O.NN.[OH-].[K+].O=[C:7]([C:16]1[CH:20]=[CH:19][S:18][CH:17]=1)[CH2:8][CH:9](C(O)=O)[C:10]([OH:12])=[O:11].Cl.[Na+].[Cl-]>C(O)CO>[S:18]1[CH:19]=[CH:20][C:16]([CH2:7][CH2:8][CH2:9][C:10]([OH:12])=[O:11])=[CH:17]1Hydrazine hydrate (1.3 mL, 1.34 g, 26.8 mmol) was added dropwise to a solution of KOH (3.54 g, 63 mmol) and 2-[2-oxo-2-(3-thienyl) ethyl]malonic acid 8(c) (4.00 g, 17.5 mmol) in ethylene glycol (30 mL). This solution was heated at reflux for 6 hours. After cooling to room temperature, the crude reaction mixture was poured into a mixture of 6N HCl (50 mL) and ice (200 g). This aqueous mixture was saturated with NaCl, then extracted with ether (3×70 mL). The combined organic extracts were dried over Na2SO4 and concentrated, in vacuo, to provide an orange oil (2.61 g) of sufficient purity to be employed in the subsequent reaction without any further purification.
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