4.5- Bis -substituted

Phosphine oxides are prepared similarly[644]. Selective monophosphiny-lation of 2,2 -bis[(lrifluoromethanesulfonyl)oxy]-l,1 -binaphthyl (784) with diphenylphosphine oxide using dppb or dppp as a ligand takes place to give optically active 2-(diarylphosphino)-1,1 -binaphthyl (785). No bis-substitution is observed[645,646]. 

Bis(substituted amino)-4,8-bisethylthio (or carboxymethylthio)-pyrimido[5,4-d]pyrimidines (464) are aminated first at the 4-position with primary or secondary amines at 180° (2 hr) and then at the 8-position (200°, 4 hr). The 4,8-bisthioxo derivative of 464 is 4,8-diaminated with ethanolamine (170°, 1 hr). 2,6-Dianilino-4,8-dioxo(or diethoxy or dibenzyloxy) derivatives of 464 react at the 4-and 8-positions with primary or secondary amines at 180°. The 2,4,6,8-tetrachloro derivative is claimed to goto the tetrakis(triethylammonio) compound. ... 

The bis(substituted) product 382 has previously been obtained in ca 53% yield via the bis-imino intermediate 383 on boiling succinodinitrile with ethyl sodiocya-... 

The Diels-Alder reaction between azonianthracene (61) and bis-substituted olefins to give 6,ll-ethanobenzo-[fo]-quinolizinium salts 62 was greatly accelerated by the action of microwave irradiation and, consequently, the reaction might be applicable to... 

In two recent reports (Mroz et al., 2007b Tegos et al., 2005) we studied the photosensitizer properties of two series of three functionalized fullerene compounds, one series with polar diserinol groups (BF1-BF3), and a second series of three compounds with quaternary pyrrolidinium groups (BF4-BF6) (Fig. 4.5). The bis-substituted and tris-substituted fullerenes are actually mixtures of regioisomers of the same molecular formula due to reaction with different double bonds. We asked the question whether the photodynamic effects displayed by these compounds operated... 

The preferential formation of mono- or bis-substituted product is determined by a minor or major molar ratio KOH/RTeTeR, respectively. 

The PFg" salts of [Ru(bpy)2(110)] and [Ru(110)3] and analogous complexes containing 4,4 -bis(substituted) ferrocenyl ligands (110 ), have been synthesized and characterized the tris(chelate) complexes are either poorly soluble or insoluble. Electropolymerization of [Ru(110 )3][PF6]2 produces an electrochromic film. The complex [Ru(bpy)2(lll)] undergoes electropolymerization on Pt and glassy carbon electrodes, although the related complex [Ru(bpy)2(112)] does not. Electrochemical and spectroscopic properties of the films indicate that they form by both head-to-tail and tail-to-tail monomer coupling. ... 

Jones TW, Gerdes RG, Ormstad K, et al. 1985. The formation of both a mono- and bis-substituted glutathione conjugate of hexachlorobutadiene by isolated hepatocytes and following in vivo administration to the rat. Chem Biol Interactions 56 251-267. 

The tetrahedral Sn2Bi2 ion has been stmcturally characterized by Corbett [72] and studied in solution by Rudolph [23]. The Sn NMR resonance at — 1,574 ppm shows coupling to one other Sn atom with a large, one-bond J( Sn- Sn) = 1,638 Hz. Recent gas phase and theoretical studies on Bi-substituted nine-atom cluster anions suggest that the isoelectronic Sng" analog, SngBis , should be static in solution [31]. 

During extensive studies, the Katritzky group utilized benzotriazole chemistry as an azomethine yhde synthetic equivalent. Initial studies, with the simple bis substituted hydroxylamine (51) had furnished a wide range of cycloadducts, from... 

One of the simplest optimization tasks is aimed to select the proper catalyst combination and the corresponding process parameters. In this case the main task is to create a proper experimental space with appropriate variable levels as shown in Table 1. This experimental space has 6250 potential experimental points (N) (N = 2 x 5 = 6250). This approach has been used for the selection of catalysts for ring hydrogenation of bi-substituted benzene derivatives. The decrease of the number of variable levels from 5 to 4 would result in significant decrease in the value of N (N= 2 X 4 = 2048). 

