Chlorocarbon reduction

Mechanisms Controlling Chlorocarbon Reduction at Iron Surfaces... 

The role of specific interactions in the plasticization of PVC has been proposed from work on specific interactions of esters in solvents (eg, hydrogenated chlorocarbons) (13), work on blends of polyesters with PVC (14—19), and work on plasticized PVC itself (20—23). Modes of iateraction between the carbonyl functionaHty of the plasticizer ester or polyester were proposed, mostly on the basis of results from Fourier transform infrared spectroscopy (ftir). Shifts in the absorption frequency of the carbonyl group of the plasticizer ester to lower wave number, indicative of a reduction in polarity (ie, some iateraction between this functionaHty and the polymer) have been reported (20—22). Work performed with dibutyl phthalate (22) suggests an optimum concentration at which such iateractions are maximized. Spectral shifts are in the range 3—8 cm . Similar shifts have also been reported in blends of PVC with polyesters (14—20), again showing a concentration dependence of the shift to lower wave number of the ester carbonyl absorption frequency. 

Diaminobiuret has been prepared only from N-tricarboxylic ester and hydrazine hydrate.1 Ethyl hydrazinecarboxylate has been prepared by reduction of nitrourethan electrolytically2 or with zinc dust and acetic acid,3 and by the action of hydrazine hydrate on diethyl carbonate,4 6 ethyl chlorocarbonate,6 and N-tricarboxylic ester.1... 

Beccalli et al. reported a new synthesis of staurosporinone (293) from 3-cyano-3-(lH-indol-3-yl)-2-oxo propionic acid ethyl ester (1464) (790). The reaction of 1464 with ethyl chlorocarbonate and triethylamine afforded the compound 1465, which, on treatment with dimethylamine, led to the corresponding hydroxy derivative 1466. The triflate 1467 was prepared from 1466 by reaction with trifluoromethanesulfonic anhydride (Tf20) in the presence of ethyldiisopropylamine. The palladium(O)-catalyzed cross-coupling of the triflate 1467 with the 3-(tributylstannyl)indole 1468 afforded the vinylindole 1469 in 89% yield. Deprotection of both nitrogen atoms with sodium ethoxide in ethanol to 1470, followed by photocyclization in the presence of iodine as the oxidizing agent provided the indolocarbazole 1471. Finally, reductive cyclization of 1471 with sodium borohydride-cobaltous chloride led to staurosporinone (293) in 40% yield (790) (Scheme 5.248). 

Traube purine synthesis. Preparation of an appropriate 4,5-diaminopyrimidine by introduction of the amino group into the 5 position of 4-amino-6-hydroxy- or 4,6-diaminopyrimidines by nitrosation and ammonium sulfide reduction, followed by ring closure with formic acid or chlorocarbonic ester. 

A major difference between the two methods of initiation is that the solvent in y-ray studies is almost inevitably the monomer itself, and these generally have lower dielectric constants than the chlorocarbon solvents most often used in the chemically initiated systems. As a result, it is not possible to compare the values of kp +) obtained from each technique without accounting for this difference in solvation. Classically, propagation involves charge dispersion in forming the transition-state complex and hence a reduction in the polarity of the system. Thus media of lower solvation power should favourably influence the process. (See reference 114 for more detailed discussion.) Experimentally the values of kp(+) from radiation-induced polymerizations are consistently higher than those obtained using stable salts as initiators, and this simplistic picture therefore seems to be confirmed. Dunn has recently carried out a detailed compilation of the available data on / p(+) and readers will find this an excellent distillation of the current position. 

Allophanyl hydrazide has been prepared previously as the hydrochloride by the zinc-hydrochloric acid reduction of 1-nitrobiuret.1 The new procedure2,3 outlined here entails the hydrazinolysis of allophanic esters in alcoholic solution. Excellent yields (80 to 84%) of allophanyl hydrazide are obtainable with a minimum of difficulty using readily available starting materials. The methyl and ethyl allophanates are prepared from urea and the corresponding chlorocarbonic esters.4... 

Hydrolyses of perchloroalkylbenzenes and related chlorocarbons Nucleophilic attack on perchloroalkylbenzenes and related compounds dealkylations 294 Reductive condensations of perchlorotoluene and other highly chlorinated trichloromethyl chlorocarbons 298 Alkylation of trichloromethyl compounds with trialkyl phosphites A conversion of trichloromethyl groups into cyano groups 312... 

REDUCTIVE CONDENSATIONS OF PERCHLOROTOLUENE AND OTHER HIGHLY CHLORINATED TRICHLOROMETHYL CHLOROCARBONS... 

Bisf trichloromethyl) chlorocarbons. The reductive condensation of perchloro-/ -xy/ene with either tin(ii) chloride or iron(ii) chloride in dioxane gives a polymeric chlorocarbon, the perchloropoly-/ -xylenediylidene (PP-xynene), a small proportion of perchloro-p-xylylene usually being formed (Ballester, 1979 Ballester et al., 1966). The configuration of this polymer is mixed cis and trans, as ascertained by its ultraviolet spectrum. The mechanism (45) has been postulated (Ballester et al., 1966). PP-xynene possesses a colossal thermal stability (up to 650°C from thermogravimetric analysis (TGA), see Fig. 6), and exceptional chemical inertness (e.g. to hot oleum, boiling red fuming nitric acid and to chlorine). 

The reductive polycondensation of bis(trichloromethyl) compounds has been extended to other chlorocarbons (Ballester et ai, 1966). From per-chloro-p-tolyl and from perchloro-l,4-dipropenylbenzenes, the so-called... 

The reductive condensation of alkylaromatic chlorocarbons with dialkyl hydrogen phosphonate in solution in the presence of copper(i) chloride takes place as indicated in the preceding section. However, when CCI4 is the solvent, reductive condensation with the latter occurs. In the case of perchlorotoluene, the products are accounted for as in (56) (M. Ballester and C. Fernandez-Llamazares, unpublished). Intermediate perchlorophenyleth-ane can be isolated, and under the reaction conditions it gives perchlorostyr-... 

The radical p—CCI3—C6CI4—CC 2 (CCI3—PB ) has been detected as an intermediate in reductive polymerization of perchloro-p-xylene, giving the polymeric chlorocarbon PP-xynene (p. 304) (Doorenbos, 1969). 

Not only hydrogen bnt other rednction agents like chlorocarbons can also be applied at that stage. The second stage is a complicated solid-state exothermic reaction of UF4 reduction with calcinm ... 

As Hodges and Garnetthad found in the case of arenes, the addition of PtCl " leads to net oxidation to give chloro-arenes or -alkanes, with reduction of Pt(IV) to Pt(II) Methane was converted to MeCH Once again, a 1°>2°>3° selectivity pattern was observed. In CF3CO2H, trifluoroacetate esters were also formed. For cyclohexane, benzene was a major product, perhaps as a result of dehydrochlorination of the chlorocarbon intermediates. 

It should be noted that a hydroxymethylated insoluble support was prepared through copolymerization of 4-hydroxymethylstyrene, styrene and divinylbenzene and also via the reduction of a carboxyl-resin with LiAlH4 by Letsinger and his associates (1963), who simultaneously and independently from Merrifield initiated solid phase peptide synthesis. In their approach the polymer was treated with phosgene and the polymeric analog of benzyl chlorocarbonate thus obtained used for the acylation of an amino acid ... 

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