This article needs attention from an expert in Chemistry. The specific problem is: Lots of missing key reagents in images and incorrect/confusing (possibly "non-chemist translation engine"?) chemical terminology.WikiProject Chemistry may be able to help recruit an expert.(September 2019)
1,3-Diphenylisobenzofuran is a highly reactive
diene that can scavenge unstable and short-lived dienophiles in a
Diels-Alder reaction. It is furthermore used as a standard reagent[6] for the determination of
singlet oxygen,[7] even in biological systems.[8] Cycloadditions with 1,3-diphenylisobenzofuran and subsequent oxygen cleavage provide access to a variety of
polyaromatics.
Preparation
The first synthesis of 1,3-diphenylisobenzofuran was reported in 1905 by A. Guyot and J. Catel.[9][10]Phenylmagnesium bromide was reacted with 3-phenylphthalide (the latter accessible from the methyl ester of 3-hydroxyphthalide with
phenylboronic acid in 95% yield[11]) to a
lactol, which gives with mineral acids upon elimination of water 1,3-diphenylisobenzofuran with 87% yield.[12]
The patent literature describes the preparation of 1,3-diphenylisobenzofuran by [4+2]cycloaddition of
1,3-butadiene and dibenzoylethylene (1,4-diphenyl-2-butene-1,4-dione, accessible from
fumaryl chloride and
benzene in the presence of
aluminium chloride.[13]).[14] Dibenzoylethylene is predominantly present in the trans configuration[15] but it can be converted into the needed cis configuration by simple heating.[16]
The 4,5-dibenzoylcyclohexene formed previously is cyclized with
acetic anhydride to the dihydroisobenzofuran. By bromine addition and hydrogen bromide elimination, 1,2-dibenzoylbenzene is formed and recyclized with
zinc acetic acid to the final product 1,3-diphenylisobenzofuran.[17] A publication from 1940 describes high yields for the individual stages of the extensive reaction sequence.[4]
The (much cheaper)
phthaloyl chloride gives also access to 1,2-dibenzoylbenzene via
Friedel-Crafts acylation with benzene,[18] which is reduced to 1,3-diphenylisobenzofuran in 78% yield using potassium borohydride.[19]
The synthesis of 1,3-diarylisobenzofurans from 2-acylbenzaldehydes and
boronic acids is less cumbersome and gives better yields,[20]
1,3-Diphenylisobenzofuran is a yellow, light- and air-sensitive, crystalline solid that is soluble in many organic solvents with a maximum absorption around 420 nm (in solution), which generates intense
fluorescence.[23] Fluorescence measurements can be performed in
DMF and
DMSO because of the stability of 1,3-DPBF in those solvents. In chloroform and carbon tetrachloride the dissolved 1,3-diphenylisobenzofuran is rapidly
photolyzed by attack of CHCl2 and CCl3radicals, even in the absence of oxygen.[24] [24 ]
With ethanol, 1,3-diphenylisobenzofuran forms an orange-yellow, fluorescent solution. On irradiation, it forms a colorless
photodimer (upon with exclusion of oxygen), upon discolouration of the solution.[25]
The compound's refractive index is 1,6700 at 25 °C and 589 nm.[3]
Use
Reagent for determination of singlet oxygen
In the presence of
methylene blue irradiated with red laser light, 1,3-diphenylisobenzofuran reacts with intermediate
singlet oxygen1O2, forming an unstable peroxide that decomposes into (colorless)
1,2-dibenzoylbenzene.[27] The detection of singlet oxygen by 1,3-diphenylisobenzofuran is based on this reaction, even in biological systems. For biological systems, water-soluble derivatives of 1,3-diphenylisobenzofuran were developed.[28] The singlet oxygen generation of
photosensitizers were monitored by photolysis of 1,3-diphenylisobenzofuran (DPBF). 1,2-Dibenzoylbenzene absorbs at <300 nm, therefore making DPBF an optimal chemical trap for detecting singlet oxygen, as most photosensitizers absorb <400-600 nm. This allows for an accurate determination of the photodegradation of the molecule.
