Ethyl Acetate → 8-Ethynyl-4-methyl-6-phenyl-4H-2,5,10b-triaza-benzo[e]azulene-3-carboxylic acid ethyl ester

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Reaction Steps

{1-[4-Bromo-2-(2-fluoro-benzoyl)-phenylcarbamoyl-ethyl}-carbamic acid tert-butyl ester 116. To a stirred solution of (2-amino-5-bromophenyl)-(2-fluoro-phenyl)-methanone (60 g, 204 mmol) 115 and the N-Boc-L-alanine 107 (38.59 g, 204 mmol) in CH2Cl2 (500 mL) was added dicyclohexylcarbodiimide (DCC) (42.09 g, 204 mmol) in CH2Cl2 (200 mL) dropwise, over a 30 min period at 0° C. The reaction mixture was allowed to stir an additional 8 h at rt. The dicyclohexyl urea which formed was filtered off and the filtrate concentrated under reduced pressure. The crude solid residue 116 was purified by recrystallization from hexane and EtOAc to afford 116 (74.9 g, 79%) mp 158-159° C.; IR (KBr, cm−1) 3332, 2931, 255, 1694, 1643, 1613, 1582, 1537, 1450; 1H NMR (CDCl3) δ 11.68 (s, 1 H), 8.71 (d, J=9.0 Hz, 1 H), 7.69 (dd, J=9.0, 2.3 Hz, 1 H), 7.55-7.62 (m, 2 H), 7.46 (td, J=7.6, 1.4 Hz, 1 H), 7.30 (t, J=7.5 Hz, 1 H), 7.21 (t, J=9.1 Hz, 1 H), 5.13 (b, 1 H), 4.37 (b, 1 H), 1.51 (d, J=7.2 Hz, 3 H), 1.45 (s, 9H). MS (EI) m/e (relative intensity) 467 (M++2, 14), 466 (M++1, 44), 465 (M+, 14), 464 (42), 329 (15), 321 (60), 295 (100), 224 (26); [α]26D=−59.1 (c 0.51, EtOAc).

Provenance & Evidence