4- -2-methoxyphenol

Toxicology. 2-Methoxyethyl acetate affects the central nervous system, the hematopoietic system, and the reproductive system in animals. 

In a recent report, shipyard painters with mean exposure concentrations of 3.03ppm had significantly lower white blood cell counts than controls, and 6 of 57 painters were leukopenic.  

Mice and rabbits tolerated 1-hour exposure to 4500 ppm with only irritation of mucous membranes guinea pigs survived the 1-hour exposure but succumbed days later. Repeated exposure to 5 00 ppm for 8 hours/day caused narcosis and death in cats, and 1000 ppm for 8 hours/day was lethal to rabbits all animals showed kidney injury. Anemia was observed in cats repeatedly exposed to 2 00 ppm for 4-6 hours. 

Dose-related increases in testicular atrophy and leukopenia have been reported in mice after administration of 63-2000 mg/kg 5 days/week for 5 weeks.  

2-Methoxyethyl acetate is hydrolyzed in vivo to form 2-methoxyethanol, which is subsequently metabolized to 2-methoxyacetic acid, a proported teratogenic substance. Consequently, the acetate is expected to show profiles of developmental and reproductive toxicity similar to those of 2-methoxyethanol (qv). In a case report, a woman who was extensively exposed to 2-methoxyethyl acetate, both dermally and probably by inhalation during pregnancy, gave birth to two sons with hypospadias. Because family history and medical examination showed no overt risks other than the significant exposure of the mother, and because 2-methoxyethyl acetate can cause teratogenic effects in animals, the malformations were attributed to the exposure. 

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Butylated Hydroxyanisole. 2- and 3-/ i -Butyl-4-methoxyphenol (butylated hydroxyanisole (BHA)) is prepared from 4-methoxyphenol and tert-huty alcohol over siUca or alumina at 150°C or from hydroquinone and tert-huty alcohol or isobutene, using an acid catalyst and then methylating. It is widely used in all types of foods such as butter, lard, and other fats, meats, cereals, baked goods, candies, and beer as an antioxidant (see Antioxidants Eood additives). Its antioxidant properties are not lost during cooking so that flour, fats, and other BHA-stabiLized ingredients may be used to produce stabilized products. 

Polymerization inhibitors are key additives which prevent premature gelation of the adhesive. The foimulator must carefully balance shelf stability and the required cure on demand. Due to its high propagation rate, MMA is difficult to inhibit. Some comments on specific inhibitors follow. The most common inhibitor to be found in component monomers is 4-methoxyphenol, which is also called the methyl ether of hydroquinone. This inhibitor is effective only in the presence of oxygen. A mechanism has been proposed, and is illustrated in Scheme 13 [128]. 

Reaction of 8-methylperhydropyrido[l,2-c][l,3]oxazine-l,3-dione 91 with PhCH2NH2 then PhCOCl and 4-methoxyphenol afforded ring-opened products 92 and 93, respectively (00JA11009). 

A novel application of a phenyl aryldiazosulfone was found by Kessler et al. (1990). l-[4-(7V-Chlorocarbonyl-7V-methylamino)phenyl]-2-(phenylsulfonyl)diazene (6.18) is an acid chloride with a potential diazonio group. The above authors showed that in organic solvents (THF, etc.) this compound reacts easily, as expected, with nucleophiles (HNu), e.g., with aliphatic, aromatic, or heterocyclic amines, with cystine dimethyl ester, or with 4-methoxyphenol at the carbonyl function, yielding... 

Methoxyethanol (EGM ) 2-Methoxyethyl acetate (EGMEA) 4-Methoxyphenol 1-Methoxypropan-2-ol Methyl acetate Methyl acetylene ... 

