Efficient approaches to S-alkyl-N-alkylisothioureas: syntheses of histamine H3 antagonist clobenpropit and its analogues.

Hiroki Yoneyama, Ayako Shimoda, Lisa Araki, Kouta Hatano, Yasuhiko Sakamoto, Takushi Kurihara, Atsushi Yamatodani, Shinya Harusawa

Index: J. Org. Chem. 73(6) , 2096-104, (2008)

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Abstract

S-Alkyl-N-alkylisothioureas were efficiently synthesized via synthetic approach (A) using 3-phenylpropionyl isothiocyanate (PPI). The utility of the approach was proved by the syntheses of clobenpropit, a potent histamine H(3) antagonist, and its analogues. Alternatively, clobenpropit could be prepared via intramolecular amide cleavage (B) with use of 2-nitrophenylacetyl isothiocyanate (NPAI).