Self gelating isoracemosol A, new racemosaceramide A, and racemosol E from Barringtonia racemosa.

Phytochemical investigation into the CHCl3 extract of the fruits of Barringtonia racemosa resulted in the isolation of two new metabolites along with isoracemosol A and betulinic acid as known metabolites. The new compounds were characterised as phytosphingosine-type ceramide [(2S,3S,4R)-2-[(2R)-2-hydroxyhexadecanoyl amino]-hexacos-8(E)-ene-1,3,4-triol, 1] and racemosol E [21ß-acetoxy-22α-(2-methylbutyroxy)-olean-12-ene-3ß,16α,28-triol, 2] on the basis of extensive spectroscopic data analysis and chemical modifications. In addition, the self-gelating property of isoracemosol A (3) was investigated for the first time, which leads to the unexpected agglomerated porous-like morphology.

Synthesis and structure of trans-bis(1,4-dimesityl-3-methyl-1,2,3-triazol-5-ylidene)palladium(II) dichloride and diacetate. Suzuki-Miyaura coupling of polybromoarenes with high catalytic turnover efficiencies.

trans-Bis(1,4-dimesityl-3-methyl-1,2,3-triazol-5-ylidene)palladium(II) dichloride has been shown to be an excellent catalyst for the multiple Suzuki-Miyaura coupling reactions of polybromoarenes to the corresponding fully substituted polyarylarenes. The reactions proceeded in excellent yields and with high turnover numbers. With 1,4-dibromobenzene the catalyst was found to be active for up to 13 consecutive cycles with a turnover number of 1260. The polyarylarenes were obtained in pure form after crystallization once without recourse to chromatographic purification. The single-crystal X-ray structures of the chloro (1) as well as the corresponding acetato (2) complexes are also reported and compared with the corresponding complexes of 1,4-diphenyl-3-methyl-1,2,3-triazol-5-ylidene as the ligand.