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Synthesis 2007(6): 911-917  
DOI: 10.1055/s-2007-965931
PAPER
© Georg Thieme Verlag Stuttgart · New York

Sodium Hydride Mediated Cascade Reaction towards the Synthesis of 1,5-Disubstituted Uracil from Cyanamides Derived from Baylis-Hillman Adducts [1]

S. Naga, G. P. Yadavb, P. R. Maulikb, S. Batra*a
a Medicinal and Process Chemistry Division, Central Drug Research Institute, PO Box 173, Lucknow 226001, India
Fax: +91(522)2623405 or 2623938; e-Mail: batra_san@yahoo.co.uk;
b Membrane and Structural Biology Division, Central Drug Research Institute, PO Box 173, Lucknow 226001, India
Further Information

Publication History

Received 21 September 2006
Publication Date:
13 February 2007 (online)

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Abstract

The substituted cyanamides generated from Baylis-Hillman adducts afford 1,5-disubstituted uracils via a sodium hydride induced cascade reaction involving sequential intramolecular attack of the hydroxy group on the nitrile group, cyclization of the resulting ureide with the ester moiety, and rearrangement of the exocyclic double bond.

Key words

heterocycles - ring closure - 1,5-disubstituted uracil - cascade reaction - Baylis-Hillman reaction

1

CDRI communication number: 7125.

1

CDRI communication number: 7125.

10

Crystal data of compound 5c: C19H20N2O3, M = 324.37, monoclinic (solvent: CHCl3), P21/n, a = 12.626 (2), b = 9.117 (1), c = 14.631 (1) Å, β = 90.81 (1)°, V = 1684.0(3) Å3, Z = 4, D c = 1.279 (2) g·cm-3,
µ (Mo-Kα) = 0.09 mm-1, F(000) = 688.0, colorless block, 0.225 × 0.20 × 0.175 mm, 4097 reflections measured (R int = 0.0234), 2972 unique, wR 2 = 0.1277, conventional R = 0.0497 on F 2 values of 1573 reflections with I > 2σ(I), (Δ/σ) max = 000), S = 0.962 for all data and 219 parameters. Unit cell determination and intensity data collection (2θ = 50°) were performed on a Bruker P4 diffractometer at 293 (2) K. Structure solutions by direct methods and refinements were by full-matrix least-squares methods on F 2. Programs: XSCANS (Siemens Analytical X-ray Instrument Inc.: Madison, WI, USA, 1996) for data collection and data processing; SHELXTL-NT (Bruker AXS Inc.: Madison, Wisconsin, USA, 1997) for structure determination, refinements, and molecular graphics. Further details of the crystal structure investigation can be obtained from the Cambridge Crystallographic Data Centre, 12 Union Road, Cambridge, CB2 1EZ, UK (CCDC deposition no. 629774). (For queries related to the X-ray structure write to maulik_prakas@yahoo.com).