Hydrochloric Acid → (E)-3-{1'-benzyl-3,4-dihydro-3-benzyl-4-oxo-spiro[2H-(1,3)-benzoxazine-2,4'-piperidin]-6-yl}-acrylic acid

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Reaction Steps

(E)-3-{1′-Benzyl-3,4-dihydro-3-benzyl-4-oxo-spiro[2H-(1,3)-benzoxazine-2,4′-piperidin]-6-yl}-acrylic acid methyl ester was obtained by reacting (E)-3-{3,4-dihydro-3-benzyl-4-oxo-spiro[2H-(1,3)-benzoxazine-2,4′-piperidin]-6-yl}-acrylic acid methyl ester (485 mg, 1.13 mmol, Intermediate 6) with benzyl bromide, according to the procedure described in Example 2, Step A, giving a white solid (544 mg, quantitative). The methyl ester (500 mg, 1.03 mmol) was hydrolyzed with HCl 20% and AcOH following the procedure described Example 55, Step B, giving (E)-3-{1′-benzyl-3,4-dihydro-3-benzyl-4-oxo-spiro[2H-(1,3)-benzoxazine-2,4′-piperidin]-6-yl}-acrylic acid as a white solid (500 mg, 95%). The resulting product was treated with NH2OTHP according to the procedure described in Example 1, Step B, giving (E)-3-{1′-benzyl-3,4-dihydro-3-benzyl-4-oxo-spiro[2H-(1,3)-benzoxazine-2,4′-piperidin]-6-yl}-N-(tetrahydro-pyran-2-yloxy)-acrylamide as a yellow solid (228 mg, 40%). Finally, removal of the THP protecting group (177 mg, 0.312 mmol) following the procedure described in Example 1, Step C gave (E)-3-{1′-benzyl-3,4-dihydro-3-benzyl-4-oxo-spiro[2H-(1,3)-benzoxazine-2,4′-piperidin]-6-yl}-N-hydroxy-acrylamide (150 mg, trifluoroacetate salt) after purification by preparative HPLC.

Provenance & Evidence