Stilbene diamine

A, while the latter consist of octahedral molecules, (d). The compounds studied were the 3,5-dimethylpyridine compound, (c), and the 3,4-dimethyl-pyridine compound, (d). The compounds containing the bidentate ligand meso-stilbene diamine, CgHs. CH(NH2)—CH(NH2). C Hs, are still more interesting. The blue and yellow forms are interconvertible in solution, and while the hydrated blue form (/n = 3-16 BM) of the dichloroacetate contains octahedral ions, (e), the yellow form (ju = 2-58 BM) contains planar ions of type (f) and octahedral... 

Since the CD spectrum of the one isomer of the [Co(i-sdda)-en]+ (Figure 12) shows a positive dominant CD peak and an overall CD curve similar to that of (+)-s-cis-[Co(edda)( -stien)]+, it might be expected to have the A-configuration. However, the A-s-cis-configuration would require the jt-stilbene-diamine backbone to have the X-conformation, forcing the large... 

Later, Bai and coworkers used both, dendrons built from chiral monomers and achiral dendritic backbone decorated with chiral selectors, to prepare CSPs. First, they tested the polyamido dendrons prepared from benzenetricarbonyl trichloride and enantiopure stilbene diamine capped with phenylurea function (see Section 15.2.2.4 and Scheme 15.10). " The separation ability decreased with the generation, possibly as a result of imperfect dendron architecture. Subsequently, the authors decorated silica-bound PAMAM with chiral selectors A-tosyl-L-phenylalanine and a chiral unit derived from 2-amino-1,2-diphenylethanol (Scheme 15.48). CSPs derived from third- and second-generation dendrons showed the highest separating ability. The second selector was inferior to the first, in spite of possessing an additional chiral center. 

X-ray structure of the major osmatc derived from rraur-stilbene and the Os04-Tomioka diamine ligand complex. 

Curcumine S. Mikado yellow, golden yellow and orange, direct yellow, stilbene yellow, diamine fast yellow A, A R diamine orange D, dianil direct yellow S, chloramine orange, naphthamine yellow, diphenyl chrysoine, diphenyl citronine, sun yellow, polar yellow, polyphenol yellow, etc. 

Chrysophenine, chrysamine, carbazol yellow, toluylene yellow and orange, stilbene yellows and oranges, benzo, Congo, diamine, and dianil yellows and oranges, 5 j pyramine orange, Pluto orange, etc., ... 

Included in this class of olefins is ( )-stilbene (entry 20), which throughout studies of AD has usually been the olefin dihydroxylated with the highest degree of enantioselectivity. Availability of (R,R) or (.5,5)-1,2-diphenyl-1,2-ethanediol (also referred to as stilbenediol or dihydrobenzoin) with high enantiomeric purities has led to reports of a number of applications, including incorporation into chiral dioxaphospholanes [50], chiral boronates [51], chiral ketene acetals [52], chiral crown ethers [53], and conversion into 1,2-diphenylethane-1,2-diamines [54]. Dihydroxylation of the substituted rran.r-stilbene 46 with Os04/NMO and DHQD-CLB gives the i ,/ -diol 47 with 82% ee in 88% yield [55]. 

Main Chain Polymers. Another system of dye attached polymers is a polyamic acid and a polyimide with a Tt-electron conjugation in the main chain. The Tt-electron conjugated system is not an intramolecular charge transfer system, unlike the azo and stilbene dye mentioned above. The polyamic acids (PAAs) were obtained through the reaction of a carboxylic acid anhydride and a diamine. A Tt-electron conjugated system exists in the diamine compound. These polyamic acids were soluble in conventional solvents and... 

A very simple yet elegant method for efficient epoxidation of aromatic and aliphatic alkenes was presented by Beller and coworkers [63, 64], FeCl3 hexahydrate in combination with 2,6-pyridinedicarboxylic add and various organic amines gave a highly reactive and selective catalyst system. An asymmetric variant (for epoxidations of trans-stilbene and related aromatic alkenes) was published recently [65] using N-monosulfonylated diamines as chiral ligands (Scheme 3.7). 

Dorr, Lewis, and co-workers found evidence through quenching experiments and flash spectroscopy for a triplex in the system trans-stilbene — amine — benzene — [105]. They quenched singlet excited trans-stilbene with various mono- and diamines and found a steric effect on the quenching constant The a, co-diamines (dabco, diaminoethane, -propane and -butane) quenched the stilbene fluorescence more efficiently than the monoamines, depending on the chain length between the amino groups. This was ascribed to the formation of cyclic radical cations, with a N-N three electron a-bond. In this case, an exciplex between diamine and stilbene is formed. 

Many fluorescent brighteners are derivatives of 4,4 diamino-stilbene-2,2 -disulfonic acid (59), an example of which is C.I. Fluorescent Brightener 32 (Fig. 13.138). In this case, successive reactions involving diamine 59 with two molecules of cyanuric chloride and two molecules of aniline followed by hydrolysis of the final chloro groups give the target compound. 

Structurally related fluorescent brighteners containing a benzotriazole moiety are made according to the route shown in Fig. 13.139. In this case, diamine 59 is tetrazotized, coupled to 2 molecules of 1,6-Cleve s acid, and the intermediate disazo stilbene structure (60) is oxidized to C.I. Fluorescent Brightener 40. Nowadays, monosulfonated benzotriazole brighteners are more important.60 The synthesis of one example is shown in Fig. 13.140 for C.I. Fluorescent Brightener 46. 

With diamine (25), 1-heptene afforded (/ )- ,2-heptanediol as the major ixoduct (86% ee) in 75% yield by this procedure but, curiously, oxidation of ( )-stilbene proceeded with lower optical yield (34% ee). Particularly efficient enantioface differentiation was achieved in the reaction of ( )-l-phe-nylpropene with a stoichiometric amount of osmium tetroxide in the presence of 1 mol equiv. of (-)-(27) when essentially optical pure (>99% ee) (15,2S)-l-phenylpropane-l,2-diol was obtained in 73% yield. This procedure is effective for mono-, ( )-di- and tri-substituted alkenes, with enantioface selection being as shown in Scheme 2 but, notably, the oxidation of (Z)-alkenes does not give satisfactory optical yields. 

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