Yield:59293-11-7 74%

Reaction Conditions:

with hydrazine in methanol at 80; for 72 h;

Steps:

143.0.143.2 (S)-Tetrahydrofuran-2-carbohydrazide and (R)-tetrahydrofuran-2-carbohydrazide, Example 143.2

(S)-Tetrahydrofuran-2-carbohydrazide and (R)-tetrahydrofuran-2-carbohydrazide, Example 143.2 (1112) To a solution of (S)-methyl tetrahydrofuran-2-carboxylate and (R)-methyl tetrahydrofuran-2-carboxylate (20 mL, 166 mmol) in MeOH (237 mL) at 23° C., was added hydrazine (10.4 mL, 332 mmol). The mixture was heated to 80° C. for 3 d. The mixture was concentrated under reduced pressure and placed under high vacuum overnight. The cake was washed with Et₂O and then with hexanes. The solid was placed on high vacuum for 16 h to provide the title compound (16 g, 123 mmol, 74% yield). ¹H NMR (400 MHz, DMSO-d₆) δ 8.96 (br. s., 1H), 4.25 (br. s., 2H), 4.15-4.22 (m, 1H), 3.81-3.91 (m, 1H), 3.67-3.75 (m, 1H), 2.01-2.11 (m, 1H), 1.75-1.88 (m, 3H).

References:

US2017/320860,2017,A1 Location in patent:Paragraph 1112