Pyrrolyl

Thiazoles with Heterocyouc Substituents. Thiazoles with heterocyclic substituents in the 2- or 4-position have been synthesized (Table II-9). Thus thioacetamide (or its a-substituted derivatives) react with bromomethyl heteroarylketones under reflux in alcohol to give the corresponding 2-methyl-4-heteroarylthiazoles heteroaryl groups in the 4-position were 2 -thienyl (213, 692) a-pyrrolyl and 3-method derivatives... 

Dimethyl-l-phenyl-3-pyrrolyl)vinyl]-6-dimethylamino-l-methylquinolimumpamoate [3546-41-6]... 

Pyrrole is soluble in alcohol, benzene, and diethyl ether, but is only sparingly soluble in water and in aqueous alkaUes. It dissolves with decomposition in dilute acids. Pyrroles with substituents in the -position are usually less soluble in polar solvents than the corresponding a-substituted pyrroles. Pyrroles that have no substituent on nitrogen readily lose a proton to form the resonance-stabilized pyrrolyl anion, and alkaU metals react with it in hquid ammonia to form salts. However, pyrrole pK = ca 17.5) is a weaker acid than methanol (11). The acidity of the pyrrole hydrogen is gready increased by electron-withdrawing groups, eg, the pK of 2,5-dinitropyrrole [32602-96-3] is 3.6 (12,13). 

N-Alkylpyrroles may be obtained by the Knorr synthesis or by the reaction of the pyrrolyl metallates, ie, Na, K, and Tl, with alkyl haUdes such as iodomethane, eg, 1-methylpyrrole [96-54-8]. Alkylation of pyrroles at the other ring positions can be carried out under mild conditions with allyhc or hensylic hahdes or under more stringent conditions (100—150°C) with CH I. However, unless most of the other ring positions are blocked, poly alkylation and polymerisation tend to occur. N-Alkylation of pyrroles is favored by polar solvents and weakly coordinating cations (Na", K" ). More strongly coordinating cations (Li", Mg " ) lead to more C-alkylation. 

Aryl-4,5-dihydropyridazin-3(2//)-ones react with pyrrolylmagnesium bromide to give 6-aryl-3(l-pyrrolyl)pyridazines or, when 1 4 molar amounts of reagents are used, a mixture of 6-aryl-3(l-pyrrolyl)pyridazines and 3,4-di(l-pyrrolyl)-4,5-dihydropyridazines (Scheme 54 (79RRC453). 

Acetic acid, 3-ethoxycarbonyl-l-methyl-2-pyrrolyl-ethyl ester reduction, 4, 287 Acetic acid, 9-hydroxyethoxy-as metabolite of dioxane, 1, 245... 

Acetic acid, 2-hydroxy-2-(2-pyrrolyl)-ethyl ester... 

Buta-1,3-diene, 1 -(2 -furyl)-pyrolysis, 4, 600 Buta-1,3-diene, 1-mercapto-thiophenes from, 4, 887 Buta-1,3-diene, 1 -(1 -methyl-2-pyrrolyl)-thermal cyclization, 4, 285 Buta-1,3-diene, l-(2-thienyl)-electrocyclization, 4, 748 Butadienes... 

Butan-3-one, 2-hydroxy-2-(indolyl)-photodecomposition, 4, 233 Butan-3-one, 2-hydroxy-2-(pyrrolyl)-photodecomposition, 4, 233 Butazolidines applications, 5, 782 Butazone, y-hydroxyphenyl-antiinflammatory agents, 5, 296 Butazone, phenyl-metabolism, 1, 239, 5, 301 synthesis, 5, 230 But-l-ene, 1-morpholino-polymers, 1, 291... 

Methane, bis(2-acetyl-l-pyrrolyl)-photoisomerization, 4, 203 Methane, bis( 1 -aryltetrazol-5-yl)dichloro-rearrangement, 5, 824 Methane, bispyrrolyl-synthesis, 4, 274 Methane, bis(2-pyrrolyl)-oxidation, 4, 271 reactions... 

Propionic acid, pyrrolyl-synthesis, 4, 232 Propionic acid, 3-(2-pyrrolyl)-intramolecular acylation, 4, 221 Propylamine, oxadiazolyl-synthesis, 6, 445... 

Pyrimidine, 2-phenyl-1,4,5,6-tetrahydro-synthesis, 3, 115 Pyrimidine, 2-phenylthio-synthesis, 3, 136 Pyrimidine, polychloro-as pharmaceuticals, 1, 157 Pyrimidine, polyfluoroalkyl-synthesis, 3, 77 Pyrimidine, 5-(2-pyrrolyl)-synthesis, 4, 228 Pyrimidine, styryl-oxidation, 3, 76 polymers, 1, 289 synthesis, 3, 76... 

H- Pyrro lo[l,2-c][l,2,4]triazol-3-ones synthesis, 6, 991 Pyrroloyl azides Curtius rearrangement, 4, 288 Pyrrolyl anions acylation, 4, 232 alkylation, 4, 235 solvent effects, 4, 236 C-alkylation... 

JCS(F)1297 (aminoacridine) 97NKK393 (aminopyridine) 97SA(A)1723 (aminoacridine) 98CL169 (2-(pyrrolyl)ethenyl)... 

A photoinduced hydrogen atom transfer in cw-l-(2-pyrrolyl)-2-(2-quino-line)ethene was reported (94JA3171).The rate eonstant A (5 —> 4) increases with increasing temperature from 2.1 10 s at 15.8°C to 7.7 10 s at 39.5°C, giving an aetivation energy of 9.4 keal/mol. 

For similar studies with pyrrolyl-quinolylethenes pyrrolylethenes see 94JA3171 and 98CL1153. 

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