V. Dyachenko
Feb 15, 2012
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0
Influential Citations
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Journal
Russian Journal of Organic Chemistry
Abstract
Thioamides Іa–Ic reacted with 2-bromo-1-cyclopropylethanone (ІІ) in dimethylformamide at 20°C to give 3-substituted 6,7-dihydro-5H-pyrrolo[1,2-c][1,3]thiazol-4-ium bromides ІІІa–IIIc. The mechanism of formation of compounds ІІІa–IIIc and the scope of application of this reactions are now being studied with account taken of the data of [2] on thermal rearrangement of 4-cyclopropyl-substituted 2-aminothiazolium bromide into 3-amino-6,7-dihydro-5H-pyrrolo[1,2-c][1,3]thiazolium bromide and the ability of cyclopropane ring to be opened by the action of HBr with formation of a 1-bromopropyl fragment [3]. yellow powder, mp 285°C (decomp.). IR spectrum: ν 2210 cm (C≡N). H NMR spectrum, δ, ppm: 2.71 m (2H, 6-H), 3.05 t (2H, 7-H, J = 7.52 Hz), 4.69 t (2H, 5-H, J = 7.51 Hz), 7.32 m (2H, 5′-H, 6′-H), 7.63 d (1H, 4′-H, J = 7.85 Hz), 7.82 s (1H, 1-H), 8.11 d (1H, 7′-H, J = 7.85 Hz), 8.56 s (1H, 3′-CH), 8.73 d (1H, 2′-H, J = 2.58 Hz), 12.88 br.s (1H, NH). Mass spectrum: m/z 292 (Irel 100%) [M – Br]. Found, %: C 54.77; H 3.68; N 11.14. C17H14BrN3S. Calculated, %: C 54.85; H 3.79; N 11.29. Compounds IIIb and IIIc were synthesized in a similar way. 3-[(1E,3E)-1-Cyano-4-(furan-2-yl)buta-1,3-dien1-yl]-6,7-dihydro-5H-pyrrolo[1,2-c][1,3]thiazol-4ium bromide (IIIb) was synthesized from 2.04 g (10 mmol) of thioamide Ib. Yield 2.37 g (68%), yellow powder, mp 280°C (decomp.). IR spectrum: ν 2218 cm (C≡N). H NMR spectrum, δ, ppm: 2.72 m (2H, 6-H), 3.09 t (2H, 7-H, J = 7.51 Hz), 4.66 t (2H, 5-H, J = 7.51 Hz), 6.72 d.d (1H, 4′-H, J = 2.1 Hz), 7.04 d and 7.06 d (1H, CH=, J = 16.0 Hz), 7.21 d (1H, 3′-H, J = 2.84 Hz), 7.69 d (1H, CH=, J = 16.0 Hz), 7.82 s (1H, 1-H), 7.89 d (1H, 5′-H, J = 1.11 Hz), 8.37 d (1H, CH=, J = 16.0 Hz). Mass spectrum: m/z 269 (Irel 100%) [M – Br]. Found, %: C 51.42; H 3.66; N 7.94. C15H13BrN2OS. Calculated, %: C 51.59; H 3.75; N 8.02. 3-[(E)-1-Cyano-2-(3-oxo-3H-benzo[f]chromen-2yl)vinyl]-6,7-dihydro-5H-pyrrolo[1,2-c][1,3]thiazol4-ium bromide (IIIc) was synthesized from 2.55 g (10 mmol) of thioamide Ic . Yield 2.6 g (65%), yellow crystals, mp 310°C (decomp.). IR spectrum: ν 1714 cm (C=O). H NMR spectrum, δ, ppm: 2.56 m (2H, 6-H), 3.27 t (2H, 7-H, J = 7.48 Hz), 5.0 t (2H, 6-H, J = 7.48 Hz), 7.71–7.76 m (2H, Harom), 7.86 t (1H, Harom, J = 8.42 Hz), 8.12 s (1H, 1-H), 8.17 d (1H, ISSN 1070-4280, Russian Journal of Organic Chemistry, 2012, Vol. 48, No. 1, pp. 143–144. © Pleiades Publishing, Ltd., 2012. Original Russian Text © V.D. Dyachenko, 2012, published in Zhurnal Organicheskoi Khimii, 2012, Vol. 48, No. 1, pp. 147–148.