Naphthyl derivatives reactions

Polyphosphoric acid is a commonly used catalyst for this reaction however, in some cases a mixture of hydrogen bromide/acetic acid gives better results. Acylation of the S-phenyl-, V-(4-tolyl)- or S-(l-naphthyl)-substituted thiobenzenepyruvic acids 3a-c affords the corresponding dibenzo[A,/]thiepins in satisfactory yields, while reaction of the S-(4-methoxyphenyl) or S-(2-naphthyl) derivatives fails to provide any thiepin.60 The intramolecular Friedel-Crafts acylation of 2-(arylsulfanyl)benzeneacetic acids also yields the corrresponding dibenzothiepins in this case the use of hydrogen fluoride sometimes results in purer products.38 The applicability of this method is restricted to the synthesis of stable bisannulated thiepins. 

On heating with sodium acetate and acetic anhydride under nitrogen, berberine (15) gave the naphthyl derivatives 61 and 62. The reaction proceeds as indicated in Scheme 15. Similar treatment of dehydroprotoberberine (54) gave the aromatized naphthylisoquinoline 63 owing to the presence of the additional double bond in ring B (52,53). 

Addition of triethylamine to the oxazaborolidine reaction system can significantly increase the enantioselectivity, especially in dialkyl ketone reductions.79 In 1987, Corey et al.80 reported that the diphenyl derivatives of 79a afford excellent enantioselectivity (>95%) in the asymmetric catalytic reduction of various ketones. This oxazaborolidine-type catalyst was named the CBS system based on the authors names (Corey, Bakshi, and Shibata). Soon after, Corey s group81 reported that another fi-methyl oxazaborolidine 79b (Fig. 6-6) was easier to prepare and to handle. The enantioselectivity of the 79b-catalyzed reaction is comparable with that of the reaction mediated by 79a (Scheme 6-36).81 The -naphthyl derivative 82 also affords high enantioselectivity.78 As a general procedure, oxazaborolidine catalysts may be used in 5-10 mol%... 

Condensation of the alkoxynaphthyldihydrooxazoles with 2-methoxy-l-naphthyllithium, prepared by bromine-lithium exchange, did not lead to the same product as the corresponding reactions with the magnesium compound, but, unexpectedly, to a rearranged isomeric 1 -bi-naphthyl derivative with high enantiomeric excess28. 

Simultaneous use of the Fricdcl-Craft catalytic properties of anhydrous hydrogen fluoride and its fluorinating activity in Cl-F replacement reactions has been utilized in the synthesis of numerous trifluoromethyl aromatics (phenyl, biphenyl, and naphthyl derivatives).246 247 The process is based on the action of carbon tetrachloride/hydrogen fluoride (excess) on aromatics, for example, formation of 16,246 17,246 18 and 19.246... 

Methyl- or 2-ethyl-benzo[Z> ]thiophenes are conveniently prepared by treatment of 2-benzo[6]thienyllithium with the appropriate alkyl sulfate <70AHC(11)177). Clemmensen or Wolff-Kishner reductions of the 2-acylbenzo[Z>]thiophenes are useful, but since acylation produces a mixture of the 2- and 3-acyl isomers (Section 3.14.2.4), these must be separated. Cyclization of phenyl phenacyl sulfide with hydrofluoric acid leads exclusively to 2-phenyl-benzo[6]thiophene, and 3-phenylbenzo[6]thiophene can be rearranged to the 2-isomer in hydrofluoric acid (Section 3.15.2.3.2). Aromatization of 2-cycIohexenylbenzo[6]thiophene, obtained by condensation of the 2-lithio reagent with cyclohexanone, gives 2-phenyl-benzo[6]thiophene, and the reaction is adaptable to the 2-(l-naphthyl) derivative also. 

The 2-aminophenoxy triazine (50) readily undergoes the Smiles rearrangement in base (equation 23) (70JHC981), or photochemically (70TL1467). Budziarek reported a similar reaction with the naphthyl derivative (51 Scheme 37) (7lJCS(C)74>. 

