Toluene chloromethylation

Benzyl chloride Toluene, a-chloro- (8) Benzene, (chloromethyl)- (9) (lQQ-44-7). 

Reinhoudt, Gray, Smit and Veenstra prepared a number of monomer and dimer crowns based on a variety of substituted xylylene units. They first conducted the reaction of 1,2-dibromomethylbenzene and a polyethylene glycol with sodium hydride or potassium Z-butoxide in toluene solution. Mixtures of the 1 1 and 2 2 (monomer and dimer) products were isolated and some polymer was formed . The reaction was conducted at temperatures from 30—60° and appeared to be complete in a maximum of one hour. The authors noted that the highest yield of 1 1 cyclic product was obtained with disodium tetraethylene glycolate instead of dipotassium hexaethylene gly-colate (see also Chap. 2) . Chloromethylation of 1,3-benzodioxole followed by reaction with disodium tetraethylene glycolate afforded the macrocycle (29% yield) illustrated in Eq. (3.20). 

The above mechanism for chloromethylation seems to be general for halo-methylation since bromomethylation gives the same ortho para ratio for toluene, ethylbenzene, and i-propylbenzene, which is entirely in accord with the halogen being substituted in a non rate-determining step of the reaction386. 

Ester (9) can easily be made from acid (H)- You might consider two approaches to this a one-carbon electrophile addition via chloromethylation (Table T 2.2) and oxidation or FGl (Table 2,3) back to p-chlorotoluene (12). The latter is easier on a large scale. The p-chlorotoluene (12) can be made either by direct chlorination of toluene or by the diazotisation route (p T 12) again from toluene. 

Via such a gas/liquid reaction, toluene-2,4-diisocyanate reacts with chlorine to give l-chloromethyl-2,4-diisocyanatobenzene [6], As a ring-substituted side product, toluene-5-chloro-2,4-diisocyanate is formed in minor quantities. 

Figure 5.22 Influence of different reactor materials on selectivity for 1 -chloromethyl-2,4-diisocyanatobenzene and toluene-2,4-diisocyanate conversion [6],...

Figure 5.23 Simulated selectivity versus conversion of toluene-2,4-diisocyanate (TDI). P, is the target product 1-chloromethyl-2,4 diisocyanatobenzene P2 is the side-product 5-toluene-5-chloro-2,4-diisicyanate Pj represents high-molecular-weight consecutive products [6],...

More specific evidence came from affinity labeling with molecules which could react with specific amino acid group sat or adjacent to the substrate site. These labels were substrate analogues and competitive inhibitors. Substituted aryl alkyl ketones were used. TV-p-toluene-sulphonyl-L-phenylalanine chloromethyl ketone (TPCK) blocked the activity of chymotrypsin. Subsequent sequence analysis identified histidine 57 as its site of binding (see Hess, 1971, p 213, The Enzymes, 3rd ed.). Trypsin, with its preference for basic rather than aromatic residues adjacent to the peptide bond, was not blocked by TPCK but was susceptible to iV-p-toluenesulphonyl-L-lysine chloromethyl ketone (TLCK) (Keil, ibid, p249). 

The active-site-directed inhibitor tosylphenylalanine chloromethyl ketone that specifically and irreversibly inhibits chymotrypsin. This chloroketone inhibitor relies on its toluene sulfonyl (or tosyl) group for binding into the aromatic binding pocket of chymotrypsin s active site. Inactivation occurs by alkylation of histidine-57 (pseudo-first order rate constant 0.2 min ). See Chymo-trypsin... 

A very interesting synthetic method of bicyclo[n.l.O]alkanes from cychc ketones via this 1,3-C,H insertion of magnesium carbenoid as a key reaction was reported (equation 22) . 1-Chlorovinyl p-tolyl sulfoxide (76) was synthesized from cyclopentadecanone and chloromethyl p-tolyl sulfoxide in three steps in high overall yield. Lithium enolate of tert-butyl acetate was added to 76 to give the adduct 77 in quantitative yield. a-Chlorosulfoxide (77) in a toluene solution was treated with i-PrMgCl in ether at —78 °C and the reaction mixture was slowly warmed to 0°C to afford the bicyclo[13.1.0]hexadecane derivative 79 in 96% yield through the reaction of the intermediate magnesium carbenoid 78. 

Thermolysis of (34) gives (33). Pyrolyses of o-(chloromethyl)toluenes give o-xylylenes, which thermally dimerize to [2]cyclophanes (80ACR65). This technique has been successfully applied to the preparation of multibridged pyridinophanes (8lAG(E)57l). 

Toluene, formaldehyde, HC.1, calcium hydroxide, and UNO , comprise the chargestock. In step 1 of this process, the toluene is reacted with concentrated HC1 at about 70°C along with paraformaldehyde. This accomplishes chloromethylation of approximately 98% of the toluene. In step 2, saponification of the chloromethyltoluene is effected with lime and H20 under pressure and at about 125°C. The product is methylbenzyl alcohol. In step 3. the methylbenzyl alcohol is oxidized with HNO3 (dilute) under a pressure of about 20 atmospheres and at a temperature of about 170°C. The main products are o-phthalic acid in HNO3 solution and insoluble terephthalic acid. 

Reaction of 2-chloromethyl-4//-pyrido[l,2-a]pyrimidin-4-ones 385 with O.O-dialkyl phosphorothioates and phosphorodithioates in a mixture of ethanol and toluene in the presence of potassium hydroxide at 60-70°C gave insectidical or nematocidal phosphorus derivative 386 (83EUP81945). 

Aminomethyl-4//-pyrido[ 1,2-a ]pyrimidin-4-ones 387 were obtained in the reaction of 2-chloromethyl derivatives 385 (R1 = H) and cyclic or disubstituted amines in boiling toluene in the presence of triethylamine for 24 hours (86FES926). When 1 mole of piperazine was reacted with... 

Benzhydryl 7-amino-3-chloromethyl-3-cephem-4-carboxylate (2.29 g) was treated with bis(trimethylsilyl)acetamide (4.06 ml) at room temperature for 50 min to give a clear solution. Top the solution was added an acid chloride solution, which was prepared from (Z)-2-hydroxyimino-2-(2-tritylaminothiazol-4-yl)acetic acid (2.04 g) and PCI5 (1.15 g) in methylene chloride (20 ml). The mixture was stirred at room temperature for 30 min, poured in cold water (200 ml) and extracted with ethyl acetate (100 ml x 3). After evaporation of the solution was obtained the syrup (4 g) which was chromatographed on a silica gel column by eluting with 10 1 and 3 1 mixture of toluene and ethyl acetate successively. After evaporation of the solvents was obtained benzhydryl 3-chloromethyl-7-[(Z)-2-methoxyimino-2-(2-tritylaminothiazol-4-yl)acetamido]-3-cephem-4-carboxylate (2.62 g, 68%). 

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