Vinyl pyridine derivatives

Nitrite salts inhibit the sometimes explosive spontaneous polymerisation of W-vinyl-pyridine derivatives . 

Figure 3 shows the production of acetaldehyde in the years 1969 through 1987 as well as an estimate of 1989—1995 production. The year 1969 was a peak year for acetaldehyde with a reported production of 748,000 t. Acetaldehyde production is linked with the demand for acetic acid, acetic anhydride, cellulose acetate, vinyl acetate resins, acetate esters, pentaerythritol, synthetic pyridine derivatives, terephthaHc acid, and peracetic acid. In 1976 acetic acid production represented 60% of the acetaldehyde demand. That demand has diminished as a result of the rising cost of ethylene as feedstock and methanol carbonylation as the preferred route to acetic acid (qv). 

A crystalline 5,5 -diene, or bis (vinyl ether), derivative of sucrose has been prepared from 6,6 -dideoxy- 6,6 -diiodo-sucrose hexa-acetate, derived from the 6,6 -ditosylate, by treatment with silver fluoride in pyridine (26). 

In marked contrast to the above results, double nitrile insertion into both the titanium-alkyl and titanium—vinyl bonds occurs to form the diazatitanacycles 74. Treatment of these titanacycles with dry hydrogen chloride affords the tetrasubstituted pyridine derivatives 75 (Scheme 14.32) [74], On the other hand, 2,3-diphenyltitanacyclobutene reacts with various nitriles to afford the products of mono-insertion, which afford the corresponding unsaturated ketones upon hydrolysis [73,74]. 

Methylisoxazolo[5,4-. ]pyridine, 132, reacts with vinyl ether in a photocyclization reaction to give a mixture of mono- and bicyclic products, including a moderate yield of the dihydropyrrolo[3,2-3]pyridine derivative as one of three major products shown in Equation (65) <2002EJ04211>. 

The 3-acetylpyridines 15 condensed with hydrazines to afford 1-substi-tuted derivatives (16 R1 = H, Ph, CONH2),25 which may also be prepared26 from the chloro vinyl pyridine 17. 

Other monomers have been successfully grafted on polyamide under UV light sources. Hence, organic acids as acrylic (72,73), methacrylic (74), ftimaric (73), itaconic (73), and styrene sulfonic in 25% aqueous solution (73). Methyl acrylate and acrylamide in the presence of photosensitizers (74,75) and acrylonitrile (76) are reported as well. Heterocyclic derivatives as vinyl pyridine and vinyl pyrrolidone under UV light using photosensitizers as benzophenone were grafted on Nylon 66 cloth (77). 

Triazines react also with electron-rich dienophiles such as ethyl vinyl ether (401 R = Et) or vinyl acetate (401 R = Ac) in boiling dioxane to yield the pyridine derivatives (376). After the usual [4 + 2] cycloaddition and nitrogen elimination from the bicyclic compound (402), the dihydropyridines (403) eliminate ethanol or acetic acid to give the aromatic pyridines (376). The dienophiles (401) can therefore be used as alkyne equivalents (69TL5171). 

Reaction of 2-aminobenzo[6]thiophene stannichloride with methyl vinyl ketone in the presence of ferrous chloride and zinc chloride yields 4-methyl[l]benzothieno[2,3-6]pyridine (176a).516 Reaction of the plumbichloride complex of 2-aminobenzo[6]thiophene hydrochloride with the diethyl acetal of acetoacetaldehyde in the presence of zinc chloride affords 176b,549 The pyridine derivative (176c) is obtained... 

Ethoxycarbonyl-2-(triphenylphosphoranylidenamino)vinyl]pyridine (43) with phenyl isocyanate gave a separable mixture of ethyl 8-anilino-l,7-naphthyr-idine-6-carboxylate (44) and an isomeric 2,6-naphthyridine derivative (formed by an alternative cyclocondensation) (reactants, PhMe, 20°C, 2 h then 180°C, sealed, 72 h 23% and 22%, respectively, after separation) analogs likewise.442... 

Bromobis[2,3-butanedione dioximato( 1 -)] (4-terf-butylpyridine)cobalt(lIl) is a tan, microcrystalline solid with greatly enhanced solubility in organic solvents compared to the chloro(pyridine) analogue. It is also the compound of choice in preparing alkylcobaloximes by the subsequent procedure because of the ease of isolation of the resultant products. In addition, the bromo(4-ferf-bupy) species react directly with electron-rich olefins, such as ethyl vinyl ether, in the presence of ethanol to yield, in this case, bis[2,3-butanedione dioximato(l-)]-(2,2-diethoxyethyl)(pyridine)cobalt(III).1J Conversion of the dimethyl sulfide compound to the pyridine derivatives is readily detected by a characteristic infrared absorption at 1600 cm 1 (pyridine stretch). The H nmr spectrum of bromobis[2,3-butanedione dioximato(1 -)] (4-ferf-butylpyridine)cobalt (III) has absorptions in the alkane region in the ratio of 3 4 at 6 1.25 ppm [Py—C (CH3)3 ] and 6 2.43 ppm (dh—CH3) from tetramethylsilane. 

Pyridylethyl derivatives of 2 are formed by reaction of a- or y-vinyl-pyridine with 2.107 Treatment of 1 or 2, as well as the 5-arylidene derivatives, with acrylonitrile in the presence of pyridine results in formation of 84 by cyanoethylation on the ring nitrogen (Scheme 2) however, cyanoethyla-tion of 5-aryl-2-iminothiazolidinones involves the exocyclic nitrogen.108 Aminoalkylation (Mannich reaction) of 2 or 2-aryl-4-thiazolidinones with formaldehyde and amines in warm alcoholic solvents affords the desired 3-alkylated product 85 (Scheme 2),109,110 whereas 3-aryl-2-iminothiazoli-dinones react with substituted anilines and aliphatic amines and formaldehyde to give the 2-arylaminomethyl derivatives 86 [Eq. (25)].111... 

Comins, D.L., and Deghani, A. 1992. Pyridine-derived triflating reagents An improved preparation of vinyl triflates from... 

Diels-Alder reactions. The amino group at Ci renders this position electrophilic, whereas C4 is nucleophilic (push-pull diene). The diene (1) can react as a vinyl keteniminium chloride (la) in reactions with simple nitriles such as acetonitrile or acrylonitrile. After treatment with base a pyridine derivative (2) is obtained. The... 

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