Download PDF
Synthesis 2006(6): 1021-1027  
DOI: 10.1055/s-2006-926351
PAPER
© Georg Thieme Verlag Stuttgart · New York

Neighboring-Group Effect: DBU-Promoted Ring Transformation of Substituted­ Isoxazoles to Substituted Pyrroles [1]

Amrendra K. Roya, Richa Pathaka, Gaya P. Yadavb, Prakas R. Maulikb, Sanjay Batra*a
a Medicinal Chemistry Division, Central Drug Research Institute, Lucknow-226001, India
b Molecular and Structural Biology Division, Central Drug Research Institute, Lucknow-226001, India
Fax: +91(522)2623405; Fax: +91(522)2623938; e-Mail: batra_san@yahoo.co.uk;
Further Information

Publication History

Received 16 August 2005
Publication Date:
27 February 2006 (online)

    Permissions and Reprints All articles of this category

Corrected by:

Neighboring-Group Effect: DBU-Promoted Ring Transformation of Substituted­ Isoxazoles to Substituted PyrrolesSynthesis 2006; 2006(07): 1220-1220
DOI: 10.1055/s-2006-926393

Abstract

A novel DBU-promoted ring transformation of substituted isoxazoles to substituted pyrroles is described.

Key words

isoxazole - pyrrole - Baylis-Hillman - DBU - ring transformation - neighboring-group effect

1

CDRI Communication No. 6618.

1

CDRI Communication No. 6618.

3

Crystal data for compound 13b: C20H22Cl2N2O3, M = 409.30, monoclinic, P2 1 /c, a = 10.891 (1) Å, b = 17.066 (1) Å, c = 11.343 (1) Å, β = 95.31 (1)°, V = 2099.2 (3) Å3, Z = 4, Dc = 1.2951 (2) gcm-3, µ (Mo-Kα) = 0.331 mm-1, F(000) = 857.51, rectangular colorless crystal, size = 0.2 × 0.2 × 0.275 mm, 4628 reflections measured [R(int) = 0.05], 3688 unique, wR2 = 0.111 for all data, conventional R = 0.062 [(Δ/σ)max = 000)] on F-values of 1274 reflections with I>2σ(I), S = 0.907 for all data and 247 parameters. Unit cell determination and intensity data collection (2θ = 50°) was performed on a Bruker P4 diffractometer at 293(2) K. Structure solutions by direct methods and refinements by full-matrix least-squares methods on F2. Programs: XSCANS [Siemens Analytical X-ray Instrument Inc.: Madison, Wisconsin, USA 1996], SHELXTL-NT [Bruker AXS Inc.: Madison, Wisconsin, USA 1997]. CCDC (deposit No: 284175) contains the supplementary crystallographic data. These data can be obtained free of charge from www.ccdc.cam.uk/conts/retrieving.html [or from the Cambridge Crystallographic Data Center, 12 Union Road, Cambridge, CB2 1EZ, UK; Fax: +44(1223)336033; E-mail: deposit@ccdc.cam.ac.uk.