Indane, 1-methyl

Figure 2.7 contains plots of repetitive injection GC/MS chromatographic peak areas (integrated total ion current) as a function of sample temperature for benzene and styrene as well as selected products representing alkyl aromatics (ethyl benzene), indanes (methyl indane) and indenes (indene) evolved from PS-catalyst samples. The plots show that benzene is by far the most abundant volatile product. All of the PS-catalyst samples produce alkyl benzenes and indanes, however samples containing HZSM-5 catalyst generate significantly lower relative yields of these products. 

Gumylphenol. -Cumylphenol (PGP) or 4-(1-methyl-l-phenylethyl)phenol is produced by the alkylation of phenol with a-methylstyrene under acid catalysis. a-Methylstyrene is a by-product from the production of phenol via the cumene oxidation process. The principal by-products from the production of 4-cumylphenol result from the dimerization and intramolecular alkylation of a-methylstyrene to yield substituted indanes. 4-Cumylphenol [599-64-4] is purified by either fractional distillation or crystallization from a suitable solvent. Purification by crystallization results in the easy separation of the substituted indanes from the product and yields a soHd material which is packaged in plastic or paper bags (20 kg net weight). Purification of 4-cumylphenol by fractional distillation yields a product which is almost totally free of any dicumylphenol. The molten product resulting from purification by distillation can be flaked to yield a soHd form however, the soHd form of 4-cumylphenol sinters severely over time. PGP is best stored and transported as a molten material. 

Hydrolysis of dimethyl 3-methyl-3//-3-benzazepine-2,4-dicarboxyiate (3) with 50% sulfuric acid, or with 20% hydrochloric acid, effects loss of the nitrogen function and formation of the indane-2-carboxylic acid 4.25... 

The acidity of benzylic protons of aromatics complexed to transition-metal groups was first disclosed by Trakanosky and Card with (indane)Cr(CO)3 [61]. Other cases are known with Cr(CO)3 [62], Mn(CO)3 [63], FeCp+ [64, 65], and Fe(arene)2+ [31, 66] but none reported the isolation of deprotonated methyl-substituted complexes. We found that deprotonation of the toluene complex gives an unstable red complex which could be characterized by 13C NMR ( Ch2 = 4.86 ppm vs TMS in CD5CD3) and alkylated by CH3I [58] Eq. (13) ... 

In l,3-Dioxo-2-(4-methyl-benzyliden)-indan werden die Oxo-Gruppen auch von ei-nem groBen Triathyl-siliciumhydrid-OberschuB nicht angegriffen9. 

Hydroxy-2-carboxyme-thyl-indan + l-Hydroxy-2-carboxy-methyl-ihdan-lacton 76 20 (F 139— 140°) (F 65-66°) 6... 

After reaction, any solid residue was filtered off and the liquid product was separated by distillation into a bottoms product and a distillate that included unreacted Tetralin and low-boiling products from both the coal and the Tetralin. As tetralin breaks down under dissolution conditions to form mainly the tetralin isomer 1-methyl indan, naphthalene and alkyl benzenes (4) it was assumed that no compound with a higher boiling point than naphthalene was formed from the solvent, and the distillation to recover solvent was therefore continued until naphthalene stopped subliming. Some residual naphthalene remained in the bottoms product its mass, as determined from nmr and elemental analysis, was subtracted from the mass of bottoms product recovered and included in the amount of distillate recovered. It was assumed that all naphthalene present came from the Tetralin, not the coal. However, as the amount of tetralin reacted was 10 times the amount of coal this assumption appears reasonable. 

Analysis Techniques. The contents of the major breakdown products of xetralin (naphthalene and 1-methyl indan) present in the distillate were determined by gas-liquid chromatography using a Hewlett Packard Series 5750 Research Chromatograph with a 62m x 0.5mm diameter glass capillary SCOT column coated with nonpolar SE 30 liquid phase (see Reference (4 ) for details). 

