Aryl derivs diaryls

Oxadiazole itself shows no absorption above 200 nm, which is consistent with the results of MO calculations. Simple 2-alkyl and 2,5-dialkyl derivatives absorb slightly above 200 nm. In contrast, electronic absorption spectra of aryl and diaryl... 

The synthesis of quinazoline derivatives by the addition of N(3)-C(4) fragment units has not previously been a major synthetic route, but 2,4-dialkyl, alkyl/aryl, and diaryl quinazolines 865 are now readily available by a new procedure that involves activation of A -arylamides 864 with trifluoromethanesulfonic anhydride and 2-chloropyridine, and subsequent addition of nitriles <2006JA14254>. Either normal or microwave heating can be used to perform the final ring-closure step. 

Other nucleophiles than amines which have been employed in the reaction are malononitrile and cyanoacetic ester anions. Both of these anions undergo a preliminary reaction with the aryl halide to form the C-aryl derivatives before they attack the ir-allylpalladium intermediate, so that diarylated products are formed (equation 31).86 Phenylmalononitrile anion reacts with iodobenzene and butadiene to give the same product in 70% yield. 

Bisfdiorgano tellurium halide] oxides are the anhydrides of diorgano tellurium hydroxide halides. Aryl derivatives can be obtained by heating diaryl tellurium halide hydroxides to 150-180°3... 

A variety of heterocyclic systems afforded the iV-aryl derivatives. 120,129-132 fyne intermediates were sometimes involved. Indeed, the reaction of the sodium anion of 5-phenyltetrazole (37) with di-/7-tolyliodonium bromide gave the two 1,5- and 3,5-diarylated derivatives as mixtures of meta- and para-io y regioisomers in a 1 1 ratio. 29... 

In the case of compounds bearing two a-hydrogen atoms, the mono- or the di-arylated derivatives can be selectively prepared by using 1.1 or 2.2 equivalents of the aryllead triacetate. This is in contrast with p-dicarbonyl compounds for which the diaryl derivatives were preferentially obtained. 

Simple tetraalkyl 2/7-imidazoles show a peak near 1575 cm (C=N stretch), while a characteristic band between 1600-1620 cm has been identified with aryl derivatives. In a series of 2,2-diaryl 1,3-dioxides the Vc=N and Vn o bands lie in the ranges 1560-1619 and 1120-1180 cm" respectively... 

Numerous l,3,4-oxadiazin-5(6//)-ones can be prepared by this type of cyclization. Examples arc 2-(l-ethyl-l-hydroxypropyl)-4-phenyl-4//-l,3,4-oxadiazin-5(6//)-one (6),40 4-phenyl-2-(4-tolyl)-4//-1,3,4-oxadiazin-5(6//)-one (7) (which is claimed to be useful as a miticide and nerna-tocide),41 4-cyanomethyl-, 4-(2-cyanoethyl)-, 4-(3-cyanopropyl)- and 4-(4-cyanobutyl)-6-methyl-2-phenyl-4//-l,3,4-oxadiazin-5(6//)-onc (8, n = 1, 2, 3 and 4, respectively) (which inhibit monoamine oxidase Type A and Type B),42 various 2,4-diaryl-4//-l,3,4-oxadiazin-5(6//)-ones 9 (which possess acaricidal activity),43 cardiotonic 2-aryl derivatives 10,44 and some heteroaryl-substituted compounds, such as 2-[4-(imida/.ol-l-yl)phenyl]-4f/-l,3,4-oxadiazin-5(6//)-one (11) (which is claimed to be cardiotonic and antihypertensive)45 and 2-(2-methylimidazo[l,2-a]pyridin-3-yl)-4//-l,3,4-oxadiazin-5(6//)-one (12) (which inhibits blood platelet aggrega-... 

The photoinduced anti-Markovnikov addition of methanol to 1,1-diphenylethene reported by Arnold and co-workers in 1973 provides the first example of the addition of a nucleophile to an arylalkene radical cation. There are now a number of studies that demonstrate the generality of nucleophilic addition of alcohols, amines, and anions such as cyanide to aryl- and diaryl-alkene radical cations. Product studies and mechanistic work have established that addition occurs at the 3-position of I-aryl or 1,1 -diarylalkene radical cations to give arylmethyl or diaryl-methyl radical-derived products as shown in Scheme I for the addition of methanol to 1,1-diphenylethene. For neutral nucleophiles, such as alcohols and amines, radical formation requires prior deprotonation of the 1,3-distonic radical cation formed in the initial addition reaction. The final product usually results from reduction of the radical by the sensitizer radical anion to give an anion that is then protonated, although other radical... 

Silver(I) carbonate was the best choice for oxidant, outperforming AgOAc. Pivalic acid was utilized as an additive. Different arenes could be employed, providing separable mixtures of arylated and diarylated products. The resulting products were converted to phenanthroline derivatives and tested in transition metal-free direct arylation and Mizoroki-Heck reactions. 

It is noteworthy that these monoaiylated products with a free ortho C-H bond adjacent to the functional group could be arylated with a different aiyl or heteroar-ylchloride using Ru(OAc)2(p-cymene) or Ru(OPiv)2(p-cymene) in water leading to unsymmetrically diarylated trifunctional (hetero)aryl derivatives in 70-83% isolated yields (Scheme 6) [89]. 

