Effective grafting of polymers onto ultrafine silica surface: Photopolymerization of vinyl monomers initiated by the system consisting of trichloroacetyl groups on the surface and Mn2(CO)10

The effective grafting of vinyl polymers onto an ultrafine silica surface was successfully achieved by the photopolymerization of vinyl monomers initiated by the system consisting of trichloroacetyl groups on the surface with Mn₂(CO)₁₀ under UV irradiation at 25 °C. The introduction of trichloroacetyl groups onto the surface of silica was achieved by the reaction of trichloroacetyl isocyanate with surface amino groups, which were introduced by the treatment of silica with 3‐aminopropyltriethoxysilane. During the polymerization, the corresponding polymers were effectively grafted onto the surface, based on the propagation of polymer from surface radicals formed by the interaction of trichloroacetyl groups and Mn₂(CO)₁₀. The percentage of poly(methyl methacrylate) grafting onto the silica reached 714.6% after 90 min. The grafting efficiency (proportion of grafted polymer to total polymer formed) in the polymerization of methyl methacrylate was very high, about 80%, indicating the depression of formation of ungrafted polymer. Polymer‐grafted silica gave a stable colloidal dispersion in good solvents for grafted polymer. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 2157–2163, 2001     

A Practical Synthesis of Tetrachloroethylene Oxide

Tetrachloroethylene oxide has been synthesized by direct oxidation of tetrachloroethylene with oxygen in the presence of ultraviolet light. This preparation resulted in a mixture of tetrachloroethylene oxide and trichloroacetyl chloride in approximately equal amounts under the most favorable conditions. Tetrachloroethylene oxide rearranges readily to trichloroacetyl chloride above 60 C with an activation energy E of 3.0 × 10⁴ cal/mole and a pre-exponential factor A of 1.9 × 10¹³. All attempts to polymerize tetrachloroethylene oxide under a variety of conditions failed.     

Reaktionen von α-Chlorcarbonsäurechloriden mit Trialkylaminen

The condensation of α,α-dichloropropionyl chloride (IVa) and of trichloroacetyl chloride (IVb) with α-chloropropionyl chloride (Ia) in the presence of triethylamine led to two acid chloride enol-esters, both as mixtures of cis- and trans-isomers, namely 1, 2-dichloropropenyl α,α-dichloropropionate (Va) and 1, 2-dichloropropenyl trichloroacetate (Vb). A mixture of triethylamine and trichloroacetyl chloride produced an oxidation-reduction reaction to give 48% 1, 2, 2, 2-tetrachloroethyltrichloroacetate (VIII) and 69% 1-diethylamino-4, 4, 4-trichloro-1-butene-3-one (IX). Basic hydrolysis of IX led to 43% of glutaconic acid (XIII). Tripropylamine reacted in the same way with trichloroacetyl chloride to yield 1-dipropylamino-2-methyl-4, 4, 4-trichloro-but-1-ene-3-one (XIX) which was readily hydrolyzed in acid solution to α-trichloroacetyl-propionaldehyde (XX).     

Cathodic reduction of hydroxycarbonyl compound trichloroacetyl esters

New coumarins and new 2-(2′,2′-dichlorovinyl) phenols have been prepared by cathodic reduction under potentiostatic conditions of trichloroacetyl esters of o-hydroxyketones and o-hydroxyaldehydes in aprotic media. Electroreductions of trichloroacetyl esters of α-hydroxy-1,4-naphthoquinone, 3-hydroxy-2-methyl-4-pyrone, methyl salicylate and benzoin have also been investigated.     

1,2-vinyl and 1,2-acetylenyl migration in Rh(II) carbene reaction: remarkable bystander effect

A series of beta-(trichloroacetyl)amino alpha-diazo carbonyl compounds have been synthesized, and their Rh(II)-catalyzed reaction was investigated. 1,2-Migration was the predominant reaction pathway, and the migratory aptitude was found to be dramatically affected by the beta-substituents. The 1,2-vinyl and 1,2-acetylenyl group migration occurs preferentially in the presence of beta-hydrogen in Rh(2)(OAc)(4)-catalyzed reaction of beta-(trichloroacetyl)amino alpha-diazo carbonyl compounds. A possible reaction mechanism is discussed.     

A Direct Synthesis of Benzothiophene-3-Carboxylic Acid from Benzothiophene

The direct synthesis of benzothiophene-3-carboxylic acid from benzothiophene utilizing Friedel-Crafts acylation with trichloroacetyl chloride, followed by basic hydrolysis is presented.     

