Reaction of 2-acylamino-3,3-dichloroacrylonitriles with methyl sulfanylacetate

Abstract

Available 2-acylamino-3,3-dichloroacrylonitriles I are important reagents in the synthesis of 1,3-azole derivatives [133]. In the present work we showed that reagents I can be applied for preparing polyfunctional thiophenes II.The structure of compounds II was confirmed by their 1 H and IR spectra, as well as by the fact that many substrates containing the O=C3CH 2 3S3C=C3C=N g g g ment undergo a similar cyclization [4,5].Treatment of substituted thiophenes II with concentrated sulfuric acid gives rise to intramolecular transacylation with subsequent annelation of the 2-oxo-2,3-dihydro-1H-1,4-thiazine system to the thiophene ring, which follows from spectral and mass spectral data.Methyl 4-acylamino-3-amino-5-(methoxycarbonylmethylsulfanyl)thiophene-2-carboxylates IIa and IIb. To a solution of 0.004 mol of nitrile Ia or Ib in 30 ml of absolute methanol, 0.0082 mol of methyl

Approaches towards the synthesis of 5-aminopyrazoles

“…Synthesis of 4-acylamino-3(5)-amino-5(3)-arylsulfanylpyrazoles 107 by the reaction of 2-acylamino-3-arylsulfanyl-3-chloroacrylonitriles 106 with hydrazine hydrate has been described. Compounds 106 were readily obtained from 105 , the addition products of carboxylic acid amides and trichloroacetaldehyde, by the reaction sequence shown in the Scheme 30 [ 72 ].…”

Synthesis and Crystal Structures of 4,5-Dihydroimidazo[1,5-b]pyrazol-6-ones

“…[12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29] The synthesis and properties of imidazo [4,5-c]pyrazoles have also received considerable attention. [30][31][32][33][34][35][36][37][38][39][40][41][42] 5-Aminopyrazoles have also been of great utility in preparing these compounds. 32,33,36,40,41 However, synthetic methodology for obtaining imidazo [1,5-b]pyrazole derivatives is notably lacking, and very little is known about these compounds.…”

“…[30][31][32][33][34][35][36][37][38][39][40][41][42] 5-Aminopyrazoles have also been of great utility in preparing these compounds. 32,33,36,40,41 However, synthetic methodology for obtaining imidazo [1,5-b]pyrazole derivatives is notably lacking, and very little is known about these compounds. 3,4 Only a few individual examples having this uncommon ring fusion have been previously prepared; for example, by cyclodehydration of substituted pyrazolylmethylacetamides leading to 2,3-dihydroimidazo [1,5-b] derivatives related to cyclized histamine, 43 preparation of 2,3-dihydro-1H-imidazo [1,5-b]pyrazole-4,6(3aH,5H)-dione from 1-(benzylideneamino)-5-(2-hydroxyethyl)hydantoin, 44 and the synthesis of hexahydro-4,4-dimethyl-1,3a-diaryl-6-oxo-1H-imidazo [1,5-b]pyrazole-3-carbonitriles from -aminoisobutyrophenone phenyl hydrazones.…”