170489-28-8Relevant academic research and scientific papers
Methoxycamalexins and related compounds: Syntheses, antifungal activity and inhibition of brassinin oxidase
Pedras, M. Soledade C.,Abdoli, Abbas
, p. 4461 - 4469 (2018/08/06)
The phytoalexin camalexin is a competitive inhibitor of brassinin oxidase, an enzyme that detoxifies the phytoalexin brassinin and is produced by an economically important plant pathogen. For this reason, the camalexin scaffold has guided the design of inhibitors of brassinin detoxification. To further understand the structure–activity relationships of camalexin related compounds, the syntheses of monomethoxy and dimethoxycamalexins were undertaken. Four monomethoxy camalexins together with 4,6-dimethoxy and 5,7-dimethoxy camalexins were prepared from the corresponding methoxyindoles using the Ayer's method. The dimethoxy derivatives were prepared from the corresponding dimethoxyindole-3-thiocarboxamides using the Hantzsch reaction; however, this method did not work for the syntheses of 4,6-dimethoxy and 5,7-dimethoxycamalexins due to the lower reactivities of the corresponding indole-3-thiocarboxamides. The antifungal activity and brassinin oxidase inhibitory activity of all methoxycamalexins and ten camalexin related compounds were investigated. Among the 20 compounds evaluated, monomethoxycamalexins were stronger antifungals than the dimethoxy derivatives. However, remarkably, 5,6-dimethoxycamalexin, 6,7-dimethoxycamalexin and 5-methoxycamalexin displayed the strongest inhibitory activity against brassinin oxidase, while 4,5-dimethoxycamalexin displayed no inhibitory effect. Altogether the structure–activity relationships of camalexin related compounds suggest that the targets for fungal growth inhibition and brassinin oxidase inhibition are unrelated and emphasize that brassinin oxidase inhibitors do not need to be antifungal.
Synthesis of the Kopsia alkaloids (+/-)-pauciflorine B, (+/-)-lahadinine B, (+/-)-kopsidasine, (+/-)-kopsidasine-N-oxide, (+/-)-kopsijasminilam and (+/-)-11-methoxykopsilongine
Magnus, Philip,Gazzard, Lewis,Hobson, Lindsay,Payne, Andrew H.,Rainey, Trevor J.,Westlund, Neil,Lynch, Vince
, p. 3423 - 3444 (2007/10/03)
Pictet-Spengler condensation of 13 with tryptamine gave 14, which was converted into 17. Treatment of 17 with phenyl chloroformate resulted in 18, which underwent transannular cyclization to,give 19. The more stable cyano-analog 22 was made by treating 18 with Tf2O/DMAP to geenrate 18f, and quenching the reaction with trimethylsilyl cyanide. Treatment of 22 with acryloyl chloride (excess) at 75 deg C gave 23, which was directly treated with N-hydroxy-2-thiopyridone/Et3N to give 24. Irradiation of 24 in the presence of r-BuSH resulted in reductive decarboxylation to give 26 and a small amount o fthe 2-thiopyridyl ether 25. Protection of the aniline nitrogen in 26 required the use of triphosgene/pyridine followed by methanol. The final step for the conversion of 27 into 28 required conjugate reduction of the α,β-unsaturated ester followed by α-hydroxylation and gave 28 (11,12-demethoxy lahadinine B). Exposure of 26 to Phl(OAc)2/MeOH cleanly gave 26a, which was directly reduced with Zn/AcOH to 29. Conversion of 29 into 30 proceeded as before, and when 30 was treated with AgBF4/THF followed by aqueous NaHCO3 it was converted into (+/-)-kopsidasine 2, completely chracterized as its derived N-oxide 2a. Treatment of 26 with AgBF4/THF followed by aqueous NaHCO3, gave 31. Oxidation of 31 with m-chloroperoxybenzoic acid resulted in the N-oxdide 32 which underwent fragmentation to give 33 when exposed to trifluoroacetic anhydrde. when the diene 33 was treated with Mn(dpm), (cat)/PhSiH3/O2 in isopropyl alcohol at 0 deg C, it was converted into kopsijasminilam 4. Peracetic acid in ErOAc (10 percent) was used to quench the AgBH4/THF conversion of 28 into 37, and resulted in 42/42a (4:1, 65 percent) along with small amounts of 38 and 41c. Application of these procedures, with some modifications, to the 11,12-dimethoxy substituted system gave (+/-)-lahadinine B 64. Treatment of 64 with triethylsilane in the presence of trifluoroacetic acid cleanly converted it into 11-methoxykopsilongine 65 (93 percent). Treatment of (+/-)-lahadinine B 64 with AgBF4/THF followed by work-up with EtOAc/MeCO3H (10 percent) gave (+/-)-pauciflorine 6 and the double bond isomer 6a.
Synthesis of (±)-lahadinine B and (±)-11-methoxykopsilongine
Magnus,Westlund
, p. 9369 - 9372 (2007/10/03)
6,7-Dimethoxytryptamine 11 was converted into the homoannular diene 19 which underwent a Diels-Alder reaction with acryloyl chloride to give 20. Subsequent radical decarboxylation in the presence of (PhSe)2 provided 22, which was converted into (±)-lahadinine B 1 and (±)-11-methoxykopsilongine 2, thus confirming their structures. (C) 2000 Elsevier Science Ltd.
Propenone derivatives
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, (2008/06/13)
The present invention relates to propenone derivatives represented by the following formula (I): STR1 wherein R1 represents hydrogen, substituted or unsubstituted lower alkyl, substituted or unsubstituted aryl, or YR5 (wherein Y represents S or O; and R5 represents substituted or unsubstituted lower alkyl, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, or a substituted or unsubstituted cyclic ether residue); R2 and R3 independently represent hydrogen, lower alkyl, or substituted or unsubstituted aralkyl, or alternatively R2 and R3 are combined to form substituted or unsubstituted methylene or ethylene; R4 represents hydrogen, hydroxy, lower alkyl, substituted or unsubstituted aralkyl, lower alkoxy, substituted or unsubstituted aralkyloxy, or halogen; and X represents substituted or unsubstituted indolyl; or pharmaceutically acceptable salts thereof.
