Pyrroles nitro

Pyrrole, 2-methyoxycarbonyl-1 -methyl-formylation, 4, 45 Pyrrole, nitro-rearrangement, 4, 297 Pyrrole, 2-nitro-nitration, 4, 211 photolysis, 4, 203 radical methylation, 4, 260 synthesis, 4, 210, 362 Pyrrole, 3-nitro- N NMR, 4, 13 nitration, 4, 211 synthesis, 4, 49, 210, 362 Pyrrole, nitroso-rearrangement, 4, 297 Pyrrole, 2-nitroso-reactions... 

Although, in general, the -excessive nature of the heterocyclic rings under discussion reduces their reactivity to nucleophilic substitution, there are a number of reactions in which the leaving group is a nitro group. An example of intramolecular nucleophilic displacement of a pyrrole nitro group is provided by the base-induced cyclization of 2-acetyl-l-(2-hydroxyethyl)-5-nitropyrrole (413 414). 

Mercury(II) acetate tends to mercurate all the free nuclear positions in pyrrole, furan and thiophene to give derivatives of type (74). The acetoxymercuration of thiophene has been estimated to proceed ca. 10 times faster than that of benzene. Mercuration of rings with deactivating substituents such as ethoxycarbonyl and nitro is still possible with this reagent, as shown by the formation of compounds (75) and (76). Mercury(II) chloride is a milder mercurating agent, as illustrated by the chloromercuration of thiophene to give either the 2- or 2,5-disubstituted product (Scheme 25). 

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... 

Pyrrole, 3-acetyl-l,2-dimethyl-4-nitro-5-(2-nitrophenyl)-reduetion, 4, 244... 

Pyrrole, 2-aeetyl-l-(2-hydroxyethyl)-5-nitro-cyelization, 4, 74 ipso substitution, 4, 243 Pyrrole, 2-aeetyl-l-methyl-dipole moment, 4, 194 photocyelization reaetions with 2,3-dimethylbut-2-ene, 4, 269 Pyrrole, 3-acetyl-4-methyl-Vilsmeier-Haaek formylation, 4, 222 Pyrrole, 2-aeetyl-3-nitro-reduction, 4, 297 Pyrrole, aeyl-basicity, 4, 207 isomerization, 4, 208 oximes... 

Pyrrole, 2-cyano-l-(2-hydroxyethyl)-5-nitro-ipso substitution, 4, 243 Pyrrole, 2-cyano-l-methyl-photochemical rearrangement, 4, 42 photolysis, 4, 203 Pyrrole, 2-cyano-3-methyl-photochemical rearrangement, 4, 202 Pyrrole, 2-cyano-4-methyl-photochemical rearrangement, 4, 202 Pyrrole, 2-cyano-5-methyl-photochemical rearrangement, 4, 202 Pyrrole, diacetoxymethyl-synthesis, 4, 274 Pyrrole, 2,4-diacetyl-synthesis, 4, 218 Pyrrole, 2,5-diacetyl-synthesis, 4, 218, 219 Pyrrole, 2,4-dialkyl-... 

N-alkylation, 4, 236 Pyrrole, 2-formyl-3,4-diiodo-synthesis, 4, 216 Pyrrole, 2-formyl-1-methyl-conformation, 4, 193 Pyrrole, 2-formyl-5-nitro-conformation, 4, 193 Pyrrole, furyl-rotamers, 4, 546 Pyrrole, 2-(2-furyl)-conformation, 4, 32 Pyrrole, 2-halo-reactions, 4, 78 Pyrrole, 3-halo-reactions, 4, 78 Pyrrole, 2-halomethyl-nucleophilic substitution, 4, 274 reactions, 4, 275 Pyrrole, hydroxy-synthesis, 4, 97 Pyrrole, 1-hydroxy-cycloaddition reactions, 4, 303 deoxygenation, 4, 304 synthesis, 4, 126, 363 tautomerism, 4, 35, 197 Pyrrole, 2-hydroxy-reactions, 4, 76 tautomerism, 4, 36, 198... 

