Chloro compounds acyl chlorides

Hydroxythiadiazoles can be converted into chloro compounds by the usual methods, for example with POCI3. The 0-acylation of the sodium salt of hydroxythiadiazoles with dimethylthiocarbamoyl chloride followed by thermal rearrangement of the thiolcarbamate and hydrolysis is a convenient route to l,2,5-thiadiazole-3-thiones <73CJC2349>. 

Amino groups can also be derivatized using acyl chlorides that form amides. A number of suitable acyl chlorides including p-chloro-, p-methoxy-, p-nitroben-zoyl-, p-tolyl-, and p-nitro-benzenesulfonyl chloride have been successfully used for sensitive UV-Vis derivatization of nonabsorbing amine compounds (231). Among all those amide derivatives, p-methoxybenzamides appear more attractive because they exhibit high molar absorptivity at the convenient analytical wavelength of 254 nm. After derivatization in tetrahydrofuran-sodium hydroxide solu-... 

Dechlorination of 4-chloro-6-methylthieno[2,3-d]pyrimidine 164 with zinc in ethanol and acetic acid at 80°C gave compound 165. The latter was subjected to the Reissert reaction using two equivalents each of tributyltin cyanide and acyl chloride in dichloromethane at room temperature. With benzoyl chloride the mono-Reissert adduct 166 was obtained, whereas with acetyl chloride the di-Reissert product 167 (86JHC545). 

Indoles 371 are selectively acylated at the 3-position to give high yields of compounds 372 on treatment with a wide variety of acyl chlorides in dichloromethane in the presence of chloro(diethyl)aluminium or chloro(dimethyl)-aluminium. The reaction proceeds under mild conditions (at 0 °C or rt, mainly for 1.5 h) and is applicable to indoles bearing various functional groups (both acid and base sensitive indoles) without NH protection (Equation 84) <20000L1485>. 

Cyanuric chloride has been used for the preparation of acyl chlorides, amides, and peptides. Conversion of cyanuric chloride into 2-chloro-4,6-dimethoxy-l,3,5-triazine (CDMT, 6) leads to a reagent that upon reaction with carboxylic acids produces the highly reactive 2-acyloxy-4,6-dimethoxy-l,3,5-triazines.P l The resulting active ester is a powerful acylating agent for alcohols and amines. The activation is performed in presence of a base, preferentially NMM, which leads to intermediate formation of 4-(4,6-dimethoxy-l,3,5-triazin-2-yl)-4-methylmorpholinium chloride (DMTMM, 7)P l (Scheme 5). This addition product is readily prepared from the commercially available CDMT (6) and NMM in THF and can be stored as solid compound in the cold.P P l It offers the advantage that it can be used in a one-... 

Quantitative conversion of 1-adamantanecarbonyl chloride to 1-adamantanecarbox-aldehyde has been accomplished by reduction of the acyl halide at carbon and mercury in MeCN containing TEAP [227]. Lozano and Barba [228] reduced 2-chloro-2-phenylacetyl chloride at mercury in methylene chloride containing TEACl and obtained derivatives of pyran-2-one and pyran-4-one. In subsequent work [229,230], these authors investigated the reduction of 2-bromo-2,2-diphenylacetyl bromide at graphite in methylene chloride containing TEABr and in the presence of inorganic sulfur compounds in the first study, a new sulfurated heterocyclic product was obtained ... 

In considering the synthesis of this compound several alternatives are possible. Two will be considered. Aniline may be sulfo-nated to sulfanilic acid, and after acetylation the chloride may be prepared by the action of phosphorus pentachloride. The acyl chloride, on ammonolysis, will give the acetylated sulfonamide. The other possibility is to use chlorosulfonic acid and introduce the sulfo and chloro groups simultaneously. Aniline is acetylated, and the acetanilide is sulfonated with excess of chlorosulfonic acid. The sulfonic acid group is introduced first, and by further reaction the acid chloride is formed ... 

A substituent which appears to be even more readily displaced by nucleophiles than alkylsulfonyl groups is 0-mesyl (OSO CH ). Conversion of a cyclic lactam to its 0-mesyl derivative is accomplished by treatment with methanesulfonyl chloride/Et N in methylene chloride solution displacement takes place readily with dlmethylamine (15 min at 20 in dioxane). This may prove to be a generally useful procedure for replacement of lactam oxygen by other nucleophiles without resorting to intermediate chloro compounds. Note that 2-trlfluoromethanesulfonyloxypyridlne (from 2(lH)-pyridone, NaH, and trifluoromethanesulfonyl chloride) is an effective reagent for cile acylation of activated aromatic compounds with carboxylic acids. 

Treatment of alkanoic acids with thionyl chloride and a catalytic amount of pyridine causes oxidation at the a-methylene group and the formation of an a-chloro-a-(chlorosulphenyl)acyl chloride, RCHiQSCOCICOCl. This usually reacts further and when R contains a benzene ring, this may be attacked with consequent formation of a fused ring system.. Unsaturated aralkanoic acids behave similarly. Extension of this work to related compounds suggests that a concerted elimination-cyciization operates. 

Various 2-oxo compounds have been subjected to a variety of reactions. Alkylation and acylation result in the formation of 1,3-disubstituted products.Similarly the Mannich reaction with morpholine gives products such as the bis compound 107. Halogenation of the 0x0 compound 108 with bromine in acetic acid," or chlorine in acetic acid, ° or with sulfuryl chloride results in formation of the monohalo derivatives 109. The chlorine atom in 109 (R = Cl) can be removed by hydrogenation over palladium on charcoal. Nitration of the chloro compound 110 with a mixture of nitric and sulfuric acids provides the nitro derivative 111, which may be catalytically reduced to the amino compound 112. If the reduction is carried out in the presence of an aldehyde, the product is a substituted amino derivative (113). Alternatively the amine 112 can be condensed with an aldehyde and the resultant Schiff base reduced to give the product 113. 

Many alkylidenephosphoranes can be transformed into new phosphonium ylides by reactions which take place in the side chain of a parent ylide, the a-C atom of the ylide group not being involved. Allylidenetriphenylphosphoranes react with a series of chloro compounds (alkyl chloioformates, acyl chlorides, 3-chloroacrylates, 2-chlorovinyl ketones, phosphorus chlorides) and other electrophilic compounds at the 7-C atom. Abstraction of a proton from the 7-position of the resulting phosphonium salts by a second mole of starting ylide (or proton migration) gives rise to the formation of -substituted derivatives of the original allylidenephosphoranes (equation 90). 

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