Accurate local spin-polarized exchange potential: Reconciliation of generalized Slater and Kohn–Sham methods

Using simple physical arguments, a local spin-polarized exchange potential, V_xσ, is constructed from the single-particle Hartree–Fock (HF ) potentials (generalized Slater method) that reduces to the usual Kohn–Sham (KS ) result in the uniform gas limit. Numerical results for 10 closed subshell atoms demonstrate that the total energy calculated employing this V_xσ is closer to the exact KS results than those of other standard exchange approximations with electron densities and highest occupied orbital eigenvalues that closely approximate the HF results.     

A novel anthracenyl tagged protecting group for "phase-switching" applications in parallel synthesis

A new "phase-switching" protecting group 1 that facilitates the parallel synthesis of carboxylic acids, esters, and carboxamides is described. Its use permits chemistries to be performed in solution, which may be conveniently monitored with conventional analytical techniques, followed by subsequent immobilization onto a solid-phase support to aid compound purification. Carboxylic acids, esters, and carboxamides are then cleaved from the solid support following activation of the "safety-catch" and treatment with the desired nucleophile.     

The Baylis-Hillman condensation of alpha,beta-conjugate cycloketones with aldehydes using diethylaluminum iodide alone as the promoter

The Baylis-Hillman condensation of three types of alpha,beta-conjugate cycloketones with aldehydes was successfully performed by using diethylaluminum iodide as the Lewis acid promoter alone without the direct use of a Lewis base. The reaction proceeded to completion at 0 degree C in CH2Cl2 within 24 h to give modest to good yields (53-72%).     

A Study of Viscosity in the Extraction System Constituted by Tributyl Phosphate and Phosphoric Acid

Data on the kinematic viscosity of phosphoric acid solutions in technical-grade tributyl phosphate and in an industrial extract from a technological purification system based on tributyl phosphate, which contain 0–18% phosphoric acid in terms of P₂O₅, at 10–70°C are presented.     

A new synthesis of α-amino acids—III: Amidoalkylation of active methylene compounds with glyoxylic acid derivatives

The synthesis of N-acyl derivatives of γ - keto - α - amino acids (3, 4, 5) by the amidoalkylation of 1,3-dicarbonyl compounds with glyoxylic acid-amide adducts (1, 2) is described. The γ - keto - α - amino acid derivatives (4, 5) were further converted to the corresponding butenolides (6, 7) and to pyrazolylglycine (12).     

Electron impact mass spectral interpretation for some thiophosphoryl-p-acetylaminobenzenesulfonamides

This work discusses the synthesis and the fragmentation patterns for 2-(p-acetylaminosulfonamido)-2-thiono-(5,5-dimethyl-1,3,2-dioxaphosphorinane)(1) and for the p-acetylaminosulfonylamides of O,O-diethylthiophosphoric acid (2), O,O-diphenylthiophosphoric acid (3), dimethylaminocyclohexylthiophosphoric acid (4), and diethylaminophenylthiophosphoric acid (5). A thionamidic-thiolimidic structure was attributed to compounds 1-5, consistent with their IR and NMR spectra. EI mass spectra at 70 eV, high resolution (HR) mass measurements and metastable ion spectra were used to elucidate the fragmentation processes and to determine the kinetic energy release values associated with the metastable ion dissociations. HR accurate mass measurements were used to confirm the compositions of the more abundant ions.     

Influence of extended π-conjugation units on carrier mobilities in conducting polymers

Carrier mobilities in thin films of copolymers with repeat units consisting of oligothiophenes bridged by Si atoms are measured over a range of doping levels, where the numbers of thienylenes in the repeat unit are 7, 8, 10, 12, and 14. The mobilities for these polymer films increased with the increase in doping level and the mobility enhancement followed an increasing order of the π-conjugation length. The magnitude of the mobility increase for the Si polymer comprising 14 thiophene units reached ca. 10⁴, implying that this π-conjugation length is almost sufficient to reproduce transport properties of polythiophenes.     

Molecular rearrangements—XII: Pyrolysis of α-phenylacetanilide

Pyrolysis of α-phenylacetanilide resulted in migration of the benzyl group to the o and p positions of the aniline nucleus and formation of CO, NH₃, toluene benzaldehyde, dibenzyl, trans stilbene, aniline, 9 phenylacridine and 2,3 diphenyl-indole. With o-toluidine as a solvent the previous products were accompanied by 2,3 diphenyl-7-methylindole and 4 amino 3 methyl diphenylmethane. With isoqumoline 1 benzyl isoquinoline and 1,1' bi-isoquinolyl were also obtained.It is concluded that the pyrolysis of phenylacetanilide depends on the homolytic fission of the amide C-N bond into anilino and phenylacetyl free radicals followed by the interaction of the primary and secondary formed radicals with the rearrangement products and solvent nuclei.     

New method for the synthesis of macrocyclic compounds

A mixture of isomers corresponding to closing of the ring at the 3 and 4 positions of the thiophene ring is formed during intramolecular acylation of 12-(5-methyl-2-thienyl)-lauryl chloride in a homogeneous medium; the reaction proceeds primarily to favor the formation of the isomer with the larger ring (80%). A method for the synthesis of macrocyclic -alkylcycloalkanones by reductive desulfurization of the corresponding bicyclic ketones, which contain thiophene rings, was developed.See Izv. Akad. Nauk SSSR, Ser. Khim., 2228 (1970) for Communication XI.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1467–1472, November, 1970.