Structural and synthetic studies on the retrofractamides—amide constituents of Piper retrofractum

Isolation, Synthesis, and Evolutionary Ecology of Piper Amides

“…7.3) described within the context of structural identification include the synthesis of piperettine, a second component of piperine extracts from P. nigrum (Spring and Stark 1950), piperstachine, an alkaloid isolated from P. trichostachyon C.DC. (Viswanathan et al 1975), wisanidine and wisanine (15), piperine-type amides isolated from P. guineense (Addae-Mensah et al 1977, Crombie et al 1977, pipericide (16) and dihydropipericide (17), insecticidal amides first isolated from P. nigrum (Miyakado and Yoshioka 1979, Banerji et al 1985, Rotherham and Semple 1998, N-5-(4-hydroxy-3-methoxyphenyl)-2E, 4E-pentadienoyl piperidine (21), and N -5-(4-hydroxy-3-methoxyphenyl)-2E-pentenoyl piperidine (22), phenolic amides isolated from P. nigrum L. (Nakatani et al 1980, Inatani et al 1981, N-isobutyl-4,5-dihydrox-2E-decenamide (sylvamide, 23), an alkenamide isolated from P. sylvaticum Roxb. (Banerji and Pal 1983), retrofractamide C (24), an unsaturated amide from P. retrofractum (Banerji et al 1985), N-(3-phenylpropanoyl)pyrrole (25), a pyrrole amide isolated from P. sarmentosum (Likhitwitayawuid and Ruangrungsi 1987), and aurantiamide benzoate (26), a phenylalanine-derived amide isolated from P. aurantiacum Wall.…”

ACAT inhibition of alkamides identified in the fruits of Piper nigrum

“…These results indicated that the olefinic C-9 was connected to the C-1 0 of the methylenedioxyphenyl group. These signals were found to be similar to those of retrofractamide C, but the molecular formula of compound 5 differed by two hydrogen atoms from that of retrofractamide C (Banerji et al, 1985). This suggests that compound 5 may represent a dehydro derivative of retrofractamide C. Based on the evidence given above, the structure of compound 5 was determined as 1-[(E), 9-(3,4-methylenedioxyphenyl)-8-nonenoyl] isobutyl amide, and named dehydroretrofractamide C (see Fig.…”

Natural and Synthetic Alkamides

“…Decades of investigations in the natural products chemistry of the Piper genus yielded an important amount of monomeric and dimeric alkamides of diverse molecular architectures contributing to their biological activities [20][21][22][23]203,[208][209][210][211][212][213][214][215][216][217][218][219]. Specifically, [4 + 2] dimers were isolated in P. chaba while [2 + 2] dimers were isolated in P. nigrum and P. longum, in both cases together with monomeric amides.…”