One-Pot Synthesis of Alkyl 3-(Diphenylphosphoryl)-3-(10H-phenothiazin-10-yl)propanoates from Alkyl Acetylenecarboxylates, Phenothiazine, and Triphenylphosphine

Abstract

Protonation of the highly reactive 1:1 intermediates, produced in the reaction between triphenylphosphine and alkyl acetylenecarboxylates by phenothiazine, leads to vinyltriphenylphosphonium salts, which undergo a Michael addition reaction with conjugate bases to produce the corresponding phosphorus ylides. The phosphorus ylides react with water forming phenothiazine containing diphenylphosphine oxide derivatives in moderate yields.

Keywords:

• Acetylenic ester
• DEPT-135 experiment
• phenothiazine
• phenothiazine containing diphenylphosphine oxide derivatives
• phosphorus ylide
• triphenylphosphine
• vinyltriphenylphosphonium salts

The authors are thankful to the Islamic Azad University–Zanjan Branch and Payam Noor University (PNU), Abhar Center for partial support of this work.