LitCovid-sentences  

PMC:7571312 / 38416-40030 JSONTXT 5 Projects

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Id Subject Object Predicate Lexical cue
T262 0-88 Sentence denotes tert-Butyl ((1S)-3-Diazo-2-oxo-1-{[(3S)-2-oxopyrrolidin-3-yl]methyl}propyl)carbamate (7)
T263 89-261 Sentence denotes A solution of N-(tert-butoxycarbonyl)-3-[(3S)-2-oxopyrrolidin-3-yl]-l-alanine (2.72 g, 10.0 mmol) in THF (100 mL) was placed under an atmosphere of N2 and cooled to −23 °C.
T264 262-419 Sentence denotes The resulting clear colorless solution was successively treated with triethylamine (2.1 mL, 15.0 mmol) followed by isobutylchloroformate (1.6 mL, 12.0 mmol).
T265 420-522 Sentence denotes The reaction mixture gradually became opaque with a fine white precipitate and after 1 h was filtered.
T266 523-695 Sentence denotes The colorless filtrate was transferred to a nonground joint flask, cooled to 0 °C, and slowly treated with a solution of diazomethane (∼35 mL, ∼16.6 mmol) in diethyl ether.
T267 696-701 Sentence denotes Note:
T268 702-835 Sentence denotes The diazomethane was generated employing a Diazald kit according to the procedure described in the Aldrich Technical Bulletin AL-180.
T269 836-928 Sentence denotes The resulting yellow clear solution was gradually warmed to room temperature (RT) over 16 h.
T270 929-1044 Sentence denotes At this time, N2 was bubbled through the reaction to remove excess diazomethane followed by in vacuo concentration.
T271 1045-1129 Sentence denotes The resulting residue was diluted with ethyl acetate (100 mL), washed once with sat.
T272 1130-1244 Sentence denotes NaHCO3 (50 mL), once with brine (50 mL), dried over MgSO4, filtered, and concentrated to give a crude yellow foam.
T273 1245-1393 Sentence denotes This material was purified by LC (150 g 230–400 SiO2, 3–4% methanol/chloroform) to afford 2.72 g (92%) of the title compound as a light yellow foam.
T274 1394-1614 Sentence denotes 1H NMR (DMSO-d6) δ 7.63 (bs, 1H), 7.42 (d, J = 8 Hz, 1H), 6.06 (bs, 1H), 3.96 (m, 1H), 3.13 (m, 2H), 2.21 (m, 1H), 2.01 (m, 1H), 1.86 (m, 1H), 1.63–1.52 (m, 2H), 1.38 (s, 9H); MS (ESI+) for C13H20N4O4m/z 319.0 (M + Na)+.