P fluoro

For the nine substituents m- andp-methyl, p-fluoro, m- and p-chloro, m- and p-bromo, and m- and p-iodo, using the results for nitration carried out at 25 °C in nitromethane or acetic anhydride - (see tables 9.1, 9.5), a plot of logjoA/ j against cr+ produced a substituent constant p = —6-53 with a standard deviation from the regression line i = 0-335, 2 correlation coefficient c = 0-975. Inclusion of... 

FLUORINECOMPOUNDS,ORGANIC - FLUORINATED AROMATICCOMPOUNDS] (Volll) p-Fluoro-a,a-bis(trifluoromethyl)benzyl alcohol [2402-74-6]... 

C6H7N 3-PICOLiNE 103.829 2.6047E-01 2.7853E-05 184.26 292 C7H7F P-FLUORO- -150.014 2.5689E-01 2.5593E-05 -70.88... 

The reaLUons of phenyltetrafluorophosphorane with numerous silylated secondary or tertiary a- or (1-hydroxy esters, ketones, nitriles, ethers, nitro, and trichloromethyl derivatives have been investigated, the corresponding a or p fluoro derivatives are obtained in yields varying from reasonable to nearly quantitative [24, 25, 26, 27 The application of phenyltetrafluorophosphorane for fliiorination of silyloxy steroids has also been reported [28]... 

A mixture of 3.2 parts 4-chloro-p-fluoro-butyrophenone, 3.5 parts 1-oxo-4-phenyl-2,4,8-triazaspiro(4,5)decane, 2 parts Na COs hd 0.1 part Kl in 200 parts hexone is refluxed with stirring for 50 hours. The mixture is cooled to room temperature, 200 parts water are added and the layers are separated. The organic layer is dried over 10 parts MgSO, ... 

Fluara-2-Methylindanane To 932 grams polyphosphoric acid at 70°C on the steam bath is added 93.2 grams (0.5 mol) p-fluoro-o-methylhydrocinnamic acid slowly with stirring. 

Selection of these regulatory mutants is often done by using toxic analogues of amino adds for example p-fluoro-DL-phenylalanine is an analogue of phenylalanine. Mutants that have no feedback inhibition or repression to the amino add are also resistant to the analogue amino add. They are therefore selected for and can be used to overproduce the amino add. Some amino add analogues function as false co-repressors, false feedback inhibitors or inhibit the incorporation of foe amino acid into foe protein. 

To achieve overproduction of phenylalanine, the micro-organism should be derepressed at the pheA level and free of inhibition at the arcG level. Both genes are located on the chromosomal DNA of the micro-organism and, by means of amino add analogues such as p-fluoro-DL-phenylalanine, it is possible to make (phenylalanine) feedback resistant mutants of E.cdi (pheA and oroF mutants). The following procedure can be used ... 

Carbocations are intermediates in several kinds of reactions. The more stable ones have been prepared in solution and in some cases even as solid salts, and X-ray crystallographic structures have been obtained in some cases. An isolable dioxa-stabilized pentadienylium ion was isolated and its structure was determined by h, C NMR, mass spectrometry (MS), and IR. A P-fluoro substituted 4-methoxy-phenethyl cation has been observed directly by laser flash photolysis. In solution, the carbocation may be free (this is more likely in polar solvents, in which it is solvated) or it may exist as an ion pair, which means that it is closely associated with a negative ion, called a counterion or gegenion. Ion pairs are more likely in nonpolar solvents. 

Substituent Effect F-nmr Shifts for BCI3 Adduct Formation with p-Fluoro-p -Substituted... 

The stable P-unsubstituted phosphinous amide H2PN(SiMe3)2 has been shown to suffer the nucleophilic displacement of the disilazane moiety by the action of thiols R-SH giving the phosphinous thioesters R-S-PH2 [13]. For the sake of brevity we shall not comment on other relevant reactions of AT-silyl phosphinous amides, such as the anionic P-silylation [115] and P-alkylation [22], the consecutive dialkylation of PH derivatives [18] and the fluorodesily-lation of P-fluoro-JV-silyl derivatives [140]. 

The relative insensitivity of Sp to changes in electronegativity of substituents which is observed for P fluoro-compounds is also evident for penta-arylphosphoranes. Thus the placement of />ara-substituents on the phenyl rings of pentaphenylphosphorane has very little effect and Sp is -f 88 1 p.p.m. for (16 Y = H, Me, or Cl). The effect on Sp of the introduction of an amino-group in the bis-biphenylenephosphorane system (17) is similar to that of an alkyl group (see Table 3). ... 

