3-trichloromethyl-5-alkyl

Bretanha et al. [118] reported tiie alternative synthesis of 1,2,4-oxadiazoles using ultrasound irradiation from tri-chloroacetoamidoxime (164) and acyl chlorides (165). The 3-trichloromethyl-5-alkyl(aryl)-l,2,4-oxadiazoles (166) have been S5mthesized in better yields (84-98%) and shorter reaction times compared to the conventional method (60-90%) which required significantly longer reaction times (20h) and toluene reflux [119]. The proposed protocol can be applied for the preparation of 1,2,4-oxadiazoles containing aryl or alkyl groups attached to their C5 side chain (Scheme 43). 

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

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]... 

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)-... 

Dichloro-s-triazine and its 6-alkyl analogs are as easily hydrolyzed by water as trichloro-s-triazine and, on suspension in aqueous ammonia (25°, 16 hr), the first is diaminated in good yield. 2,4-Bistrichloromethyl-6-methyl- and -6-phenyl-s-triazines (321) require a special procedure for mono-alkoxylation (0-20°, 16 hr, alcoholic triethylamine) disubstitution occurs at reflux temperature (8 hr). Aqueous triethylamine (100°, 3 hr) causes complete hydroxy-lation of 2,4,6-tris-trichloromethyl-s-triazine which can be mono-substituted with ammonia, methylamine, or phenoxide ion at 20°. 

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. 

The results obtained from the alkylation of benzene with (trichloromethyl)silanes are summarized in Table XIV. 

As shown in Table XIV, the reactivity of (trichloromethyl)silanes varied depending upon the substituent on silicon. The reactivity and yields of (trichloromethyl)-methyldichlorosilanes were slightly higher than those of (trichloroinethyl)tri-chlorosilanes in the aluminum chloride-catalyzed alkylation as similarly observed in the alkylations with (ai-chloroalkyl)silanes and (dichloroalkyl)silanes. The electron-donating methyl group on the silicon facilitates the alkylation more than the electron-withdrawing chlorine. The minor products, (diphenylmethyl)chloro-silanes, were presumably derived from the decomposition of (triphenylmethyl)-chlorosilanes. 

To examine the decomposition of (triphenylmethyl)chlorosilanes to (diphenyl-methyOchlorosilanes during the alkylations of benzene with (trichloromethyl)-... 

A.s. shown in Table XV, the decomposition of (triphenylmethyl)methyldichloro-silane did not occur at room temperature, but occurred at the reflux temperature of benzene to give (diphenylmethyl)methyldichlorosilane in 10 and 20% yields after I and 2 h reaction periods. The results indicate that the decomposition occurs in the alkylation reaction conditions of benzene with (trichloromethyl)chlorosilanes a.s observed in the decomposition of tetraphcnylmethane to triphenylmethane. ... 

A method that provides an alternative route to dichlorocarbene is the decarboxylation of trichloroacetic acid.161 The decarboxylation generates the trichloromethyl anion, which decomposes to the carbene. Treatment of alkyl trichloroacetates with an alkoxide also generates dichlorocarbene. 

R1 = aryl, alkyl, benzyl, PhCH2OCH2, (EtO)2CHCH2, (EtO)2CHCH2CH2 or 2-aminoethyl R2 = aryl, alkyl, cyclohexen-1-yl or (EtO)2CH E+ = l2, C02, CIC02Me, HC02Et, PhCHO, PhNCO, trichloromethyl carbonate, or carbamoyl chloride... 

Hendry, D.G., Mill, T., Piszkiewicz, L., Howard, J.A., Eigenman, H.K. (1974) A critical review of H-atom transfer in the liquid phase chlorine atom, alkyl, trichloromethyl, alkoxy and alkylperoxy radicals. J. Phys. Chem. Ref. Data 3, 944-978. 

Alkylation of flra-chloroaniline (13-1) with 2,2,2-triiluoroethyl trichloromethyl-sulfonate affords the corresponding trifluroethylated derivative (13-2). Reaction of the anion from that with aziridine proper leads to the formation of the diamine (13-3). Acylation of that compound with ortfio-fluorobenzoyl chloride (13-4) proceeds to... 

Scheme 36 SPPS of N-Alkylated Peptides by the Bis(trichloromethyl) Carbonate Method,3°l...

Elemental chlorine is able to chlorinate alkyl side chains e.g., 2-methyI-pyrazine reacted with chlorine in acetic acid at 100°C to form mainly the trichloromethyl derivative (84M16). 

Alkyl groups attached to the triazine ring are quite prone to halogena-tion [77CCC2182 84MI7 89H(29)2253 90H(31)1933], A 70% yield of 6-dichloromethyl-5-trichloromethyl-2-phenyl-l, 2,4-triazine was obtained when 5,6-dimethyl-2-phenyl-l,2,4-triazine was heated at 90°C with chlorine dissolved in an acetic acid-acetic anhydride-sodium acetate mixture [90H(31)1933]. Thionyl chloride similarly chlorinated 58 in the fused saturated ring [89H(29)2253] (Scheme 53). 

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