Radicals alkylic

Anion radical Alkyl radical Halide anion... 

Guanine, 9-/3-D-ribofuranosyl-, 5, 536 Guanine, 6-thio-tautomerism, 5, 509 toxicity, 1, 141 Guanine, 8-trifluoromethyl-synthesis, 5, 574 Guanines, thio-synthesis, 5, 572 Guanosine arylation, 5, 538 dipole moment, 5, 522 free radical alkylation, 5, 543 hydrobromide... 

UV spectra, 5, 517 bromination, 5, 540 dipole moment, 5, 523 free radical alkylation, 5, 543 free radical methylation, 5, 544 IR spectra, 5, 518, 519 irradiation, 5, 543 mass spectra, 5, 519 metabolism, 1, 234 monoprotonated tautomerism, 5, 509 oxidation, 5, 539 1-oxides... 

Imidazo[4,5-c]pyridine, 2,3-dimethyl-radical alkylation, 5, 621 Imidazo[4,5-c]pyridine, 2-ethoxy-synthesis, 5, 635... 

Beyer synthesis, 2, 474 electrolytic oxidation, 2, 325 7r-electron density calculations, 2, 316 1-electron reduction, 2, 282, 283 electrophilic halogenation, 2, 49 electrophilic substitution, 2, 49 Emmert reaction, 2, 276 food preservative, 1,411 free radical acylation, 2, 298 free radical alkylation, 2, 45, 295 free radical amidation, 2, 299 free radical arylation, 2, 295 Friedel-Crafts reactions, 2, 208 Friedlander synthesis, 2, 70, 443 fluorination, 2, 199 halogenation, 2, 40 hydrogenation, 2, 45, 284-285, 327 hydrogen-deuterium exchange, 2, 196, 286 hydroxylation, 2, 325 iodination, 2, 202, 320 ionization constants, 2, 172 IR spectra, 2, 18 lithiation, 2, 267... 

Quinolinium 2-dicyanomethylene-1,1,3,3-tetracyanopropanediide dimensions, 2, 110 Quinolinium iodide, 1-alkyl-Ladenburg rearrangement, 2, 300 Quinolinium iodide, 1-methyl-Ladenburg rearrangement, 2, 300, 335 Quinolinium iodide, [l-methyl-4-[3(5)-pyrazolyl]-blood sugar level and, 5, 291 Quinolinium perchlorate, 1-ethoxy-hydroxymethylation, 2, 300 Quinolinium perchlorate, 1-methyl-nitration, 2, 318 Quinolinium salts alkylation, 2, 293 Beyer synthesis, 2, 474 electrophilic substitution, 2, 317 free radical alkylation, 2, 45 nitration, 2, 188 reactions... 

Goldschmidt and Minsinger " isolated some of the products formed during the decomposition of several diacyl peroxides in pyridine (Table IV). The yields obtained are so far the highest reported for any free-radical alkylation. 

The development of the autoxidation theory, in which the propagating radicals, alkyl, and alkylperoxyl (R ROO ), and the hydroperoxide (ROOH) are the key intermediates, has therefore led to a comprehensive theory of antioxidant action Scheme 2 shows the two major... 

In this section wc consider the properties and reactions of three classes of carbon-centered radicals alkyl radicals (3.4. l.l), aryl radicals (3.4.1,2) and acyl radicals (3.4.1.3). 

FREE-RADICAL ALKYLATION OF QUINONES 2-PHENOXYMETHYL-l,4-BENZOQUINONE... 

The reaction is a free-radical alkylation in which radicals are derived from a carboxylic acid by decarboxylation with Ag+/S20a-. If has the advantage that the reaction medium can be adjusted so that the monoalkylatcd product precipitates as it is formed, whereby di- or polyalkylation5 is suppressed. 

The radical alkylation of ketones is achieved by their conversion into the desired N-silyloxy enamines 81 (Scheme 13). The reaction of 81 with diethyl bromomalonate in the presence of EtsB (0.5 equiv) in benzene was performed in open air and stirred at room temperature for 3h. With nitro compounds it is achieved by their conversion into the desired ]V-bis(silyloxy)enamines (82) (Scheme 13). When the reaction is carried out with 82 and alkyl iodides with an electron-withdrawing substituent at the a-position, using V-70 as radical initiator (2,2 -azobis(4-methoxy-2,4-dimethylvaleronitrile)), it underwent a clean radical alkylation reaction to yield an oxime ether. Successful radical alkylation of... 

Even more pronounced steric effects have been observed for the free radical alkylation of protonated N-heterocyclic bases by the procedure of Minisci69, b d. Quinoline is attacked selectively in the 2- and 4-position by nucleophilic alkyl radicals in sulfuric acid. The largest radicals, t.-butyl, react exclusively in the 2-position because of steric hindrance by the peri-hydrogen when attack occurs at the 4-position. 

A Sml2-induced reductive cyclization of (V-(alkylketo)pyrroles provided an entry into medium ring 1,2-annelated pyrroles <06EJO4989>. An oxidative radical alkylation of pyrroles with xanthates promoted by triethylborane provided access to a-(pyrrol-2-yl)carboxylic acid derivatives <06TL2517>. An oxidative coupling of pyrroles promoted by a hypervalent iodine(III) reagent provided bipyrroles directly <060L2007>. 

Methyl-l,2,4-triazole 37 undergoes radical alkylation to give monoalkylated 1-methyl-1,2,-4-triazoles 48a-e in which the new substituent is in the 5-position no addition products resulting from alkylation in the 3-position were observed (Equation 14 and Table 3) <2001TL7353>. 

Evidently, the activation energy for a thermally neutral reaction with participation of a hydrogen atom or a radical (alkyl, alkoxyl, etc.) is higher in these cases where there is a iT-bond or an aromatic ring adjacent to the attacked C—H bond. This effect is a property of the structures themselves, and the n-bond exerts a dual effect on the reaction center. On the one hand, by weakening the C—H bond the ir-bond in the a-position lowers the enthalpy... 

A. Behavior of BENA in Radical Reactions Until recently, data on the behavior of BENAs in radical reactions have been lacking in the literature. However, several successive approaches to radical alkylation of BENA at the (3-C atom have been recently developed by Korean researchers (527). 

It was demonstrated (527) that radical alkylation of BENAs can be performed in the absence of totic organotin compounds (Scheme 3.259). 

A typical atom transfer sensitization process is shown in Figure 3.7 the alkylation of an unsaturated acid via a radical produced from an alcohol by hydrogen abstraction (in a green solvent, water). This principle has been applied to a large series of radical alkylation reactions, where the radical precursor is an alcohol, an ether, or even an alkane. ... 

More recently, Kim and coworkers have developed a novel radical alkylation reaction of organic nitro derivatives 16a-d via bis(silyloxy)enamines 17a-d (Scheme 16). This method enables not only P -alkylation to the nitro gronp, bnt also the conversion of the nitro group (16a-d) into an oxime ether fnnctionahty (18a-d). The irradiation of a solntion of 16a-d with iodomethyl phenyl snlfone (or ethyl iodoacetate) and hexamethylditin in benzene at 300 nm give the oxime ethers 18a-d in good yields. 

Even more pronounced steric effects have been observed for the free radical alkylation of protonated N-heterocyclic bases by the procedure of Minisci ... 

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