Chloride, alkyl pyridines

As with polybut-l-ene and many other vinyl monomers that contain an asymmetric carbon, isotactic, syndiotactic and atactic stmctures may be drawn. Using co-ordination catalysts such as mixtures of cobalt chlorides, aluminium alkyls, pyridine and water high-1,2 (high vinyl) polymers may be obtained. One product marketed by the Japan Synthetic Rubber Company (JSR 1,2 PBD) is 91% 1,2, and 51-66% of the 1,2 units are in the syndiotactic state. The molecular mass is said to be several hundred thousand and the ratio MJM is in the range 1.7-2.6. 

If the temperature is not kept below 25°C during the reaction of primary alcohols with p-toluenesulfonyl chloride in pyridine, it is sometimes observed that the isolated product is not the desired alkyl p-toluenesulfonate but is instead the corresponding alkyl chloride. Suggest a mechanistic explanation for this observation. 

In a typical reaction, a series of C - O linked pyrazinone-triazoles were irradiated with an excess (3.5 equiv) of DMAD in o-DCB. The reactions were completed in 6-20 min at 180 °C, using a maximum irradiation power of 200 W. After spontaneous elimination of the corresponding isocyanate or cyanogen chloride, the pyridines and pyridinones were formed in combined yields of 71-99%. It is noteworthy that the pyrazinones with an aryl moiety at the N-1 position yielded pyridines as major products, while those with ben-zyUc or alkyl ester moieties at the N-1 position furnished the corresponding pyridinones as major products. 

R = CHj, R = and adenocarpine(16 R = CH=CHPh, R = H) ° are likewise dehydrogenated to 2,3 -bipyridine, and related dehydrogenation reactions afford substituted 2,3 -bipyridines. Ullmann and Grignard reactions have been used to synthesise 2,3 -bipyridine, whereas the Gomberg reaction of 3-pyridinediazonium chloride with pyridine and alkyl pyridines affords 2,3 -bipyridine, along with other isomeric bipyridines, and alkyl substituted 2,3 -bipyridines, respectively. " Photolysis of 3-... 

Compound 142 was prepared by reacting 141 with chloroacetic acid under basic conditions which were accompanied by the loss of CO2. Acetylation and benzoylation of 141 with boiling AC2O or benzoyl chloride in pyridine yielded the corresponding 3-acetyl(benzoyl) derivatives 143 and 144, respectively <1994H(38)57>. Alkylation of 6-benzyl-5,6,7,8-tetrahydropyrido[4,3-tf pyrimidin-4(3//)-one 145 with l-(2-methoxyphenyl)-4-(2-chloroethyl)piper-azine afforded the 3-substituted derivative 146 <2000DEP19900544>. 

Symmetrical ethers are obtained from the dehydration of two molecules of alcohol with H2SO4 (see Section 5.5.3). Alcohols react with p-toluenesul-phonyl chloride (tosyl chloride, TsCl), also commonly known as sulphonyl chloride, in pyridine or EtsN to yield alkyl tosylates (see Section 5.5.3). Carboxylic acids, aldehydes and ketones are prepared by the oxidation of 1° and 2° alcohols (see Sections 5.7.9 and 5.7.10). Tertiary alcohols cannot undergo oxidation, because they have no hydrogen atoms attached to the oxygen bearing carbon atom. 

Mannitol hexanitrate is obtained by nitration of mannitol with mixed nitric and sulfuric acids. Similarly, nitration of sorbitol using mixed acid produces the hexanitrate when the reaction is conducted at 0—3°C and at —10 to —75°C, the main product is sorbitol pentanitrate (117). Xylitol, ribitol, and L-arabinitol are converted to the pentanitrates by fuming nitric acid and acetic anhydride (118). Phosphate esters of sugar alcohols are obtained by the action of phosphorus oxychloride (119) and by alcoholysis of organic phosphates (120). The 1,6-dibenzene sulfonate of D-mannitol is obtained by the action of benzene sulfonyl chloride in pyridine at 0°C (121). To obtain 1,6-dimethanesulfonyl-D-mannitol free from anhydrides and other by-products, after similar sulfonation with methane sulfonyl chloride and pyridine the remaining hydroxyl groups are acetylated with acetic anhydride and the insoluble acetyl derivative is separated, followed by deacetylation with hydrogen chloride in methanol (122). Alkyl sulfate esters of polyhydric alcohols result from the action of sulfur trioxide—trialkyl phosphates as in the reaction of sorbitol at 34—40°C with sulfur trioxide—triethyl phosphate to form sorbitol hexa(ethylsulfate) (123). 

TV-Alkyl- and iV-aryl-JV-thiobenzoylglycines (106) and hot acid anhydrides or acid chlorides in pyridine yield28,64 meso-ionic 4-acyl-1,3-thiazol-5-ones (105, R3 = R-CO), but at room temperature 4-acylation is avoided.65... 

