1 -Ferrocenylethyldimethylamine ( 7) is readily obtained from 1 -ferrocenylethanol by treatment with phosgene and then dimethylamine. The resolution of 7 with (i?)-(+)-tartaric acid is particularly easy and both antipodes are obtained in high yield. Qualitatively the steric course of the lithiation 7 -> 8 is predictable and proceeds with high stereoselectivity (96:4). Subsequent reactions of 8 with trimethylchlorosilane, formaldehyde, or benzophenone produce 9a-c. The quaternization of 9 in the presence of nucleophiles leads to substitution of the dimethylamino group in 9 with complete configurational retention, which is confirmed by nmr and the cycle {9a, 10, 14,13 j. The retention is due to the ease of formation of 11 and its configurational stability under suitable conditions. The reactions presented here provide a basis for convenient, predesignated stereoselective syntheses and
[1] During the Lindenberger Aerosol Characterization Experiment (LACE 98), impactor sampling of aerosol particles in the size range of 0.1 to 25 m was performed. The atmospheric concentrations of the elements sodium to lead (11 Յ Z Յ 83) were determined by total reflection X-ray fluorescence analysis. Approximately 15,500 individual particles were examined by high-resolution scanning electron microscopy and energydispersive X-ray microanalysis, and about 3800 particles were examined by transmission electron microscopy combined with energy-dispersive X-ray microanalysis. On the basis of morphology and chemical composition the particles were classified into 10 different groups: ammonium sulfates, calcium sulfates, sea salt, metal oxides/hydroxides, carbonates, silicates, soot, biological particles, carbon/sulfate mixed particles, and rest of carbon-rich particles C rest . The phases present in the different particle groups were determined by selected area electron diffraction in the transmission electron microscope. In addition, the heterogeneous phase composition of agglomerates was studied in detail. On the basis of the size distribution and the relative abundance of the particle groups, the average and size-resolved complex refractive index of the total aerosol were calculated. The real part of the average refractive index mainly depends on the abundance of metal oxide/hydroxide particles and varied between 1.52 and 1.57 on the different sampling days. The average imaginary part varied between 0.031 and 0.057 depending on the amounts of soot and carbon/sulfate mixed particles. The average complex refractive index deduced from the analysis of individual aerosol particles is in good agreement with the results of photometer measurements of dried filter samples.
472 472 485 485 592 587 Table 1. Properties of compounds (3al-(3d), ( 4 a ) . and ( 4 b ) . 4.37 4.37 4.34 4.34 4.27 4.11 Received, March 23rd, 1964 [ Z 703/535 IE]A solution 0.02 mole of N-ethyl-2-chlorobenzothiazolium fluoroborate ( I ) , RI = CzHs, R 2 = H, and 0.01 mole of tris-(hydroxymethy1)phosphine (2) in 10 ml of N,N-dimethylformamide (DMF) was treated at 0 "C under nitrogen with 0.03 mole of diisopropylethylamine dissolved in 10 ml of DMFand yielded orange-red crystals of ( 3 6 ) , with elimination of formaldehyde.We obtained analogous compounds from variously substituted 2-chlorobenzothiazolium salts and 2-chloroquinolinium salts; it appears therefore that phosphacyanines (3) R2 R2 or ( 4 ) (i.e. analogues of the azacyanines) have been formed (yields: 40-50 7:). Some of their properties are listed inTable 1 . Compound H H OCH3 OCH, H CH3 225-230 214-220 208-220 215-123 126 (decomp.) 178-185Oxidation of (3a) -(Sd), (4u), and (46) by alkaline hydrogen peroxide affords 2-benzothiazolones or 2-quinolones, together with phosphoric acid, in quantitative yields.The NMR-spectra are compatible with the cyanine structure; the chemical shift of the phosphorus resonance (-26.05 pprn), however, is unexpectedly large and without parallel [*I.The excellent agreement of the electron spectra with those of the analogous aza-and rnethinecyanines supports the constitution proposed.The observation that 4-cyano-2,6-diphenylphenol ( I ) can be dehydrogenated to a stable, green phenoxyl radical [ I ] prompted us to prepare further arylcyanophenols. 2-Cyano-4,6-diphenylphenol (2) was obtained from 2,4-diphenylanisole by bromination, conversion into the corresponding organolithium compound, carboxylation, preparation of the amide, dehydration, and demethylation with pyridine/HCl [2]. Compound (2) can be dehydrogenated to a red, stable phenoxyl radical. 2,6-Dicyano-4-phenylphenol (3) was prepared from 4hydroxydiphenyl by condensation with formaldehyde to give 2,6-bishydroxymethyl-4-phenylphenol, methylation, oxidation to the dicarboxylic acid, conversion into the diarnide, dehydration, and demethylation. Phenol (3) is oxidized with lead tetraacetate in glacial acetic acid to give a blue radical which has not yet been closely investigated. Finally, we have prepared 2,4,64ricyanophenol (4) by conversion of methoxytrimesic acid into the triamide, dehydration, and demethylation. Like picric acid, (4) is a strong acid (pKc = 1.0 at 20°C and ionic strength p -0.02); it has not yet been oxidized. b H OH C: d35 C N OH 6 H The half-wave potentials were measured polarographically i n acetonitrile/water (9: I ) containing 0.01 M N(CH3)40H and N(CH3)dCI with a rotating graphite electrode and a silver! 384
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.