Dienophile in Diels-Alder reactions
Isobenzofurans like 1,3-diphenylisobenzofuran are among the most reactive Diels-Alder dienes known to date,[29] and are useful for scavenging short-lived and unstable olefins and alkynes. The group led by
Georg Wittig made important contributions to this topic.
With the unstable
cyclohexyne, 1,3-diphenylisobenzofuran reacts to a tricyclic compound that gives a 9,10-diphenylcyclohexenonaphthalene after hydrogenation and hydrogen abstraction.[30]
1,3-Diphenylisobenzofuran gives similarly with
benzyne (dehydrobenzene) an oxygen-bridged anthracene (in 85% yield), which can be reduced with zinc to 9,10-diphenylanthracene (88% yield).[31]
Cyclopropenone (which is unstable above its melting point of -29 °C) reacts quantitatively at room temperature with 1,3-diphenylisobenzofuran to form a Diels-Alder adduct,[32] which is exclusively an exo isomer.[33]
The twice occurring Diels-Alder reaction of 1,3-diphenylisobenzofuran with
p-benzoquinone yields almost quantitatively a product that can be reacted further with
p-toluenesulfonic acid to give a
pentacene derivative in 49% yield.[37]
W. Friedrichsen (1999), "Recent Advances in the Chemistry of Benzo[c]furans and Related Compounds", Adv. Heterocycl. Chem., Advances in Heterocyclic Chemistry, vol. 73, pp. 1–96,
doi:
10.1016/S0065-2725(08)60940-X,
ISBN9780120207732
R. Rodrigo (1988), "Progress in the chemistry of isobenzofurans: Applications to the synthesis of natural products and polyaromatic hydrocarbons", Tetrahedron, vol. 44, no. 8, pp. 2093–2135,
doi:
10.1016/S0040-4020(01)81720-8
^
abCarl L. Yaws (2015), Thermophysical Properties of Chemicals and Hydrocarbons, 2nd Edition, Oxford, UK: Elsevier Inc., p. 604,
ISBN978-0-323-28659-6
^
abR. Adams; M.H. Gold (1940), "The Synthesis of 1,3-Diphenyldihydroisobenzofurans, 1,3-Diphenylisobenzofurans and o-Dibenzoylbenzenes from the Diene Addition Products to Dibenzoylethylene", Journal of the American Chemical Society, vol. 62, no. 1, pp. 56–61,
doi:
10.1021/ja01858a012
^J.A. Howard; G.D. Mendenhall (1975), "Autoxidation and photooxidation of 1,3-diphenylisobenzofuran: A kinetic and product study", Canadian Journal of Chemistry, vol. 53, no. 14, pp. 2199–2201,
doi:
10.1139/v75-307
^P. Carloni; et al. (1993), "On the use of 1,3-diphenylisobenzofuran (DPBF). Reactions with carbon and oxygen centered radicals in model and natural systems", Res. Chem. Intermed., vol. 19, no. 5, pp. 395–405,
doi:
10.1163/156856793X00181,
S2CID94802096
^A. Guyot, J. Catel, Bull. Soc. Chim. France, [3] (35), 1124 (1906)
^M. Kuriyama; N. Ishiyama; R. Shimazawa; R. Shirai; O. Onomura (2009), "Efficient synthesis of 3-arylphthalides using palladium-catalyzed arylation of aldehydes with organoboronic acids", Journal of Organic Chemistry, vol. 74, no. 23, pp. 9210–9213,
doi:
10.1021/jo901964k,
PMID19873994
^D.V. Klemm; A. Tuncay (1989), "Photochemical and thermal isomerization of trans- and cis-1,2-dibenzoylethylene: A microscale approach", J. Chem. Educ., vol. 66, no. 6, p. 519,
Bibcode:
1989JChEd..66..519K,
doi:
10.1021/ed066p519
^US 2356907, R. Adams, "1,3-Diphenylisobenzofurans and process for preparing the same", published 1944-08-29, assigned to E.I. du Pont de Nemours & Co.