The unsubstituted nitrogen atom in 1,2,4-dithiazolidines is more prone to electrophilic reactions. Both the potassium salt 11 and the initial product 12 can participate in alkylation and acylation reactions. Alkylation of salt 11 with alkyl halides is carried out in DMF or MeCN and compound 12 can react with alkyl halides in MeCN in the presence of inorganic bases (NaH, Bu OK, AcONa, NaHCOj, CS2CO3) NaHCO( proved to be the base of choice. Yields of alkylation products 26 in some cases reach 85-90%. Compound 12 was acylated by benzoyl chloride in pyridine to form the iV-benzoyl derivative 25 (Scheme 15) <2000SL1622, 20030BC3015>. 

Alkyl nitrites, which are readily prepared by reaction of the corresponding alcohols with nitrosyl chloride in pyridine, absorb UV in two regions - a broad band centered at ca. 210 nm (e 1000-1700) and a structured band at ca. 360-380 nm... 

Alkyl nitrones -> i -alkylamides. The methyl nitrones (I) derived from A -3-ketosteroids on treatment with p-toluenesulfonyl chloride in pyridine rearrange to... 

The antibiotic emimycin was first isolated (107) from Streptomyces No. 2021-1 and subsequent work (108) showed it to be 3-hydroxypyrazine 1-oxide which from infrared evidence (Nujol) was assigned the pyrazine structure (99, R = H) [alkyl derivatives have been assigned similar structures (978)]. It had an acidic pAi, 6.2 (108) and was a stronger acid than 2-hydroxypyrazine [acidic pA 8.23 (1082)]. Emimycin did not form acetyl derivatives under a variety of conditions acetic anhydride and pyridine, acetyl chloride and pyridine, or acetic anhydride and sulfuric acid (108). 

Beckmann rearrangement of a,3-unsaturated oximes usually gives rise to a,3-unsaturated lactams. However, treatment of unsaturated A-methyl nitrone (22) with p-toluenesulfonyl chloride in pyridine leads to selective migration of the vinylic rather than the alkyl bond, producing enamide (23) in 60% yield (equation 11). ... 

In the laboratory of T.-L. Ho, the total synthesis of the novel marine sesquiterpene (+)-isocyanoallopupukeanane was completed." In the endgame of the synthesis, it was necessary to install the isocyano group onto the tricyclic trisubstituted alkene substrate so that it will occupy the more substituted carbon atom (according to Markovnikov s rule). The Ritter reaction was chosen to form the required carbon-nitrogen bond. The alkene substrate was dissolved in glacial acetic acid and first excess sodium cyanide followed by concentrated sulfuric acid was added at 0 °C. The reaction mixture was stirred at ambient temperature for one day and then was subjected to aqueous work-up. The product A/-alkyl formamide was subsequently dehydrated with tosyl chloride in pyridine to give rise to the desired tertiary isocyanide which indeed was identical with the natural product. 

The rearrangement of ketone nitrones with tosyl chloride in pyridine has been described in full. The reaction has resemblances to the Beckmann rearrangement of oximes, but does not depend upon nitrone stereochemistry, and gives N-alkyl-(usually A-methyl) lactams. 

The liquid ammonia was then driven off, an equivalent of the ketone was added, and the mixture refluxed for completion of the aldolization. Lithium amide proved to be superior to sodium amide for these condensations. /-Butyl esters were preferred because they are readily cleaved by pyrolysis or by acid. Dehydration to the a,fi-unsaturated esters could be effected with thionyl chloride and pyridine. Hauser and Lindsay succeeded in effecting aldol condensation with ethyl acetate, which undergoes self-condensation very readily two equivalents of base were used. Sisido has reported further alkylations of /-butyl esters. 

An aryl cyclopropyl ketone reacted with hydroxylamine followed by a mixture of tosyl chloride and pyridine to give the corresponding 7V-arylcyclopropanecarboxamide as the sole product in fair yield.Alkyl cyclopropyl ketones, on the other hand, afforded mixtures of the corresponding A-alkylcyclopropanecarboxamide and A7-cyclopropylalkanamide in excellent total yield on reaction with hydrazoic acid (Schmidt reaction) in the presence of sulfuric acid or trichloroacetic acid, an example is the formation of 3. When sulfuric acid was used, the amide ratio was sensitive to the acid strength of the reaction mixture. ... 

As mentioned in the discussion of the pathways to indoles (Scheme 27), a detailed indole synthesis with two points of diversity based on the Heck reaction has been reported [164]. The indole core structure was synthesized via a 5-exo-tng transition state, which provided the exocyclic double bond that subsequently underwent exo to endo double-bond migration. The anthranilate building block was prepared in solution and immobilized by a method previously described for the loading of 2-aminobenzophenones [Ij. After Fmoc cleavage, the resulting 4-bromo-3-amino-phenyl ether was treated with acid chlorides and pyridine in CH2CI2. As outlined in Scheme 29, alkylation of the anilide with substituted allyl bromides was achieved in the presence of lithium benzyloxazoHdinone in THF. The reaction mixture was treated with base for 1 h and then an aUylic halide was added and the mixture was vortexed for 6 h at room temperature. The alkylation reactions were... 

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