Trichloromethyl reaction

N-Acylation is readily carried out by reaction of the alkaU metal salts with the appropriate acid chloride. C-Acylation of pyrroles carrying negative substituents occurs in the presence of Friedel-Crafts catalysts. Pyrrole and alkylpyrroles can be acylated noncatalyticaHy with an acid chloride or an acid anhydride. The formation of trichloromethyl 2-pyrryl ketone [35302-72-8] (20, R = CCI3) is a particularly useful procedure because the ketonic product can be readily converted to the corresponding pyrrolecarboxyUc acid or ester by treatment with aqueous base or alcohoHc base, respectively (31). 

BenZotrichloride Method. The central carbon atom of the dye is supphed by the trichloromethyl group from iJ-chlorobenzotrichloride. Both symmetrical and unsymmetrical triphenyhnethane dyes suitable for acryhc fibers are prepared by this method. 4-Chlorobenzotrichloride is condensed with excess chlorobenzene in the presence of a Lewis acid such as aluminium chloride to produce the intermediate aluminium chloride complex of 4,4, 4"-trichlorotriphenylmethyl chloride (18). Stepwise nucleophihc substitution of the chlorine atoms of this intermediate is achieved by successive reactions with different arylamines to give both symmetrical (51) and unsymmetrical dyes (52), eg, N-(2-chlorophenyl)-4-[(4-chlorophenyl) [4-[(3-methylphenyl)imino]-2,5-cyclohexadien-l-yhdene]methyl]benzenaminemonohydrochloride [85356-86-1J (19) from. w-toluidine and o-chloroaniline. 

Benzimidazole, l-methyl-2-trichloromethyl-substitution reactions, 5, 432 Benzimidazole, naphthoyl-, 1, 327 Benzimidazole, 5-nitro-alkylation, 5, 390 Benzimidazole, 6-nitro-1-oxide... 

Bromotrichloromethane can also be used effectively in the addition reaction. Because of the preferential abstraction of bromine, a trichloromethyl unit is added to the less substituted carbon atom of the alkene ... 

Intramolecular hydrogen abstraction reactions have also been observed in mediumsized rings. The reaction of cyclooctene with carbon tetrachloride is an interesting case. As shown in the equation below, whereas bromotrichloromethane adds to cyclooctene in a completely normal manner, carbon tetrachloride gives some 4-chloro-l-trichloromethyl-cyclooctane as well as the expected product ... 

Primary alkyl chlorides are fairly stable to fluorine displacement. When fluorinated, 1-chloropropane is converted to 1-chloroheptafluoropropane and 1-chloto-2-methylbutane produces 39% l-chlorononafluoro-2-methylbutane and 19% perfluoro-2-methylbutane. Secondary and tertiary alkyl chlorides can undergo 1,2-chlorine shifts to afford perfluonnated primary alkyl chlorides 2-Chloro-2-methylpropane gives l-chlorononafluoro-2-methylpropane, and three products are obtained by the fluorination of 3-chloropentane [7] (equation 1). Aerosol fluorina-tion of dichloromethane produces dichlorodifluoromethane which is isolated in 98% purity [4 (equation 2). If the molecule contains only carbon and halogens, the picture is different. Molecular beam analysis has shown that the reaction of fluorine with carbon tetrachlonde, lodotrichloromethane, or bromotrichloromethane proceeds first by abstraction of halogen to form a trichloromethyl radical [5]... 

Seyferth et al. (//O) have also synthesized N,N-diethyl-trichlorovinyl-amine (128, R CjHj) from the reaction of triethylamine and phenyl-(trichloromethyl)mercury (138). The best yield was 23 %, obtained when a benzene solution of the amine (45 mM) was added to a refluxing solution of phenyl(trichloromethyl)mercury (10 mM) in benzene. Although no mechanistic study was attempted because of the low yields and the intractable nature of the reaction mixture, the authors proposed the following mechanistic sequence ... 

Trichloroacetic acid behaves somewhat similarly in that protonation of the enamine occurs l7J7d). Subsequent decarboxylation of the trichloro-acetate gives trichloromethyl anion, which adds to the iminium cation to give the trichloromethyl amine derivative. Thus the enamine (113) undergoes reaction with trichloroacetic acid to give N-[l-(trichloromethyl)cyclo-hexyl]-morpholine (8). The latter compound undergoes rearrangement on... 

A similar sequence of reactions has been shown to take place with the dienamine derived from isophorone and morpholine (77). Reaction of this enamine with trichloroacetic acid gave a trichloromethyl derivative which was not isolated but which undergoes rearrangement and hydrolysis with base to give the diene acid (210). 

At low temperature a 1 1 adduct of thioacetic acid and an enamine could be prepared (709). The previously described reaction of aminomethylene ketones with hydrogen peroxide was extended to bisaminomethylene compounds. However, acylated cyclohexenamines led to cyclopentane-carboxamides (770), Trichloromethyl adducts of enamines and the rearranged amine derivatives were described in a further study (777). 

Ciamician-Dennstedt reaction on pyrrole, as well as pyrazoles, indoles, and Phenyl(trichloromethyl)mercury has been used as a dichlorocarbene... 

The Ciamician-Dennstedt reaction has been used to prepare macrocycles. Reaction of 2,3-alkyl linked indole derivatives 10, 11, 13, and 15 with phenyl(trichloromethyl)-... 

The activating effect of a trichloromethyl group is seen in the 2-dechlorination reactions of 2-chloro-4,6-bis(trichloromethyl)-s-tria-zine (175) with arylsulfonylhydrazides (24 hr) and heterocyclic amines (3 hr) at 20° and with unbasifled primary and secondary alcohols (65°, 30 min). The 4,6-diphenyl or 4,6-bis(4-chlorophenyl) analogs do not react in this manner. ... 

On the basis of the reaction of alkyl radicals with a number of polycyclic aromatics, Szwarc and Binks calculated the relative selectivities of several radicals methyl, 1 (by definition) ethyl, 1.0 n-propyl, 1.0 trichloromethyl, 1.8. The relative reactivities of the three alkyl radicals toward aromatics therefore appears to be the same. On the other hand, quinoline (the only heterocyclic compound so far examined in reactions with alkyl radicals other than methyl) shows a steady increase in its reactivity toward methyl, ethyl, and n-propyl radicals. This would suggest that the nucleophilic character of the alkyl radicals increases in the order Me < Et < n-Pr, and that the selectivity of the radical as defined by Szwarc is not necessarily a measure of its polar character. 

Another acylated ampicillin derivative with expanded antimicrobial spectrum is piperacil1 in (19). Its synthesis begins with 1-ethyl-2,3-diketopiperazine (j7, which itself is made from ]i-ethylethylenediamine and diethyl oxalate), which is activated by sequential reaction with trimethylchlorosilane and then trichloromethyl chioroformate to give This last... 

Relative rate constants for reaction of methyl, trifluoromethyl, trichloromethyl,13 and t-butoxy radicals22,23 with the fluoro-olcfins arc summarized in Table 1.2. Note the following points ... 

Between these two extremes of spontaneous rearrangement and total failure to rearrange, Braverman and Stabinsky36-38 have observed intermediate behavior. The reaction of crotyl alcohol with C13CSC1 afforded an equilibrium mixture of both crotyl trichlormethanesulfenate (13) and a-methylallyl trichloromethyl sulfoxide (14, equation 9). 

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