41078-15-3

The coupling reactions of diazotized thienocoumarin derivatives with p-acetaminophen, salicylic acid and acetylsalicylic acid gave four products in which the benzene ring of the phenolic reagents were primarily substituted by two 3-diazenyl-4H-thieno[3,4-

The in situ formed 4-oxo-4H-thieno[3,4-c]chromene-3-diazonium sulfate (5) in the coupling reactions involving the parent 2-aminothiophene (4) and various phenolic and arylamines’ couplers, readily undergoes homocyclotrimerization at low temperature to aff

A series of azo disperse dyes based on aminothienochromene were synthesized. The fastness properties of the dyed samples were measured. Most of the dyed fabrics tested displayed excellent washing and perspiration fastness and moderate light fastness.

The reactivity of 2-aminothiophenes in two different anellations: (a) [b]-anellation to a saturated carbocycle and (b) [3,4-c]-anellation to benzopyrans, towards typical acetylenic dienophiles has been investigated. Because of the absence of conjugation, the thiophenes of type (a) do not undergo [4+2]-cycloaddition with acetylenic dienophiles. Instead, the N-vinylated products 2 and 3 were obtained with dimethyl acetylene dicarboxylate (DMAD). Electron poor alkynes react with the thiophenes of type (b) in three main ways: DMAD reacts in a [4+2]-mode in dioxane to give the products 7, 8 and 14; a Michael addition type reaction also takes place at the doubly vinylene homologous carbon atoms (C-1 in the starting materials 4, 9 and 10) in dioxane, methanol or ethanol. Methyl propiolate reacts in a similar way. The doubly N-vinylated product 26 was obtained from 10 in toluene and the C-1 vinylated products 24B and 27 were obtained from 9 in dioxane and 10 in methanol. The reaction of 10 with phenyl ethyl propiolate in dimethylformamide gave no addition product, instead a dimer of the acetylenic reagent was the isolated product. The accuracy of the assigned structures 5, 12 and 13a could be achieved on the basis of a single-crystal X-ray structure analysis of compound 13a. The reaction mechanism and the nature of the isolated products are dependent on the nature of the solvent. No addition reaction was observed between 17 and DMAD. The influence of the N-substitution on the nature of the addition (Michael or Diels-Alder) could be settled through the reactions of 18 and 21 with DMAD, which gave 19 and 14 (via 22), respectively as the only isolable products.

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The reaction of 1 with enaminones (3a-c) affords either the enaminones 4a-c or a mixture of 4a-c and the α,β-unsaturated ketones 9a-c depending on applied reaction conditions. Compounds 4a-c rearranged into 9a-c on long reflux in dioxane solution in prese

Several new dibenzopyrans as well as novel thiadiazaacenaphthenes are obtained via 4 + 2 addition of the thienocoumarins (1) and thienopyridazines (2) to electron-poor olefins.

The thieno [3,4:3',4'] benzo [b] pyranone (3b) and the thieno [3,4-c] quinoline (3c) are prepared via reacting 4-methylcoumarin-3-carbonitrile (9a) and 4-methyl-2-oxo-1,2-dihydroquinolin-3-carbonitrile (9b) with elemental sulphur, Similarly the thieno [3,4:3',4'] naphtho [1,2-b] pyran (11) is prepared from reaction of (10) and elemental sulphur. The condensed thiophenes (3b,c) and (11) react with a variety of electronpoor olefins to yield products of addition followed by hydrogen sulphide elimination. The reaction of (3b,c) and (11) with ethyl propiolate in refluxing dioxane/acetic acid mixture affords the condensed thiepins (24a,c). The nature of product of reaction of (3b,c) and (11) with dimethyl acetylenedicarboxylate is dependent on applied reaction conditions. Thus the reaction of (3b,c) and (11) with dimethyl acetylenedicarboxylate in refluxing dioxane afforded condensed thiepins while at 250°C products of addition and desulfurization are obtained. Whereas thienopyridazinones (1a,b) react with ethyl acrylate and diethyl fumarate to yield thiadiazaacenaphthenones (31a-c) respectively, compounds (1a,b) react with N-phenylmaleimide to yield phthalazine (32). The thienopyridazinone (1c) failed to react with the same reagents under similar conditions.