Two New Butenolide Derivatives from Erigeron acer

Two new butenolide derivatives, named as erigeracerin A and efigeracefin B, which are a pair of epimers, were isolated from Erigeron acer. Their structures were elucidated by spectroscopic analysis including 2D NMR and HR-ESI-MS.

First Synthesis of (±)-3-(5-Hyd roxy-4-Methyl-7-Isopropyl-3E,7-Octadienyl)- △~2-Butenolide

An efficIent total synthesis of (±)-3-(5-hydroxy-4-methyl-7 △-butenolide, a new fi1n1esane-b;.Fed homosesquiterPeIle lactone. starting from geraniol through eightsteps are described.

FIRST SYNTHESIS OF(±)-3-[(5-HYDROXY)HOMOGERANYL]-△~2-BUTENOLIDE

A new farnesane-based sesquiterpene lactone, 3- [(5-hydroxy) homogeranyl]-△2-butenolide, was synthesized for the first time starting from trans, trans-farnesol through five steps in an overall yield of 6. 4 % as its racendc form.

First Synthesis of Mosquito Larvicidal Butenolides I and II

Utilizing aldol condensation and β-elimination as the key steps, butenolidesⅠ and Ⅱ in excellent enantiomeric purity have been concisely synthesized for the first time.According to the rotation difference between synthetic samples and natural products, the rotationswere corrected by the calculation upon HPLC measurements. In addition, an efficient way tosynthesize methyl pentadec-14-enoate was developed.

Transalkylation of N-methyl tertiary amines with 3,4-dibromobutenolides

The selective transalkylation of N-methyl tertiary amines with 3,4-dibromobutenolides is described. The N-methyl group of the parent tertiary amines was replaced by alkenyl units of the butenolides; and a series of butenolide-containing tertiary enamines were obtained in moderate to good yields. Interestingly, the product 2b has shown a promising anticancer activity against HeLa cell lines （IC50 = 0.19μmol/L）.

First Total Synthesis of 6-Oxodendrolasinolide

An efficient total synthesis of 6-oxodendrolasinolide 1, a new farnesane-based homosesquiterpene lactone, starting from geraniol 2 through twelve steps is described. Our work involved two key steps： （1） regioselective alkylation of the anion of vinyldithian 5 with allylic chloride 31, （2） Corey＇s oxidative lactionization method2.

THE EXPERIMENTAL STUDY ON THE EFFECTS OF SIX MYCOTOXINS ON THE CULTURAL CHONDROCYTES

The effects of deoxynlvalenol (DON), T--2 toxin, nivalenol (NIv), hutenolide (BuT).alternariol methyl ether(AME) and monlliformin (cON ) on rabbit articular chondrocytes were observed by using the method of chondrocyte monolayer culture. The amounts or DNA in chondrocytesand glucuronate in matrix were measured. And the chondrocytes were observed by inversion microscope and transmission electron microscope (TEM). The results showed that the cultured chondrocytes were damaged by all the six mycotoxinsl and the synthesis of DNA and the divided reproductionof chondrocytes were restrained; the damage errect was more evident, esl,ecially in the early stage ofculturel the higher concentration or toxin in the media was used, the lower density of the culturalckondrocytes was observed; the cells were even round damaged and dead, so long as the media contolued toxin. When the six mycotoxins arrected the cultural chondrocytes r.spectively, three dirfereut kinds or ultrastructural changes in ckondrocytes were seen by TEa. The relationship betweenmycotoxiu and KBD was preliminarily discussed, and some problems still need further investigation..

Design, Synthesis and Insecticidal Activities of Novel 5-Alkoxyfuran-5(H)-one Derivatives

A series of novel 5?alkoxyfuran-2(5H)-one derivatives was synthesized, and characterized by 1H NMR, 13C NMR and HRMS. Biological activities of all the title compounds were evaluated systematically. Preliminary bioassays indicated that most of the compounds exhibited moderate insecticidal activities against Aphis craccivora and Nilaparvata lugens at 100 mg/L. Compounds 4h and 4w exhibited 100% mortality rate against Aphis craccivora at 100 mg/L, and compound 4h exhibited good mortality rate against Aphis craccivora and Nilaparvata lugens (60% and 75%, respectively) even at 4 mg/L. The results demonstrated the impact of various chemical groups on insecticidal activities and provided a potential clue for further exploring novel high-effective broad-spectrum insecticides.

Antifouling mechanism of natural product-based coatings investigated by digital holographic microscopy

Using natural product-based antifouling coatings has proven to be an effective strategy to combat biofouling.However,their antifouling mechanisms are still unclear.In this study,the antifouling mechanism of natural product-based coatings consisting of bio-sourced poly(lactic acid)-based polyurethane and ecofriendly antifoulant(butenolide)derived from marine bacteria was revealed by observing 3D bacterial motions utilizing a 3D tracking technique-digital holographic microscopy(DHM).As butenolide content increases,the density of planktonic marine bacteria(Pseudomonas sp.)near the surface decreases and thus leads to a reduced adhesion,indicating that butenolide elicits the adaptive response of Pseudomonas sp.to escape from the surface.Meanwhile,among these remained cells,an increased percentage is found to undergo subdiffusive motions compared with the case of smaller dose of butenolide.Further experiments show that butenolide can accelerate their swimming velocity and reduce flick frequency.Antibacterial assay confirms that butenolide-based coating shows high efficacy of antifouling performance against Pseudomonas sp.but without killing them like 4,5-dichloro-2-n-octyl-4-isothiazolin-3-one(DCOIT).

Facile synthesis of CF_3-substituted dienamides via one-pot tandem reactions

A one-pot reaction sequence of sequential phosphine-promoted tandem annulations of aryl trifluoromethyl ketones and MBH（Morita-Baylis-Hillman） carbonates and DBU-mediated aminolysis was developed. This method provides a step-economical approach to trifluoromethylated dienamides with diverse structural complexity from readily available starting materials in moderate yields.