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Synlett 2011(20): 2997-3001  
DOI: 10.1055/s-0031-1289889
LETTER
© Georg Thieme Verlag Stuttgart ˙ New York

Sterically Controlled Stereoregulation in Aldol Reactions of 3-Aryl-1-alkyl Dihydrothiouracils

Varun Kumar, Gopal L. Khatik, Vipin A. Nair*
Department of Medicinal Chemistry, National Institute of Pharmaceutical Education and Research, Sector 67, Mohali, Punjab 160 062, India
e-Mail: vn74nr@yahoo.com;
Further Information

Publication History

Received 19 July 2011
Publication Date:
11 November 2011 (online)

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Abstract

Aldol reactions of 3-aryl-1-alkyl dihydrothiouracils were investigated with respect to the orientation of the exocyclic group at N1, electronic effects of the aryl substituent at N3 and the steric demands of the electrophile. The reactions highlight the preference for formation of the anti aldol diastereomer with increasing steric constraints of the reactants.

Key words

aldol reaction - cyclization - aldehyde - dihydrothio­uracils - stereoselectivity

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