Synlett 2005(19): 3008-3010  
DOI: 10.1055/s-2005-921902
LETTER
© Georg Thieme Verlag Stuttgart · New York

Synthesis of Two New Azabicyclophosphinic Acids as Constrained Analogues of TPMPA

David Orain*, Henri Mattes
Global Discovery Chemistry-NeuroScience, Novartis Institute for Biomedical Research Basel, WKL-122.2.43, Basel 4002, Switzerland
Fax: +41(61)6968250; e-Mail: david.orain@novartis.com;
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Publikationsverlauf

Received 3 October 2005
Publikationsdatum:
04. November 2005 (online)

Abstract

Utilization of the Polniaszek reagent Cl2PNi-Pr2/AlCl3 was used on amino dienes to generate new azabicyclophosphinic acid as constrained analogues of TPMPA.

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Typical Procedure for Cyclization/Oxidation.
To a suspension of AlCl3 (1.3 g, 10 mmol) in CH2Cl2 was added dropwise, at -20 °C and under N2, Cl2PNi-Pr2 (2.0 g,10 mmol) in CH2Cl2. Then, the mixture was stirred at r.t. for 1 h. The mixture was cooled down to -20 °C and N-benzyl diallylamine (936 mg, 5 mmol) in CH2Cl2 was added dropwise. The mixture was allowed to warm up to r.t., stirred at r.t. for 16 h and refluxed for 1 h. The mixture was cooled down to 0 °C and 10 mL of a solution of 0.2 M EDTA-sat. NaHCO3 (1:1) was added carefully. The mixture was then stirred at r.t. for 5 h. Then, 100 mL of H2O were added and the aqueous phase was extracted several times with CHCl3. The organic phases were combined, washed with brine, dried over Na2SO4 and concentrated in vacuo to afford a crude yellow oil (2 g). Purification was achieved by flash chromatography over silica gel using EtOAc-MeOH (100:0 to 80:20) as eluent. After concentration of the fractions, a yellow paste (1.05 g, 63%) was obtained.

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1H NMR (400 MHz, D2O): δ = 3.55 (m, 2 H), 3.03 (m, 2 H), 2.85 (m, 2 H), 1.82 (m, 2 H), 1.40 (m, 2 H).

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1H NMR (400 MHz, D2O): δ = 5.87 (d, J = 31.7 Hz, 1 H), 3.79 (d, J = 14.0 Hz, 1 H), 3.56 (d, J = 15.9 Hz, 1 H), 3.42 (dd, J = 12.8 Hz, J = 2.4 Hz, 1 H), 3.01 (m, 1 H), 2.30 (m, 1 H), 2.15 (m, 2 H), 2.00 (m, 1 H), 1.63 (m, 1 H).