Pyrrole, 2,5-diphenyl

Pyrrole, 2,4-dimf,thyl-3-ethyl-, 21,67 Pyrrole, 2,4-diphenyl-, 27, 33 Pyrrolidine, 1-butyl-, 25,14... 

The oxidative coupling of 3,4-dimethyl-or 3,4-diphenyl-isoxazolin-5-one by activated Mn02 produced a 4,4 -bis(isoxazolinone) (519) and 2,4 -bis(isoxazolinone) (520). Hydrogenation of (519) over Pt02/H0Ac produced a pyrrole derivative while similar reaction of (520) produced an isomeric pyrrole (80JHC763). These reactions are shown in Scheme 152. 

Ethylene, /3-(dimethylamino)-nitro-in pyrrole synthesis, 4, 334 Ethylene, dithienyl-in photochromic processes, 1, 387 Ethylene, furyl-2-nitro-dipole moments, 4, 555 Ethylene, l-(3-indolyl)-2-(pyridyl)-photocyclization, 4, 285 Ethylene, l-(2-methyl-3-indolyl)-l,2-diphenyl-synthesis, 4, 232 Ethylene, (phenylthio)-photocyclization thiophenes from, 4, 880 Ethylene carbonate C NMR, 6, 754 microwave spectroscopy, 6, 751 photochemical chlorination, 6, 769 synthesis, 6, 780 Ethylene oxide as pharmaceutical, 1, 157 thiophene synthesis from, 4, 899 Ethylene sulfate — see 2,2-dioxide under 1,3,2-Dioxathiolane... 

Furo[2,3-amino-synthesis, 4, 986 Furo[3,4-d]pyrimidinedione synthesis, 4, 987 Furopyrimidines, 4, 986 Furo[2,3-d]pyrimidines synthesis, 4, 986 Furo[3,2-d]pyrimidines synthesis, 4, 987 Furo[3,2- 6]pyrone synthesis, 4, 994 Furo[3,2-c]pyrone synthesis, 4, 993 Furo[3,2-6]pyrrole, hexahydro-biological activity, 6, 1024 1 H-Furo[3,4-6]pyrrole-2,3-dione, 4,6a-diphenyl-6-(phenylimino)-6,6a-dihydro-synthesis, 6, 1004 Furopyrroles... 

Imidazolium halides pyrolysis, 5, 449 Imidazolium ions acylation, 5, 402 H NMR, 5, 352 hydrogen exchange, 5, 417 nucleophilic attack, 5, 375 reactivity, 5, 375 ring opening, S, 375 Imidazolium oxides in pyrrole synthesis, 4, 344 Imidazolium perchlorate, 1,3-diphenyl-acylation, 5, 402 Imidazolium salts 1-acetyl-... 

A considerable extension of that method was reached by the condensation of 1,2- and 1,3-dithiolium- 1,3-thiaselenium- and 1,2,4-thiadiazolium salts with pyrroles, 2- or 4-phenyl- 2,4-diphenyl- and 4,5-diphenyl imidazoles (70TL481). At room temperature and in acetonitrile solution some of... 

Photolysis of (Z)-3-phenyl-2-(2-phenylvinyl)-2//-azirine (1) in benzene solution yields 1-phenyl-3//-2-benzazepine (2) in excellent yield.39 However, the stereochemistry of the alkenyl side chain and the solvent used are important in determining the outcome of the reaction. For example, the E-isomer of the 2//-azirine 1 on photolysis in benzene solution yields 2,3-diphenyl-pyrrole as the major product (85 %) the pyrrole is also obtained on heating the Z- or E-isomer in benzene solution. In contrast, irradiation of the Z-isomer in methanol yields only acyclic products. 

Irradiation of 4-methyl-5,7-diphenyl-3//-l,2-diazepine at — 70°C gives 5-methyl-l,6-diphenyl-4,6a-dihydro[l,2]diazeto[l,4-a]pyrrole in 83% yield.105... 

R-trans)-5-(4-fluoro-phenyl)-2-(1 -methylethyl)-N,4-diphenyl-1 -[2-(tetra-hydro-4-hydroxy-6 oxo-2H-pyran-2-yl)ethyi]-1 H-pyrrole-3-carboxomide (VII)... 

In a similar way to the above, azidopropenoylfuro[3,2- ]pyrroles such as 27 can be thermolyzed in a mixture of diphenyl ether and tributylamine to give the 8-oxo-7,8-dihydropyrrolo[2, 3 4,5]furo[3,2-r]pyridines 28, again via the intermediate isocyanates. The lactam 28 can be chlorinated and reduced using standard methods (POCI3 then Zn/AcOH) to give the pyrrolo[2, 3 4,5]furo[3,2-r]pyridines 29 <1995M753> (Scheme 8). 

Carbalkoxy- and cyanosubstituted N-alkyl aziridines 421, however, undergo 1,3-dipolar cycloaddition to the C /C2 bond of diphenyl cyclopropenone followed by elimination of CO to form the dihydro pyrrole derivatives 422, which may lose HCN (when R2 = CN) yielding pyrroles 42323A ... 

