Diphenyl Ether Ortho-para Activator

The activation or deactivation of the ring can be predicted more or less by the sum of the D Electron Donating Group ortho/para-directing . For example, acetylation of aniline gives acetanilide first step in the following equation, which.

Reviewa Department of Environmental Health, Harvard School of Public Health, Boston, MA 02115, United Statesb Department of Epidemiology, Harvard School of Public Health, Boston, MA 02115, United Statesc Department of Anatomy, Physiology and Pharmacology, Auburn University, AL 36849, United Statesd Division of Cellular and Molecular Toxicology, National Institute of Health Sciences, Tokyo 158-8501, Japane Department of Pharmacology and Environmental Endocrinology Lab, Center for Bioenvironmental Research, Tulane University, New Orleans, LA 70112, United Statesf Instituto de Bioingeniería, Universidad Miguel Hernández de Elche, Elche 03202, Alicante, Spaing Department of Anatomy and Cellular Biology, Tufts University School of Medicine, Boston, MA 02111, United Statesh Biochemisty and Molecular Biology Department, University of Texas Medical Branch, Galveston, TX 77555, United Statesi Laboratory of Molecular and Cellular Neurobiology, University of Massachusetts Amherst, MA 01003, United Statesj University of Cincinnati College of Medicine, Department of Pharmacology and Cell Biophysics, Cincinnati, OH 45267, United StatesReceived 12 April 2007, Accepted 18 May 2007, Available online 29 May 2007

Bisphenol A BPA, 2,2-bis 4-hydroxyphenyl propane; CAS 80-05-7 is a chemical used primarily in the manufacture of polycarbonate plastic, epoxy resins and as a non-polymer additive to other plastics. Recent evidence has demonstrated that human and wildlife populations are exposed to levels of BPA which cause adverse reproductive and developmental effects in a number of different wildlife species and laboratory animal models. However, there are major uncertainties surrounding the spectrum of BPA s mechanisms of action, the tissue-specific impacts of exposures, and the critical windows of susceptibility during which target tissues are sensitive to BPA exposures. As a foundation to address some of those uncertainties, this review was prepared by the In vitro expert sub-panel assembled during the Bisphenol A: An Examination of the Relevance of Ecological, In vitro and Laboratory Animal Studies for Assessing Risks to Human Health workshop held in Chapel Hill, NC, Nov 28-29, 2006. The specific charge of this expert panel was to review and assess the strength of the published literature pertaining to the mechanisms of BPA action. The resulting document is a detailed review of published studies that have focused on the mechanistic basis of BPA action in diverse experimental models and an assessment of the strength of the evidence regarding the published BPA research.Abbreviations4-tert-OP, 4-tertiary octylphenol; 17α-EE, 17alpha-ethinyl estradiol; AR, androgen receptor; ARE, androgen response element; BADGE, bisphenol A diglycidyl ether; BFDGE, bisphenol F diglycidyl ether; BP-3, p,p -dihydroxybenzphenone; BP-4, 2,2-bis m-methyl-p-hydroxyphenyl propane; BP-5, 2,2-bis p-hydroxyphenyl perfluoropropane; BPA, 2,2-bis 4-hydroxyphenyl propane; BPA-OMe, 2,2-bis 4-methoxyphenyl propane; BPE, 1,1-bis 4-hydroxyphenyl ethane; BPF, 4,4 -methylenebisphenol; BPM, 4,4 - 1,3-phenylenedisopropylidene bisphenol; BPP, 4,4 - 1,4-phenylenedisopropylidene phenol; BPS, 4,4 -sulfonyldiphenol; BPZ, 4,4 -cyclohexylidenebisphenol; DDE, o,p -dichlorodiphenylethylene; o,p -DDT, 1,1,1-trichloro-2- o-chlorophenyl -2- p-chlorophenyl ethane; DEHP, bis 2-ethylhexyl phthalate; DES, diethylstilbesterol; DHT, dihydrotestosterone; DMSO, dimethyl sulfoxide; E2, 17beta-estradiol; EDC, endocrine disrupting chemical; ELISA, enzyme-linked immunosorbent assay; ER, estrogen receptor; ERE, estrogen response element; ETOH, ethanol; GFAP, glial fibrillary acidic protein; GFP, green fluorescent protein; GH, growth hormone; HBSS, Hank s buffered saline solutions; h, hour; HRP, horseradish peroxidase; inos, inducible nitric oxide synthase; KLH, keyhole limpet hemocyanin; LPS, lipopolysaccharide; min, minute; NO, nitric oxide; NP, nonylphenol; OP, octylphenol; PCB, polychlorinated biphenyl; PMA, phorbol 12-myristate 13-acetate; PR, progesterone receptor; PSA, prostrate specific antigen; RIA, radio-immuno assay; RT-PCR, reverse transcription-polymerase chain reaction; RXR, retinoid X receptor; s, second; TCDD, 2,3,7,8-tetrachloro-dibenzo-p-dioxin; T3, L-3,3, 5-triiodothyronine; T4, 3,3, 5,5 -tetraiodo-l-thyronine; TR, thyroid hormone receptorKeywordsBisphenol A BPA, 2,2-bis 4-hydroxyphenyl propane; Endocrine disruption; Endocrine disrupting chemical EDC ; Rapid signaling; Estrogen receptor; Androgen receptor; Thyroid receptor; Thyroid hormone; GPR30; Non-classical membrane estrogen receptor; Immune system; Allergic resonse; In vitro mechanisms; Cell specificity; Expert panel review

