2-Methyl-4-chlorophenoxyacetic acid MCPA

Common broadleaf weeds in turfgrasses, such as those listed in Table 19.1, are also controlled by other herbicides such as 2,4-D, dicamba, dichloroprop, 2-methyl-4-chlorophenoxyacetic acid (MCPA), mecoprop, clopyralid, and tri-clopyr, or combinations of these products (Bingham and Shaffran, 1982 Bingham et al., 1986 Coats et al., 1994 Johnson and Murphy, 1995 Murphy and Johnson, 1995). 

MCPA, l-methyl-A-chlorophenoxyacetic acid, Methoxone, CgH ClOj. Made by chlorination of o-cresol followed by reaction with chloroethanoic acid. While crystals, m.p. 118-119 C. As usually obtained, crude MCPA contains both 4- (60%) and 6- (40%) chloro-isomers, and is a light brown solid. Selective weedkiller. 

Apart from the sorbents already mentioned in connection with HPTLC pre-coated layers, a micro-crystalline cellulose has also been produced in an average particle size and a narrow particle size distribution suitable for HPTLC (9.). HPTLC pre-coated plates cellulose P 254 s (E. Merck, Darmstadt), composed of this microcrystalline cellulose, were used to separate Trevespan 6058. This is a mixture of the substances ioxynil (3,5-diiodo-4-hydroxy-benzo-nitrile), flurenol (9-hydroxyfluorenecarboxylic acid) and MCPA (2-methyl-4-chlorophenoxyacetic acid). For comparison purposes Trevespan 6038 was also separated on HPTLC pre-coated plates silica gel 60 F 254 (E. Merck, Darmstadt). 

MCPA. (2-methyl-4-chlorophenoxyacetic acid 4-chloro-2-methylphenoxyacetic acid). 

A further decanuclear nickel cage contains two fused pentanuclear nickel(II) metallocrowns. " The cage has the formula [Ni2(mcpa)2][Ni4(shi)2(pko)2(MeOH)2] [Ni4(shi)3(pko)(MeOH)(H20)] (Hmcpa = 2-methyl-4-chlorophenoxyacetic acid, Hpko = di-(2-pyiidyl)ketone oxime, H3shi = salicylhydroxamic acid). The cage was made in good yield by reaction of nickel chloride with... 

Methyl-4-chlorophenol, sodium salt. See Sodium p-chloro-m-cresol 2-Methyl-4-chlorophenoxyacetic acid. See MCPA... 

Methyl-4-chlorophenoxyacetic acid, see MCPA Methyl chlorophos, see Trichlorfon l-(2-Methylcychohexyl)-3-phenylurea, see Siduron A -(2-Methylcyclohexyl)-A7-phenylurea, see Siduron Methyl demeton-O-sulfoxide, see Oxydemeton-methyl Methyl 5-(2,4-dichlorophenoxy)-2-nitrobenzoate, see Bifenox... 

Industrially, chloroacetic acid is used in the production of a wide variety of useful compounds, e g. drugs, dyes, pesticides. Most reactions taking advantage of the high reactivity of the C-Cl bond. It is the precursor to the herbicide glyphosate. The herbicides MCPA (2-methyl-4-chlorophenoxyacetic acid) and dimethoate are prepared by alkylation with chloroacetic acid. Chloroacetic acid is converted to chloroacetyl chloride, a precursor to adrenaline (epinephrine). Displacement of chloride by sulfide gives thioglycolic acid, which is used as a stabilizer in PVC and a component in some cosmetics. 

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