In our solvent optimization study of NaBH(4) reduction, NMP was found to enhance the reactivity. A chemoselective debromination of the bromide and sulfonates can be attained in the new borohydride reagent system: NaBH(4)-LiOTf-NMP. This mixed system worked as an alternative to NaBH(3)CN and Bu(3)SnH for the S(N)2 type displacement of alkylbromide and sulfonate. Also mentioned is an expedient reduction
Enhanced reactivity of NaBH4 was observed as a solution in N-methylpyrrolidone (NMP). Thus, a simple protocol for debromination of alkyl bromide and sulfonate is devised with NMP as a key solvent. Also described is a new mixed borohydride system, NaBH4-LiOTf-NMP, which works as an alternative to NaBH3CN for the S(N)2 type displacement. No reports have ever revealed usefulness of NMP in borohydride reduction. (C) 2001 Elsevier Science Ltd. All rights reserved.
Synthetic study on the unique dimeric arylpiperazine: access to the minor contaminant of aripiprazole
The dimeric derivative of Aripiprazole was synthesized via the two notable synthetic technologies as a key step: (1) efficient aldehyde bis-arylation by Bi(OTf)(3) and (2) facile Wynberg amination at room temperature. The synthesis has established the structural identity with the minor contaminant sometimes present in Aripiprazole. (C) 2002 Elsevier Science Ltd. All rights reserved.