Similarity with Benzoylation

Similarity with Benzoylation. The most significant point of similarity between benzoylation and sulphonylation is that both of them may be used to accomplish reasonably well defined crystalline derivatives not only of hydroxyl compounds but also of primary and secondary amines. [Note. It is, however, pertinent to observe here that the tertiary amines cannot be subjected to sulphonylation.] 

Dissimilarity with Benzoylation. It has been observed that there is one vital difference between the benzoyl and the sulphonyl derivatives of amines. Importantly, when the primary- and secondary-samnes are made to react with Benzoyl Chloride, it gives rise to mono-and di-substituted structural analogues of benzamide and when subjected to treatment with Benzenesulphonyl Chloride, 3neld similar derivatives of benzene sulphonamide. 

Explanation. Benzamide—a carboxylic acid amide, essentially possesses very feeble amphoteric properties exclusively, by virtue of the fact that it rmdergoes hydrolysis to give the corresponding acid and ammonia as shown below  

Therefore, benzamide is practically neutral in character, and its derivatives are virtually insoluble in dilute aqueous solutions of acids or alkalis. 

Benzenesulphonamide—a sulphonic acid amide, on the contrary is virtually devoid of basic characteristics, hut more importantly has its acidic characteristics enhanced considerably and significantly as illustrated below  

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Ylid esters such as 266 react similarly. With benzoyl aizide the trizole 267 was obtained in 63% yield... 

Because of the chemical similarity between benzoyl nitrate and the acetyl nitrate which is formed in solutions of nitric acid in acetic anhydride, it is tempting to draw analogies between the mechanisms of nitration in such solutions and in solutions of benzoyl nitrate in carbon tetrachloride. Similarities do exist, such as the production by these reagents of higher proportions of o-substituted products from some substrates than are produced by nitronium ions, as already mentioned and further discussed below. Further, in solutions in carbon tetrachloride of acetyl nitrate or benzoyl nitrate, the addition of acetic anhydride and benzoic anhydride respectively reduces the rate of reaction, implying that dinitrogen pentoxide may also be involved in nitration in acetic anhydride. However, for solutions in which acetic anhydride is also the solvent, the analogy should be drawn with caution, for in many ways the conditions are not comparable. Thus, carbon tetrachloride is a non-polar solvent, in which, as has been shown above,... 

Indole can be nitrated with benzoyl nitrate at low temperatures to give 3-nitroindole. More vigorous conditions can be used for the nitration of 2-methylindole because of its resistance to acid-catalyzed polymerization. In nitric acid alone it is converted into the 3-nitro derivative, but in a mixture of concentrated nitric and sulfuric acids 2-methyl-5-nitroindole (47) is formed. In sulfuric acid, 2-methylindole is completely protonated. Thus it is probable that it is the conjugate acid which is undergoing nitration. 3,3-Dialkyl-3H-indolium salts similarly nitrate at the 5-position. The para directing ability of the immonium group in a benzenoid context is illustrated by the para nitration of the conjugate acid of benzylideneaniline (48). 

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). 

Incorporation of extensive branching in the side chain similarly does not decrease pharmacologic activity. Reductive alkylation of aminoalcohol, 42, with isobutyraldehyde affords the amine, 43. Acylation of the amine with benzoyl chloride probably goes initially to the amide (44). The acid catalysis used in the reaction leads to an N to 0 acyl migration to afford iso-bucaine (45). ... 

Under free radical conditions, we found that the bulk polymerization of 4-allyloxystyrene gave an insoluble crosslinked polymer with AIBN. Similar results were previously reported for the polymerization with benzoyl peroxide (8). The cationic polymerization of /7-alkoxystyrene monomers have been shown to proceed at rates that are comparable to vinyl ethers (12,13). As expected from these studies, we found that alkenyloxystyrene monomers also have a high degree of cationic reac-... 

Lack of selectivity in the reaction of the /3-D-glucoside derivative with one molar equivalent of benzylthiocarbonyl chloride has also been noted 40% of the 2,3-diester and 40% of the starting material were isolated.40 Similarly, unimolar benzoylation of phenyl 4,6-0-benzylidene-/3-D-glucopyranoside gave only 9% of the 3-ester, together with 47% of the 2,3-diester.41 Acylation of benzyl 4,6-0-benzylidene-/8-D-glucopyranoside with acetic anhydride-pyridine-pyridine hydrochloride yielded,42 in contrast to the reaction with the... 