^Houben-Weyl Methods of Organic Chemistry (1973), Organometallic Compounds of Group II of the Periodic Table, 4th Edition, vol. XIII/2a, Stuttgart: Thieme, p. 419,
ISBN978-3-13-213204-7
^M. Cava; M.J. Mitchell; A.A. Deana (1960), "Condensed cyclobutane aromatic compounds. XIII. An attempted synthesis of 1,2-diphenylbenzocyclobutene", Journal of Organic Chemistry, vol. 25, no. 9, pp. 1481–1484,
doi:
10.1021/jo01079a005
^J. Jacq; B. Bessières; C. Einhorn; J. Einhorn (2010), "Regiospecific synthesis of functionalised 1,3-diarylisobenzofurans via palladium- and rhodium-catalysed reaction of boronic acids with o-acylbenzaldehydes under thermal or microwave activation", Org. Biomol. Chem., vol. 8, no. 21, pp. 4927–4933,
doi:
10.1039/c0ob00110d,
PMID20740250
^A. Kotali; P.G. Tsoungas (1987), "Oxidation of N-aroylhydrazones of o-hydroxyaryl ketones with lead(IV)acetate: A facile route to aromatic o-diketones", Tetrahedron Lett., vol. 28, no. 37, pp. 4321–4322,
doi:
10.1016/S0040-4039(00)96497-9
^J. Jacq; C. Einhorn; J. Einhorn (2008), "A versatile and regiospecific synthesis of functionalised 1,3-diarylisobenzofurans", Org. Lett., vol. 10, no. 17, pp. 3757–3760,
doi:
10.1021/ol801550a,
PMID18666776
^M. Wozniak; F. Tanfani; E. Bertoli; G. Zolese; J. Antonsiewicz (1991), "A new fluorescence method to detect singlet oxygen inside phospholipid model membranes", Biochim. Biophys. Acta, vol. 1082, no. 1, pp. 94–100,
doi:
10.1016/0005-2760(91)90304-Z,
PMID1849016
^A. Schönberg; A. Mustafa; G. Aziz (September 1, 1954), "Diels-Alder Reaction. II. Experiments with 2-Styrylchromones. On the Nature of the Dimer of 1,3-Diphenylisobenzofuran", Journal of the American Chemical Society, vol. 76, no. 18, pp. 4576–4577,
doi:
10.1021/ja01647a020
^C. Schmitz; J.M. Aubry; J. Rigaudy (1982), "A new access to the anthracene core: Synthesis of two water soluble singlet oxygen traps derived from 1,3-diphenylisobenzofuran and 9,10-diphenylanthracene", Tetrahedron, vol. 38, no. 10, pp. 1425–1430,
doi:
10.1016/0040-4020(82)80224-X
^D. Tobia; B. Rickborn (1987), "Substituent effects on rates of inter- and intramolecular cycloaddition reactions of isobenzofurans", Journal of Organic Chemisty, vol. 52, no. 12, pp. 2611–2615,
doi:
10.1021/jo00388a055
^M.P. Cava; J.P. VanMeter (1969), "Condensed cyclobutane aromatic compounds. XXX. Synthesis of some unusual 2,3-naphthoquinonoid heterocycles. A synthetic route to derivatives of naphtho[2,3-b]biphenylene and anthra[b]cyclobutene", Journal of Organic Chemistry. Org. Chem., vol. 34, no. 3, pp. 538–545,
doi:
10.1021/jo01255a012
^Houben-Weyl Science of Synthesis (2009), Compounds with All-Carbon Functions, vol. 45b, Stuttgart: Thieme, p. 1038,
ISBN978-3-13-146551-1
^G.P. Miller; J. Briggs (2002), "Progress towards the synthesis of tris- and tetrakis[60]fullerene adducts", Electrochem. Soc. Proc., vol. 2002–12, pp. 279–284,
ISBN1-56677-333-4