In fact, the reaction proceeded as expected [23]. Thus, by heating the l-[o-(l-alkynyl)phenyl]cyclopropanol complexes 36-Co2(CO)6 in refluxing 2-propanol, 2,3-dihydro-1-naphthalenone derivatives 37 are obtained as a mixture of (Aland (Z)-isomers in moderate yield accompanied by a substantial amount of an ethyl ketone derivative formed by ring opening of the cyclopropanol moiety. Furthermore, when an analogous naphthyl derivative 38 was employed, the reaction proceeded cleanly and the 2,3-dihydrophenanthren-l-one derivative 39 was obtained in 83 % yield (Scheme 17). The obvious difference in reactivity between phenyl and naphthyl derivatives is probably due to the presence of hydrogen at the peri position of the latter. To avoid steric repulsion between the alkyne-Co2(CO)6 moiety and this hydrogen, the molecule adopts a conforma-... 

The 1- and 2-naphthoxide ions also reacted with z -bromobenzonitrile261, p-iodoanisole262 and 1- and 2-iodo- substituted naphthalenes262,263. In the reaction of 1-naph-thoxide ions a mixture of 2- and 4-monosubstituted naphthyl derivates (192 and 193, respectively) together with the 2,4-disubstituted compounds 194 were observed (equation 139). Thus,/7-bromobenzonitrile, 1-iodo- and 2-iodonaphthalenes gave 192 (25%, 22%, <1%), 193 (40%, 36%, 37%) and 194 (<1%, 20%, 15%), respectively. 

The radical nucleophilic substitution is perfectly suited for tandem reactions [180]. Recent examples have been reported by the Rossi group (Scheme 66). Dihydrobenzofuranes and dihydroindoles substituted at the 3-position were prepared from ortho-functionalized haloaromatic compounds in high yields [181]. The nucleophiles involved in the initial electron transfer and subsequent coupling are varied. In particular, starting form naphthyl derivative 210, phosphinyl anions lead to tricyclic phosphine oxide 211 (after oxidation) in 98% yield. 

Naphthalene (49) reacts with sodium in liquid ammonia to form a red complex which is quenched by methanol to form the 1,4-dihydro derivative (51), and may therefore be assumed to be the dianion (50).- If alcohol is present in the reaction mixture, then the 1,4,5,8-tetrahydro derivative (52) is formed (Scheme 6). 1-Naphthyl derivatives are reduced in the unsubstituted ring, whereas there is a maiked preference for reduction of the substituted ring in 2-methyl- and 2-methoxy-substituted isomers. This preference is not as well defined for bulkier substituents, however, and is reversed in the case of 2-f-butylnaphthalene further details are in a 1970 review. Because of the facile isomerization of the 1,4-dihydro isomers to conjugated derivatives, overreduction occurs readily and ether groups are fairly readily hydrogenolyzed. It is therefore important to select the reaction conditions with care.- ... 

The following isomers are represented 2H, 4H and 3H, 4H. A benzo-1,2-thiazete 447 has been proposed as an intermediate in the reaction of phenyl nitrene (triplet) with the thiazo derivative 446 a sulfurane structure 448 was suggested for one product of the reaction of perfluoropropyliminosulfur difluoride with per-fluoropropene. Stable benzo- and naphthyl-l,2-thiazetyl radicals (e.g., 452) are obtained by thermolysis of 5-amino compounds 449, 450, and 451. Electron-spin resonance studies established the structures. The magnitude of the spin density on nitrogen in derivatives of 452, which carry a substituent para to the nitrogen atom, depends on the nature of the substituent. Loss of sulfur from the naphthyl derivative 453 occurs at temperatures above 150°C. ... 

In 2010, Rueping s group reported the first enantioselective approach toward the synthesis of 4-substituted-4,5-dihydro-l//-[l,5]benzodiazepin-2(3//)-ones, which resemble cyclic (3-amino acids [65]. Due to the basic nature of these benzodiaze-pinones, the reactions conducted with various chiral phosphoric acid diesters gave only very low conversion, while improved reactivity was obtained when the corresponding Wtriflyl phosphoramides were employed as catalysts, with 2-naphthyl derivative selected as the best-performing one. Microwave irradiation proved to be beneficial to further improve the yields, and the reduction, followed by subsequent... 

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