Regioselective and stereospecific acylation across oxirane- and silyloxy systems as a novel strategy to the synthesis of enantiomerically pure mono-, di- and triglycerides

A trifluoroacetate-catalyzed opening of the oxirane ring of glycidyl derivatives bearing allylic acyl or alkyl functionalities with trifluoroacetic anhydride (TFAA), provides an efficient entry to configurationally homogeneous 1(3)-acyl- or 1(3)-O-alkyl-sn-glycerols. Selective introduction of tert-butyldimethylsilyl- (TBDMS), or triisopropylsilyl- (TIPS) transient protections at the terminal sites within these key intermediates secures 1(3)-acyl- or 1(3)-O-alkyl-3(1)-O-TBDMS (or TIPS)-sn-glycerols as general bifunctional precursors to 1,2(2,3)-diacyl-, 1(3)-O-alkyl-2-acyl- and 1,3-diacyl-sn-glycerols and hence triester isosters. Incorporation of a requisite acyl residue at the central carbon of the silylated synthons with a subsequent Et(3)N.3HF-promoted, direct trichloroacetylation across the siloxy system by trichloroacetic anhydride (TCAA), followed by cleavage of the trichloroacetyl group, affords the respective 1,2(2,3)-diacyl- or 1(3)-O-alkyl-2-acyl-sn-glycerols. Alternatively, a reaction sequence involving: (i) attachment of a trichloroacetyl fragment at the stereogenic C2-centre of the monosilylated glycerides; (ii) replacement of the silyl moiety by a short- or long-chain carboxylic acid residue by means of the acylating agent: tetra-n-butylammonium bromide (TBABr)-carboxylic acid anhydride (CAA)-trimethylsilyl bromide (TMSBr); and (iii) removal of the trichloroacetyl replacement, provides pure 1,3-diacyl-sn-glycerols. The TBABr-CAA-TMSBr reagent system allows also a one-step conversion of 1,2-diacylglycerol silyl ethers into homochiral triglycerides with predefined asymmetry and degree of unsaturation. These compounds can also be accessed via a two-step one-pot approach where the trichloroacetyl derivatives of 1,2(2,3)- or 1,3-diacyl-sn-glycerols serve as triester building blocks for establishing the third ester bond at preselected C3(1)- or C2-positions within the glycerol skeleton at the very last synthetic stage. In all instances, the target compounds were produced under mild conditions, in high enantiomeric purity, and in practically quantitative yields.     

Selective synthesis of N-substituted pyrrolo[1,2-a]pyrazin-1(2H)-one derivatives via alkyne cyclization

A novel and efficient synthesis of N-substituted pyrrolo-pyrazinone derivatives has been developed. A trichloroacetyl group connected to the pyrrole ring was converted into the desired carboxamide derivatives. Promoted by NaH, the pyrrole carboxamide derivatives underwent a tandem reaction with propargyl bromide to afford pyrrolo-pyrazinones with high efficiency under very mild conditions. The mechanism for the formation of the products is discussed and supported by DFT calculations.     

Reactions of trichloroacetyl isothiocyanate with organic azides

Benzyl azide reacts with trichloroacetyl isothiocyanate to give 7a in chloroform solution, and 11 in acetone solution. These 1,2,4-oxathiazolidines were characterized by ¹³C nmr spectroscopy (Scheme 2), but could not be isolated since they deteriorated via the carbodiimide 8a into the 1,2,4-thiadiazolidine 9a . The oxathiazoline 6a is assumed as an intermediate and was trapped by isocyanates and dicyclohexylcarbodiimide to give the 1,2,4-thiadiazolidines 10a,b and 12 respectively. Isopropyl azide also reacts with trichloroacetyl isothiocyanate to give the labile oxathiazolidine 7b , which decomposes to the carbodiimide 8b and the 1,2,4-thiadiazolidine 9b . In the case of diphenylmethyl azide, however, no evidence was obtained for the presence of the oxathiazolidine 7c in the ¹H nmr spectra; only the carbodiimide 8c was observed. A mechanistic rationalization is presented in Scheme 1.     

Reactions of diazaphospholes with isocyanates

Conclusions A new derivative of a two-coordinated phosphorus atom, and specifically 2-acetyl-4-trichloroacetamido-5-methyl-1,2,3-diazaphosphole, was obtained by the reaction of 2-acetyl-5-methyl-1,2,3-diazaphosphole with trichloroacetyl isocyanate.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, pp. 1182–1183, May, 1984.     

Spectroscopic and Dielcometric Study of the Kinetics of Alcoholysis of Trichloroacetyl Chloride with Butanol

The kinetics of alcoholysis of trichloroacetyl chloride with butanol in carbon tetrachloride were studied by dielcometry and IR spectroscopy. The reaction is reversible, and it involves intermediate formation of 1-butoxy-1,2,2,2-tetrachloroethanol and 1,1,2,2,2-pentachloroethanol.     