Erythromycin has efficacy similar to tetracycline, but it induces higher rates of bacterial resistance. Resistance may be reduced by combination therapy with benzoyl peroxide. Erythromycin can be used for patients who require systemic antibiotics but cannot tolerate tetracyclines, or those who acquire bacterial resistance to tetracyclines. The usual dose is 1 g/day with meals to minimize GI intolerance. 

The formation of Reissert derivatives of the antineoplastic agent ellipticine (225) (Scheme 29) and their reactions have been extensively studied by Popp and co-workers 39,49-51). The ellipticine Reissert compound 226 could be prepared either with benzoyl chloride and potassium cyanide in a dichloromethane-water system or, better, with benzoyl chloride and trimethylsilyl cyanide in dichloromethane. In similar manner 9-methoxyellipticine and a number of 6-substituted ellipticines have also been converted to the corresponding Reissert compounds. 

Highest yields are obtained when the reaction is carried out in boiling toluene until all water and ethanol are eliminated by azeotropic distillation. Other /S-ketocarboxylic esters such as ethyl benzoyl acetate, o-methoxybenzoyl acetate and ethyl acetonedicarboxylate react similarly with aromatic amidoximes (50). 

The Reissert-Henze and the Feely-Beavers-Tani reactions are considered together in this section because of their similarity. The former involves cyanation of acyloxy (formed in situ) (Scheme 113), and the latter alkoxy (Scheme 114), quaternary salts. The Reissert-Henze reaction is a facile, fairly general reaction for quinoline and isoquinoline AT-oxides (Table 19) with cyanation occurring a to the ring nitrogen. Certain substituents inhibit reaction, for example a 1-methyl group (equation 125), and others undergo replacement (Scheme 130) (81H(15)98l). Reaction of 1-methylisoquinoline 2-oxide with benzoyl chloride... 

Selective dibenzoylation64 of methyl a-L-fucopyranoside (20) with benzoyl chloride-pyridine at a low temperature gave the amorphous 2,3-dibenzoate in high yield (80-85%) methyl 3-O-benzoyl-a-L-fuco-pyranoside was also isolated, in 6% yield. [Similar treatment of methyl 6-deoxy-a-L-mannopyranoside (a-L-rhamnopyranoside) gave the corresponding 2,3-dibenzoate in 50% yield, although, in this compound,... 

In a mechanistically similar process, the neutral palladium(II) dipyridylamine complex (24), obtained by deprotonation of complex (23), underwent reaction with benzoyl chloride to give the substituted complex (25) together with some free ligand (Scheme 8).33 This particular reaction sequence could not be generalized because of the relative instability of other metal complexes related to compound (24). However, a more extensive series of electrophilic substitutions could be carried out on the neutral complex (26), which displayed ambident nucleophilic behaviour by reaction with benzyl chloride and benzoyl chloride at nitrogen and reaction with benzenediazonium fluoroborate at carbon (Scheme 9). 

Benzoylation of benzoylmethylene triphenylarsorane (20) with benzoyl bromide gave a kinetically controlled acylated product, which on treatment with sodium acetate in chloroform afforded thermodynamically controlled dibenzoylmethylene triphenylarsorane (21) (56). Acylation with carbonic acid anhydride (32, 56), phenylisocyanate (32), or chloroformic ester (32) gave in no case O-acylated product. Similarly, reaction with acetic anhydride afforded l,3-dioxo-l-phenyl-butylidene-(2)-triphenylar-sorane (56). 

The first representative of this group, a /3-acylamino-a,/8-unsaturated ester, yielded 67 through pyrolysis in diphenyl ether205-207 [Eq. (53)]. A modification of this method used a Schiff s base instead of die TV-acyl derivative of a j8-amino-a,j8-unsaturated acid.208 Similarly, enamino esters react with benzoyl chloride to yield 6//-l,3-oxazines.209... 

The radical end (7) may be formed via homolytic decomposition of the vanadium-carbon bond in the presence of MMA and be stabilized by the vanadium ion. This stabilization is likely to cause a living radical polymerization of MMA. A similar conclusion has been reached by Lee et al. 113) who found that a mixture of chromium acetate with benzoyl peroxide initiated a living radical polymerization of MMA at low temperatures below 30 °C. 

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