A limited number of pure substances are available from NIST, primarily clini-cally-relevant compounds such as cholesterol, urea, uric acid, creatinine, glucose, cortisol, tripalmitin, and bilirubin (NIST SRM website). These compounds are certified for purity (greater than 99 %) and are used as primary calibrants in definitive methods for these clinical analytes (see below). Several additional pure substances are available for specific applications such as microchemistry, i.e. elemental composition (acetanilide, anisic acid, cystine nicotinic acid, o-bromobenzoic acid, p-fluoro-benzoic acid, m-chlorobenzoic acid), polarimetric standards (sucrose and dextrose), acidimetric standard (benzoic acid and boric acid). Only three pure substance NIST RMs are available for environmental contaminants, namely the chlorinated pesticides, lindane, 4,4 -DDT, and 4,4 -DDE. 

Fig. 15. (A) Cyclization reaction to afford a metallocyclophosphazene (20) (B) thermolysis of N-silyl-P-(fluoro)phosphoranimine (21) to afford alkyl cyclophosphazenes.

Tanner et al. (58) investigated the asymmetric aziridination of styrene using bis(aziridines) such as 85. Low induction is observed with these ligands, Eq. 64. A significant electronic effect was noted with the p-fluoro-phenyl substituted bis(az-iridine) 85c (59). A binaphthyl-derived diamine was used as a ligand for the copper-catalyzed aziridination of dihydronaphthalene (81). The product was formed in 21% ee and 40% yield, Eq. 65. Other structurally related ligands proved to be less selective in this reaction. 

Alkyl- and aryl-hydrazones of aldehydes and ketones readily peroxidise in solution and rearrange to azo hydroperoxides [1], some of which are explosively unstable [2], Dry samples of the p-bromo- and p-fluoro-hydroperoxybenzylazobenzenes, prepared by oxygenation of benzene solutions of the phenylhydrazones, exploded while on filter paper in the dark, initiated by vibration of the table or tapping the paper. Samples were later stored moist with benzene at —60°C to prevent explosion [3], A series of a-phenylazo hydroperoxides derived from the phenyl-or p-bromophcnyl-hydrazones of acetone, acetophenone or cyclohexanone, and useful for epoxidation of alkenes, are all explosive [4], The stability of several substituted phenylazo hydroperoxides was found to be strongly controlled by novel substituent effects [5],... 

N-Methylpyrrolidinone 2-Pyrrolidinone, 1-methyl- (8,9) (872-50-4) p-Fluorostyrene Styrene, p-fluoro- (8) Benzene, 1-ethenyl-4-fluoro- (9) (405-99-2)... 

An alternative approach to preventing the formation of dihydroartemisinin by simple P450 metabolism is to replace the methyl function in artemether with an aryl function. Phenoxy analogues of DHA can easily be prepared in a one-step synthesis from dihydroartemisinin in a manner similar to the preparation of Ic and Id. In addition to having superior in vivo activity to artesunate and artemether, analogues substituted with a p-fluoro (71a) or trifluoromethyl group (71b), in the phenoxy ring, resist metabolism to DHA . ... 

In Section 1.1.1, L-deprenyl (2) was discussed as a potent selective MAO B inhibitor. Its p-fluoro analogue, fludeprenyl (7), was shown to retain the irreversible and selective inhibitory effects of its parent compound, with similar potency in vitro in rat tissue and in vivo in mice [33]. Both compounds have also been reported to have similar protective actions against transient global cerebral ischemia in gerbils. With L-deprenyl (2), these effects occurred at doses below those which inhibit MAO B, while the effects of the p-fluoro analogue 7 occurred only at doses that also inhibit MAO B activity [33b,34]. 

S. Yasar, J. Gaal, Z. Justinova, J. Bergman, Discriminative stimulus and reinforcing effects of p-fluoro-l-deprenyl in monkeys. Psychopharmacology 182 (2005) 95-103. 

Condensation of benzyl glycinate -toluenesulfonate salt with 4,5-diphenyl-1,3-dioxol-2-one affords 154, which can be converted to the 4,5-diphenyl-3-substituted-2(3//)-oxazolones 155 by sequential treatment with an aldehyde/LiHMDS followed by diaminosulfur trifluoride (DAST). Hydrogenolysis then affords the p-fluoro-a-amino acids 156 in excellent yields without any concomitant cleavage of the... 

Fluorination of unsaturated 5(47/)-oxazolones 758 affords the expected difluori-nated derivatives 759. Basic hydrolysis of 759 yields a p-fluoro-a-keto acid 760 that is reductively aminated to give an e t/jw-p-fluoro-a-amino acid 761... 

R. Guedj, A.I. Ayi u. M. Remli, Synthesis and Properties of Monofluorinated Compounds of Biological Interest, fi-Fluoro a-Amino Acids and homologous P-Fluoro-Derivates of Pyruvic Acid, Ann. Chim. (Paris) 9, 691 (1984). 

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