Ortho-, meta- and para- disubstituted benzene regioisomers meta director Why are esters -OCOR and amides -NHCOR less activating than ethers -OR.

The list of input items for which data required. Aluminium Chloride Anhydrous Minimum Purity 99.5 Bromine-- liquid Card Board Coated/ Uncoated Caustic Soda Flakes.

Jul 30, 2015 - Chirality Conjugation Esters Ethers Fundamentals Glossary Hydrocarbons Substituents can either be meta directing or ortho-para directing. Electron donating groups are alkyl groups, phenyl groups or Note. Electron donating groups are said to be ortho/para directing and they are activators.

So far we have only seen

electrophilic aromatic substitution of benzene but substituted benzenes can

also undergo further substitution to give polysubstituted systems.

How easy is the second

substitution compared to the first.

Where does E2

substitute relative to E1,

where there are 3 possibilities:

relative rate is expressed

with respect to benzene

The rate data shows that

toluene is more reactive or activated with respect to benzene and the

product distribution shows that the methyl group directs the new substituent

to the ortho- and para- positions

In contrast, trifluoromethylbenzene is less reactive or deactivated with

respect to benzene and directs the new substituent to the meta position.

The origin of these effects

and application to substituents in general is discussed on the following page.

Here is a table that shows

the effect of substituents on a benzene ring have on both the rate and orientation

of electrophilic aromatic substitution reactions.

Thought provoking

questions..

Why are esters -OCOR and

amides -NHCOR less activating than ethers -OR and amines -NH .

Why do esters and amides

appear in the table twice, once as an EDG and once as an

EWG.

Why are amines -NH2 better

activators than alcohols -OH .

RESONANCE

effects are those that occur through the p system

and can be represented by resonance structures. These can be either electron

donating e.g. -OMe where p electrons are

pushed toward the arene or electron withdrawing e.g. -C O where p

electrons are drawn away from the arene.

INDUCTIVE effects

are those that occur through the s system due to

electronegativity type effects. These too can be either electron donating

e.g. -Me where s electrons are pushed toward

the arene or electron withdrawing e.g. -CF3, NR3

where s electrons are drawn away from the arene.

A simplified approach to

understanding substituent effects is given here, based on the isolated molecule

approach. The text uses the more rigorous approach of drawing the resonance

structures for the intermediate formed by attack at each of the o-, m-

and p- positions.

Halogen substituents are

a little unusual in that they are deactivating but still direct ortho-

/ para-. The reason is that they are both inductive electron withdrawing electronegativity

and resonance donating lone pair donation. The inductive effect lowers

the reactivity but the resonance effect controls the regiochemistry due to the

stability of the intermediates.

Besides the electronic effects,

substitutents can also influence product distributions due to steric effects.

From the following data, notice how the yield of the para-nitro product increases

as the size of the alkyl group -R increases and blocks the ortho- positions.

The regioselectivity for

further substitution of disubstituted benzenes can usually be predicted by looking

at the cumulative effects of the substituents.

As a suggested method, look

at each of the substituents, label their directing effects, then indicate the

sites where they would promote reactivity with small arrows. Some issues

that can arise are shown by the following worked examples.

Requires a lower energy of activation because aromaticity is regained. . Two ways in All ortho/para directors are activators, except for halides. All meta.

The ortho/para/meta directing is only important when synthesizing specific benzene-based rings. Certain CH 3 methyl ; C 6H 5 phenyl Well, electron-donating groups are activators and ortho-para directors because they stabilize the.

A Department of Environmental Health, Harvard School of Public Health, Boston, MA 02115, United States; b Department of Epidemiology, Harvard School of Public Health.

In vitro molecular mechanisms of bisphenol A action