5950-12-9Relevant articles and documents
Mild, Metal-Free and Protection-Free Transamidation of N-Acyl-2-piperidones to Amino Acids, Amino Alcohols and Aliphatic Amines and Esterification of N-Acyl-2-piperidones
Subramani, Muthuraman,Rajendran, Saravana Kumar
, p. 3677 - 3686 (2019/06/08)
Amides are indispensable building blocks of biological systems, pharmaceuticals, and materials. We report a highly selective method for the synthesis of amides via transamidation process. Transamidation of N-acyl-2-piperidones with a broad range of amines is demonstrated under exceedingly mild and metal-free reaction condition that relies on the amide bond twist to weaken the amidic resonance. Transamidation proceeds under the neat condition at room temperature, in short reaction times (30–90 min) with good yields. Considerable variation is tolerated with both amine and imide substrates. Of note, amines bearing carboxylic acids (glycine and serine) and hydroxyl groups (dopamine, tyramine, etc.) are well tolerated which are otherwise problematic under the metal-catalyzed protocol. Our current method is applicable for transamidation of both alkyl and aryl-N-acyl-2-piperidones. The practical value of the method is highlighted by the synthesis of four natural product amide alkaloids in high yields under mild reaction conditions. In the absence of nucleophilic amines, N-acyl-2-piperidones undergoes esterification with EtOH at elevated temperature. Single crystal X-ray analysis of an N-acyl-2-piperidone shows amide bond twist, τ = –20.39° and pyramidalization, χN = –11.73°. This weakens the amidic conjugation and might be the factor controlling the reactivity and selectivity of these imides. We envision that the N-acyl-2-piperidone scaffold would be useful in the synthesis of pharmaceuticals and materials.
Piperine analogs as potent Staphylococcus aureus NorA efflux pump inhibitors
Sangwan, Payare L.,Koul, Jawahir L.,Koul, Surrinder,Reddy, Mallepally V.,Thota, Niranjan,Khan, Inshad A.,Kumar, Ashwani,Kalia, Nitin P.,Qazi, Ghulam N.
experimental part, p. 9847 - 9857 (2009/04/11)
Based on our recent findings that piperine is a potent Staphylococcus aureus NorA efflux pump inhibitor (EPI), 38 piperine analogs were synthesized and bioevaluated for their EPI activity. Twenty-five of them were found active with potentiating activity equivalent or more than known EPIs like reserpine, carsonic acid and verapamil. The inhibitory mechanism of the compounds was confirmed by efflux inhibition assay using ethidium bromide as NorA substrate. The present communication describes the synthesis, bioevaluation and structure related activity of these efflux pump inhibitors.
Effects of piperine analogues on stimulation of melanocyte proliferation and melanocyte differentiation
Venkatasamy, Radhakrishnan,Faas, Laura,Young, Antony R.,Raman, Amala,Hider, Robert C.
, p. 1905 - 1920 (2007/10/03)
A wide range of piperine analogues has been synthesised in order to undertake a structure-activity study of their ability to stimulate melanocyte proliferation. Results demonstrate that an aromatic ring containing at least one ether function and a carbonyl group containing side chain is essential for this activity. A number of highly active piperine analogues have been identified, for instance 1-(3,4-methylenedioxyphenyl)-penta-2E,4E-dienoic acid methyl ester (5a), 1-E,E-piperinoyl-isobutylamine (4f) and 1-(3,4- methylenedioxyphenyl)-pentanoic acid cyclohexyl amide (20). A selection of analogues has also been evaluated for their effect on melanocyte morphology and melanogenesis. The piperine analogues altered cell morphology by increasing dendrite formation leading to bi-, tri- and quadripolar cells. These same analogues were found to increase total melanin in cell cultures, although melanin content per cell was not significantly altered from control in the presence of these compounds.
