Indan derivatives

Diphenylalkene, cyclohexylbenzene, and dialkyltetralin- and indane derivatives can be formed from the dienes (12-14) [100]. 

Another carbocationic domino process by the same group resulted in the formation of indane derivatives using cyclopropyl carbinol compounds as starting mate-... 

It is reasonable to assume that 5 and styrene generate the diradical 527, which collapses to give 528 at 30 °C under kinetic control. At temperatures of 75 °C and above, the last step is reversible and an equilibrium is established in that 528 and the methylenecyclobutane derivative 529 maintain a ratio of 1 6 [215]. The [2 + 2]-cydoadduct 530 of 5 to phenylacetylene should be formed analogously via a diradical of the type 527 and is closely related in its structure to the cephalosporin derivatives 437 and 438 (R= Ph, Scheme 6.89). In addition to 530, 2-phenylindene was obtained, which has to be considered as the product of the thermal rearrangement of 530 [216]. Akin to such a process, 526 [194] and 529 [215] were converted into indane derivatives on heating. 

Scheme 20.46 Cascade radical cyclization leading to an indan derivative.

The Sankyo company have shown that conformational restriction of the arylacetamide fragment of the Zambeletti/Glaxo series as in the indane derivative (49) preserves kappa selectivity (kappa A) = 0.67 nM, mu K, = 698 nM, mouse phenylquinone-induced writhing ED50 = 1.3 mg/kg s.c.) [72]. This aromatic group contains two of the rings found in the acenaphthene derivatives (26, 27) described above. 

Zinnen, H.A. (1993) Zeolitic para-xylene separation with indan and indan derivatives as heavy desorbent. U.S. Patent 5,159,131. 

With triethylamine in toluene, S2CI2 converted indane derivative 227, probably activated by the enedithio group, into pentathiepin 228 in low yield (1974JCS(P1)447 Scheme 121). 

A different reaction mode was observed in the Pd-catalyzed co-cyclization of the 2-bromo-l-en-6-yne 76 and 4-octyne 77. After an intramolecular carbopalladation of the triple bond in 76, the formed alkenylpalladium bromide carbopalladates 77 and this is followed by another intramolecular carbopalladation or 67r-electrocyclization and dehydropalladation to yield the oligosubstituted indane derivative (Scheme 22). ... 

Formation of indan derivatives is usually expected only when benzylic or tertiary carbocations are involved in cyclialkylation.146 Tetralin formation through... 

The reaction of alkylbenzenes with ethylene in the presence of sodium occurs with successive replacement of one or two benzylic hydrogens to produce mono-and diethylated compounds.235 Propylene reacts to form isomeric products with the preponderance of the branched isomer236 [Eq. (5.61)]. When potassium is used as catalyst, indan derivatives can also be formed237 [Eq. (5.62)] ... 

Highly efficient indane-derived C2-symmetric bis(oxazoline)/Cu(OTf)2 complex [36] and transition-metal (Ni, Fe, Co, Cu, Zn, etc.) hydrate complexes of 4,6-dibenzofiirandiyl-2,2 -bis(oxazoline) [37] have been developed for enantioselective Diels-Alder addition of acryloyl oxazolidinone derivatives (Eq. 8A.19). 

Hydration of several 1,2,3-triones including indane derivatives (70 Scheme 4) has been studied in dioxane-water mixtures.1053 Monohydration gives a 2,2-diol (71) forward rates and equilibrium constants have been measured over a wide range of solvent composition. Based on activation parameters, kinetic isotope effects, a Hammett treatment, and a second-order rate dependence on water, two water molecules are suggested to play distinct roles, one as nucleophile, the other as general acid-base, similar to dialdehydes.105b,c... 

However, diprotonated and triprotonated indane derivatives (92 and 93) have been reported.33... 

Finally, we turn to sulfur-containing species. Many indane derivatives may be suggested. However, there are only a few for which the enthalpy of formation has been determined phenylene trithiocarbonate (benzo-l,3-dithiole-2-thione) (X = Z = S, Y = CS) (XI), the isomeric benzo-l,2-dithiole-3-thione (X = Y = S, Z = CS) (X) [50],... 

In the above we considered indane derivatives that lacked endocyclic double bonds, i.e., indene and its derivatives. However, we recall the invocation of partial double bond character between the X, Y, and/or Z groups in many of the above species. Why don t we now consider indene and its derivatives More precisely, let us consider indene (XXVII) itself, with [-X-Y-] = -CH=CH- and Z = CH2 and the related reaction ... 

A similar synthesis of enantiopure (l )-sulfinamides 123 from indane-derived toluenesulfonyl 1,2,3-oxathiazolidine-2-oxide 121 has been developed. This method includes chemoselective ring opening with inversion of configuration at the sulfur atom, using Grignard reagent at the first step and lithium amide in liquid ammonia in the second step (Scheme 17) <2002JA7880>. Intermediate stable and crystalline sulfinate esters 122 were isolated in >95% yield in diastereopure form. 

