Presence Of Titanium Tetrachloride Research Articles

Branched-chain sugar nucleosides. IV. 9-(3-Deoxy-3-C-"hydroxymethyl"-β(and α)-D-allofuranosyl and ribofuranosyl)adenine

Hydroboration followed by alkaline hydrogen peroxide oxidation of 1,2:5,6-di-O-isopropylidene-3-C-methylene-α-D-ribo-hexofuranose (2) yielded 3-deoxy-3-C-"hydroxymethyl"-1,2:5,6-di-O-isopropylidene-α-D-allofuranose (3) and partially hydrolyzed 3 in a total yield of 88%. Compound 3 was hydrolyzed selectively to the 1,2-monoisopropylidene derivative 5, which was converted via benzoylation followed by acetolysis into the 1,2-diacetate 7. Condensation of the latter compound with chloromercuri-N-benzoyladenine in the presence of titanium tetrachloride, followed by deblocking with methanolic sodium methoxide, yielded 9-(3-deoxy-3-C-"hydroxymethyl"-β(and α)-D-allofuranosyl)adenine in yields of 44 and 4% respectively, based on 7. The over-all yield of 10 based on 3 is 20%. Sodium metaperiodate oxidation of 10, followed by sodium borohydride reduction of the aldehydo-derivative, afforded 9-(3-deoxy-3-C-"hydroxymethyl"-β-D-ribofuranosyl)adenine (11) in 81% yield.Direct acetolysis of 3, followed by conversion of the mixture of peracetates into a mixture of glycosyl chlorides, and finally condensation of the latter with 8 gave the blocked crystalline β-D-nucleoside 9 in an over-all yield of about 9%, based on 3. Subsequent unblocking of 9 gave a nucleoside having the same physical constants as 10.

Branched-chain sugar nucleosides. III. 9-(3-Deoxy-3-C-methyl-β-D-allofuranosyl and ribofuranosyl)adenine

Condensation of triphenylphosphinemethylene (Wittig reagent) with 5-O-benzyl-1,2-O-isopropyl-idene-α-D-erythro-pentafuranos-3-ulose and with 1,2:5,6-di-O-isopropylidene-α-D-ribo-hexofuranos-3-ulose (1) afforded 5-O-benzyl-1,2-O-isopropylidene-3-deoxy-3-C-methylene-α-D-ribofuranose in 36% yield and 1,2:5,6-di-O-isopropylidene-3-C-methylene-α-D-ribo-hexofuranose (2) in 55% yield, respectively. A detailed study of the affect of reaction conditions on the yield of the unsaturated sugar is described. Hydrogenation of 2 proceeded stereoselectively to yield 4 which was hydrolyzed selectively to the 1,2-O-monoisopropylidene derivative 5. Benzoylation of the latter gave 6 which was converted by acetolysis to the 1,2-diacetate 7. Condensation of this compound with 6-benzamidochloromercuripurine in the presence of titanium tetrachloride followed by deblocking with methanolic sodium meth-oxide, yielded 9-(3-deoxy-3-C-methyl-β-D-allofuranosyl)adenine (10) in 48% yield based on 7. Sodium metaperiodate oxidation of 10, followed by sodium borohydride reduction of the aldehydo derivative, afforded 9-(3-deoxy-3-C-methyl-β-D-ribofuranosyl)adenine (11) in 85% yield.

Thiophen derivatives. Part XVII. The preparation and structure of some benzo[b]thiophen aldehydes

Benzo[b]thiophen is formylated in position 3 by dichloromethyl butyl ether in the presence of titanium tetrachloride, whereas 3-methylbenzo[b]thiophen reacts at position 2; benzo[b]naphtho[2,1-d]thiophen gives the 5-formyl derivative in the same reaction.

Synthesis of tetrose nucleosides I. Adenine nucleosides of erythrose and threose

D- and L -Erythrose and D - and L -threose were individually converted to their triacetates which were condensed with chloromercuri-6-benzamidopurine in the presence of titanium tetrachloride. After deacylation, the four crude mixtures of anomeric nucleosides were each resolved on a strong anion exchange resin, leading to the isolation of all eight possible 9-tetrafuranosyladenines. The anomeric configurational assignments were made by consideration of the mechanism of nucleoside condensation (Baker's trans rule) and by Hudson's rules of isorotation. Preliminary results of tests for biological activity with Streptococcus faecalis 8043 and with adenosine deaminase are reported.

Polymerization of ethylene in the presence of titanium tetrachloride and alkyl aluminum halides

1. The kinetics of the polymerization of ethylene and the kinetics of the reduction of titanium tetrachloride by diethylaluminum chloride were compared at 30°, molar ratios AlEt2Cl ∶ TiCl4 0.6 ∶ 1, 1.2 ∶ 1, and 2.4 ∶ 1; initial AlEt2Cl concentration 7.4 · 10−3 M. 2. The influence of additions of AlEtCl2 on the kinetics of the polymerization of ethylene was studied under conditions of a steady-state action of the catalyst TiCl4-AlEt2Cl and under conditions when the rate of polymerization in the presence of TiCl4 and AlEt2Cl varies with time. 3. In the catalytic systems that arise in the interaction of TiCl4 and organoaluminum compounds, in addition to aluminum alkyls, there are other cocatalysts (titanium alkyls or complexes of TiCl4 with titanium alkyls or aluminum alkyls), which, being adsorbed on the surface of the catalytic precipitate, form the most active centers of polymerization.

