Alkylation chloroalkylation

Method of Camilleri, Watts, and Boraston The Camilleri et al. method [62] is based on an atom contribution derived as a solvent-accessible surface area of the individual atoms in a molecule. The authors have computed the surface areas for over 200 benzenes and PAHs substituted with one or more groups of the following type alkyl, chloroalkyl, alkoxy, hydroxyl, amino, and carbonyl. Estimation results with this method have been compared with those obtained with CLOGP. 

In the past few years, similar reactions using numerous dichlorosilane derivatives were investigated to yield preceramic polymers. Some routes use several different types of chlorosilanes as starting materials (e.g., Refs. 33-35) Analogous to the preparation of polysilanes, polycarbosilanes can also be synthesized using a similar route. Alkyl chloroalkyl chlorosilanes are used as starting materials for this purpose [2]. 

Franc and Dvoracek showed that some functional groups and bond types may be identified by degradation of the sample in a microreactor, and gas chromatographic separation of the volatile reaction products. Details of the method and apparatus are given, and results are presented for the degradation of alkyl- aryl- and chloralkyl-silanes and siloxanes (with concentrated sulphuric acid saturated with vanadium pentoxide) of alkoxysilanes (with hydriodic acid at 75 C) and of vinylsilanes (by saturation with chlorine on a water bath followed by decomposition with concentrated sulphuric acid at 175°C). Alkyl, chloroalkyl, phenyl, chlorophenyl, alkoxyl and vinyl groups, and s Si-Si s and =Si-H bonds were all detected by these procedures. 

A number of studies have focused on the synthesis of polymers with functionalized sidechains. For example, long-chain alkyl, chloroalkyl, chloro, and alkoxy substitutes polyferrocenylsilanes have been reported. Polymers with... 

Protonated /V-chloroalkyl amines under the influence of heat or uv light rearrange to piperidines or pyrroHdines (Hofmann-Lriffler reaction) (88). The free-radical addition of alkyl and dialkyl-/V-chloramines to olefins and acetylenes yields P-chloroalkji-, P-chloroalkenyl-, and 8-chloroalkenylamines (89). Various N-hiomo- and N-chloropolyfluoroaLkylarnines have been synthesized whose addition products to olefinic double bonds can be photolyzed to fluoroazaalkenes (90). 

The kinetics of formation and hydrolysis of /-C H OCl have been investigated (262). The chemistry of alkyl hypochlorites, /-C H OCl in particular, has been extensively explored (247). /-Butyl hypochlorite reacts with a variety of olefins via a photoinduced radical chain process to give good yields of aUyflc chlorides (263). Steroid alcohols can be oxidized and chlorinated with /-C H OCl to give good yields of ketosteroids and chlorosteroids (264) (see Steroids). /-Butyl hypochlorite is a more satisfactory reagent than HOCl for /V-chlorination of amines (265). Sulfides are oxidized in excellent yields to sulfoxides without concomitant formation of sulfones (266). 2-Amino-1, 4-quinones are rapidly chlorinated at room temperature chlorination occurs specifically at the position adjacent to the amino group (267). Anhydropenicillin is converted almost quantitatively to its 6-methoxy derivative by /-C H OCl in methanol (268). Reaction of unsaturated hydroperoxides with /-C H OCl provides monocyclic and bicycHc chloroalkyl 1,2-dioxolanes. 

In analogy to alkylation with chloroalkyl ethers, methyl ot-methoxyperfluoro-propionate reacts with 2,6-dimethylphenol to give the bispheiiol [7] (equation 7)... 

An interesting intermediate 30 was proposed to result from the sequential addition of pyridine to tetrachlorocyclopropene (31). Compound 30 represents an alkyl nitrogen ylide with two 1-chloroalkyl pyridinium moieties in the same molecule. Pyridines with electron-withdrawing groups and heterocycles with an electron-deficient nitrogen, for example, pyridine-3-carbaldehyde or quinoline, react with 31 to yield the corresponding mono-substituted products 32a and 32b (83JOC2629) (Scheme 8). 

