A-naphthylmethyl groups

The fact that the naphthyl carbonyl compounds attain a ir,ir triplet is somewhat analogous to the quenching of the benzophenone n,n triplet by added naphthalene (Table II), and is consistent with the triplet energy levels (benzophenone 69 kcal mole-1 naphthalene 60 kcal mole-1). This intramolecular energy transfer takes place even if the naphthalene is insulated from the benzophenone by a methylene group, since 4-(l -naphthylmethyl) benzophenone 24 emits from the naphthalene moiety when irradiated in the carbonyl n-> tt region.82 The photochemical reactivity of this ketone has not been reported. 

In 1992, Legros and Fiaud found palladium-catalyzed benzyiic alkylation of naphthylmethyl and 1-naphthylethyl esters 103 with sodium dimethyl malonate 104 in dimethylformamide (DMF) to give the corresponding benzyiic alkylated products 105 in high yields (Equation (41)). " When trifluoroacetyl group is used as a leaving group of the ester partner, catalytic alkylation proceeds quite smoothly even at room temperature. In this reaction system, no reaction occurs with benzyiic acetates. 

Pyran decomposes in contact with moist air or adds but its tetrasubstituted derivatives, e.g. (155), are stable and are usefully converted into naphthalenes (156) by treatment with perchloric acid. A 4-benzyl or 4-naphthylmethyl substituent is essential. Pyran ring opening occurs and is followed by cyclization and elimination of a simple ketone which is formed from the 2- or 6-substituent. Alkyl groups at C-2 or C-6 are converted into the ketone more easily than a phenyl group (64LA(678)202). 

Benzimidazoles, too, are readily alkylated either in neutral or basic medium. As with the uncondensed compounds, the former conditions are complicated by salt formation, but to a lesser extent since benzimidazoles are less basic. It is often valuable to vary the initial amounts of alkali and alkyl halide in order to improve yields. The best yields of 1-alkylbenzimidazole (76-83% for primary and 50-60% for secondary alkyl and aralkyl bromides) result with two moles of bromide and 1.5 moles of alkali per mole of benzimidazole (66RCRI22). There is severe steric hindrance to the alkylation of 2-arylben-zimidazoles in alkaline medium, but reactions with the silver salts seem more successful. The rapid and almost quantitative reaction between a benzimidazole and dimethylphenyl-alkylammonium chlorides in aqueous sodium hydroxide provides a very convenient method of introducing a primary aralkyl group (benzyl, a-naphthylmethyl). There has been little systematic study of the dkylation of unsymmetrical benzimidazoles, though much the same criteria should apply as in the uncondensed compounds. In this respect the observation that 1-bromopropane reacts with the anion of 2,6-dimethyl-4-nitrobenzimidazole to give... 

Heptakis 6-0-t-butyldimethylsilyl-P-cyclodextrin, on reaction with 4-chloro-methyl-A -methyl-2-nitroaniline, affords the mono-3-substituted benzyl ether. P-Cyclodextrin carrying a 2-(naphthylmethyl) group at 0-6 exists with the aromatic rings within the cavity to an extent which is very temperature dependent. Temperature can therefore be used to control the degree of complexing of the aromatic system with a fluorescent naphthalene compound. Heptakis-[2,3-di-0-acetyl-6-deoxy-6-iodo]-P-cyclodextrin treated with 6-methoxycarbonyl-2-naphthol allowed access to the compound having naphthoic acid substituents at all of the primary positions, and this forms a very stable 1 1 complex with a merocyanine laser dye which is a mimic of the antenna function in photosynthesis and shows promise as a photochemical microreactor. Mono-[6-0-(8-qui-nolyl)]-P-cyclodextrin has been reported, and the stabilities of inclusion complexes with amino acid guests have been described. ... 

The photolysis of 5-naphthylmethyl-A/-p-tosylsulfimides 36 carried out using a high pressure mercury lamp with a Pyrex filter under nitrogen atmosphere for 2 h afforded the Stevens rearrangement product 37, dipyridal disulfide 38 and 39. The products 38 and 39 are formed by photolysis of 37 in a secondary photochemical step. The reaction of 36e did not proceed under similar conditions revealing that a naphthyl group is necessary in this reaction as a chromophore to accept photoirradiation and to initiate the photoreaction. 

Equation (4.94) can be used to predict quantitatively the effect of heteroatoms in different positions in a given system. One can, for example, predict from the distribution of formal charge in the a-naphthylmethyl anion (21) that heteroatoms should have a greater effect in the ring carrying the exo-cyclic group. Thus the methyl groups in 1-methylisoquinoline (22) and... 

Not only the copolymers of AMPS and DodMAm but also the copolymers of AMPS and a methactylamide A -substituted with cyclododecyl, adamantyl, or naphthylmethyl groups (Chart 3) form either a unimolecular flower-like or higher-order micelle (i.e., tertiary structure) depending on the hydrophobe content in die copolymer. An important feature for these copolymers is that such unimer micelles are formed even at hi polymer concentrations in water. Some of the requiate structures for polymers to form unimer micelles are (i) the hydrophobes should be sufficiently bulky, (ii) the sequence distribution of hydrophobic and electrolyte monomer units should be random, and (iii) the hydrophobes should be linked to the polymer main chain via amide spacer Ending (22). 

The n-BuLi-initiated AROP of monomers carrying two methyl groups at the Si-atom and bulky substituents in the third position (l,l-dimethyl-3-a-naphthyl-, l,l-dimethyl-3-a-naphthylmethyl-, and l,l-dimethyl-3-diphenylmethyl-1-silacyclobutanes) also proceeded very efficiently and easily [44]. 

The first case was discovered by Hans Dahn and U. Solms. " These authors had prepared A -9-fluorenyl-A -methyl-A -(l-naphthylmethyl)amine (343) by reduction of the naphthoyl precursor with lithium aluminum hydride in refluxing DEE. When the reaction was repeated in refluxing THF, W-methyl-A -9-[9-(l-napthylmethyl)fluorenyl]amine (344) was isolated after 16 h in 56% yield. This time the hy de had acted as a reducing agent and as a base at the same time, triggering a Stevens-like [l,2]-migration of the naphthylmethyl group to the unionized 9-fluorenyl position. The tertiary amine 343, the... 

All the above compounds yield excimer fluorescence when excited in room-temperature solution. However, because the rotational potential of the C—X bond and the nonbonded interactions of the substituents of the X atom differ from those of the C—C bond 126), the amount of excimer fluorescence from R(C—X—C)R differs from that of R(C—C—C)R. The heteroatom X can also influence the rotational state of the side groups R, as illustrated by the formation of the anti-photodimer in bis(l-naphthylmethyl)ether u2), but not in l,3-bis(l-naphthyl)propane 10). Finally, compounds having n 3 may exhibit excimer fluorescence, if the linkage contains one or more heteroatoms. For example, the—C—O—C—C— linkage in a,to-bis(2-naphthyl) compound allows excimer fluorescence to be observed in room-temperature solution39). 

Apart from lengthening the chain by one carbon atom, this reaction provides a compound with two readily modified functional groups. Many other halogen compounds offer a more complex picture. Radical-derived products are sometimes obtained, but in other cases a heterolytic mechanism must operate, for example to give a methyl ether when naphthylmethyl iodides are irradiated in methanol (5.651. 

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