Acetyl Chloride related reagents

Ethoxycarbonyl chloride is, by virtue of resonance involving the ester function, less reactive than acetyl chloride, and the reagent has found application for selective O-acylation in the steroid field.34 With this reagent, methyl 4,6-O-benzylidene-a-D-glucopyranoside yielded35 2- and 3-esters in the ratio 24 1, and the related benzyl-thiocarbonyl chloride gave the 2-ester in 58% yield.36... 

Alcohol Compounds.—That the carbohydrates are, in fact, alcohol compounds is shown, both by their relation to poly-hydroxy alcohols and by their reactions. Carbohydrates possess alcohol characters in that they undergo distinctly alcoholic reactions. Like all alcohols they react with acetyl chloride or acetic anhydride. In.practice the latter reagent is used. They form acetyl derivatives, or esters, just as ethyl alcohol does. 

The trimethylammonium butyrate (TMAB) isotopic tags, which are synthesized as amine-reactive AMiydroxysuccinimide derivatives, were first described by Regnier and coworkers (72). The chemical name of the TMAB-A-hydroxysuccinimide reagent (TMAB-NHS) is [3-(2,5-dioxopyrroli-din-l-yloxycarbonyl)propyl] trimethylammonium chloride. The label incorporates a quaternary amine so that the labeled peptide retains a positive charge in place of the free amine (unlike acetylation and related labels described in the next section). 

To start our investigations, we examined the conversion of 2,3-dimethyl-2-butene (1) into 3,3,4-trimethyl-4-penten-2-one (2) as a model reaction (eq. 1). The choice of acetic anhydride as the acetylating agent was made in the light of related studies on the acylation of aryl ethers. Our work in this field had shown that acetic anhydride was the most effective reagent for the Friedel-Crafts acylation of anisole in the presence of Hp zeolite. A lower degree of conversion was achieved with acetyl chloride, while hardly any reaction occurred with ethyl acetate or acetic acid [6]. 

Related Reagents. Trichlorosilane triethylsilane dimethyl-(3) phenylsilane chlorotris(triphenylphosphine)rhodium(T) hydrogen peroxide potassium fluoride tetrabutylammonium fluoride acetyl chloride aluminum chloride. 

Acyl halides, such as acetyl chloride, and acid anhydrides, such as acetic anhydride, are used exclusively as reagents rather than as solvents. Consequently, their physical properties, such as boiling points and dielectric constants, are of less interest than those of other acyl derivatives. Because neither acyl hahdes nor acid anhydrides form tntermolecular hydrogen bonds, their boiling points are similar to structurally related carbonyl compounds of approximately the same molecular weight. 

Related Reagents. Acetyl Chloride Acetyl Bromide Iso-propenyl Acetate Vinyl Acetate Acetyl Cyanide. 

Related Reagents. Acetic Anhydride Acetyl Chloride Acetyl Cyanide Benzoic Anhydride Benzoyl Trifluoromethanesul-fonate p-Nitrobenzoyl Chloride. 

Related Reagents. Acetyl Chloride Bromotrimethylsi-lane A-Chlorosuccinimide-Dimethyl Sulfide Dichloroborane Diethyl Etherate Hydrogen Chloride Iodine lodotrimethyl-... 

The Bischler-Napieralski synthesis of l-methyl-3,4-dihydroisoquinoline (18) from N-(2-phenylethyl)acetamide (19) in the presence of heat and acid (72) was not predicted by the Electrophilic Aromatic module of CAMEO this module of CAMEO predicted instead the formation of methyl 2-acetyl-phenethylamine, 20 (Scheme 5). In a related case, CAMEO predicted (when the Electrophilic Aromatic module was chosen) that 4-anilino-butan-2-one (21) would undergo intramolecular cyclization to form 4-hydroxy-4-methyl-tetrahydroquinoline, 23 (Scheme 6). Apparently, CAMEO correcdy perceives the eneamine character of 21 as necessary for this reaction to occur. It was noted in this case that ring formation, as predicted by CAMEO, depended upon the presence of mineral acid, but did not occur if a Lewis acid (e.g., stannic chloride) was selected instead as the reagent. It is known, however, that intramolecular cyclization of 21 does occur in the presence of a Lewis acid and yields 4-methyl-quinoline, 22, as product (74). 

Regioselective debenzoylation of nucleoside 2, 3 5-tri-O-benzoates using hydrazine hydrate has been reported. With 1 mol reagent in acetic acid-pyridine the 3 5-di-O-benzoyl derivative was produced when the bases were adenine, guanine, or indole, whereas with excess hydrazine hydrate in 1 1 chloroform-methanol, 98% of the 5-O-benzoyl derivative was produced (base = adenine or uracil). 3, 5-Di-O-benzoyl-2-deoxy-nucleosides gave a 90% yield of a 1 1 mixture of 3 - and 5-O-benzoyl nucleosides with 1 mol hydrazine hydrate in pyridine. Treatment of the mannose orthoacetate (5) with benzoyl chloride in pyridine gave 2,3,4,6-tetra-O-acetyl-a-D-mannopyranosyl chloride and ethylbenzoate, whereas the related orthoester of mu co-inositol (6) gave 66% of the correspond-... 

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