2-Methyl-1, 2, 3, 4-Tetrahydronaphthalene

Hydrogenation of l-methvlnaphthalene The main product resulted from hydrogenation of the unsubstituted ring to give 2-methyl - 5,6,7,8-tetrahydronaphthalene whose content at 30.6 wt % was over twice that of 2-methyl - 1,2,3,4-tetrahydronaphthalene (14.8 wt %) resulting fiom hydrogenation of the methyl-substituted ring. The next major product at 10.7... 

Georges Darzens (at the Ecole Polytechnique in Paris, France) in 1926 described the conversion of 2-benzylpent-4-enoic acid 3 into 4-methyl-tetrahydronaphthalene-2-carboxylic acid 4 that has proceeded under the influence of concentrated sulfuric acid. Subsequent dehydrogenation and decarboxylation yielded a naphthalene derivative. This work was followed by a series of extended reports. The outcome of Darzens et al. (Levy, Heinz) sequence of works in this area has been reviewed. ... 

Tetrahydronaphthalene [119-64-2] (Tetralin) is a water-white Hquid that is insoluble in water, slightly soluble in methyl alcohol, and completely soluble in other monohydric alcohols, ethyl ether, and most other organic solvents. It is a powerhil solvent for oils, resins, waxes, mbber, asphalt, and aromatic hydrocarbons, eg, naphthalene and anthracene. Its high flash point and low vapor pressure make it usehil in the manufacture of paints, lacquers, and varnishes for cleaning printing ink from rollers and type in the manufacture of shoe creams and floor waxes as a solvent in the textile industry and for the removal of naphthalene deposits in gas-distribution systems (25). The commercial product typically has a tetrahydronaphthalene content of >97 wt%, with some decahydronaphthalene and naphthalene as the principal impurities. 

The first quantitative study of the reaction of 4-methyl-l-(methylsulfinyl)benzene with benzaldehyde or 1,2,3,4-tetrahydronaphthalen-l-one showed that these additions proceeded with very low diastereoselectivity5. 

FIGURE 1. ORD spectrum of (+)-irans-9-methyl-l,4,9,10-tetrahydronaphthalene, (dots). The two lines are computational results with (dashed) or without (continuous line) correction for the solvent refractive index. Reprinted with permission from Reference 9. Copyright 1961 American Chemical Society... 

Reaction of 299 with benzaldehyde was found to give an equimolar mixture of diastereomeric j3-hydroxysulfoxides (314). Addition of 299 to a-tetralone 300 was more satisfactory, since the corresponding diastereomeric/3-hydroxysulfoxides 301 were formed in a 1.8 1 ratio. Their subsequent desulfuration with Raney nickel yielded levorota-tory 1-hydroxy-1-methyl-1,2,3,4-tetrahydronaphthalene 302 of unknown absolute configuration and optical purity. Similarly, addition of 299 to cyclohexene oxide leads to the formation of diastereomeric /3-hydroxysulfoxides 303 in a 2 1 ratio which, after separation, may be desulfurized to give (R,R)- and (S,S)- trans-2-methylcyclo-hexanols 304, respectively. Analysis of NMR spectra of the... 

In another paper from the Jackson Laboratories of the du Pont Company (Calcott et al., 34) there is reported a repetition of some of the reactions of Simons and Archer, as well as additional ones. Mono-, di-, and 1,2,4,5 tetraisopropylbenzene were obtained from propylene and benzene both l -chloro-i-butylbenzene and di-(l/-chloro)-d-butylben-zene were obtained from 3-chloro-2-methyl-propene-l and benzene p-f-butyltoluene and di-i-butyltoluene were obtained from diisobutylene and toluene tetraisopropylnaphthalene was obtained from propylene and naphthalene naphthyl-stearic acid was obtained from oleic acid and naphthalene mixed isopropyltetrahydronaphthalene was obtained from propylene and tetrahydronaphthalene 2,4,6-triisopropylphenol was obtained from propylene and phenol a mixture of monoisopropylated m-cresols was obtained from propylene and wi-cresol and di-(s-hexyl)-diphenyl oxide was obtained from hexene-3 and diphenyl oxide. 

