Synlett 2002(9): 1491-1492
DOI: 10.1055/s-2002-33538
LETTER
© Georg Thieme Verlag Stuttgart · New York

Regioselective Synthesis of Highly Functionalized Biaryls through Carbanion Induced Ring Transformation of 2H-Pyran-2-ones [1]

Abhishek Shanker Saxena, Atul Goel, Vishnu Ji Ram*
Medicinal Chemistry Division, Central Drug Research Institute, Lucknow 226001, India
Fax: +91(522)223405; e-Mail: vjiram@yahoo.com;
Further Information

Publication History

Received 9 July 2002
Publication Date:
17 September 2002 (online)

Abstract

An expedient synthesis of highly functionalized unsymmetrical biaryls 3 of which one of the two phenyl rings substituted with carbomethoxy, amino and nitrile functionalities is described and illustrated by carbanion induced ring transformation of 6-aryl-3-carbomethoxy-4-methylsulfanyl-2H-pyran-2-one 1 using malononitrile 2 as a source of carbanion in moderate yield.

1

C.D.R.I. Communication No. 6290.

1

C.D.R.I. Communication No. 6290.

18

General Procedure for the Synthesis of 3a: A mixture of 6-aryl-3-carbomethoxy-4-methylsulfanyl-2H-pyran -2-one 1(0.28 g, 1 mmol), malononitrile (0.07 g, 1 mmol) and powdered KOH (0.06 g, 1 mmol) in dry DMF (12 mL) was stirred at r.t. for 30 h. At the end reaction mixture was poured into ice water with vigorous stirring and finally neutralized with 10% HCl. The solid thus obtained was filtered and purified on a silica gel column using chloroform as eluent; white solid, yield 0.12 g (40.26%), mp 170 °C. IR (KBr): νmax = 3444, 2209 (medium and sharp), 1672 cm-1. 1H NMR (200 MHz, CDCl3): δ = 2.45 (s, 3 H, SCH3), 3.98 (s, 3 H, OCH3), 6.41 (brs, 2 H, NH2), 6.55 (s, 1 H, ArH), 7.47-7.54 (m, 5 H, ArH). MS (EI): m/z = 298 (M+), 266. Anal. Calcd for C16H14N2O2S: C, 64.41; H, 4.73; N, 9.39. Found: C, 64.54; H, 4.77; N, 9.44. 3d: White solid; mp 185 °C. IR (KBr): νmax = 3422, 2208 (medium and sharp), 1680 cm-1. 1H NMR (200 MHz, CDCl3): δ = 2.44 (s, 3 H, SCH3), 3.98 (s, 3 H, OCH3), 6.42 (brs, 2 H, NH2) 6.50 (s, 1 H, ArH), 7.47 (s, 4 H, ArH). 13C NMR (200 MHz, CDCl3): δ = 17.06, 52.26, 93.23, 109.76, 114.31, 117.31, 129.43, 130.12, 135.99, 136.9, 147.54, 151.88, 153.07, 164.49. MS (EI): m/z = 332, 300, 176. Anal. Calcd for C16H13ClN2O2S: C, 57.74; H, 3.94; N, 8.41. Found: C, 57.83; H, 3.98; N, 8.52.