Itahara has also found that the phenylation of A-aroylpyrroles can be achieved using Pd(OAc>2 [30, 31]. Although A-benzoylpyrrole (22) yields a mixture of diphenylpyrrole 23, cyclized pyrrole 24, and bipyrrolyl 25 as shown, l-(2,6-dichlorobenzoyl)pyrrole 26 gives the diphenylated pyrrole 27 in excellent yield. The IV-aroyl groups are readily cleaved with aqueous alkali and the arylation reaction also proceeds with p-xylene and p-dichlorobenzene. Unfortunately, N-methyl-, iV-acetyl-, and A-(phenoxycarbonyl)pyrroles give complex mixtures of products. 

Tour has utilized dibromopyrrole 108 to prepare zwitterionic diiodopyrrole 110, which in turn was employed in a synthesis of diphenyl derivative 111 and pyrrole polymers [10,11],... 

If the nitrogen atom of the pyrrole ring was substituted, then pyrrolo[2, 3-6]pyridinecarboxylates (1097) were obtained in 68-74% yields on the thermal cyclization of (V-(l-substituted 2-pyrrolyl)aminomethyIenemalo-nates (1096) by heating in diphenyl ether at 250°C for 20 min [75JCS(P1)1910 89JHC1029]. 

X-Ray crystal diffraction studies of 4-acetyl-3-diazo-2,5-diphenyl-pyrrole (1) and of 3-diazoindazole (2) are the only examples reported because of difficulties in obtaining suitable crystals [78AX(B)293 88UP1] (Fig. 1). 

In 1972 Cava and Sprecker reported the formation of analogs of 149, in which one of the two sulfur atoms is replaced by oxygen or nitrogen (Scheme 9). Reactions of tetrabenzoylethane (146) with HCl or methylamine in acetic acid afforded 3,4-dibenzoyl-2,S-diphenylfuran (152) or 3,4-dibenzoyl-l-methyl-2,5-diphenyl pyrrole (153), respectively. 

Finally, reaction of 2,4-diphenyl-5(4//)-oxazolone 322 with 4-phenyl-A -tosyl-1-azabuta-1,3-diene was found to be highly dependent on the experimental conditions. At room temperature the sole product was 323 that arises from alkylation of 322 by addition at the imine carbon. However, heating 322 and 4-phenyl-A-tosyl-1-azabuta-1,3-diene gave rise to several products including a 2-pyridone 324, 2,3,6-triphenylpyridine 325, and the pentasubstituted pyrroles 326 and 327. The authors postulated two different reaction mechanisms. Here, both a 1,3-dipolar cycloaddition of the oxazolone and a nucleophilic addition of the oxazolone are possible and that may account for the formation of 324—327. The marked differences in reactivity of 4-phenyl-A-tosyl-l-azabuta-l,3-diene relative to A-alkyl- or A-aryl-1-aza-1,3-dienes was attributed to the powerful electron-withdrawing nature of the tosyl group (Scheme 7.107). ... 

Examples of the simple reactions include the conversion of the ester group of 27 into hydrazides (Equation 10), such as 28 <2004JCCS1325>, and replacement of the amino moiety of 27 with the pyrrole ring via reaction with 2,5-dimethoxytetrahydrofuran to produce 29 (Scheme 3) <2004JCCS1325>. Identical chemistry has been conducted on the corresponding diphenyl derivative <1994PS(89)193>. 

The [4+1] annulation of 1-azadienes to pyrroles can also be achieved through their carbonyl iron complexes (Scheme 6). Novel complex (1,4-diphenyl-2-methyl-l-azabutadiene)tricarbonyliron (0) 24 was obtained in 40% yield from the corresponding azadiene 23 and Fe2(CO)9 then nucleophilic attack by methyl lithium and quenching with tert-butyl bromide, as the proton source, gave 2,5-dimethyl-l,3-diphenylpyrrole 26 in 70% yield, probably through the anionic intermediate complex 25 [88TL1425 90JCS(P1)761]. 

Nitroketones are reduced to pyrroles by diphenyl disulfide and triphenylphosphine (86JCS(Pl)2243). Since 7-nitroketones are accessible by Michael additions of nitroalkanes to enones, this is a potentially versatile method (Scheme 40). 

The formation of 3-pyrrolylcarbinols (280) from the photochemically induced reaction of pyrrole, or its 1-alkyl derivatives, with aliphatic aldehydes and ketones is thought to proceed via an oxetane intermediate (279) (79JOC2949). In contrast, the analogous reaction of 1 -phenylpyrrole with benzophenone leads to the formation of the diphenyl(2-pyrrolyl)car-binol, whilst the oxetane (281) has been isolated from the photoaddition of 1-benzoylpyrrole and benzophenone (76JHC1037, B-77MI30500). 2-Benzoyl-1-methylpyrrole undergoes a normal Paterno-Buchi photocyclization with 2,3-dimethylbut-2-ene, via the n -> v triplet... 

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