Diphenylphosphoryl azide → 17-Aminoheptadecanoic acid tert-butyl ester

Participants

Reaction Steps

Acetonitrile (10 mL) was added to octadecanedioic acid mono-tert-butyl ester (500 mg, 1.3 mmol) and TEA (0.226 mL, 1.6 mmol) was added. Diphenylphosphonic azide (0.37 g, 1.3 mmol) was added in a solution of acetonitrile (1 mL). The mixture was stirred at reflux for 2 h, and at RT for 16 h. The reaction was concentrated under vacuum, and suspended/dissolved in 1:2, AcOEt:heptane (2 mL) and applied to a dry bed of silica (2×4 cm dia). It was eluated with 1:2 AcOEt:heptane (2 mL) and 1:1 AcOEt:heptane (60 mL). The eluate was concentrated to dryness. The residue was partly suspended in THF (2 mL) and 1 N NaOH (2 mL) was added. The turbid solution/suspension was stirred for 1 h at RT. Water (15 mL) was added and this was extracted with AcOEt (2×25 mL), adding some brine to aid separation. The organic phase was washed with sat. NaCl, dried, filtered and conc. to dryness. To the residue was added 20% acetonitrile/water (15 mL), TFA (15-20 ul) and DMSO (1 mL). A filtration of the mixture failed, so the filter and the solution were extracted with DCM (2×60 mL). The organic extracts were concentrated to yield the crude product (0.14 g),

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