Thiophene 3- amino-, cycloaddition

Benzo[6]thiophene, 2-acetyl-3-hydroxy-synthesis, 4, 892 Benzo[6]thiophene, 2-acyl-synthesis, 4, 918 Benzo[6]thiophene, 3-acyl-synthesis, 4, 918- 19 Benzo[6]thiophene, acylamino-synthesis, 4, 815 Benzo[6]thiophene, alkenyl-synthesis, 4, 917 Benzo[6]thiophene, 2-alkoxy-synthesis, 4, 929 Benzo[6]thiophene, 3-alkoxy-synthesis, 4, 929 Benzo[6]thiophene, 4-alkoxy-synthesis, 4, 930 Benzo[6]thiophene, 2-alkyl-synthesis, 4, 877-878 Benzo[6]thiophene, 2-alkylthio-synthesis, 4, 931 Benzo[6]thiophene, 2-amino-diazotization, 4, 810 reactivity, 4, 797 stability, 4, 810 synthesis, 4, 869, 924-925 tautomerism, 4, 38 Benzo[6]thiophene, 3-amino-cycloaddition reactions, 4, 68 synthesis, 4, 109, 881, 925 Benzo[6]thiophene, 4-amino-synthesis, 4, 925 Benzo[6]thiophene, 5-amino-synthesis, 4, 925 Benzo[6]thiophene, 7-amino-synthesis, 4, 925 Benzo[6]thiophene, 3-t-amyl-synthesis, 4, 915 Benzo[6]thiophene, 2-aryl-synthesis, 4, 881... 

Thiophene, 2-amino-3-cyano-5-phenyl-synthesis, 4, 888-889 Thiophene, 3-amino-4,5-dihydro-cycloaddition reactions, 4, 848 Thiophene, 2-amino-3-ethoxycarbonyl-ring opening, 4, 73 Thiophene, 2-amino-5-methyl-synthesis, 4, 73 Thiophene, 2-anilino-synthesis, 4, 923-924 Thiophene, aryl-synthesis, 4, 836, 914-916 Thiophene, 2-(arylamino)-3-nitro-synthesis, 4, 892 Thiophene, azido-nitrenes, 4, 818-820 reactions, 4, 818-820 thermal fragmentation, 4, 819-820 Thiophene, 3-azido-4-formyl-reactions... 

Thiophene-3-carboxylic acid, 2-amino-azo dyes from, 1, 329 cycloaddition reactions, 4, 789 reactions, 4, 810... 

Die Addition von elementarem Schwefel an (3-Phenyl-allyliden)-malonsaure-ethylester-nitril ergibt 2-Amino-3-ethaxycarbonyl-5-thiobenzoyl-thiophen in 40%iger Ausbeute an-stelle dieser Cycloaddition kann man auch direkt Zimtaldehyd mit Malonsaure-ethylester-nitril und Schwefel umsetzen und erhalt so das Thiophen-Derivat in 64% Ausbeute2. 

The presence of an amino substituent in the thiophene facilitates these (2 + 2)-cycloaddition reactions. Thiophenes lacking such a substituent require temperatures of 100-200° to react with dimethyl acetylenedicarboxylate or dicyanoacetylene.76,77 However, it is most likely that a Diels-Alder addition rather than a (2 + 2)-cycloaddition is the first step in the formation of the resulting benzene derivatives.78 A similar reaction of tetramethylthiophene with dicyanoacetylene in the presence of aluminum trichloride occurred at room temperature.79 The (2 + 2)-cycloadduct, 6,7-dicyano-l,3,4,5-tetramethyl-2-thiabicyclo[3.2.0]hepta-... 

The parent compound has not yet been synthesized. However, substituted thiepins are stable and accessible by various routes. For instance, 3-amino-substituted thiophenes and activated alkynes undero a [2+2] cycloaddition followed by electrocyclic cyclobutene fission (see p 74) to give the thiepin 1 ... 

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