Nitro diphenyl ethers

A yield of 84 per cent of u-nitrodiphenyl ether boiling at i83-i85°/8 mm. is obtained when o-nitrochloro benzene is used. For the preparation of j-nitro diphenyl ether, the method of Ullmann and Sponagel, using m-bromonitrobenzene, seems to be the best, since m-chloro nitrobenzene gives large amounts of tarry matter. 

A foreign compound, which may act in this way is the herbicide nitrofen (2,4-dichloro-4 -nitro diphenyl ether), which causes a variety of malformations lethal to the neonate. There is no growth retardation or embryolethality at doses, which are teratogenic, however (Fig. 6.27), and therefore this exhibits the first type of dose-response relationship (see above). The... 

Many herbicides are nitro-PCDEs such as nitrofen and DNP [28,29]. Different diphenyl ether herbicides are presented in Table 3. The use of nitrofen, 2,4-di-chloro-4 -nitro-diphenyl ether, was restricted to crops without detectable residues at harvest in the 1980s, since it has caused neonatal deaths in rats [30]. A aminoderivative of PCDEs, Aminofen, is an intermediate in the chemical industry and has been used in the manufacture of herbicides Illoxan and Diclofop-methyl [4]. Amino-PCDEs are also impurities of Eulan WA New that contains... 

When 4-nitrophenol (69) was treated with pentaphenylbismuth (4) or with tetraphenylbismuth-onium tosylate (7) in the presence of a base, the stable covalent (4-nitrophenoxy)tetraphenylbismuth (70) was isolated. Its thermal decomposition, by refluxing a toluene solution for 4 hours, led to 4-nitro-diphenyl ether (71) in 98% yield.23-25... 

FIGURE 6.18 The dose-response patterns for teratogenicity caused by the herbicide nitrofen (2,4-dichloro-4 -nitro diphenyl ether). Pregnant rats were treated on day 11 with nitrofen. Data from Manson, J.M., Teratogens, in Casarett and Doull s Toxicology, edited by C.D.Klaassen, M.O.Amdur andJ. Doull (New York Macmillan), 3rd Edition, 1986. 

Kato and associates (1978) reported on the acaricidal activity of 4-nitro-diphenyl ethers of the general structures shown below ... 

The mode of action studies suggest that nitro-diphenyl ethers act on the photosynthetic systems of plants. Two pathways are involved, one requiring light, the other not. Thus they can inhibit noncyclic electron transport and coupled photophosphorylation in chloroplasts, and in mitochondria they inhibit electron transport. (Matsunaka, 1969a, 1969b and Moreland et al.. 1970). 

What 4-nitro diphenyl-ethers have we made which control >80% of weed RST when applied at 4 Ibs/acre postemergence ... 

Electron Transport Between Photosystem I and Photosystem II Inhibitors. The interaction between PSI and PSII reaction centers (Fig. 1) depends on the thermodynamically favored transfer of electrons from low redox potential carriers to carriers of higher redox potential. This process serves to communicate reducing equivalents between the two photosystem complexes. Photosynthetic and respiratory membranes of both eukaryotes and prokaryotes contain stmctures that serve to oxidize low potential quinols while reducing high potential metaHoproteins (40). In plant thylakoid membranes, this complex is usually referred to as the cytochrome b /f complex, or plastoquinolplastocyanin oxidoreductase, which oxidizes plastoquinol reduced in PSII and reduces plastocyanin oxidized in PSI (25,41). Some diphenyl ethers, eg, 2,4-dinitrophenyl 2 -iodo-3 -methyl-4 -nitro-6 -isopropylphenyl ether [69311-70-2] (DNP-INT), and the quinone analogues,... 

In the first synthesis of T, the diphenyl ether was formed from -methoxyphenol and 3,4,5-triiodonitrobenzene. The nitro group was replaced by a nitril which was then built up into the alanyl side chain by a series of steps (10). 

Nitrodiphenyl ether has been prepared by heating p-nitro-chlorobenzene with potassium phenoxide and phenoD and by the nitration of diphenyl ether. ... 

Tile same methodology as mentioned for the preparation of (9) was applied for the synthesis of 8-nitro-l,6-naphthyridines. Heating diethyl N- 3-nitropyridin-4-yl)aminomethylenemalonate (12) in diphenyl ether yields ethyl 8-nitro-l,6-naphthyridin-4(lH)-one 3-carboxylate (13) (63JCS4237, 30%) and acid treatment of 4-( y, y-diethoxypropylamino)-5-nitro-2-(/3,/3 -trifluoroethoxy)-pyridine (14) gives in a similar way 8-nitro-5-(/3, /3-triflu-oroethoxy)-l,2-dihydro-l,6-naphthyridine (15, 76%). Subsequent oxidation with chloranil, acid hydrolysis, and methylation with methyl iodide gives 8-nitro-6-methyl-l,6-naphthyridin-5(6H)-one (16,63%) (81JHC941). 

