2.5- Diaryl-2 -methoxy

Aryl-2-methoxy- 2,5-Diaryl-2 -methoxy-azobenzole azobenzole... 

The position of the macrocycle on the thread of a rotaxane can be controlled through repulsive electrostatic interactions generated in a reversible way. Photoin-duced heterolysis of rotaxanes with diaryl-methoxy-cycloheptatriene- and aryl-alk-oxy-acridane-based molecular threads was used in the group of Abraham to demonstrate this concept. Abraham, Grubert, Grummt, and Buck [93] synthesized a rotaxane composed of the tetracationic macrocycle cyclobis(paraquat-p-phenylene) CBPQT (Fig. 9bl) and a thread that incorporated a diaryl-methoxy-cycloheptatriene unit (Fig. 9b2) the thread was folded. In the initial situation (Fig. 9b6), the macrocycle is located at the diary 1-methoxy-cycloheptatriene station (station 1), but due to folding, it interacts also with the aromatic station 2 (for the sake of convenience, the thread in... 

Fig. 9b2 is represented in an unfolded form). Heterolytic photolysis (360 nm) of the diaryl-methoxy-cycloheptatriene unit (Fig. 9b3) produces a tropylium ion, the lifetime of the ionic state being 15 s. Repulsive interactions with the tetracationic macrocycle (Fig. 9bl) produce the displacement of the latter from station 1 to station 2 (Figs. 9b2 and 9b7). The process is thermally reversible, and it showed no fade after ten cycles. 

Structural modifications (including introduction of an acetylene unit) of the thread of this type of rotaxane by Schmidt-Schaffer, Grubert, Grummt, Buck, and Abraham [94], allowed preparation of photoswitchable rotaxanes with an unfolded molecular thread. As an alternative to photolysis, treatment of the rotaxane containing the diaryl-methoxy-cycloheptatriene unit with TFA produces the diaryl-tropylium cation, and addition of solid NaHC03 in methanol can then be used to regenerate the diaryl-methoxy-cycloheptatriene station of the rotaxane. 

Abraham, Wlosnewski, Buck, and Jacob [95] invented a new type of photoswitchable rotaxane based on the above principles where the diaryl-methoxy-cycloheptatriene unit is replaced by 9-aryl-9-methoxy-acridanes (Fig. 9b4) that undergo photoheterolysis (313 nm light) with formation of acridinium ions (Fig. 9b5). Duo, Jacob, and Abraham [96] demonstrated that such devices can be deposited and can operate on gold nanoparticles. 

Lithiumalanat in siedendem Bis-[2-methoxy-athyl]-ather reduziert 1,1-Diaryl-athylene bei gleichzeitiger Me-thylierung durch das Losungsmittel5 (Diphenyl-methan-Derivate werden ebenfalls methyliert6). Natrium-bis-[2-methoxy-athoxy]-aluminiumhydrid reduziert und methyliert selbst 1,1-Diphenyl-athylen (in Kohlenwasser-stoff-Losung)7 und Arene8. 

Lithiumalan at liefert mit mittelstandigen Alkinen in Bis-[2-methoxy-athyl]-ather bei 125-138°, mit 1,2-Diaryl- und 1-Aryl-l-alkinen bereits bei 66° in Tetrahydrofuran im Gegensatz zu den Dialkyl-aluminiumhydriden nach Hydrolyse hauptsachlich tram-Olefine6 7. Aus Hexin-(3) erhalt man z.B. nach der ersten Arbeitsweise bei 96,5%igcm Um-satz ein Gemisch aus 96,1% trans- und 3,9% cis-Hexen-(3)7. 

Cyclohexyl-[2- (bzw. 4)-methoxy-phenyl]- 410 Diaryl- 541 Dicyclohexyl- 274 Dinaphthyl-(l)- 411... 

A detailed study of the interaction of diaryl sulfides with AICI3 (unsubstituted and p-chloro, methoxy, and fluoro) at -60°C showed the corresponding thianthrene radical ions(H-) to have been formed. Bis (4-nitrophenyl)disulfide produced thianthrene radical ion(l-l-) itself. The... 

The reaction proceeds via ANRORC-recyclization induced by alkoxide ion, and subsequent oxidative aromatization. Authors believe that aroma-tization occurs at the expense of disproportionation of the intermediate dihydropyridine because yields never exceed 50%. These results were reproduced and expanded (00PHA269), and used in a synthesis of 4,6-diaryl-2-methoxy-3-cyanopyridines and annulated methoxypyridines (88TL2703) (with low yields). 

