Yield:51859-60-0 87%

Reaction Conditions:

with triethylamine in chloroform at 20; for 24 h;

Steps:

7,9a-Epoxy[1,3]thiazolo[2,3-a]isoindole-6(9bH)-carboxylic acids (24)

7,9a-Epoxy[1,3]thiazolo[2,3-a]isoindole-6(9bH)-carboxylic acids (24)
Method A
(two-step).
Freshly distilled furfural (10.9 mL, 0.13 mol) was added in one portion to a stirred solution of 2-aminoethanethiol hydrochloride (15.0 g, 0.13 mol) and anhydrous Na₂CO₃ powder (27.6 g, 0.26 mol) in CHCl₃ (250 mL) at room temperature.
The mixture was stirred at room temperature for 24 h.
The precipitate of inorganic salts was filtered off, washed with CHCl₃ (2*50 mL) and the solvent was then evaporated under reduced pressure.
The residue was purified by column chromatography (silica gel, hexane/EtOAc, 1/1) to provide 2-(2-furyl)-1,3-thiazolidine as a yellow oil, which crystallized upon cooling to give a yellow powder (17.8 g, 87%); [found: C, 54.20; H, 5.82; N, 9.04. C₇H₉NOS requires C, 54.17; H, 5.84; N, 9.02%]; ν_max (KBr) 3188, 1484, 930, 733 cm^-1; δ_H (400 MHz, CDCl₃) 7.38 (1H, dd, ³J_4',5' 1.6, ⁴J_3',5' 0.6 Hz, H-5'), 6.34 (1H, dd, ³J_3',4' 3.1, ⁴J_3',5' 0.6 Hz, H-3'), 6.31 (1H, dd, ³J_3',4' 3.1, ³J_4',5' 1.6 Hz, H-4'), 5.59 (1H, s, H-2), 3.54-3.52 (1H, m, H-5A), 3.19-3.04 (3H, m, H-4, H-5B), 2.16 (1H, br s, NH); δ_C (100.6 MHz, CDCl₃) 152.7 (C-2'), 142.5 (C-5'), 110.2 and 107.5 (C-3' and C-4'), 65.4 (C-2), 52.4 (C-4), 36.0 (C-5). GC-MS (EI, 70 eV) m/z 155 (82, M⁺), 154 (9), 122 (11), 109 (78), 108 (26), 96 (51), 95 (51), 94 (100), 81 (73), 80 (74), 67 (22), 53 (23), 52 (37), 45 (36), 39 (70%).

References:

Zubkov, Fedor I.;Nikitina, Eugenia V.;Galeev, Timur R.;Zaytsev, Vladimir P.;Khrustalev, Victor N.;Novikov, Roman A.;Orlova, Daria N.;Varlamov, Alexey V. [Tetrahedron,2014,vol. 70,# 8,p. 1659 - 1690]