Pentafluorophenyl hydrazine

Well-defined substitution patterns in the target molecules can be constructed by a combination of fluorine-free or fluoro-substituted (1,3 ee) components with fluorine-free and fluoro-substituted (1,2 nn) compounds. A representative example for the introduction of fluorine and fluoro-substituted groups into five-membered heterocycles via both educts is the reaction of fluoro-substituted chalcones and pentafluorophenyl hydrazine (88JIC773). 

Addition of water and pentafluorophenyl-hydrazine in dilute phosphoric acid addition of a known amount of labeled formaldehyde as internal standard equilibration for 2 hours at 50 °C extraction with hcxanc/methy lenc chloride. 

Sheen, J.F. and Her, G.R., Application of pentafluorophenyl hydrazine derivatives to the analysis of nabumetone and testosterone in human plasma by liquid chromatography-atmospheric pressure chemical ionization-tandem mass spectrometry, Anal. Bioanal. Chem., 380(7-8), 891, 2004. 

Ethoxy-1,1,1 -trifluoro-3-butene-2-one and 3-trilluoroacetyl-3,4-dihydro-2//-pyran react with phenylhydrazine in ethanol, forming the corresponding trifluoromethyl derivatives of pyrazole (01JFC(107)107). Under the same reaction condition treatment these compound with pentafluorophenyl hydrazine or tetrafluorophenyl hydrazine did not give the expected N-fluorinated phenyl pyrazole, it give undehydrated products—5-hydroxy-1-pentafluorophenyl-5-trifluoromethyl-4,5-dihydropyrazole (the molecular structure was identified by X-ray analysis) (01JFC(107)107) (Scheme 101). 

The condensation reaction of carbonyl compounds with halogen-containing derivatization chemicals (so-called elec-trofoiic reagents like pentafluorophenyl hydrazine, 2,4,6-trichlorophenyl hydrazines) and, especially, pentafluoro-benzyl hydroxylamine that has been consid-... 

Malondialdehyde (MDA) is a secondary carbonyl compound that arises from lipid peroxidation pathway. Gas chromatographic analysis of pentafluorophenyl-hydrazine derivatized carbonyl compounds was successfully used to assess antioxidant activity of vegetable oils (Stashenko et al., 1997). 

Sample is derivatized with pentafluorophenyl hydrazine, and the hydrazone derivative is extracted by SPME and injected Sample is mixed with 80 % aqueous MeOH and heated. After cooling is diluted with MeOH and injected... 

Pentafluorophenyl)hydrazine, P-00020 Pentafluorophenyl isolhiocyanate, see P-00018 (Pentafluorophenyl)methyl carbonochloridate,... 

Tns(pentafluorophenyl)phosphine is also replaced when the 4 fluonne reacts with hydrazine [55, 66] (equation 34)... 

The second approach uses the more reactive isocyanates, which can be prepared from the corresponding primary amines by treatment with phosgene [254], Oligomers of hydrazine-derived ureas have been prepared as peptide mimetics on PEG in solution [255]. For this purpose, protected pentafluorophenyl carbazates have been used to convert support-bound hydrazines into ureas (Figure 16.25). 

Finally, hydrazine reduction of [AuCl(C6F5)2(PPh3)] yields (255) [Au(C6F5)(PPh3)], and it was found in general that elimination of chloride occurs more readily upon reduction than loss of the pentafluorophenyl group does. 

Reactions of pentafluorophenyl-substituted pyrylium perchlorates with hydrazine hydrate are known to give 1,2-diazepines. 2-Pentafluorophenyl-4,6-diphenylpyrylium perchlorate reacts with hydrazine hydrate like the unfluorinated analogue, forming 3,5-diphenyl-7-pentafluorophenyMH-l,2-diazepine. However, the 2,6-di(pentafluorophenyl)-... 

Aryihydrazono-2,4-dioxo-4-pentafluorophenyl butanoates (24) react with hydrazine (or phenylhydrazine) unexpectedly, pyridazine-5,6-dione derivatives are produced.93... 

Abbreviations Ac acetyl AIBN azobisisobutyronitrile All allyl Bn benzyl Bz benzoyl ClAc chloroacetyl DAST diethylaminosulfur trifluoride DBU l,8-diazabicyclo[5.4.0]-undec-7-ene DDQ 2,3-dichloro-5,6-dicyano-/)-benzoquinone DMDO dimethyldioxirane DMTST dimethyl(methylthio)sulfonium trifluoromethanesulfonate Fmoc 9-fluorenyl-methoxycarbonyl HDTC hydrazine dithiocarboxylate IDCP iodonium di-collidine perchlorate Lev levulinoyl MBz 4-methylbenzoyl Me methyl MEK methyl ethyl ketone MP 4-methoxyphenyl NBS iV-bromosuccinimide NIS A-iodosuccinimide Pent n-pentenyl Pfp pentafluorophenyl Ph phenyl Phth phthaloyl Piv pivaloyl PMB 4-methoxybenzyl TBAF tetrabutylammonium fluoride TBDMS tcrt-butyldimethylsilyl TBDPS tert-butyldiphenylsilyl TCA trichloroacetyl TES triethylsilyl Tf trifluoromethanesulfonyl TMS trimethylsilyl Tol 4-methylphenyl Tr trityl Troc 2,2,2-trichloroethoxycarbonyl Ts tosyl. 

Photolysis of 2-, 3- and 4-fluorophenylazide (39a,b,c) in aniline gives the products (40), (41) and (42) in the yields shown in Scheme 8. " With 2,6-difluoro- and 2,3,4,5,6-pentafluorophenyl azide, however, ring expansion to azepine products analogous to (42) is suppressed, and the corresponding unsymmetrical azobenzenes cf. 41) are formed in 50% and 55% yield, respectively. The azobenzenes are presumed to arise from insertion of a singlet nitrene into an N-H bond of aniline, followed by oxidation of the resulting hydrazine. 

Z = F Y = F, Z = Me). Decafluoro-l,4-dihydronaphtha] ie also reacts with piperidine, sodium methoxide, hydrazine, ammonia, and pentafluorophenyl lithium at the 6-position, and the 1,2-dihydronaphthaIene gives the 6- and 7-mono-substituted products wdth the first two of these reagents. ... 

---