1,1-Dimethyl tetralin

The sole precursor of 1,4-dimethyltetralin should be largely in the axial-methyl conformation because of the peri interaction. Accordingly, the product is largely cis. Conversely, the sole precursor of 2,3-dimethyl-tetralin does not have a peri interaction and the product is mostly trans. 

Data for the 1,6-dimethyldecalins are in Table XXXII. The best available sample of 1,6-dimethylnaphthalene contained a few percent of 1,7-dimethylnaphthalene as impurity. Hydrogenation on palladium yielded nearly equal amounts of the isomeric 1,6- and 2,8-dimethyl-tetralins. Retention times were shifted enough (see Fig. 18) so that the separated tetralin isomers contained reduced amounts of the 1,7-impurities. 

The following liquids may be used (boiling points are given in parentheses) — chlorobenzene (132-3°) bromobenzene (155°) p-cymene (176°) o-dichloro-benzene (180°) aniline (184°) methyl benzoate (200°) tetralin (207°) ethyl benzoate (212°) 1 2 4-trichlorobenzene (213°) isopropyl benzoate (218°) methyl salicylate (223°) n-propyl benzoate (231°) diethyleneglycol (244°) -butyl benzoate (250°) diphenyl (255°) diphenyl ether (259°) dimethyl phthalate (282°) diethyl phthalate (296°) diphenylamine (302°) benzophenone (305)° benzyl benzoate (316°). 

The linear co-oxidation dependence was observed for the following pairs of hydrocarbons (333 K, initiator AIBN) tetralin-ethylbenzene, phenylcyclopentane-ethylbenzene, phenyl-cyclohexane-ethylbenzene, tetralin-phenylcyclohexane, cyclohexene-2-butene, 2,3-dimethyl, and cyclohexene-pinane [8]. 

In this paper, we report a study of the photocatalytic oxidation in the neat-liquid phase and at room temperature of various model hydrocarbons containing one or two C6 rings (cyclohexane, methyl- and dimethyl-cyclohexane, cyclohexene, decalin and tetralin) over TiC>2 to further investigate the possibilities of heterogeneous photocatalysis in the field of fine chemicals. Bibliographic investigations gave no references on the photocatalytic oxidation of the various hydrocarbons cited above, except for cyclohexane (refs 6 - 8) with which wa have initiated the study of liquid cycloalkanes (ref. 9). 

The occurrence of musk fragrances (polycyclic musks in particular) in room air samples and house dust from 59 apartments and 74 kindergartens in Berlin in 2000 and 2001 was reported by Fromme et al. (2004a). Results are reviewed in Table 11.2. Musk compounds most often detected in the indoor air and dust were HHCB [1.3.4.6.7.8-hexahydro-4.6.6.7.8.8- hexamethylcyclopenta-(g) 2-benzopyrane, Galaxolide , Abbalide , Pearlide ], AHTN [7-acetyl-1.1.3.4.4.6-hexa-methyl-tetraline, Tonalide , Fixolide ] andmusk ketone (4-t-butyl-2.6-dimethyl-3.5-dinitroacetophenone). 

The ene hydrazine 100, prepared from dimedone and methylhydrazine, forms the Michael adduct 101 with dimethyl acetylenedicarboxylate. The adduct is converted into a mixture of pyrrole and pyridone derivatives, 103 and 104, in boiling tetralin. These products arise by a [3.3]sigmatropic shift in the adduct with cleavage of the nitrogen-nitrogen bond to give 102, followed by cyclization and elimination of ammonia and methanol, respectively (equation 42)63. 

Tetralin 2,2-Dimethyl-6,7-methylen-dioxy-3-oxo- E19a, 1011 [Cycli-sierung (rad.)]... 

Alkyl-2-phenylquinazolines 9 are readily available by reaction of 5,S -dimethyl-A-(A-aryl-benzimidoyl)sulfimides 7 with enamines 8 in refluxing Tetralin (1,2,3,4-tetrahydronaphthalene). The mechanism of quinazoline ring formation probably involves a thermal cleavage of the imidoylsulfimides into imidoyl nitrenes, nitrene addition to the enamine double bond and subsequent rearrangement of the aziridine intermediate thus formed to the final product 9. Small amounts (10-15%) of 4-unsubstituted quinazolines 10 are obtained as byproducts. The formation of these byproducts involves a known intramolecular rearrangement of the benz-imidoylsulfimides employed. ... 

The 1,3-diazines have also been prepared by a reaction of enamines and 5,5-dimethyl-A - A-arylbenzimidoyl)sulfimides 360 in boiling tetraline The mechanism of the ring formation probably involves a thermal cleavage of the imidoylsulfimides 360 into imidoylnitrenes 361 and dimethyl sulfide. The nitrene can then react with the enamine to give an aziridine intermediate 362 which rearranges to a 3,4-dihydroquinazoline 363. Subsequent elimination of amine yields the quinazoline 364 °. 

So far, the occurrence of seven polycyclic musks has been reported. Their chemical names, chemical structures and molecular formulae are described elsewhere (Rimkus, 1999). The structural feature of all polycyclic musks is an indane or tetraline skeleton, which is highly substituted mainly by methyl groups (Fig. 1). 7-Acetyl-l,l,3,4,4,6-hexamethyl-l,2,3,4-tetrahydronaphthalene (AHTN, trade name Tonalide) and 1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethylcyclopenta[g]-2-benzo-pyrane (HHCB, trade name Galaxolide) are the most abundant ones. In this study, also 4-acetyl-1,1 -dimethyl-6-fert-butylindane (ADBI, trade name Celestolide) and 6-acetyl-l,l,2,3,3,5-hexamethylindane (AHMI, AHDI, trade name Phantolide) are investigated (Fig. 1). Important physicochemical properties of these compounds, which determine their environmental distribution and transport (e.g. solubility), are presented in chapter 4.1.1, in Ricking et al. (2003) as well as in Simonich et al. (2000). 

Michael addition of 5-(2-alkyl-l-methylhydrazino)-2-phenylpyridazin-3(2//)-ones to dimethyl acetylenedicarboxylate produces 5- 2-alkyl-2-[l,2-bis(methoxycarbonyl)vinyl]-l-methylhydrazi-no -2-phenylpyridazin-3(2//)-ones, which cyclize on heating in Tetralin at 220 °C by a Diels -Reese reaction68 to give methyl 3-(alkylamino)-l-methyl-2,5-dioxo-6-phenyl-l,2,5,6-tetrahy-dropyrido[2,3-rf]pyridazine-4-carboxylates l.69... 

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