Catalyst benzylation

Reactions of the Side Chain. Benzyl chloride is hydrolyzed slowly by boiling water and more rapidly at elevated temperature and pressure in the presence of alkaHes (11). Reaction with aqueous sodium cyanide, preferably in the presence of a quaternary ammonium chloride, produces phenylacetonitrile [140-29-4] in high yield (12). The presence of a lower molecular-weight alcohol gives faster rates and higher yields. In the presence of suitable catalysts benzyl chloride reacts with carbon monoxide to produce phenylacetic acid [103-82-2] (13—15). With different catalyst systems in the presence of calcium hydroxide, double carbonylation to phenylpymvic acid [156-06-9] occurs (16). Benzyl esters are formed by heating benzyl chloride with the sodium salts of acids benzyl ethers by reaction with sodium alkoxides. The ease of ether formation is improved by the use of phase-transfer catalysts (17) (see Catalysis, phase-thansfer). 

Heating Af-substituted pyrazoles with benzoyl chloride at 200 °C gives quite high yields of 4-benzoylpyrazoles, even in the absence of catalysts. Benzylation of Af-substituted pyrazoles proceeds similarly in the 4-position (66AHC(6)347). 

No catalyst) Benzyl chloride Benzal chloride Benzotrichloride Rapid side-chain chlorination of toluene proceeds in the dark with sulphuryl chloride in the presence of dibenzoyl peroxide (O 001-0 005 mol per mol of SOjClj) as catalyst ... 

Olefin metathesis, in particular ring closing metathesis (RCM), remains a popular route to the synthesis of piperidines. This is exemplified in the following references which employed an RCM reaction utilizing Grubbs first generation catalyst (benzyl -... 

Primary aliphatic amines can be oxidized to aldehydes or ketones. Other reagents used have been V-bromoacetamide (for benzylic amines), 3,5-di-tert-butyl-l,2-benzoquinone, and aqueous NaOCl with phase-transfer catalysts. Benzylic amine salts PhCHRNRj H" " Cl (R,R = H or alkyl) give benzal-dehydes or aryl ketones when heated in DMSO. Several indirect methods for achieving the conversion RR CHNH2 RR C=0 (R = alkyl, aryl, or H) have been reported. ... 

Heteropolyacids + phase transfer catalysts Benzyl alcohol Benzaldehyde... 

The effect of type of catalyst on the reactivity of phenol and benzyl alcohol with phenyl isocyanate can be seen in Table III. In the case of tertiary amine (DMCHA), there is a relatively small difference in the reactivity of both the phenol and benzyl alcohol with phenyl isocyanate. Using DBTDL as catalyst, benzyl alcohol was found to be 26 times more reactive than phenol in the reaction with phenyl isocyanate. 

Using PdCl2(TPPMS)2 as catalyst, benzyl chloride could be carbonylated to form phenylacetic acid in 93% yield. The reaction is accelerated by addition of surfactants [63],... 

Toluene/Cl2 Benzyl chloride Composite catalyst Benzyl chloride produced by catalytic and photochlorination of toluene 44... 

Catalyst benzyl dimethylamine. Catalyst Arquad quarternary ammonium salt. ... 

The "IMlkinson s catalyst/benzyl imine system for orthoalkylation can be applied to RhCl(PPh3)3-catalyzed orthoalkenyla-tion of aromatic benzyl imine with both terminal and internal alkynes. Equation 70 illustrates reaction of the benzyl imine of acetophenone with several terminal alkynes giving mono- and doubly-alkenylated products, depending on the substituents in the alkyne and aromatic imine. 

In the absence of TEMPO or a metal catalyst, benzylic alcohols can be oxidized with alumina-supported PhI(OAc)2 using microwave irradiation. The reaction is conducted without solvent and is completed in 1-3 min. 

Imines (34) have been C-alkylated to give amines (35), in an unusual alkyl transfer arising from C-C cleavage. Hantzsch ester analogues such as (36) can act as hydride-transfer agents, but they have now been used to transfer alkyl groups, using Brpnsted or Lewis acid catalysts. Benzyl-substituted dihydropyridines (i.e., 36, with R = Bn) are particularly efficient. Evidence for a concerted transfer process is discussed. 

It is interesting to note that the very widely used Makosza catalyst , benzyl triethyl ammonium chloride, does not show high efficiency in this study. 4) Phosphonium ions are somewhat more effective and thermally stable than the corresponding ammonium catalysts and both are better than arsonium systems. 5) Substitution of the quaternary ion by alkyl rather than aryl groups yields more effective catalysts. 6) Reaction rates are generally greater in orf/io-dichlorobenzene (and presumably in other chlorocarbon media) than in benzene, and botli are better than heptane. In connection with this latter point, Ugelstad and coworkers have studied the reactions of quaternary ammonium phenoxide ions with alkyl halides in a variety of media and concluded that the... 

Arata and Hino found that better catalysts could be obtained by calcining Fe(OH)3 at 573 — 873 K. The hydroxide was prepared by hydrolyzing FeCls or Fe(N03)3 9H20. The alkylation reactions were carried out at room temperature with 50 cm of toluene solution (0.5 mol 1 ) of benzyl chloride, t-butyl chloride or acetyl chloride and 0.1 g (for benzylation or t-butylation) or 0.5g (for acetylation) of catalyst. Benzylation and t-butylation was completed within 2 min and 10 min, respectively. For acetylation with acetyl chloride, the reaction was slow, the conversion being 28% after 6 h of reaction. The reaction with acetyl bromide is slighdy faster conversion of 30% was obtained after 4 h.The isomer distribution of alkyltoluenes was 42% ortho, 6% meta and 52% para for benzylation and 3% meta and 97% para for butylation with /-butyl chloride. It was presumed that iron chloride formed on the surface of amorphous iron oxide by its reaction with hydrogen chloride is a catalytically active species for alkylation. 

Heat activated curing agents and catalysts benzyl dimethylamine (BDMA)... 

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