A -nitrosamines have been divided into two classes (Wang et al. 2002), as shown in Fig. 20.4 Class I includes diaUcyl, alkyl aryl, and diaryl derivatives, and Class II includes the A -nitrosamines, IV-nitrosoureas, IV-nitrosocarbamates, A -nitrosoguanidines, and A -acyl-A -nitroso compounds. Class II nitrosamines act as frani -nitrosating agents toward thiol nucleophiles, readily yielding nitrosothiols (Oh and Williams 1989). A -nitrosamines are potential NO-/NO donors via cleavage of the N—NO bond, N-aryl-N-nitrosamines being viewed as more prone to release of NO. 

We may now inquire into the reason for the difference between the behavior of carbonium ions and ammonium or oxonium ions assuming, as is reasonable (87), that the difference in activity coefficient ratios does not reside in the free bases. An attractive explanation may be advanced at once that the carbonium ions derived from aryl carbinols or olefins involve a much greater degree of charge delocalization than that in the onium ions and this should have a profound effect on how tightly the ion is solvated. At least three facts eliminate the de-localization theory. Firstly, the small NO+ ion, in which delocalization is restricted, has activity coefficient behavior like a polyaryl carbonium ion (82). Secondly, aryl and diaryl ketones behave for the most part as proper Hammett bases (324,328) although considerable delocalization occurs in their ions. Thirdly, the same acidity function seems to apply equally well to pyrrole bases whether or not they have much charge delocalization in their ions (357). 

Carbon-sulfur bonds can be formed by the reaction of elemental sulfur with a lithio derivative, as illustrated by the preparation of thiophene-2-thiol (201) (700S(50)104). If dialkyl or diaryl disulfides are used as reagents to introduce sulfur, then alkyl or aryl sulfides are formed sulfinic acids are available by reaction of lithium derivatives with sulfur dioxide. 

The reaction has been extended to indazole (67BSF2619) from which both isomers have been obtained, and to pyrazolones (68BSF5019). In the latter system N-, O- and C-aryl and even diaryl derivatives have been isolated from the reaction with l-fluoro-2,4-dinitrobenzene. 

Diacyl-3,4-dihydroxythiophenes have been formulated as dienol tautomers (77T191). The same holds for 2,5-diaryl- and 5-aryl-2-carboxy derivatives (91JHC1449). ESR investigations of 6-halogeno-benzo[h] thiophene-2,3-semidiones (Scheme 13) have been reported (81JOC751). 

Reduction of 3,5,5-tris-aryl-2(5// )-furanones 115 (R, R, R = aryl) with dimethyl sulfide-borane led to the formation of the 2,5-dihydrofurans 116 in high yields. However, in the case of 3,4-diaryl-2(5//)-furanones 115 (R, R = aryl R = H or r = H R, R = aryl), the reduction led to a complicated mixture of products of which only the diarylfurans 117 could be characterized (Scheme 36) (88S68). It was concluded that the smooth conversion of the tris-aryl-2(5//)-furanones to the corresponding furan derivatives with the dimethylsulfide-borane complex in high yields could be due to the presence of bulky aryl substituents which prevent addition reaction across the double bond (88S68). 

In Figure 13.2, the intensity of the ion at m/z 170 represents a molecular ion of an aromatic compound. The characteristic losses from the molecular ion (M - 1, M - 28, and M - 29) suggest an aromatic aldehyde, phenol, or aryl ether. The molecular formula of Ci2H 0O is suggested by the molecular ion at m/z 170, which can be either a biphenyl ether or a phenylphenol. The simplest test to confirm the structure is to prepare a TMS derivative, even though m/z 11 strongly indicates the diaryl ether. 

Sulfones are thermally very stable compounds, diaryl derivatives being more stable than alkyl aryl sulfones which, in turn, are more stable than dialkyl sulfones allyl and benzyl substituents facilitate the homolysis by lowering the C—S bond dissociation energy17. Arylazo aryl sulfones, on heating in neutral or weakly basic media at 100°C, yield an aryl and arenesulfonyl radical pair via a reversible one-bond fission followed by dediazoni-ation of the aryldiazenyl radical (see Scheme 2 below)20. However, photolysis provides a relatively easy method for generating sulfonyl radicals from compounds containing the S02 moiety. 

Aryl- und 1,3-Diaryl-aceton-oxime, Aryl-acetaldoxime, ungesattigte Oxime mit kon-jugierter C=C-Doppelbindung und deren O-Alkyl- und O-Acyl-Derivate sowie 3-Phe-... 

In contrast, when excess amounts of the HHTs derived from simple aliphatic glycinate esters, such as 25, were used in excess in reactions with diaryl phosphites (SO), the related glyphosate aminals containing aryl phosphonate esters 46 were isolated in low yield (5-15%). Like many aminals, these triesters 46 were acid-sensitive and were quantitatively converted to the corresponding triester strong acid salts 47 upon treatment with either HCl or methanesulf onic acid (27). 

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