In 1972, van Leusen, Hoogenboom and Siderius introduced the utility of TosMIC for the synthesis of azoles (pyrroles, oxazoles, imidazoles, thiazoles, etc.) by delivering a C-N-C fragment to polarized double bonds. In addition to the synthesis of 5-phenyloxazole, they also described reaction of TosMIC with /7-nitro- and /7-chloro-benzaldehyde (3) to provide analogous oxazoles 4 in 91% and 57% yield, respectively. Reaction of TosMIC with acid chlorides, anhydrides, or esters leads to oxazoles in which the tosyl group is retained. For example, reaction of acetic anhydride and TosMIC furnish oxazole 5 in 73% yield. ... 

As discussed in Chapter 6, nitro compounds are converted into amines, oximes, or carbonyl compounds. They serve as usefid starting materials for the preparation of various heterocyclic compounds. Especially, five-membered nitrogen heterocycles, such as pyrroles, indoles, ind pyrrolidines, are frequently prepared from nitro compounds. Syntheses of heterocyclic compounds using nitro compounds are described partially in Chapters 4, 6 and 9. This chapter focuses on synthesis of hetero-aromadcs fmainly pyrroles ind indolesi ind saturated nitrogen heterocycles such as pyrrolidines ind their derivadves. 

The Michael dclclidon of nitro ilkdnes to a,fi-unsdnirdted ketones gives Y-nitroketones, which re convetted into pyrroles by reduction of the nitro group with and PhSSPh fEq. 10.2. ... 

The condensation of nitro ilkenes with enamino- ketones or enamino-esters CGrob-Camenisch reacdoni has been v/idely used for pyrrole synthesis fEq. 10.4. This process is now carried out v/ith resin-boiind enamino-ketones for combinatoriM syntheses of pyrroles. ... 

Another pyrrole synthesis based on intramolecidar subsdnidon of the nitro group by amino funcdon is presented in Eq. 10.7, in which the Michael addidon of enamines to nitroalkenes is... 

Benzyl isocyanoacetate is a nsefnl reagent for the preparadon of benzyl 5-nnsnbsdnited pyrrole-2-carboxylates, which are widely used In the synthesis of porphyrins." Ono and coworkers have prepared pyrroles snbsdnited with various snbsdnients at the fi-posidons."" Because the reqidsite fi-nitro acetates for nitroalkenesi are readily available by the Henry... 

Many other biologically active pyrroles have been prepared by this reaction. 3-Cyano-3,4-disubsdnited pyrroles are prepared by thereacdon ofisocyanoacetonitnie v/ithfi-nitro acetates. 

Nitro ilkenes derived from galdctose or other carbohydrates are converted directly into pyrroles siibsdnited v/ith such carbohydrates at the fi-posidon. They are important precursors for water-soluble porphyrins fEq. 10.29. Such kmds of porphyrins are good candidates for photodynamic therapy of cancer and have been extensively snithed. 

Heterocyclic aromatic nitro compounds are more reactive toward nucleophiles than carbo-cyclic aromatic nitro compounds Various heterocyclic aromatic nitro compounds are thus converted into the corresponding pyrroles by the Barton-Zard reaction fEq 10 37 ... 

In another series of experiments, the nitroporphyrin 6 (M = H2) or its metal derivatives 6 (M = Cu, Ni) have been used to attach heterocyclic rings to the nitro-substituted pyrrole ring of the macrotetracycle.112,113... 

Propionic acid, 2-iodo-3-nitro-, ethyl ester [Propanoic acid, 2-iodo-3-mtro-, ethyl ester], 65 2//-Pyran, 3,4-dihydro-, 51 2//-PYR AN-2-ONE, 49 2H Pyran 2-one, 5 bromo 5,6-dihydro, 50 27/-PYRAN-2-ONE, 5,6 DIHYDRO-, 49 PYRIDINE, 2,3,4,5 TETRAHYDRO, 118 Pyridines, -substituted, 34 a Pyrone-6-carboxyhc acid [2H Pyran-6-Larboxyhc acid 2-oxo ], 51 Pyrroles, 34... 

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