Pyrrole-3-carbaldehyde, 1 -methyl

In 1970, Hiraoka reported that 2-cyanopyrrole, irradiated in methanol with a low-pressure mercury arc for 20 h, gave a mixture of 3-cyanopyrrole and pyrrole-2-carbaldehyde [70JCS(CC)1306]. l-Methyl-2-cyanopyrrole (38) also gave this reaction (Scheme 15) [71JCS(CC)1610]. In this case, the author isolated the product of the isomerization 39, the product of the shift in C-2 of the IV-methy 1 group 40, and a third product that was assumed to be derived from the addition of methanol to the Dewar pyrrole 41. The reaction depends on the temperature used in fact, no reaction occurred when the reaction was performed at -68°C. This result is in agreement with the presence of a thermal-activated step [78JCS(CC)131]. More... 

Substituted hydrazones 254 and 255 were synthesized by the reaction of the corresponding furo[3,2- ]pyrrole-5-carbohydrazides with 6-substituted 4-oxochromene-3-carbaldehydes 252 and methyl 2-formylfuro[3,2- ]pyrrole-5-car-boxylates 253 under MW irradiation as well as by the classical method(C). The beneficial effect of the MW irradiation on these reactions was a shortening of the reaction time and an increase in the yields <2005CCC2101> (Scheme 25). 

The condensation of furo[3,2- ]pyrrole-type aldehydes 8g and 265-267 with hippuric acid was carried out in dry acetic anhydride catalyzed by potassium acetate as is shown in Scheme 26. The product methyl and ethyl 2-[( )-(5-oxo-2-phenyl-l,3-oxazol-5(4//)-ylidene)methyl]furo[3,2- ]pyrrol-5-carboxylates 268a-d were obtained. The course of the reaction was compared with the reaction of 5-arylated furan-2-carbaldehydes with hippuric acid. It was found that the carbonyl group attached at G-2 of the fused system 8 is less reactive than the carbonyl group in 5-arylated furan-2-carbaldehydes in this reaction <2004MOL11>. The configuration of the carbon-carbon double bond was determined using two-dimensional (2-D) NMR spectroscopic measurements and confirmed the (E) configuration of the products. 

Methyl 2-[3-(trifluoromethyl)phenyl]-4/7-furo[3,2-4]pyrrole-5-carboxylate 81a was made by thermolysis of the corresponding methyl 2-azido-3- 5-[3-(trifluoromethyl)phenyl]-2-furyl propenoate 378, which was formed by condensation of 5-[3-(trifluoromethyl)phenyl]furan-2-carbaldehyde 377 with methyl azidoacetate under sodium meth-oxide catalysis (Scheme 40) <2006KGS825>. 

The first synthesis of the parent compound of the benzo[4,5]thieno[2,3-f]pyrrole ring system 387 <2003T1477> and its derivatives was accomplished using the same synthetic sequence (Scheme 42). Starting with 2-methyl-benzo[ ]thiophene-3-carbaldehyde 388, an intermediate 389 was obtained. Treatment of bromo compound 389 with sodium azide in ethanol led to the stable triazoline 390. 1,3-Dipolar cycloreversion of 390 was induced by a catalytic amount of />-TsOH to give the parent 2//-benzo[4,5]thieno[2,3-c]pyrrole 387. Alternatively, direct treatment of bromo compound 389 with excess ammonia furnished 387 in one step. Compound 387 was treated with di-/-butyl dicarbonate and 4-dimethylaminopyridine (DMAP) to give iV-BOC derivative 391. Reaction of 389 with... 

Milkiewicz and coworkers [16] prepared a series of novel tetra-substituted furo[3,2-b Ipyrroles from the methyl or ethyl 3-bromo-2-phcnyllliro 3,2-/ pyrrole-5-carboxylate 40, which was prepared from 3-bromo-2-phenylfuran-2-carbaldehyde 39. The compounds 40 were subjected to a Suzuki coupling with 4-chlorophenyl boronic acid to form 41, which was treated with a variety of alkylating agents to afford the corresponding esters 42. The esters were then saponified to acids 43 (Scheme 6). 

Scheme 13 a 6-Substituted-4-oxochromene-3-carbaldehydes 84, TsOH b methyl 2-formyl-fum 3,2-7) pyrrole-5-carboxylales 80, TsOH [24]... 

Benzindolizidine systems 963 are generated in moderate yields by a hexabutylditin-mediated consecutive radical addition, cyclization, and oxidation process from easily accessible l-(2-iodoethyl)indoles 962 and methyl acrylate, in one step (Scheme 186) <2000TL10181>. l-(2-Iodoethyl)-l//-pyrrole-2-carbaldehyde was also subjected to the tandem radical addition-cyclization process, and the indolizidine derivative 964 was isolated in modest yield as the major product together with a small amount of starting material (Equation 229). 

Tietze et al. (88LA9) (Scheme 77) alkylated 2-hydroxybenzaldehyde with 5-bromo-2-methylpent-2-ene and 1 //-pyrrole-2-carbaldehyde with l-bromo-3-methyl-but-2-ene and obtained the corresponding aryl aldehydes 246 and 248. Condensation of the latter with pyrazol-3-one 262 in acetonitrile containing ethylenediamine diacetate as a catalyst provided (7 /Z)-4- 2-[(4-methylpent-3-enyl)oxy]benzylidine -pyrazol-3-one 247 and ( /Z)-4- [l-(3-methylbut-2-enyl)-177-pyrrol-2-yl]methylene -pyrazol-3-one 249, in 67 and 99% yield, respectively. 

K.43) l//-Pyrrole-2-carboxaldehyde, 1-methyl-, l-methylpyrrole-2-carbaldehyde, V-methyl pyrrolealdehyde, 2-formyl- 1-methylpyrrole [1192-58-1]... 

Mitsui T, Kimoto M, Harada Y, Sato A, Kitamura A, To T, Hirao 1, Yokoyama S (2002) Enzymatic incorporation of an unnatural base pair between 4-propynyl-pyrrole-2-carbaldehyde and 9-methyl-imidazo [(4,5)-b]pyridine into nucleic acids. Nucleic Acids Res Suppl 2 219-220... 

Vasil tsov, A.M., A.V. Ivanov, LA. Ushakov et al. 2007. Selective thiylation of 1-vinyl-pyrrole-2-carbaldehydes Synthesis of 2-[bis(ethylsulfanyl)methyl]-l-vinylpyrroles and l-(2-ethylthioethyl)pyrrole-2-carbaldehydes - novel pyrrole synthons. Synthesis 3 452-456. 

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