Thieno pyrrole-5-carboxylates

Thieno[3,2-6]pyrrole-2-carboxylic acid, 5-aryI-synthesis, 4, 819... 

The crystal structure of ethyl 4//-thieno[3,2-3]pyrrole-5-carboxylate 55 indicates an ethoxycarbonyl group attached to a planar thieno[3,2-/)]pyrrole ring system <2004AXE2493>. 

The influence of catalysts (AICI3 and SnCU) acid chlorides, and solvents (dichloroethane, nitromethane) in the acylation of methyl 2-methyl-4/f-thieno[3,2- ]pyrrole-5-carboxylate 75 was studied. Conditions for the regioselective acylation processes were found and four types of compounds 76a-f, 77a-e, and 78 were obtained. 

Fig. 6 Methyl 2-me.thyl-4//-thicno 3,2-hlpyrrole-5-carboxylate 48, methyl 3-acetyl-2-methyl-4//-thieno 3,2-b pyrrole-5-carboxylate 49a, methyl 2-methyl-3-propanoyl-4//-thieno [3,2-h]pyrrole-5-carboxylate 49b, methyl 3-chloroacetyl-2-methyl-4//-thieno[3,2-h]pyrrole-5-carboxylate 49c, methyl 3-dichloroacetyl-2-methyl-4//-thieno[3,2-h]pyrrole-5-carboxylate 49d, methyl 2-methyl-3-trichlomacctyl-4//-thicno 3,2-h]pyrrole-5-carboxylate 49e, methyl 2-methyl-3-(2-methylpropanoyl)-4/7-thieno[3,2- ]pyrrole-5-carboxylate 49f, methyl 3,6-diacetyl-2-methyl-4//-thieno[3,2-h]pyrrole-5-carboxylate 50a, methyl 6-acetyl-2-methyl-3-propanoyl-4//-thieno [3,2-h]pyrrole-5-carboxylate 50b, methyl 6-acetyl-3-chloroacetyl-2-methyl-4//-thieno [3,2-h]pyrrole-5-carboxylate 50c, methyl 6-acetyl-3-dichloroacetyl-2-methyl-4//-thieno[3,2-h]pyrrole-5-carboxylate50d, methyl 6-acetyl-2-methyl-3-trichloroacetyl-4//-thieno[3,2-h]pyrrole-5-carboxylate 50e, methyl 6-acctyl-2-mcthyl-4//-thicno 3,2-h pyrrole-5-carboxylate 51 [17]...

Recently, the synthesis of 5-aryl-2-oxopyrrole derivative 210 as synthon for the highly substituted pyrrole 211 as starting compound for fused heterocycle 212 was published [56], Diethyl 6-bcnzyl-5-phenyl-6//-thieno[2,3-/ ]pyrrolc-2,4-dicarboxylatc 212 was prepared from ethyl l-benzyl-5-chloro-4-formyl-2-phcnyl-l //-pyrrolc-3-carboxylate 211 and ethyl 2-sulfanylacetate in refluxing ethanol (Scheme 41). 

The nitration of ethyl 4/f-thieno[3,2- ]pyrrole-5-carboxylate (68 R = C02Et) has been carried out <84JHC215> using cupric nitrate in acetic anhydride with low yields obtained after purification by column chromatography (69 R = C02Et) 34%, (70 R = C02Et) 42%, (71 R = C02Et) 3%. 

The nitration of ethyl 6//-thieno[2,3-6]pyrrole-5-carboxylate (146) has been carried out... 

A 100-mL toluene solution of acrylate (0.2 M, 20 mmol) was heated at 145°C for 60 min and then cooled to room temperature. After evaporation of the solvent, the residue was purified by column chromatography to afford 1.2 g 6H-thieno[2,3-b]pyrrole-5-carboxylic acid ethyl ester as a white solid, in a yield of 31% for two steps, Rf = 0.5 (EtOAc/hexanes, 1 4). 

Dihydro-l,2-oxazine ring. Aq. 30%-H2O2-soln. added to a mixture of methyl 5-p-tolyl-5,6-dihydro-4H-thieno[2,3-c]pyrrole-2-carboxylate and formic acid, stirred 36 hrs. whereby the solid dissolves after 1-2 hrs. and an exothermic reaction ensues -> methyl 5-p-tolyl-4,5-dihydro-7H-thieno[3,2-d] [l,2]oxazine-2-carboxyl-ate. Y 74%. F. e. s. J. Feijen and H. Wynberg, R. 89, 639 (1970). 

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