The harsh conditions needed to introduce five or more nitro groups into diphenyl ether lead to the destruction of the aromatic ring. Highly nitrated derivatives of diphenyl ether can be prepared by an indirect route 2,2, 4,4, 6-pentanitrodiphenyl ether (92) is the product from the controlled nitration of (91), which is obtained from the reaction of picryl chloride (87) with sodium o-nitrophenolate. ... 

The 2-nitroethanol obtained by this procedure is quite satisfactory for synthetic purposes, such as the preparation of nitro-ethylene. The small amount of light petroleum ether dissolved in the 2-nitroethanol can easily be removed under reduced pressure. Most of the remaining diphenyl ether can be removed by one redistillation under vacuum, since the fore-run is relatively rich in diphenyl ether. The main fraction has n-u 1.4425-1.4431. Although vacuum redistillation of 2-nitroethanol which has been freed by the present procedure from higher condensation products of formaldehyde with nitromethane is relatively safe, it is recommended that the procedure be carried out behind a safety shield or a barricade. 

The nitro groups in 3,5-dinitrodiaryl ethers may be readily replaced with the residues of mono-and bis-phenols. The simplest 3,5-dinitrodiaryl ether - 3,5-dinitrodiphenyl ether - was reacted with 4-aminophenol or 4-acetamidophenol with the formation of 3-nitro-5-[4-amino(amido)]-phenoxydiphenyl ether subsequent transformation of this product led to 3-amino-5-(4-aminophenoxy)-diphenyl ether [24] (Scheme 4.9). 

Heating diethyl (l-isoquinolylamino)methylenemalonates in diphenyl ether gave ethyl 4-oxo-4//-pyrimido[2,l-a]isoquinoline-3-carboxylates (97) (78USP4127720). Cyclization of diethyl[(4-amino-l-isoquinolyl)amino] methylenemalonate in a mixture of acetic anhydride and pyridine in methylene chloride at ambient temperature afforded ethyl 7-acetylamino-4-oxo-4//-pyrimido[2,l-a]isoquinoline-3-carboxylate [84JAP(K)84/172472]. The 7-nitro derivative was prepared similarly. Cyclization of diethyl [(7-methoxy-3-methyl-l-isoquinolyl)amino]methylenemalonate in polyphos-phoric acid at 130°C for 6 h gave 10-methoxy-6-methyl-4//-pyrimido[2,l-a]isoquinolin-4-one in 29% yield [94IJC(B)795]. 

Diaryl ethers, such as diphenyl ether, do not react with hydrogen iodide even at 200°.) There is no easy way to convert arenols to aryl halides, except where activation is provided by 2- or 4-nitro groups. Thus 2,4-dinitrobenzenol is converted to l-chloro-2,4-dinitrobenzene with phosphorus pentachloride ... 

Allison et al. prepared the catalyst by decomposing nickel formate in a paraffin-paraffin oil mixture in a vacuum of a water-stream pump.45 The nickel catalyst thus prepared was not pyrophoric, not sensitive to air and chloride, and showed excellent catalytic properties in the hydrogenation of aqueous solutions of aromatic nitro compounds such as the sodium salts of m-nitrobenzenesulfonic acid, o-nitrobenzoic acid, and p-nitrophenol at pH 5-6. Sasa prepared an active nickel catalyst for the hydrogenation of phenol by decomposing nickel formate in boiling biphenyl [boiling point (bp) 252°C], diphenyl ether (bp 255°C), or a mixture of them (see eq. 11.12)42... 

McCombie H, MacMillan WG, Scarborough HA (1931), J. Chem. Soc. Trans. / 529-535. Some substitution products of 2-nitro- and 2-acetamido-diphenyl ethers and the corresponding diphenylene oxides"... 

The starting substances for the synthesis of the required diphenyl ethers are suitably substituted o-nitrochlorobenzenes, which react with phenols containing in the ortho position a methoxy, nitro, or halogen group. 

The nitration of aromatic ethers leads to a mixture of nitro ethers and nitrophenols in proportions which depend upon experimental conditions. Benzoyl nitrate favors almost exclusively the formation of o-nitrophene-tole however, detailed directions are lacking. Treatment of diphenyl ether with nitric acid in acetic anhydride-acetic acid gives a se[>arable mixture of the ortho and para isomers (86% total). ... 

Aclonifen or 2-chloro-6-nitro-3- phenoxybenzenamine Diphenyl ether Inhibits carotenoid biosynthesis Preemergence control of weeds in winter wheat, potatoes, etc. 11-13... 

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