I-Butyl chloroformate

In contrast to this demonstration of bimolecularity, Hall and Lueck82 showed the possibility of acylium ion formation from benzoyl chloride by its reaction with mercuric perchlorate. In common with dimethylcarbamyl chloride, dimethylsulphamyl and tetramethyldiamidophosphochloridate, benzoyl chloride reacted readily to form the corresponding acylium ion /i-butyl chloroformate however was inert. Kivinen138 studied the effect of mercuric chloride on the ethanolysis of 4-methoxybenzoyl chloride, benzoyl chloride and 4-nitrobenzoyl chloride and obtained the following approximate relative rates for the effect of mercuric chloride (0.30 M) in ethanol, 4-MeO, 2.91 4-H, 1.00 4-NOz, 1.03, confirming the SN2 character of the 4-nitro-... 

Peptide synthesis /-Amyl chloroformate. Bis-(2,4-dinitrophenyl)carbonate. Bis-o-phenylene pyrophosphite. i-Butyl chloroformate. sec-Butyl chloroformate. /-Butyl chloroformate. /-Butyl 2,4,5-trichlorophenyl carbonate. CopoIy(ethylene-N-hydroxymaleimide). N,N-Diethyl-I-propynylamine. Di-(p-nitrophenyl)sulfate. Ethoxyacetylene. N-Ethoxycarbonyl-2-ethoxy-l,2-dihydroquinoline. N-Ethylbenzisoxazolium fluoroborate. Ethyl chloroformate. N-Ethyl-5-phenylisoxazolium-3 -sulfonate. N-Hydroxysuccinimide trifluoroacetate. Methyl-morpholine. 4-Methylthiophenol. p-Nitrophenol. Oxalylchloride. Pentachlorophenol. Pentamethylbenzyl chloride. /-Pentyl chloroformate. Phenacyl bromide. Polyhexamethylene carbodiimide. Tetraethyl pyrophosphite. 1,2,4-Triazole. 

Dimethylaminopyridine (DMAP) is widely used (in catalytic quantities) to activate anhydrides in a similar manner. The salt derived from DMAP and i-butyl chloroformate is stable even in aqueous solution at room temperature. The more stable these salts are, the higher their catalytic activity in acylation... 

The importance of the solvent, in many cases an excess of the quatemizing reagent, in the formation of heterocyclic salts was recognized early. The function of dielectric constants and other more detailed influences on quatemization are dealt with in Section VI, but a consideration of the subject from a preparative standpoint is presented here. Methanol and ethanol are used frequently as solvents, and acetone,chloroform, acetonitrile, nitrobenzene, and dimethyl-formamide have been used successfully. The last two solvents were among those considered by Coleman and Fuoss in their search for a suitable solvent for kinetic experiments both solvents gave rise to side reactions when used for the reaction of pyridine with i-butyl bromide. Their observation with nitrobenzene is unexpected, and no other workers have reported difficulties. However, tetramethylene sulfone, 2,4-dimethylsulfolane, ethylene and propylene carbonates, and salicylaldehyde were satisfactory, giving relatively rapid reactions and clean products. Ethylene dichloride, used quite frequently for Friedel-Crafts reactions, would be expected to be a useful solvent but has only recently been used for quatemization reactions. ... 

The reactions of phenyl-, i-butyl- and fluoroboron-capped hexachloride iron(II) precursors with aliphatic amines proceeded under steady-state conditions of the solvent, temperature, and reaction time to produce clathrochelates of only one type irrespective of the nature of the substituent at the boron atom (Scheme 18). Therefore, the reactions of the phenylboronic Fe(Cl2Gm)3(BC6H5)2 precursor were studied. The reaction of precursor with n.-butylamine in DMF, benzene, THF, and /i-butylamine as the solvent led to the formation of only tetrasubstituted clathrochelate, whereas the reaction in chloroform unexpectedly resulted in trisubstituted clathrochelate, which underwent further functionalization in DMF with re-butylamine and cyclohexylamine but did not react with diethylamine (Scheme 18). 

Mixed anhydride synthesis. For use of the reagent in peptide synthesis, see Butyl chloroformate. The principle involved is illustrated by a procedure for the preparation of diethyl benzoylmalonate (3). Benzoic acid is condensed with cathyl chloride in toluene in the presence of triethylamine to produce the mixed anhydride (I), and an ethereal solution of ethoxymagnesium malonic ester (2), prepared from mulunic ester, magnesium, ethanol, and a trace of carbon tetrachloride as catalyst, is added... 

An alternative approach to increasing the rate of esterification is to activate further the intermediate (2). N-Bromosuccinimide has been used for this purpose, but unsaturation in the carboxylic acid or alcohol is not tolerated. More generally useful is the addition of an activated halide, usually A//y/ Bromide, to a chloroform solution of (1) and a carboxylic acid, resulting in formation of the acylimidazolium salt (3) (eq 4). Addition of the alcohol and stirring for 1-10 h at room temperature or at reflux affords good yields of ester in a one-pot procedure. These conditions work well for the formation of methyl, ethyl, and i-butyl esters of aliphatic, aromatic, and a,/3-unsaturated acids. Hindered esters such as i-butyl pivalate can be prepared cleanly (90% yield). The only limitation is that substrates must not contain functionality that can be alkylated by the excess of the reactive halide. 