Applications Ideally, multiply hyphenated systems should be assembled rapidly in response to real need. Access to these means is restricted to a few laboratories only. Multiple LC hyphenations have been used to analyse test mixtures of polymer additives see Table 7.74. The relative ease with which SEC-UV using CDCI3 as a solvent can be coupled to on-line 1II NMR and an in series off-line FUR (Scheme 7.12b), has been shown for a mixture of polymer additives (BHT, Irganox 1076, DIOP) [666]. Figure 7.35 shows representative spectra for on-flow NMR and MS and off-line FTIR of 2,6-di-f-butyl-4-methoxyphenol. 

Table 10. Catalytic enantioselective epoxide ring opening with 4-methoxyphenol 105 promoted by gallium hetero-bimetallic complexes in the presence of MS 4A.

Tiible 11. Enantioselective ring opening of various tneso-epoxides with 4-methoxyphenol (105) promoted by Ga-Ii-linked-BINOL complex (116). 

T. Iida, N. Yamamoto, N. Matsunaga, H.-G. Woo, M. Shibasaki, Enantioselective Ring Opening of Epoxides with 4-Methoxyphenol Catalyzed by Gallium Hetero-bimetallic Complexes An Efficient Method for the Synthesis of Optically Active 1,2-Diol Monoethers, Angew. Chem Int. Ed. EngL 1998,32 2223-2226. 

Commercial samples may contain 2,6-di-t-butyl-4-methoxyphenol which must be removed before use... 

Method A The glucopyranosyl bromide (1 mmol) in CH2C12 (10 ml) and HzO (10 ml) is added to the phenol (3 mmol) and TEBA-C1 or Adogen (0.2 mmol) in aqueous KOH or NaOH (25 mmol) and the mixture is stirred at room temperature for 8-60 h. The organic phase is separated, washed with H20, dried (MgS04), and evaporated to yield the O-aryl derivative (68% from phenol 60% from 2-cresol 53% from 3-chlorophenoI, 54% from 4-methoxyphenol 56% from 4-nitrophenol 57% from 1-naphthol 44% from thio-phenol 36% from 8-hydroxyquinoline). 

Pesticides containing methyl or other alkyl substituents maybe linked to N or 0 (i.e., N- or O-alkyl substitution). An N- or O-dealkylation catalyzed by microorganisms frequently results in loss of the pesticide activity. Phenylurea (see Chap. 1) becomes less active when microorganisms AT-demethylate the molecules (e. g., the conversion of Diuron to the normethyl derivative, Fig. 7). The subsequent removal of the second AT-methyl group renders the molecule fully nontoxic [169]. On the other hand, the microbial O-demethylation of Chloroneb creates the non-toxic product 2,5-dichloro-4-methoxyphenol (Fig. 7). 

It should be noted that one of these diols, the hydroquinone, did not provide any oligomer in the first step. This was due to the formation of the quinone structure which made it impossible to use hydroquinone directly in the substitution reaction. An alternate method was used to overcome this problem which involved the use of 4-methoxyphenol to obtain the sulfone product, followed by cleavage of the methyl ether to the diol (VIII) with boron tribromide. This set of reactions is outlined in Figure 5. 

The photolysis of 4-nitroanisole in degassed acetonitrile or benzene yields 4-nitro-soanisole and 2-nitro-4-methoxyphenol is). Triphenylene (Et = 67 kcal mole i 4-nitroanisole t=59.5 kcal mole i has been used to sensitize the reaction, which is suppressed completely by nitric oxide. A rationale for the formation of the products observed is given below. 

Methoxychlor-DDE and p,p-dimethoxybenzophenone were formed when methoxychlor in water was irradiated by UV light (Paris and Lewis, 1973). Compounds reported from the photolysis of methoxychlor in aqueous, alcoholic solutions were p,p-dimethoxybenzophenone, p-methoxybenzoic acid, and 4-methoxyphenol (Wolfe et al., 1976). However, when methoxychlor in milk was irradiated by UV light (A. = 220 and 330 nm), 4-methoxyphenol, methoxychlor-DDE, p,p-dimethoxybenzophenone, and l,l,4,4-tetrakis(p-methoxyphenyl)-l,2,3-butatriene were formed (Li and Bradley, 1969). 

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