Besides 3-chloro-6-iodopyridazine, selective Suzuki reaction was also studied on 4-acetyl-6-chloro-5-iodo-3-meth-oxypyridazine 175 (Scheme 42) <1995JHC1057>. C-5 Selective arylation could be achieved using a slight excess of arylboronic acid while a large excess of organometallic compound easily gave access to 4-acetyl-5,6-diaryl-3-methoxy-pyridazine 176 if desired. 

On treatment with phosphorus pentachloride, 4,5-diaryl-2(37/)-oxazolones 297 are reported to afford 5-chloro-4,5-diaryl-2(5//)-oxazolones 298, rather than the expected 2-chloro-4,5-diaryloxazoles. The 5-chloro-products react with methanol to give 4,5-diaryl-4,5-dimethoxy-2-oxazolidinones 299, which are further converted on heating to 4,5-diaryl-5-methoxy-2(5//)-oxazolones 300 (Fig. 5.76). ... 

Weitere Beispiele fur diese Art der Mitsunobu-Reaktion sind die Umwandlung eines 2,2-Diaryl-ethanols in 2-Amino-I-(4-benzyloxy-phenyl)-l-(2-benzyloxy-3-methoxy-phenyl)-ethan2 und die Umwandlung von 5-Hydroxy-2-methyl-l-hexen-3-in in 5-Phthalimido-2-methyl-l-hexen-3-in, das (wie oben formuliert) in 5-Amino-4-ethyl-l-hydroxy-2-methyl-2,3-hexadien ubergefuhrt werden kann3 ... 

Chlor-ethyl)-l,4-diaryl-2-oxo-azetidine reagieren mit Natriumcyanid in Methanol unter Umlagcrung und Bildung von Pyrrolidinen, z.B. trans-1,2-Diphenyl-3-methoxy-carbonyl-pyrrolidin (65%) bzw. trans-3-Methoxycarbonyl-l-(4-methoxy-phenyl)-2-(3-py-ridinyl)-pyrrolidin (52%)3 ... 

At least one of the hexadiene radical cations (20 +) can be viewed as a species containing spin and charge in two separate (though equivalent) molecular fragments. This separation can be enforced in systems of lower symmetry in this context, we mention two radical cations derived from l,l-diaryl-2-methylenecyclopropane (23), and 6-methoxy-l,2,3,4,6-pentamethyl-5-methylenebicyclo [2.2.0]hex-2-ene (25). 

Band group IV appears at 330 nm if no auxochromic substituent is attached to the molecule. 6-Methoxy-substitution displaces the maximum to 318 nm, while substitution in position 6 displaces the band bathochro-mically. This band is also characteristic for 1,3-diaryl-substituted salts, and it appears at —320-325 nm in acidic alcoholic solutions (87RRC417). 

In the second group of radical cations to be discussed here, spin and charge are stabilized in two separate fragments of the molecule. In early examples of this family the charge was stabilized by diaryl or methoxy substitution. We mention the ring-opened trimethylenemethane radical cations (152), the various di-... 

In the reaction of 1-naphthoxide ions, a mixture of 2- and 4-aryl-, along with 2,4-diaryl-l-naphthol, is formed. However, substitution occurs only at C4 with the 2-Me-substituted anion (50-70% yields) [1[. On the other hand, 2-naphthoxide ions react with ArX to give substitution only at Cj of the naphthalene ring [32, 33]. The reactivity of the 2-naphthoxide ions allows the synthesis of naphthylpyridines, naphthylquinolines, and naphthylisoquinolines via their coupling reactions with the corresponding halo arenes, in good to excellent yields (50-95%) [33], The photostimulated reaction between 2-naphthoxide ions and l-iodo-2-methoxy-naphthalene was explored in liquid ammonia, as a novel approach to the synthesis of [1,1 ] binaphthalenyl-2,2 -diol (BINOL) derivatives (Scheme 10.23). This procedure has also been applied to the synthesis of BINOL in moderate yield (40%), which represents the first report of an SRN1 reaction in water [34]. 

Although mostly alkoxy carbene complexes have been benzannulated, other types of carbene complexes are equally well suited. These include aryloxy carbene complexes as well as acyla-mino and thioalkylidene complexes, and even complexes with no heteroatoms, such as diaryl carbene complexes, are suitable (see below). Besides the commonly used methoxy and ethoxy carbene complexes, alkoxy carbene complexes with a longer alkyl chain have also been successfully reacted. The benzannulation of aryloxy carbene complexes has recently been studied to probe electronic effects [28a]. Aryloxy alkylidene complexes of type 21 have been used to prepare diaryl ethers 22, which constitute a common substructure in many important types of natural products [28b]. The benzannulation methodology provides an access to phenyl naphthyl ethers in yields of 60-93 % under mild conditions (Scheme 11). 

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