Diisopropylethylamine → tert-butyl 2-methyl-2-[(Z)-[1-[2-[(2-methylpropan-2-yl)oxycarbonylamino]-1,3-thiazol-4-yl]-2-[[(2R,3S)-2-[(5-methyltetrazol-1-yl)methyl]-4-oxoazetidin-3-yl]amino]-2-oxoethylidene]amino]oxypropanoate

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Reaction Steps

Prepared in an analogous manner to example 4, step 3 using (Z)-2-(((1-(tert-butoxy)-2-methyl-1-oxopropan-2-yl)oxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetic acid (130 mg, 0.302 mmol), DIPEA (158 μL, 0.906 mmol) and HATU (115 mg, 0.302 mmol) in DCM:DMF (2:1, 3.0 mL) at 0° C. followed by a solution of (3S,4R)-3-amino-4-((5-methyl-1H-tetrazol-1-yl)methyl)azetidin-2-one (55 mg, 0.30 mmol) in DCM:DMF (2:1, 3.0 mL). After stirring at rt for 1 h it was concentrated in vacuo, dissolved in EtOAc, washed with water then brine, dried over Na2SO4 and concentrated in vacuo. The crude residue was purified via silica gel chromatography (Acetone-DCM), affording the title compound (133 mg, 74%) as a solid. LCMS: Rt=0.92 min, m/z=594.2 (M+1) Method 2m_acidic.

Provenance & Evidence