Isobutyl Sulfonate. With Silver(I) p-Tobienesulfonate, alkyl chloroformate forms sulfonic carbonic anhydride which when heated liberates carbon dioxide, producing alkyl sulfonate. In order to find out the mechanism of the decomposition of the mixed anhydride, reaction of isobutyl chloroformate and silver p-toluenesulfonate was investigated. If the free alkyl cation, i.e. isobutyl carbonium ion, is formed, the rearrangement to i-butyl and r-butyl carbonium ion would be expected, finally resulting in the formation of j-butyl p-toluenesulfonate. r-Butyl p-toluenesulfonate is unstable and is not expected to survive under the reaction conditions. In fact, decomposition gave a mixture of isobutyl p-toluenesulfonate and J-butyl />-toluenesulfonate in a 0.8 1 mol ratio, with a quantity of isobutene and free p-... 

Nearly all of the benzyl chloride [100-44-7], henzal chloride [98-87-3], and hen zotrichl oride /P< -(97-i manufactured is converted to other chemical intermediates or products by reactions involving the chlorine substituents of the side chain. Each of the compounds has a single primary use that consumes a large portion of the compound produced. Benzyl chloride is utilized in the manufacture of benzyl butyl phthalate, a vinyl resin plasticizer benzal chloride is hydrolyzed to benzaldehyde hen zotrichl oride is converted to benzoyl chloride. Benzyl chloride is also hydrolyzed to benzyl alcohol, which is used in the photographic industry, in perfumes (as esters), and in peptide synthesis by conversion to benzyl chloroformate [501-53-1] (see Benzyl ALCOHOL AND p-PHENETHYL ALCOHOL CARBONIC AND CARBONOCm ORIDIC ESTERS). 

Chloro-17-nitroso-3/i-hydroxy-5a-androstane 213, generated from the oxime 212 of epiandrosterone and t-butyl hypochlorite, reacts with cyclohexadiene in chloroform/metha-nol at — 20 °C to yield, after two weeks, epiandrosterone and the bridged dihydrooxazine 214 in an enantiomeric excess of better than 95%108. 

Eor the former solvent log D = -1.92 (experimental) vs. -1.98 (calculated) and for the latter log D = 0.76 (experimental) vs. 0.88 (calculated). Obviously, succinic acid with two carboxylic groups that strongly donate hydrogen bonds (assigned a = 1.12 as for acetic acid) prefers the basic (in the Lewis basicity, hydrogen-bond-accepting sense) tri-n-butyl phosphate ( i = 0.82, measured for the wet solvent) over water (P = 0.47) and naturally also chloroform (P = 0.10). 

Comparison of the configuration of the stannane with the prodncts of reaction reveals that primary alkyl halides that are not benzyhc or a to a carbonyl react with inversion at the lithium-bearing carbon atom. In the piperidine series, the best data are for the 3-phenylpropyl compound, which was shown to be >99 1 er. In the pyrrolidine series, the er of the analogous compound indicates 21-22% retention and 78-79% inversion of configuration. Activated alkyl halides such as benzyl bromide and teri-butyl bromoacetate afford racemic adducts. In both the pyrrolidine and piperidine series, most carbonyl electrophiles (i.e. carbon dioxide, dimethyl carbonate, methyl chloroformate, pivaloyl chloride, cyclohexanone, acetone and benzaldehyde) react with virtually complete retention of configuration at the lithium-bearing carbon atom. The only exceptions are benzophenone, which affords racemic adduct, and pivaloyl chloride, which shows some inversion. The inversion observed with pivaloyl chloride may be due to partial racemization of the ketone product during work-up. 

To detect peptides and amino acid derivatives using the chlorine peptide spray the following procedure is carried out. Solution I (1% tert-butyl hypochlorite in cyclohexane) and solution II (1% soluble starch and 1% KI in water) are prepared. To prepare solution II starch is dissolved in boiling water first and potassium iodide is added to the cold solution. A small amount of chloroform is added to inhibit bacterial growth. 

A tentative reservation exists about this work. As reported, in a communication, it as yet gives no explanation for the unexpected solubility of poly(r t-butyl isocyanide) in chloroform, nor does it describe a safeguard against the mutual solubility, i.e. plasticization, of polyisocyanides, which is a possibility between the non-crosslinked, otherwise insoluble support medium and the mobile solute. Yet, the rotation data is compelling. 

When HPLC is used as part of the analysis, the mobile phase is typically a mixture of methanol and methyl-tert-butyl ether (i.e., 50 50, v/v), although other HPLC solvents for LC/MS using APCI (e.g., water, tetrahydrofuran) can be used. It is important to note that if combustible nonaqueous solvent systems are used, water or a halogenated solvent such as methylene chloride or chloroform should be added to the mobile phase postcolumn to suppress ignition in the ion source. In addition, the APCI source must be vented outside the laboratory and should not allow air into the ionization chamber. A scan range of m/z 300 to 1000 will include the known carotenoids and their most common esters. 

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