Chloronitro compounds

OOMIl, 01 Mil). Similar reactions of 1,2-dihydroxybenzene derivatives 237 with various less activated 2,6-dinitrochlorobenzene derivatives provided usually low yields of the corresponding dioxins (59JCS1899, 84JHC1073). To improve the yields, especially with less activated chloronitro compounds, a two-step... 

An aromatic amine, A chloronitro compound MCA Case History No. 1964... 

An explosion has been reported with o-chloronitro compounds Rondestvedt Johnson Synthesis 1977,851. For a review of the use of hydrazine, see Futst Berio Hooton Chem. Rev. 1965, 65. 51-68, pp. 52-60. See also Yustc Saldana Walls Tetrahedron Lett. 1982, 23, 147 Adger Young Tetrahedron Lett. 1984, 25. 5219. 

CHEMOSELECTIVE HYDROGENATION OF AROMATIC CHLORONITRO COMPOUNDS WITH AMIDINE MODIFIED NICKEL CATALYSTS. 

To date, the best studied modified systems are Pt catalysts inhibited with sulfur compounds, morpholine or phosphorous compounds (ref. 5). Raney nickel modified with dicyandiamide has also been reported to be able to hydrogenate aromatic chloronitro compounds with very good selectivities and activities. Since nickel is an attractive alternative to precious metal catalysts we decided to search for other types of inhibitors and to investigate the stage at which dehaiogenation occurs. 

With ammonia or amines it yields the corresponding amines, the reactions being characteristic of such chloronitro compounds. 

Hydrolysis of chloronitro compounds. The chlorine atom in chlorobenzene and in its homologues becomes reactive after one or more nitro groups have been introduced into the ring. This is used widely in the preparation of nitrophenols and their ethers. The preparation of dinitrophenol, dinitroanisole and dinitro-phenetole may serve as a classical example (see Chapter XVI). 

In catalytic hydrogenation, chlorine is replaced by hydrogen in chlorinated aromatic hydrocarbons (equations 41 and 42), phenols (equation 43), amines (equation 44), carboxylic acids (equation 45), and nitro compounds (equation 46). - Hydrogenolysis of chlorine in chloronitro compounds takes precedence over reduction of nitro groups, provided that contact with the halogen-free product is not too long. The reaction is achieved using palladium on carbon or tetrakis(triphenylphos-... 

Nitrosyl chloride can be added to a double bond to yield dichlorides, di-chloronitroso compounds and also chloronitro compounds of the type Cl— —C—NO2 through the secondary reaction of oxidation [114-117]. 

Chloroolefins are formed in good yield by the action of sodium methoxide on vicinal chloronitro compounds whose nitro group is attached to tertiary... 

Chloronitro compounds are prepared by treating nitronate anions with NCS in aqueous dioxane, or alternatively by reaction of ketoximes with NCS (eq 14). Oxidative decarboxylation of carboxylic acids with Lead(IV) Acetate and NCS has been used effectively for the synthesis of tertiary alkyl chlorides (eq 15). ... 

Reetz showed that these complexes have substrate specificity with respect to aromatic unsaturated compounds in alkene hydrogenation [21,203]. Moreover, rhodium complexes were active in alkene hydroformylation [21,203-205], and so were platinum, rhodium and iridium complexes in hydrogenation of aromatic chloronitro compounds [206],... 

In hydrogenation of chloronitro compounds, the maximum selectivity was exhibited by platinum complexes with 76 which yielded aminochlorobenzenes at a selectivity above 95% [206]. 

The differing effects of hydrogen ion or of base concentration on thiocyanate substitution rates into rans-[CoCl2 enal and into trans-[CoCl(N02)en2]+ in methanol or ethanol support an earlier hypothesis that the mechanisms are not identical for these two complexes, but that there is considerable solvent assistance in the case of the chloronitro-compound. However, one should recall an earlier study in mixed aqueous alcoholic solvents which indicated no diflFerence in substitution mechanisms for these two complexes. Chloride and thiocyanate substitution at cis-[CoCl2diars]+ in methanol both involve formation of the same inter-mediate. Solvolysis of optical and geometrical isomers of [CoCl2en2]+ in an optically active solvent, propane-1,2-diol, results in stereospecific substitution. ... 

A chemical reaction of an aromatic amine with a chloronitro compound went out of control due to ferric chloride catalysed side reactions when the reaction mass became acidic. Natural soda ash used as an acid acceptor in the non-aqueous system was ineffective. The exothermic side reactions developed pressures above those normally encountered in the process. Synthetic soda ash had been used for all previous batches over a 20-year period. The difference in crystallinity made the natural soda ash less effective than the synthetic type normally used and it acted like an undercharge of soda ash. This permitted an acid build-up which formed ferric chloride as the reactor was made of stainless steel. 

The direct conversions of cyclic ketones into cyclic nitro-alkanes (20) and -alkenes (21) are valuable synthetic reactions, and two new methods to effect these transformations have greatly broadened the scope and use of these processes. In one, use is made of a-chloronitroso-derivatives, readily available from oximes, which are smoothly transformed into (20) via the corresponding a-chloronitro-compounds. In the latter method, trisylhydrazones are easily converted into vinylstannanes which undergo a highly effective replacement of tin by nitro with tetranitromethane in DMSO to give (21). 

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