Tetralin has been shown to undergo thermal dehydrogenation to naphthalene and rearrangement to methyl indan in either the absence or presence of free radical acceptors [ 1, 2]. The presence of free radical acceptors usually accelerates the rearrangement reaction. Even with alkylated Tetralins>... 

The basic reactions of Tetralin and derivatives have been extended to the use of 1-13C labels and 1,2-dihydronaphthalene, with and without a source of free radicals. The studies with Tetralin were monitored equally well with C-NMR and GLC techniques. The rate constant for the conversion of Tatralin to methyl indan in the presence of dibenzyl at 450°C was 6.4 x 10 min i which is consistent with that previously reported [2]. 

The most significant observation by NMR is the redistribution of the label in the methyl indan isomer. 

Concentration of 2-methyl indan and 2- C-1-methyl indan were very low. 

Dihydronaphthalene (DHN) is frequently assumed to be an intermediate in hydrogen transfer reactions. While this appears reasonable, efforts to detect and/or measure this intermediate have never been very successful. Assuming that DHN is present, we have briefly explored its role in hydrogen transfer and methyl indan formation. 

DHN. Apparently DHN both thermally dehyrogenates to naphthalene and disproportionates to Tetralin and naphthalene. In all of the runs, there was a sizable amount of hydrogen released when the reactors were opened. When DHN was heated at 450°C for either 15 or 180 minutes, the ratio of naphthalene to etralin was 1.8. Increased methyl indan formation occurred with time. With the introduction of dibenzyl, the anticipated [2] increased isomerization of T etralin to methyl indan occurred. These results suggest that the rearrangement of hydroaromatics does not proceed through the dihydro-... 

Since the Tetralin studies showed that isomerization yielded predominantly the 1-methyl indan isomer and that the... 

Ring closure between an adjacent pair of aromatic substituents is also possible an example is the formation of indan from l-methyl-2-ethyl-benzene 11,109). In fact, Csicsery 109) found that the rate of cyclization of l-methyl-2-ethylbenzene to indan over platinum was somewhat faster than that of n-butylbenzene to methylindan, indicating that kinetically there is nothing to be gained by having ring closure at an aromatic carbon... 

Osborn, A.G., Scott, D.W. (1978) Vapor-pressure and enthalpy of vaporization of indan and five methyl-substituted indans. J. Chem. Thermdyn. 10, 619-628. 

However, one of the most common mechanisms is undoubtedly proton transfer but whereas in alkene polymerizations this reaction leaves a terminal double bond, in arylene polymerizations these are generally not found. Instead the terminal group is usually a substituted indane formed by an internal Friedel-Crafts alkylation [8, 21, 23], e.g., for a-methyl styrene ... 

K. Le Barbu Debus, F. Lahmani, A. Zehnacker Rentien, N. Guchhait, S. S. Panja, and T. Chakraborty, Fluorescence spectroscopy of jet cooled chiral (+/ ) indan 1 ol and its cluster with (+/ ) methyl and ethyl lactate. J. Chem. Phys. 125, 174305 (2006). 

FIGURE 9. MM2-85 calculated torsional potential surface for the two-angle driver of the side chain of (S)-4-hydroxy-2-[(dimethylamino)methyl]indan 70. Reproduced with permission from Reference 108... 

Fig. 9.8 presents another, more complex type of phosphate prodrugs, namely (phosphoryloxy)methyl carbonates and carbamates (9-26, X = O or NH, resp.) [84], Here, the [(phosphoryloxy)methyl]carbonyl carrier appears quite versatile and of potential interest to prepare prodrugs of alcohols, phenols, and amines. The cascade of reactions leading from prodrug to drug as shown in Fig. 9.8 involves three steps, namely ester hydrolysis, release of formaldehyde, and a final step of carbonate hydrolysis (X = O) or A-decar-boxylation (X = NH). Three model compounds, a secondary alcohol, a primary aliphatic amine, and a primary aromatic amine, were derivatized with the carrier moiety and examined for their rates of breakdown [84], The alcohol, indan-2-ol, yielded a carrier-linked derivative that proved relatively... 

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