lithium chloropalladite afforded acemic benzylmaakiain. Hydrogenolysis, formation of the allyl ether and its... 

Iodine in combination with [bis(acyloxy)iodo]arenes is a classical reagent combination for the oxidative iodination of aromatic and heteroaromatic compounds [99], A typical iodination procedure involves the treatment of electron-rich arenes with the PhI(OAc)2-iodine system in a mixture of acetic acid and acetic anhydride in the presence of catalytic amounts of concentrated sulfuric acid at room temperature for 15 min [100,101]. A solvent-free, solid state oxidative halogenation of arenes using PhI(OAc)2 as the oxidant has been reported [102]. Alkanes can be directly iodinated by the reaction with the PhI(OAc)2-iodine system in the presence of f-butanol under photochemical or thermal conditions [103]. Several other iodine(in) oxidants, including recyclable hypervalent iodine reagents (Chapter 5), have been used as reagents for oxidative iodination of arenes [104-107]. For example, a mixture of iodine and [bis(trifluoroacetoxy)iodo]benzene in acetonitrile or methanol iodinates the aromatic ring of methoxy substituted alkyl aryl ketones to afford the products of electrophilic mono-iodination in 68-86% yield [107]. 

In the 1990s, Tingoli and coworkers developed a general approach to various arylselenated products by the reaction of unsaturated compounds with diaryl diselenides and (diacetoxyiodo)benzene [600-603]. Various phenylselenated products are formed in good yields from the reaction of alkenes with diphenyl diselenide and (diacetoxyiodo)benzene in acetonitrile. In particular, cyclohexene under these conditions stereoselectively affords fra i -l-acetoxy-2-(phenylseleno)cyclohexane (541) in good yield (Scheme 3.214) [603]. 

Cyclic phenylselenated products are obtained when this reaction is applied to alkenes containing hydroxy, benzamido, enolizable ketones and carboxylic acids as remote functional groups. For example, the alkenol derivative 542 reacts with diphenyl diselenide and (diacetoxyiodo)benzene in acetonitrile to furnish C-glycoside 543 in moderate yield (Scheme 3.215) [603]. 

The selenodecarboxylation of cinnamic acid derivatives 554 with diaryldiselenides promoted by (diace-toxyiodo)benzene in acetonitrile affords vinyl selenides 555 in moderate yields (Scheme 3.220). A similar reaction of arylpropiolic acids gives the respective alkynyl selenides in 60-90% yields [604]. 

TABLE 4.5 Competitive nitrations of toluene and benzene with 1 -nitropyridinium tetrafluoroborates in acetonitrile at 25 °... 

The solvent is then evaporated, and the unconverted sterol is recovered by precipitation from an appropriate solvent, eg, alcohol. The recovered sterol is reused in subsequent irradiations. The solvent is then evaporated to yield vitamin D resin. The resin is a pale yeUow-to-amber oil that flows freely when hot and becomes a brittie glass when cold the activity of commercial resin is 20 30 x 10 lU/g. The resin is formulated without further purification for use in animal feeds. Vitamin D can be crystallized to give the USP product from a mixture of hydrocarbon solvent and ahphatic nitrile, eg, benzene and acetonitrile, or from methyl formate (100,101). Chemical complexation has also been used for purification. 

Tetracyanoethylene oxide [3189-43-3] (8), oxiranetetracarbonitnle, is the most notable member of the class of oxacyanocarbons (57). It is made by treating TCNE with hydrogen peroxide in acetonitrile. In reactions unprecedented for olefin oxides, it adds to olefins to form 2,2,5,5-tetracyanotetrahydrofuran [3041-31-4] in the case of ethylene, acetylenes, and aromatic hydrocarbons via cleavage of the ring C—C bond. The benzene adduct (9) is 3t ,7t -dihydro-l,l,3,3-phthalantetracarbonitrile [3041-36-9], C22HgN O. 

The work of Hyatt on cyclotriveratrylene—derived octopus molecules contrasts with this. Of course, these species have the advantage of ligand directionality absent in the benzene-derived octopus molecules. Except for the shortest-armed of the species (i.e., n = 1), all of the complexing agents (i.e., n = 2—4) were capable of complexing alkali metal cations. Synthesis of these species was accomplished as indicated below in Eq. (7.7). These variations of the original octopus molecules were also shown to catalyze the reaction between benzyl chloride and potassium acetate in acetonitrile solution and to effect the Wittig reaction between benzaldehyde and benzyltriphenylphos-phonium chloride. 

By the procedure described in the preceding experiment, 30 g (0.11 mole) of tri-phenylphosphine dissolved in 100 ml of acetonitrile is converted to triphenylphosphine dibromide. After the addition of the bromine has been completed, the cooling bath is removed, the flask is set up for vacuum distillation, and the solvent is removed. To the residue is added /7-chlorophenol (10.3 g, 0.08 mole), and the flask is heated at 200° (mantle, wax bath, or sand bath) until HBr ceases to be evolved (about 2 hours). The flask is cooled and the contents are steam distilled affording crude / -chlorobromo-benzene in about 90% yield. Recrystallization from benzene gives the pure product, mp 65-66°. 

A report by Businelli et al. suggests a remarkable solvent dependence for the comhinationidispToportionation Tatio.10"1 These authors found that 1-phenylpentyl radicals (concentration, temperature unspecified) gave only combination in benzene solvent but combination disproportionation products in a 1 1 ratio in acetonitrile solvent. 

The reaction was extended to PhCH2X (X = Cl or Br) which gives the hexa(phenyl-ethyl)benzene complex. The new free aromatic ligand is easily disengaged by photolysis in acetonitrile [76a] Eq. (20). This line of research is now offering us the perspective of making new discotic liquid crystals using suitably substituted... 

Photolysis of several 2-azidophenazines has been shown to afford quinoxahnes. Thus irradiation of 2-azidophenazine (576, R = H) in cyclohexane or acetonitrile gave, among other products, 3-(2-cyanovinyl)-2-quinoxalmecarbaldehyde (577) in <17% yield and irradiation of 2-azido-l-methoxyphenazine in degassed benzene or acetonitrile gave, among other products, a separable mixture of cis- and frawi-isomers of methyl 3-(2-cyanovinyl)-2-quinoxalinecarboxylate (578), each in low yield. 3 ... 

HydTOX5 proline-derived polyesters are usually readily soluble in a variety of organic solvents (benzene, toluene, chloroform, dichloro-methane, carbon tetrachloride, tetrahydrofuran, dimethylformamide, etc.) As expected, the solubility in hydrophobic solvents increased with increasing chain length of the N protecting group, while the solubility in polar solvents decreased. For example, poly(N-hexanoyl-hydroxyproline ester) is slightly soluble in ether but easily soluble in acetonitrile, while poly(N-palmitoylhydroxyproline ester) is readily soluble in ether but virtually insoluble in acetonitrile. 

Because Me3SiI (TIS) 17 is relatively expensive and very sensitive to light, air, and humidity, it is usually prepared in situ from TCS 14 and Nal in acetonitrile [1-6], although other solvents such as CH2CI2, DMF, benzene, or hexane have also been used [5, 6] (Scheme 12.1). It is assumed that TIS 17 forms, in situ, with MeCN, a (T-complex 1733 [2, 3-6], yet Me3SiI 17 can also be prepared by treatment of hex-amethyldisilane 857 with iodine in organic solvents [4-6]. The chemistry of TIS 17 has been reviewed [4—6]. 

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