Fig. 2. Schematic representation of the polymers formed by reaction of either mono-substituted or bis-substituted lipids in a lipid bilayer.

The above data suggest that a crosslinked bilayer vesicle is essentially a single polymer molecule (really two, one in each half of the bilayer). In other words the polymerization of the lipid monomers exceeded a gel-point. This concept raises the question of what mole fraction of bis-substituted lipid is necessary to achieve a gel-point for a bilayer composed of a crosslinker lipid, i.e. bis-lipid, and a mono-substituted lipid. Approximately 30% of the lipids in a bilayer vesicle of SorbPCs must be bis-SorbPC (4) in order to produce a polymerized vesicle that could not be dissolved by detergent or organic solvent [29], A complementary study of Kolchens et al. found that the lateral diffusion coefficient, D, of a small nonreactive lipid probe in a polymerized bilayer of mono- and bis-AcrylPC was dramatically reduced when the mole fraction of the bis-AcrylPC, was increased from 0.3 to 0.4 [24]. The decreased freedom of motion of the probe molecule indicates the onset of a crosslinked bilayer in a manner consistent with a 2-dimensional gel-point. 

Next, let us consider the dependence of carrier concentration on for Bi- or Ag-doped PbS. This problem is related to the method of controlled valency, developed by Verwey and Kroger and Vink. It is assumed, as observed, that Bi substitutes for Pb in the crystal and acts as a donor. The equilibrium equations for this case are the six independent ones, eqn (1.204) to eqn (1.211), which describe the chemical equilibrium in pure PbS, and the following two equations ... 

Several extensions of these reactions are possible with respect to the electrophilic reagent as well as to the structure of the adduct. Thus functionalized alkyl groups, such as 2-hydroxyethyl and 2-hydroxy-2-phenylethyl, can be introduced into the pyridine ring at the position by treating l-lithio-2-phenyI-l,2-dihydropyridine with ethylene epoxide and styrene epoxide, respectively.144 When polyhalides such as CF3I are used, bis-(substituted-pyridyl)methanes and the dimeric substituted dipyridyls are obtained along with other products.144... 

Bis-substitution of stilbene produces stronger fluorescence and the bis-triazine derivatives of diaminostilbenes have proved to be the most successful brighteners for cellulosics, in particular, and polyamides (60MI11200). The variety of substitution permutations in (90) is almost endless and many primary and secondary homocyclic and heterocyclic amines, thiols and phenols have been used. Synthesis of such compounds is straightforward and utilizes the convenient selectivity to substitution of cyanuric chloride. 4,4 -Diaminostilbene-2,2 -disulfonic acid condenses readily at 0-5 °C with cyanuric chloride, under slightly acidic conditions. In this case cyanuric chloride behaves as a monofunctional acid chloride and, although some by-products are unavoidable, two molecules of cyanuric chloride condense... 

Gallop et al. [80] reported the preparation of p-lactams via a [2+2] cycloaddition reaction of ketenes with resin-bound imines derived from amino acids (Scheme 9). This is another solid-phase adaptation of the Staudinger reaction, which could lead to the synthesis of structurally diverse 3,4-bis-substituted 2-azetidinones [81]. In addition, a novel approach to the synthesis of A-unsubstituted-p-lactams, important building blocks for the preparation of p-lactam antibiotics, and useful precursors of chiral p-amino acids was described [82]. 

Fused 1,2,5-triazepinones 220 and 221 were obtained by cyclization of the corresponding isocyanate and bis-substituted urea, which, in turn, were prepared from the nitro compounds 218 and 219 (Scheme 48) <2000JHC1539>. 

The coupling of aryl triflates with diphenylphosphine (432) catalysed by Ni and Pd complexes is an important synthetic method for optically active bidentate phosphines. Bis-substitution of optically active 2,2/-bis[(trifluoromethanesulfonyl)-oxy]-l,l/-binaphthyl (431) with Ph2PH (432) to give 433 has been achieved using NiCl2(dppe)... 

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