Besides simple alkyl-substituted sulfoxides, (a-chloroalkyl)sulfoxides have been used as reagents for diastereoselective addition reactions. Thus, a synthesis of enantiomerically pure 2-hydroxy carboxylates is based on the addition of (-)-l-[(l-chlorobutyl)sulfinyl]-4-methyl-benzene (10) to aldehydes433. The sulfoxide, optically pure with respect to the sulfoxide chirality but a mixture of diastereomers with respect to the a-sulfinyl carbon, can be readily deprotonated at — 55 °C. Subsequent addition to aldehydes afforded a mixture of the diastereomers 11A and 11B. Although the diastereoselectivity of the addition reaction is very low, the diastereomers are easily separated by flash chromatography. Thermal elimination of the sulfinyl group in refluxing xylene cleanly afforded the vinyl chlorides 12 A/12B in high chemical yield as a mixture of E- and Z-isomers. After ozonolysis in ethanol, followed by reductive workup, enantiomerically pure ethyl a-hydroxycarboxylates were obtained. 

Phosphine, (2-bromophenyl)dichloro-, 2,991 Phosphine, (w-chloroalkyl)dichloro-, 2, 991 Phosphine, chlorodimethyl-, 2, 991 Phosphine, chloro(dimethylamino)-, 2, 991 Phosphine, chlorodiphenyl-, 2, 990 Phosphine, cyclohexyl(o-anisyl)methyl-rhodium complexes asymmetric hydrogenation, 6, 251 Phosphine, [(dialkylphosphino)alkyl]diphenyl-, 2, 994 Phosphine, dichloromethyl-, 2, 991 Phosphine, dichlorophenyl-, 2, 990 Phosphine, diethylphenyl-, 2, 992 Phosphine, dimethyl-, 2,992 Phosphine, dimethylphenyl-, 2,992 Phosphine, diphenyl-, 2, 992 Phosphine, ethyldiphenyl-, 2, 992 Phosphine, ethylenebis(diethyl-, 2, 993 Phosphine, ethylenebis(diphenyl-, 2,993 Phosphine, ethylenebis(phenyl-, 2,992 Phosphine, ethylidynetris[methylene(diphenyl-, 2,994 Phosphine, [(ethylphenylphosphino)hexyl]diphenyl-, 2, 994... 

In the case of a-chloroalkyl aryl sulphoxides, the chloroalkyl group is easily replaced by an alkyl or aryl group of a Grignard reagent (equation 370). Bromomethyl sulphoxides react slowly and give the products in low yields, while iodomethyl sulphoxides are unreactive presumably due to steric hindrance (Table 29)678. 

FRIEDEL-CRAFTS ALKYLATIONS OF ARENES WITH (CHLOROALKYL)SILANES... 

Chloroalkyl)silancs have been reported to react with aromatic compounds in the presence of aluminum chloride cataly.st to give the corresponding alkylation... 

As observed in the alkylation with (ro-chloroalkyl)silanes, both the spacer length between the C—Cl and silicon and the substituents on the silicon atom of... 

In the alkylation of benzene with (dichloroalkyl)chlorosilanes in the presence of aluminum chloride catalyst, the reactivity of (dichloroalkyl)silanes increases as the spacer length between the C—Cl and silicon and as the number of chloro-groups on the silicon of (dichloroalkyl)chlorosilanes decreases as similarly observed in the alkylation with (cD-chloroalkyl)silanes. The alkylation of benzene derivatives with other (dichloroalkyl)chlorosilanes in the presence of aluminum chloride gave the corresponding diphenylated products in moderate yields.Those synthetic data are summarized in Table XI. 

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. 

SCHRMI- 2. Mechanism tor the Fricdel-Crafts alkylation of ben/.cne with (chloroalkyl)silane. 

An examination of some of the factors influencing the chemical and enzymatic hydrolysis of nicotinic acid esters was undertaken [45-48]. Twenty-five esters of nicotinic acid were prepared whose pro-moiety was a simple alkyl (unbranched, sec-, or /er/-alkyl), a chloroalkyl, a hydroxyalkyl, an alkoxyalkyl, a carbamoylmethyl, an aminoalkyl, a cycloalkyl, an arylalkyl, or an aryl group (Table 8.5). 

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