Synlett 2010(14): 2122-2124  
DOI: 10.1055/s-0030-1258519
LETTER
© Georg Thieme Verlag Stuttgart ˙ New York

Intramolecular Aza-Wittig Reaction: A New Efficient Tool for the Construction of Piperazine 2,5-Dione Derivatives

K. C. Majumdar*, Krishanu Ray, Sintu Ganai
Department of Chemistry, University of Kalyani, Kalyani 741235, West Bengal, India
e-Mail: kcm_ku@yahoo.co.in;
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Publikationsverlauf

Received 4 June 2010
Publikationsdatum:
27. Juli 2010 (online)

Abstract

A new efficient approach for the synthesis of unsymmetricaly substituted piperazine 2,5-dione derivatives is described by using intramolecular aza-Wittig reaction as the key step. The reaction conditions are very simple, offer easy isolation, and excellent yields of the products.

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General Procedure for the Preparation of Compound 6a
To a solution of compound 3a (100 mg, 0.36 mmol) in THF (5 mL) was added Ph3P (142 mg, 0.54 mmol). The mixture was stirred at r.t. for 30 min. After completion of the reaction (as monitored by TLC), THF was completely evaporated, and the crude product was purified by column chromatog-raphy over silica gel (60-120 mesh) using PE-EtOAc (1:1) as eluant to give the pure product 6a in 96% yield.
Yield 96%, solid, mp 208-210 ˚C. IR (KBr): νmax = 1655, 1689, 3243 cm. ¹H NMR (400 MHz, CDCl3): δ = 7.27-7.38 (m, 5 H), 6.26 (br s, 1 H), 4.61 (s, 2 H), 4.10 (s, 2 H), 3.86 (s, 2 H). ¹³C NMR (125 MHz, DMSO-d 6): δ = 44.4, 48.2, 49.0, 127.4, 127.8, 128.5, 136.2, 164.3, 165.5. HRMS: m/z calcd for C11H12N2O2: 227.0797 [M+ + Na]; found: 227.0797 [M+ + Na].