Formation of β-Lactones by[2+2] Cycloaddition of Dichloroketene with Unreactive Carbonyl Compounds

We report a modified process that dichloroketene generated in situ from trichloroacetyl chloride and Zn powder reacts with unreactivate carbonyl groups to afford dichloro-β-lactones in moderate to good yields. Subsequently, monochloro-β-lactones, β-lactones and β-hydroxy ester are obtained by dechlorination under different reaction conditions.     

Electrophilic substitution reactions of dipyrroheptane

Dipyrroheptanes have been reacted with a number of electrophiles, including aryldiazonium salts, acyl chlorides and isocyanates to give selectively the mono- or disubstituted derivatives. The bis(trichloroacetyl) dipyrroheptane can be used for the synthesis of amide and ester derivatives.     

Stereocontrolled entry to 1-oxapenams and 1-oxacephems from carbohydrates

N-Benzyl-2-carboxy-2-deoxypento and hexopyranosylaminolactams readily available via addition of trichloroacetyl isocyanate to substituted glycals, were transformed into enantiomerically pure N-benzyl-4-alkoxy-3-hydroxymethylazetidinones-2. The transformation involved the glycolic cleavage which was followed by sodium borohydride reduction. The above compounds can serve as starting materials for the synthesis of 1-oxapenams and 1-oxacephems.     

A theoretical study on decomposition and rearrangement reaction mechanism of trichloroacetyl chloride (CCl3COCl)

In the present study, the possible decomposition and rearrangement reaction profile of trichloroacetyl chloride have been studied using UMP2/6‐311++G (2d, 2p) level of ab initio and UB3LYP/6‐311++G (2d, 2p) level of density functional theory methods. The harmonic vibrational frequencies were calculated at the same level of theory used for the characterization of stationary points and zero‐point vibrational energy corrections. The potential energy barrier and activation energy between each step of the reaction have been calculated for the seven possible reaction pathways (Ia–c, IIa–b, IIIa–b). The trichloroacetyl chloride is an asymmetric ketone where the two α bonds of acetyl chloride, the C? C and C? Cl bonds are strong with dissociation energy of 72 kcal/mol. The phosgene (COCl₂), dichloroketene (CCl₂CO), carbon dichloride (CCl₂), carbon tetrachloride (CCl₄), and carbon monoxide (CO) are the major dominant products on the decomposition of the trichloroacetyl chloride. These resultant products are more hazards than the parent trichloroacetyl chloride molecules. The positive value of the reaction energy indicate that the overall reaction profile is found to be endothermic at the UMP2 and UBLYP/6‐311++G(2d, 2p) levels of theory, respectively, at UMP2/6‐311G** optimized geometry. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011     

Catalytic and stereoselective glycosylation with glycosyl N-trichloroacetylcarbamate

Catalytic and stereoselective glycosylation efficiently proceeded by activating a glycosyl N-trichloroacetylcarbamate with a catalytic amount of Lewis acids in the presence of a glycosyl acceptor and molecular sieves 5 Å. Catalytic and one-pot dehydrative glycosylation of a 1-hydroxy carbohydrate was also performed stereoselectively by the reaction with trichloroacetyl isocyanate followed by activation with a catalytic amount of activators.     

Formation of trichlorophosphazopentafluorophenyl from pentafluoroaniline and its trihaloacetyl derivatives

Conclusions In contrast to the unfluorinated anilides, the trifluoro- and trichloroacetyl derivatives of pentafluoroaniline form trichlorophosphazopentafluorobenzene when treated with PCl₅. The same compound was obtained by the reaction of pentafluoroaniline with PCl₅.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2635–2637, November, 1978.     

Electrophilic substitutions of olefinic hydrogens : Acylation of1,1-bisalkylthio 1,3-alkadienes and trans-n-acetyl-n-isopropyl-1-amino-1,3-butadiene

Reactions of the title compounds with trifluoroacetic anhydride and trichloroacetyl chloride occurred regioselectively to give corresponding 4-triholoacetylated compounds in excellent yields. In contrast, 1,1-bisethylthio-1,3-hexadiene gave preferentially 2-acylated compounds.     

Synthesis of Pyranthiones

A general method for the preparations of pyranthiones is particularly useful for preparing substituted xanthiones which are unavailable by established procedures. Reaction of a xanthone with p-tosyl isocyanate or with trichloroacetyl isocyanate produces the corresponding imino derivatives, which upon treatment with n-butylamine followed by hydrogen sulfide gives the desired xanthione in good yield.     

Synthesis of substituted 1H-pyrrolo[3,2-c]quinolines

1H-2-Phenylpyrrolo[3,2-c]quinoline (1a) is made by thermal cyclization of quinol-4-yl hydrazone. Subsequent substitution of the C-3 hydrogen atom of the pyrrole ring of 1a with chlorine and a formyl group is easily achieved by reacting 1a with trichloroacetyl chloride and phosphorus oxychloride in DMF, respectively.