Reagents for Condensation Reactions (1H-Benzotriazol-1-yloxytripyrrolidinophosphonium Hexafluorophosphate) (HPMC encapsulated)

• 4-Bromobenzoic Acid [B0553]
• Morpholine [M0465]
• Reagents for Condensation Reactions (HPMC encapsulated) (1H-Benzotriazol-1-yloxytripyrrolidinophosphonium Hexafluorophosphate) [R0296]
• DMF

Reagents for condensation capsule (1H-benzotriazol-1-yloxytripyrrolidinophosphonium hexafluorophosphate) (one capsule) was added to a solution of 4-bromobenzoic acid (40 mg, 0.20 mmol, 1.0 eq.) and morpholine (17 μL, 0.20 mmol, 1.25 eq.) in DMF (1 mL) at room temperature and the mixture was stirred for 2 hours. The reaction solution was diluted with ethyl acetate (5 mL) and filtered through Celite. The organic layer was washed with 1 mol/L HCl aq. (5 mL), sat. NaHCO₃ aq. (5 mL) and brine (20 mL), dried over sodium sulfate and concentrated under reduced pressure. The crude product was purified by silica gel chromatography (hexane: ethyl acetate = 1:1 - 1:2) to afford (4-bromophenyl)(morpholino)methanone (65 mg, 97% yield) as a white solid.

The reaction mixture was monitored by UPLC.
The shape of the capsule is like below image and each capsule includes 1H-benzotriazol-1-yloxytripyrrolidinophosphonium hexafluorophosphate (ca. 0.25 mmol).
The material of the capsule is water-soluble HPMC (hydroxypropyl methylcellulose).

(4-Bromophenyl)(morpholino)methanone

¹H NMR (400 MHz, CDCl₃); δ 7.57 (d, J = 8.4 Hz, 2H), 7.30 (d, J = 8.4 Hz, 2H), 3.74-3.44 (m, 8H).

• Hydrophobic Pockets of HPMC Enable Extremely Short Reaction Times in Water
  • D. Petkova, N. Borlinghaus, S. Sharma, J. Kaschel, T. Lindner, J. Klee, A. Jolit, V. Haller, S. Heitz, K. Britze, J. Dietrich, W. M. Braje, S. Handa, ACS Sustainable Chem. Eng. 2020, 8, 12612.

• HPMC: A Biomass-Based Semisynthetic Sustainable Additive Enabling Clean and Fast Chemistry in Water
  • S. Sharma, T. N. Ansari, S. Handa, ACS Sustainable Chem. Eng. 2021, 9, 12719.