The conversion of methyl ( ra is-2-iodo-l-tetralin)carbamate to l,2,3,4-tetrahydronaphthalene(l,2)imine is described in Organic Syntheses.1... 

Methoxy-7-methoxycarbonyl-1,2,3,4-tetrahydronaphthalene 2-Naphthalene-carboxylic acid, 5,6,7,8-tetrahydro-3-methoxy-, methyl ester (78112-34-2), 65, 98 Methyl acrylate (96-33-3), 66, 54, 59 dimerization by Pd(II), 66, 52 Methylamine, N-benzylidene-, 65, 140 METHYL 4-0-BENZOYL-6-BROMO-6-DEOXY-a-0-GLUCOPYRANOSIDE ... 

On gradual heating to 300 C with four equivalents of antimony(V) fluoride and simultaneous distillation of the reaction product, octafluoronaphthalene is transformed to perfluoro-1,2.3,4-tetrahydronaphthalene in 77% yield.94 Under similar conditions 2-substituted hepta-fluoronaphthalenes(R = H, Cl) give a mixture of octafluoronaphthalene and the corresponding 6-substituted undecafluoro-1,2,3,4-tetrahydronaphthalenes in about 40 % yield while the major fluorination product of the compound with R = CF3 is perfluoro(6-methyl-1,2,3,4-tetrahydro-naphthalene) (50%).97... 

The starting materials required for preparing the 2,3-disubstituted tetrahydronaphthalenes were 5,6,7,8-tetrahydro-2-naphthol (obtainable from tetrahydronaphthalene) and methyl 3-hydroxy-2-naphthoate, which was reduced to the known tetrahydro ester (Vc) and the latter saponified to the known tetrahydroacid. 

Many aromatic hydrocarbons, for example, benzene, ethylbenzene, toluene, cymene and tetrahydronaphthalene, yield additive compounds.5 Such are also formed with liquid cyclic hydrocarbons in the absence of moisture and phenols, and use has been made of this fact to remove sulphur dioxide from a dry gas containing it.6 Additive compounds are also formed with methyl alcohol, thus CH30H.S02 and 2CH30H.S02, the existence of which has been demonstrated definitely by means of the freezing-point curve.7 The additive compound with camphor has already been mentioned (p. 109). 

The a-pyrone adduct (430) on heating gave benzo[c]furan, isolated in 30% yield. Pyrolysis of l,4-oxido-l,2,3,4-tetrahydronaphthalene (431) at 650 °C and 0.1 Torr results in quantitative formation of benzo[c]furan. 1-Methyl-, 1,3-dimethyl-and l-benzyl-benzo[c]furanshave been prepared in quantitative yield by the flash pyrolysis technique (76TL2507). 

Polyketide synthesis. Polyketides (2) are obtained on reaction of the sodium lithium dianion (1) of methyl acetoacetate with dimethyl glutarates. When refluxed with Ca(OAc)2 in CH3OH, 2 cyclizes to l-oxo-l,2,3,4-tetrahydronaphthalenes in 30-75% yield.1... 

Cyclohexadienol was prepared by Rickborn in 1970 from reaction of the epoxide of 1,4-cyclohexadiene with methyl lithium.100 A hydrate of naphthalene, 1-hydroxy-1,2-dihydro-naphthalene was prepared by Bamberger in 1895 by allylic bromination of O-acylated tetralol (1-hydroxy-l,2,3,4-tetrahydronaphthalene) followed by reaction with base.101 Hydrates of naphthalene and other polycylic aromatics are also available from oxidative fermentation of dihydroaromatic molecules, which occurs particularly efficiently with a mutant strain (UV4) of Pseudomonas putida.102,103 The hydrates are alcohols and they undergo acid-catalyzed dehydration to form the aromatic molecule by the same mechanism as other alcohols, except that the thermodynamic driving force provided by the aromatic product makes deprotonation of the carbocation (arenonium ion) a fast reaction, so that in contrast to simple alcohols, formation of the carbocation is rate-determining (Scheme 6).104,105... 

Furniture polish (spray) Branched alkanes, cycloalkanes, 8 l-butanol-3-methyl-acetate, tetrahydronaphthalene... 

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