Trifluoromethylphenyl groups

Sterol biosynthesis inhibiting insecticides. The earliest examples of sterol biosynthesis inhibitors were triadimefon, imazalil, and triarimol. These compounds act by blocking the C14 alpha demethylation step in ergosterol biosynthesis [54], Further work in this area has resulted in numerous fungicides, a number of them containing aromatic fluorine, perfluoroalkyl ethers, and the trifluoromethylphenyl group (Fig. 11). In this section, we will discuss the trifluoromethylphenyl sterol biosynthesis inhibitors, such as triflumizole and fluotrimazole. 

Two phytoene desaturase herbicides have been introduced since 2000 picolina-fen (Pico ) [182], introduced in 2001 by BASF, and beflubutamid [183], introduced in 2003 by Ube Industries. The primary mode of action of picolinafen and beflutamid is interference of carotenoid biosynthesis at the phytoene desaturation level, causing bleaching of the plant affected. As in previously developed phytoene desaturase herbicides, a meta-substituted trifluoromethylphenyl group is key for activity in this class of herbicides, pointing to the need for a lipophilic and electron-withdrawing group at this position of the molecule. 

Sandman et. l. (8) have found the N-phenyl-2-phenoxynicotin-amides to be powerful inhibitors of phytoene desaturase. Several bleaching herbicides that inhibit the phytoene to phytofluene transformation have the same 3-trifluoromethylphenyl group (8, 9). This group includes norflurazon, metflurazon, fluridone, 7luometuron and fluorochloridone. In the nicotinamide series the same 3-trifluoromethylphenyl group gives optimum herbicide activity. 

Mobility Based on Thiazole Oligomers with Trifluoromethylphenyl Groups, J. Am. Chem. Soc. 127, 14996-14997, 2005. 

S. Ando, R. Murakami, J. i Nishida, H. Tada, Y. Inoue, S. Tokito, and Y. Ya-mashita. n-Type Organic Field-Effect Transistors with Very High Electron Mobility Based on Thiazole Oligomers with Trifluoromethylphenyl Groups. Journal of the American Chemical Society, 127(43) 14996-14997, 2005. 

This moiety is a feature of either an arylanilide (X = N log P = 2.45,3.36 80, 82, respectively), arylether (X = O log P = 4.90,5.37,4.28 83, 85, 86, respectively) or of a substituted N-methyl-enaminone structure (X = C-C bond log P = 1.87, n.d. 81, 84, respectively) in a five- or six-membered heterocycle, respectively. It is assumed that the biochemical activity of these compounds is determined by the properties of the meto-trifluoromethylphenyl group, such as high lipophilicity (for X = O) and an electron-withdrawing nature. Furthermore, there are strict requirements for substitution at the five- or six-membered heterocycle of the inhibitor, especially at the position most distant from the carbonyl group (for more details see Chapter 4.1). 

Qu and Chi added four electron-withdrawing p-trifluoromethylphenyl groups in addition to two TIPS-ethynyl groups to the heptacene core [57]. The synthesis of the required substituted heptacenequinone 49 was achieved by a Diels-Alder reaction of the transient isonaphthofuran with benzoquinone followed by dehydration. Addition of the TIPS-acetylide and subsequent oxidation with SnCl2/H20 furnished the desired substituted heptacene 50 (Fig. 24) [57]. 

Side chain fluonnaied aryl isocyanates are an important group of substances used in the manufacture of biologically active compounds The synthetic routes to the meta- and para trifluoromethylphenyl isocyanates permit the chlorine-fluonne exchange with hydrogen fluoride to proceed under moderate conditions and in a virtually quantitative manner (equation 22)... 

Penfluridol Penfluridol, 4-(4-chloro-3-trifluoromethylphenyl)-l-[4,4-Z M-(p-fluorophenyl) butyl]-4-piperidinol (6.6.12), is synthesized implementing a Grignard reaction between l-carbomethoxypiperidin-4-one and 4-chloro-3-trifluoromethylphenylmagnesium bromide, giving l-carbomethoxy-(4-chloro-3-trifluoromethylphenyl)-4-piperidinol (6.6.10). Upon alkaline hydrolysis of the carbomethoxy group, it turns into (4-chloro-3-trifluo-romethylphenyl)-4-piperidinol (6.6.11), the alkylation of which with l,l-( ti(4-fluo-rophenyl)butyl bromide (6.6.3) gives penfluridol (6.6.12) [67-69],... 

The structures of the imidazo[4,5-r/ [l,2,3]triazoles 54a (Ar = Ph) and 55 have been firmly established by X-ray diffraction <2002ARK80, 2002J(P1)1968> the trifluoromethylphenyl sttucture 55 adopts the P-1 space group <2002J(P1)1968>. 

A large number of synthetic pyrethroids with a variety of aromatic and aliphatic fluorine substituents have been commercialized, and will be discussed in the sections on fluorinated ether, aromatic fluorine, and fluorinated aliphatic groups, respectively. Fluvalinate (Mavrik ) [50] is a trifluoromethylphenyl pyrethroid, initially introduced by Zoecon (later Zandos Ag) and later replaced by tau-fluvalin-ate, which contains two of the four isomers of fluvalinate. Tau-fluvalinate (Apistan ) is a synthetic pyrethroid used for the topical treatment of honeybees against the parasitic mite Varroa jacobsoni. Mite resistance to tau-fluvalinate has been reported [51],... 

Alkyl aryl and dialkyl selenides, aside from the parent compounds methyl phenyl selenide (Scheme 13, a) and trifluoromethylphenyl methyl selenide (Scheme 13, b), cannot be easily metallated. It was expected that the extra stabilization provided by the cyclopropyl group would be sufficient to permit the metallation of cyclopropyl selenides, but that proved not to be the case. ... 

The optimum substitution pattern on the phenyl group of the ether moiety in the N-benzyl series of compounds is consistent with the pattern seen in N-alkyl and N-phenyl series. In the N-benzyl series, consistently high levels of herbicidal activity are obtained with the 3-trifluoromethylphenyl ethers. Replacing the phenyl ether by a 3-trifluoromethylphenyl amine or N-methyl-3-trifluoromethylphenylamine group resulted in total loss of herbicide activity. The substituted benzyl ethers and aliphatic ethers had very low levels of herbicide activity. 

As can be seen from Table IV, the nitrophenyl analogs of the nicotinamides are inactive. Interestingly, the 2-(3-trifluoromethylphenyl ) benzamides (compound IV minus the nitro group) were moderate herbicides (less than 50% weed control at 1 lb). These compounds are also bleaching herbicides as are the well known 3-phenoxybenzamides. The 3-phenoxybenzamides are also known to be inhibitors of phytoene desaturase (11). 

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