Synthesis of 2-Acyl-1-benzyl-, 1-phenylethyl- and spirobenzyltetrahydroisoquinolines

N-Acyl-1-benzyl-, 1-phenylethyl-and 1-spirobenzyltetrahydro-isoquinolines are obtained from N-acyl-2-phenylethylamines and arylalkyl aldehydes or cyclic ketones in acidic media.     

Novel Iodine Reagent System for Regioselective Cleavage of Epoxides to Alcohols

Epoxides are converted regioselectively to corresponding higher substituted alcohols with greater yields using diphosphorus tetraiodide (P₂I₄) as a reducing agent and a catalytic amount of tetraethylammonium bromide at room temperature.     

Synthesis of Cycloartocarpesin Trimethyl Ether

The synthesis of chromenoflavone, cycloartocarpesin trimethyl ether (1b) has been achieved through the aroylation of lithium enolate of evodionol (2) with 2,4-dimethoxybenzoyl chloride followed by cyclodehydration of the β-diketone (3) with D-toluenesulphonic acid.     

(S)-(−)-2-Methyl-2-Phenylsuccinic Anhydride,a Novel Resolving Reagent and its Application to Resolution of CIS-5-Amino-4-Phenyl-1,3-DIOXANE

Abstract

A new resolving reagent, (S)-(?)-2-methyl-2-phenylsuccinic anhydride (5) for the resolution of amines via covalent bond formation and its application to the resolution of aminodioxane (±)-(1) is described. The d.e. of the amides (7) and (8) has been determined by studying ¹H-NMR spectra.     

Homochiral Ketals in Organic Synthesis. Enantioselective Synthesis of (4S, 5S)-4,5-Dihydroxycyclopent-2-En-1-One Isopropylidine Ketal

The title compound has been synthesized in 17% yield over six steps from 2-cyclopenten-1-one. The key step is catalytic osmylation of 4-bromo-2-cyclopenten-1-one 1,4-di-O-benzyl-D-threitol ketal to produce a chromatographically separable mixture of diastereomeric diols.     

THE CRYSTAL STRUCTURE OF 2-[(N,N-DIMETHYLAMINO)METHYL]BENZENETELLURENYL CHLORIDE

The crystal structure of 2-[N,N-dimethylamino)methyl]benzenetel-lurenyl chloride (2), a compound previously formulated as bis[[2-(N,N-dimethylamino)methyl]phenyl] ditelluride bis hydrochloride (1a), was determined. In the molecule 2, tellurium is bonded to the carbon of the phenyl group [2.120(3) Å], the nitrogen of the ortho dimethylamino substituent [2.362(3) Å], and the chlorine atom [2.536(1) Å]. There also is an intermolecular interaction of the tellurium atom with the phenyl ring of a neighbouring molecule [3.655(1) Å], resulting in the formation of zigzag chains along the b axis. The noncentrosymmetric space group of the crystal can be explained by the chiral surrounding of tellurium.     

X-Ray Investigations on Celluloses Grafted by the Thiocarbonation Method

It is a pleasure for me to contribute to the symposium held in honor of my colleague and old friend Vivian Stannett. The topic of this contribution is results of x-ray investigations on graft modified cellulose fibers.     

New Proof of the Number of Ways of Forming Noncyclic n-Mers

When every valency in n monomer units is assigned an individual index number, a unique formula can be written for each non-cyclic n-mer by systematically listing the pairs of valencies forming the (n - 1) bonds. The chosen system allows the formulae to be partitioned into families and subfamilies and the number of ways of pairing the valencies in any set to be deduced. This leads to a new method of calculating the number of ways of forming noncyclic n-mers.     

Polymer Intermediates and Polymers Derived from 5-t-Butyl-m-Xylene

Abstract

A series of condensation polymer intermediates, which included several new compositions, was prepared from 5-t-butyl-m-xylene (I) so that the effect of the bulky t-butyl group on polymer properties could be determined. Compound (I) was oxidized with nitric acid to obtain 5-t-butyl-isophthalic acid (II), which was converted successively to the diacid chloride, the diamide, the dinitrile, and finally to 5-t-butyl-m-xylene-α,α′-diamine (VI); the overall yield was 80%. The dimethyl ester of (II) was prepared and converted to 5-t-butyl-m-xylene-α,α′-diol (VIII), a new composition, in 79.5% overall yield; the diphenyl ester was also prepared. The sodium salt of (II) was catalytically reduced to obtain 5-t-butyl-1,3-cyclohexanedicarboxylic acid (IIa) in 95% yield. (IIa) was converted successively to the diacid chloride, the diamide, the dinitrile, and finally to 5-t-butyl-1,3-cyclohexanebis(methylamine) (VIa), a new composition; the overall yield was 37%. (IIa) was also converted to the dimethyl ester and finally to 5-t-butyl-1,3-cyclohexanedimethanol (VIIIa), a new composition; the overall yield was 64%. Condensation polymers were prepared from the intermediates (II), (IIa), (VI), (VIa), (VIII), and (VIIIa). These polymers had higher glass transition temperatures (T_g) than corresponding polymers containing no t-butyl groups. This general effect of the t-butyl group to increase the T_g value of the polymer was noted in all polymers prepared, regardless of whether the intermediate carrying the t-butyl group was a diacid, a diol, or a diamine, or whether the polymer was a polyamide, a polyester, or a polyurethane.     

Acrylonitrile Copolymerization. VIII. Radical Determination by the Spin-Trapping Technique

The technique of spin trapping of polymer radicals by 2-methyl-2-nitrosopropane has been applied to the study of acrylonitrile copolymerization. Provided the concentration of the spin trapping agent is kept low, and the samples are kept at low temperature during storage before obtaining the ESR spectra, quantitative studies of styrene-acrylonitrile copolymerization are possible. However, the spin-trapping reaction is a competitive one, and the trapping efficiency is dependent on the reactivity of the radicals present. In the case of acrylonitrile copolymerization with either vinyl chloride or vinyl acetate, these two last radicals are trapped preferentially. Furthermore, the cyclization reaction observed with many acrylonitrile copolymerization is nearly eliminated in the presence of the spin-trapping agent.