O-dichloro

The following liquids may be used (boiling points are given in parentheses) — chlorobenzene (132-3°) bromobenzene (155°) p cymene (176°) o-dichloro-benzene (180°) aniline (184°) methyl benzoate (200°) teti-alin (207°) ethyl benzoate (212°) 1 2 4-trichlorobenzene (213°) iaopropyl benzoate (218°) methyl salicylate (223°) n-propyl benzoate (231°) diethyleneglycol (244°) n-butyl benzoate (250°) diphenyl (255°) diphenyl ether (259°) dimethyl phth ate (282°) diethyl phthalate (296°) diphenylamine (302°) benzophenone (305)° benzyl benzoate (316°). 

The high boiling point residue contains p- (b.p. 173°, m.p. 53°) and o-dichloro-benzene (b.p. 179°), which may be separated, upon cooling in ice, the moderately pure solid para isomer separate out. 

This aldehyde synthesis is applicable to compounds of the aromatic series having a labile hydrogen atom (phenyl ethers,1 naphthols,2 dialkylanilines,3-4 naphthostyril,2 anthrones 2) and to certain hydrocarbons of requisite reactivity (anthracene,5-6 7 1,2-benzanthracene,6 3,4-benzpyrene,3 7 pyrene,8 styrene,9 and a, a-diarylethylenes 9). With polynuclear hydrocarbons the best results are secured by the use of a solvent such as o-dichloro-benzene. 9-Anthraldehyde has also been prepared by the action of hydrogen cyanide and aluminum chloride on anthracene in chlorobenzene.10... 

The 1H NMR spectra of the polymers were obtained with a Varian HR-300 spectrometer, at 110-120° C, using 5-10% solutions of polymer in hexachloro-butadiene. The effect of temperature and solvent on the H NMR spectrum of a cationically prepared poly(4-methyl-l-pentene) was investigated. Figure 1-3 show the results obtained with carbon disulfide, carbon tetrachloride, o-dichloro-benzene, p-dichlorobenzene, and hexachlorobutadiene. 

At the lowest ratio (0.67) at which a homogeneous solution (o-dichloro-benzene solvent) can be obtained a slow reaction leads predominantly to the carbon-carbon coupled product, 3.3, 5,5 -tetra-methyldiphenoqui-none. When the ligand ratio is increased, C-O coupling to yield polymer gradually increases and at a ten to one ratio only minor amounts of diphenoquinone are formed. In contrast Endres has found (Fig. 2) that... 

In the reaction of activated aryl halides with phenoxide and thiophenoxide in chloro- or o-dichloro-benzene at reflux, pyridinium salts (48 R, R = —-CH2CH2CHMeCH2CH2— R = Me, Bu", n-C6Hi3 R = CH2CHEtBu, CH2BU1) proved to be superior catalysts to simpler onium salts, like TBAB, due mainly to their greater thermal stability.162... 

Thiolate anions37 38 and oxime alkoxides38 react under phase transfer conditions to give aryl sulfides and O-aryl oximes, respectively the o-dichloro benzene complex can be converted selectively to the monosubstitution product (equation 9). The arylation of oximes leads to a simple process for benzofuran formation (equation 10). Simple primary and secondary amine nucleophiles react smoothly in the absence of added base, in a very general and efficient process for aniline derivatives.49... 

Besides o,/ -dibromopropan-l-ones, there are references related to using o,/ -dichloro [26], o-chloro [19] and a-iodo derivatives [27] in the Gabriel reaction. Bicyclic aziridines 16 were obtained by the treatment of ce-iodocyclohexene 14 with benzylamines 15 in the presence of cesium carbonate in xylene [27] (Scheme 1.4). 

The position of substitution is critical. In one position the new group will lead to an enhancement of activity, while in another position it will result in a reduction of activity. For example, the antihypertensive clonidine with its o,o -dichloro substitution is more potent than its m,p-dichloro analogue (Figure 4.3). 

Similar reactions could also be performed on o-dichloro-substituted pyridazines (Scheme 31) (75JCS(P1)534 81JHC1165 82JHC1447). 

One hundred and sixty-three grams (1.11 moles) of o-dichloro-benzene is nitrated by the addition at 60° with stirring of a mixture of 200 ml. of concentrated sulfuric acid and 175 ml. of nitric acid (sp. gr. 1.42). The reaction is complete after 2 hours of stirring. The product is washed several times with water, dried over calcium chloride, and distilled. A 95% yield of 3,4-dichloronitrobenzene boiling at 254r-257° is obtained. 

Methylpyrazine heated with dimethylformamide and sulfur in o-dichloro-benzene at about 150-180° (with and without iodine as catalyst) gave 2-N-methyl(thiocarbamoyl)py razine and 2-A, yV-dimethyl(thiocarbamoyl)pyrazine (1268,... 

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