Synthesis of 3′-Deoxynucleosides II: Synthesis of 9-(3-Deoxyaldofuranosyl) Adenines Derived from 3-Deoxy-D-glucose

Diacetone glucose was tosylated at the 3-position and the tosyl group eliminated with potassium hydroxide to yield the furanoseen which on reduction gave rise to 1, 2: 5, 6-di- O -isopropylidene-3-deoxy-D-galactofuranose. This was hydrolyzed selectively to the 1,2-monoacetone derivative, which was converted via benzoylation and acetolysis to the 1,2-diacetate, 5,6-dibenzoate. Condensation of this compound with chloromercuri-6-benzamidopurine in the presence of titanium tetrachloride, followed by deblocking with methanolic sodium methoxide, yielded the nucleoside 9-(3-deoxy- β -D-galactofuranosyl) adenine. In a separate procedure, the 1,2- O -isopropylidene-3-deoxy-D-galactofuranose was oxidized with periodate and reduced with borohydride to give 1,2- O -isopropylidene-L-arabinofuranose, convertible to the corresponding adenine-L-arabinofuranoside by procedures similar to those employed for the galacto-derivative.

Synthesis of 3′-Deoxynucleosides I.: Synthesis of 9-(3-Deoxyaldofuranosyl) Adenines Derived from 3-Deoxy-d-galactose

Diacetone glucose was tosylated at the 3-position and the tosyl group eliminated with potassium hydroxide to yield the furanoseen which on reduction gave rise to 1, 2: 5, 6-di- O -isopropylidene-3-deoxy-D-galactofuranose. This was hydrolyzed selectively to the 1,2-monoacetone derivative, which was converted via benzoylation and acetolysis to the 1,2-diacetate, 5,6-dibenzoate. Condensation of this compound with chloromercuri-6-benzamidopurine in the presence of titanium tetrachloride, followed by deblocking with methanolic sodium methoxide, yielded the nucleoside 9-(3-deoxy- β -D-galactofuranosyl) adenine. In a separate procedure, the 1,2- O -isopropylidene-3-deoxy-D-galactofuranose was oxidized with periodate and reduced with borohydride to give 1,2- O -isopropylidene-L-arabinofuranose, convertible to the corresponding adenine-L-arabinofuranoside by procedures similar to those employed for the galacto-derivative.

Catalytic alkylation of tetralin. Communication 11. Alkylation of tetralin in presence of titanium tetrachloride

1. Conditions were found for the alkylation of tetralin in presence of titanium tetrachloride with C7-C10 normal primary alcohols, with a mixture of secondary C9 alcohols, and with 1-nonene. The yields of the 6-alkyltetralins formed were 55–56, 74.6, and 65.5% respectively. 2. A mechanism is suggested for the alkylation of tetralin with alcohols in presence of titanium tetrachloride.

The kinetics and mechanism of the polymerization of α-olefins in the presence of complex catalysts

As was shown in previous work [1] during the polymerization of ethylene in the presence of titanium tetrachloride and tri-ethyl-aluminium, a sharp fall in the rate of polymerization with time is observed and is connected with a conversion which is taking place in the catalyst itself. The components of the catalyst react so readily with each other, that even a considerable reduction of the temperature (from 70 to 56°) does not succeed in slowing down the process of conversion of the catalyst to the less active form, and in stabilizing the catalytic system at a high level of activity. Because of the rapid interaction of TiCl 4 and Al(C 2H 5) 3 it is experimentally difficult to establish how the utilization and dissociation of the most active catalytic complex takes place and what the activity of the system is at the zero moment of time, when the composition of the catalyst must consist only of TiCl 4 and Al(C 2H 5) 3. As a result of the supposition, that the decrease of the catalytic activity of the system with time, is, in the first place, connected with a strong reduction of titanium we chose, for the subsequent investigations, di-iso-butyl-aluminium chloride, the reducing properties of which are less than those of tri-ethyl-aluminium [2]. A study of the kinetics of the polymerization of ethylene in the presence of TiCl 4+Al( iso-C 4H 9) 2Cl was carried out ethylene pressures from 50 to 250 mm, with ratios of Al( iso-C 4H 9) 2Cl: TiCl 4 from 0.69: 1 to 3.3:1, at intervals of temperature from 30 to 70°, in a medium of heptane.

Synthesis of crystalline polyvinylcyclohexane

AbstractThe least known field of stereospecific polymerization is the polymerization of vinylcycloalkanes. At the same time polyvinylalkanes and especially polyvinylcycloalkanes may be of considerable interest as a new class of crystalline polyvinyl compounds. With this in mind the synthesis of polyvinylcyclohexane has been carried out and its properties have been investigated. Polymerization of vinylcyclohexane takes place in the presence of titanium tetrachloride and isobutylaluminum or of chromium oxides on aluminum silicate. The polymer obtained with different catalysts and under varying conditions (temperature, solvent, catalyst concentration, etc.) according to x‐ray data has a high degree of crystallinity. The melting point is 325° and the intrinsic viscosity from 0.5 to 1.5. A characteristic feature is its good solubility in naphthenic and aromatic hydrocarbons. The structure of the polymer has been established and thermomechanical curves have been determined for polymers obtained on various catalysts.

225. Polymerizations of ethylene in the presence of titanium tetrachloride and certain metal alkyls

225. Polymerizations of ethylene in the presence of titanium tetrachloride and certain metal alkyls