Phosphine-catalyzed regiospecific (3 + 2) cyclization of 3-nitroindoles with allene esters.

A phosphine-catalyzed regiospecific (3 + 2) cyclization of 3-nitroindoles with allene esters has been established, which constructed indole-fused five-membered rings in good yields (up to 86%). This reaction serves as a powerful method for the construction of indole-fused five-membered rings. In addition, this reaction provides a useful strategy toward settling the challenge of utilizing other 1,3-dipoles or 1,3-dipole surrogates to perform (3 + 2) cyclizations with 3-nitroindoles in different catalytic modes, which will enrich the chemistry of nitroindoles and catalytic asymmetric dearomatization cyclizations.

Catalytic asymmetric aza-ene reaction of 3-indolylmethanols with cyclic enaminones: enantioselective approach to C3-functionalized indoles.

The catalytic asymmetric aza-ene reactions of 3-indolylmethanols with cyclic enaminones and the highly enantioselective aza-ene reactions utilizing cyclic aza-ene components have been established, which directly assemble isatin-derived 3-indolylmethanols and dimedone-derived enaminones into C3-functionalized chiral indoles with one all-carbon quaternary stereogenic center in high yields and excellent enantioselectivities (up to 99% yield, up to 95:5 er).

5-Phenyl-3,4,4a,5,6,12c-hexa-hydro-2H-benzo[f]pyrano[3,2-c]quinoline.

In the title compound, C(22)H(21)N, the pyridine ring adopts a distorted boat conformation, while the adjacent pyran ring adopts a chair conformation; the heterocyclic rings make a dihedral angle of 40.1 (2)° with each other.

2-[3-(2-Chloro-phen-yl)-5-oxo-1,5-diphenyl-pentyl-idene]malononitrile.

In the title compound, C(26)H(19)ClN(2)O, the 2-chloro-phenyl group forms dihedral angles of 59.6 (1) and 31.9 (1)° with the phenyl rings. The two phenyl rings are inclined at a dihedral angle of 32.9 (1)° with respect to each other. In the crystal, an inter-molecular C-H⋯N hydrogen bond links the mol-ecules into a polymeric chain running along the c axis.

[Study of the sensitizing effects of surfactants on the determination of aluminum by air-acetylene flame atomic absorption spectrometry].

The sensitizing effects of ten surfactants, such as cetyl trimethyl ammonium bromide (CTMAB) and cetyl pyridinium chloride (CPC), on the determination of aluminum were studied. The results showed that the cationic surfactants in the experiment were good sensitizers for the determination of aluminum, and the sensitization time was about 3.0. On the other hand, anionic surfactants had inhibition action, while particular surfactants had no action. With the sensitizing agent of CTMAB, the operating parameters of the spectrometer and the effects of CTMAB, solution medium and interfering elements in aluminum-nickel alloy sample were studied. The content of aluminum in aluminum-nickel alloy sample was determined by air-acetylene flame atomic absorption spectrometry, the linear range of aluminum of this method was 0.10-2.0 g x L(-1), the relative standard deviation was 2.6%, and the recoveries were in the range of 97%-103%.