摘要 |
The present invention relates to a novel process, useful for preparing key intermediates of formula (I) in the synthesis of various compounds, among them compounds which are potent and specific antagonists of D3 receptors, in which X may be Nitrogen or Sulfur; Het means aryl or heteroaryl; each of which may be substituted by 1 to 4 groups J selected from: halogen, C1-C6 alkyl C1-C6 alkoxy, halo C1-C6 alkyl C2-C6 alkenyl, C2-C6 alkynyl, halo C1-C6 alkoxy, -C(O)R<SUB>1</SUB>, nitro, hydroxy, -NR<SUB>2</SUB>R<SUB>3</SUB>, cyano or a group Z; R<SUB>1 </SUB>is a C1-C4 alkyl -OR<SUB>3 </SUB>or -NR<SUB>3</SUB>R<SUB>4</SUB>; R<SUB>2 </SUB>is hydrogen or C1-C6 alkyl; R<SUB>3 </SUB>is hydrogen or C1-C6 alkyl; R is H, C1-C6 alkyl aryl, benzyl; each of which may be substituted by 1 to 4 groups J; according to the following Scheme 1: in which step a means a reaction in basic conditions of compounds (IIA) with 3-thiosemicarbazide derivatives, followed by a treatment with an inorganic base and n-propane phosphonic cyclic anhydride and final pH adjustment with inorganic acids to give compounds of formula (II).
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