On rapid cooling of hot saturated solution of 6b and of the indane derivative 6d, crystals of the E (for 6b) and Z (for 6d) forms could be isolated. No rate data or barriers are given but a half-life of ca 2 h for 6d at ambient temperature in toluene can be inferred from one of the figures, corresponding to an approximate free energy barrier to E-Z isomerization of 23 kcal mol - x. 

The indane derivative (R)-4-[l-(3-(2-indanyloxy)-4-methoxyphenyl)-2-(4-pyridyl) ethyl]aniline, (III), and derivatives (2) have been prepared and is described. 

The H NMR chemical shifts of these carbenium ions, unsaturated dimers, and indan derivatives are summarized in Tables 2-5. 

Although indan formation is significant in styrene polymerizations, j3-proton elimination is much faster than intramolecular alkylation [292]. Unsaturated styrene and a-methylstyrene dimers are prepared quantitatively under high dilution at elevated temperatures without cyclization to indan derivatives [293]. In this case, the carbocations must be quenched before intramolecular cyclization becomes significant at high conversion. However, indan formation competes with depropagation at temperatures above 50° C, which is much too high for unsaturated styrene dimers (D =) to homopolymerize. As outlined in Eq. (95), the unsaturated dimers form indans (Din) in the presence of acid. 

At lower temperatures (- 70° C) with lower equilibrium monomer concentrations, unsaturated dimers rapidly form tetramers without producing a significant amount of trimers [295]. This indicates that the unsaturated dimer prefers to dimerize, with depropagation and indan formation less probable. 1,2-Hydride shifts may also occur, as indicated by the large variety of dimer stereoisomers formed, as well as by spectral changes in the stopped-flow studies of the dimerization. Eq. (96) outlines the variety of isomeric indan derivatives formed at later stages of the reaction by a combination of hydride shifts (cf., Section V.A.4) and intramolecular cyclizations. 

Because the concentration of carbocations in a real polymerization is very low, model NMR studies have been used to obtain a deeper insight into the nature of the growing species. These experiments are restricted to sufficiently stable carbocations, such as those derived from vinyl ethers. Styrene derivatives are not stable enough and participate in Friedel-Crafts alkylation. For example, derivatives of a-methylstyrene easily deproto-nate, dimerize and then form intramolecularly indan derivatives. 

Block copolymerization between monomers of similar reactivities such as isobutene and various styrenes (styrene, p-chloro-, p-methyl-, and p-f-butylstyrenes, and indene) [284-288], as well as arMeSt and 2-chloroethyl vinyl ether [226], involves fewer limitations and is more successful. A detailed description of the copolymerization of ar-methylstyrene with 2-chloroethylvilnyl ether has been reported [226]. Because the reactivities of both monomers are similar, AB and BA block copolymers were prepared. However, the enhanced formation of indan derivatives was observed when vinyl ether was used as the first block. 

Fig. 137. Synthesis of oxa- or oxa-phospha-indan derivatives from phenolic Man-...

In similar investigative studies for bimetalhc single-source precursors, an iron indane derivative was synthesized by the reaction Na[(Cp)(CO)2Fe]0.5THF with BrIn[(CH2)3NMe2]2 in THF (Scheme 18)). The analogous Ni, Co, and Mn intermetallic complexes were also successfully prepared with either cyclopentadiene or carbonyl ligands. Photolysis of the indium-iron derivative [ Cp(CO)2Fe 2ln(CH2)3NMe2)2]... 

The importance of stereoelectronic effects has been assessed quantitatively by comparing the CH3/CH2CH3 and CH3/CH2tBu reactivity ratios (statistically corrected) in the radical cations of p-ethyltoluene (ETT), p-neopentyltoluene (NPT), 5,6-dimethylindane (DMI), and 2,2,5,6-tetramethylindane (TMI) (Scheme 35) [148], In the two indane derivatives the methylene groups in positions 1 and 3 bear a substituent which resembles an ethyl and a t-butyl group, respectively. In the p-xylene series, on going from ETT + to NPT"" a dramatic 1400-fold decrease in reactivity is observed for deprotonation from the methylene position, behavior which is readily explained on the basis of a stereoelectronic effect (see above and Scheme 34). 

An analogous reaction occurs during the reduction of 4-nitroisopropylbenzene in sulfuric acid, which in a four-electron reduction forms 5-amino-3-(4-aminophenyl)-1,1,3-trimethylindan (XXIV) the initially formed phenylhydroxylamine loses water to the equivalent of / -amino-a-methylstyrene, which dimerizes to the indan derivative [127]. 

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