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1.
Nahoko Yamaji Manabu Horikawa Hideo Naoki Terumi Nakajima 《Tetrahedron letters》2004,45(28):5371-5373
A novel polyamine toxin, named MG30, was isolated from the venom of the spider, Macrothele gigas, and its structure was elucidated by two-dimensional NMR and mass analysis. In addition, the enantioselective synthesis of MG30 was achieved to assign its absolute stereochemistry. 相似文献
2.
Nikolay Manov 《Tetrahedron》2004,60(10):2387-2391
A solid-phase route for synthesis of 15N-labeled acylpolyamines is described. Utilizing alkylation at benzylic N-atom as a key step, 15N-atoms are incorporated by stepwise construction of the polyamine framework on the solid support. The derivatives were used as reference compounds for the investigation of the MS/MS behavior of spider toxins. 相似文献
3.
The surface tensions of aqueous poly(N-vinylformamide) (PNVF), polyvinylamine (PVAM), and PNVF–PVAM copolymers were measured as functions of pH. The nonionic PNVF
gave a pH-independent surface tension of 68 mN/m. The surface tension of PVAM was pH dependent; at pH 10 it was 56 mN/m, whereas
it was 71.5 mN/m at pH 3.5. The transition from higher to lower surface tension values occurred most dramatically between
pH 8 and 9, reflecting the dissociation behavior of the amine groups. The copolymers showed intermediate behavior.
Received: 20 August 2001 Accepted: 26 September 2001 相似文献
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Zhuo Li Yang Zhang Fang-Hong Tong Ting-Ting Jiang Hui-Ping Zheng Jian-Nong Ye Qing-Cui Chu 《中国化学快报》2014,25(4):640-644
A hollow-fiber liquid-phase microextraction (HF-LPME) method has been developed for the purification and preconcentration of biogenic polyamines and their precursor amino acids in human saliva. Putrescine (Put), cadaverine (Cad), spermidine (Spe), ornithine (Orn), lysine (Lys), and arginine (Arg) were determined by the CE-LIF detection after microextraction. Several factors that affect extraction efficiency, separation, and detection were investigated. Under the optimum conditions, six analytes could achieve baseline separation within 30 min, exhibiting a linear calibration at three orders of magnitude (r2 〉 0.998); the obtained enrichment factors of HF-LPME were between 19 (for Orn) and 2] 8 (for Cad), and the LODs were in the range of 0.0072-0.26 nmol/L. The proposed HF-LPME/CE-LIF method has been successfully applied for the sensitive analyses of the real-world saliva samples collected from healthy volunteers and different patients with oral diseases, providing a potential method for primary non-invasive diagnosis of some oral diseases. 相似文献
6.
Dr. Rakesh Chilivery Dr. Gousia Begum Vahinipathi Chaitanya Dr. Rohit Kumar Rana 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(21):8237-8242
A bio-inspired method is used to render controlled wrinkling surface patterns on supramolecular architectures assembled from polyoxometalate (POM) clusters. It involves a polyamine-multivalent anion interaction generating positively charged coacervates, which while dictating the assembly of POM into spherical structures further facilitate an interesting surface morphogenesis with wrinkling patterns. This spontaneous surface wrinkling depends on the type of multivalent anion and the pH. As the polyamine-anion interaction becomes stronger, the wrinkles turn denser with lesser depth, which eventually undergoes post-buckling to engender a complex surface pattern. Interestingly, the order of influence exerted by different anions on the morphology follows the Hofmeister series. Moreover, the mild synthesis conditions keep the functional POM units dispersed in the sphere with a structural transformability to their lacunary form. 相似文献
7.
Functions of the polyamines in neutral rosin sizing were investigated using X-ray photoelectron spectroscopy(XPS) and laser diffraction particle analysis. The polyamine with a higher charge density and a smaller unite size could retainmore rosin and cover larger fiber surfaces. The XPS spectra demonstrated that polyallylamine.(PAAm) and polyvinylamine(PVAm) could react with a rosin size to form a-OC-N-CO-structure, but polydimethylamino ethyl methacrylate(PDMAEMA) could not, The formation of this structure may be a key step for effective sizing. 相似文献
8.
A series of four novel hydrazine-modified diamine conjugates (7a-b, 8a-b) were synthesized and evaluated for cytotoxicity against Melanoma B 16, α-difluoromethylornithine (DFMO)-treated B 16, spermidine (SPD)-treated B 16, Mouse leukemia L 1210 and Hela cell lines. Both the DFMO-B 16 and SPD-B 16 experiments indicated that conjugates 7a-b and 8a-b could recognize the polyamine transporter (PAT) and enter the cells in part or in whole via PAT, although they were not as efficient as the reference, 9- anthracenemethyl homospermidine (1). 2007 Chao Jie Wang. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved. 相似文献
9.
The structure elucidation of a novel natural product pavettamine (1), the causal agent of the plant toxicosis gousiekte, is reported. The structure was defined by analysis of NMR and MS data and the relative configuration followed from the 13C NMR data of the acetonide derivative. The absolute stereochemistry was established by total synthesis from (2S)-malic acid using chiral sulfoxide methodology as (2S,4R,8R,10S)-1,11-diamino-6-aza-undecane-2,4,8,10-tetraol. 相似文献
10.
Juan Á. BiscegliaJimena E. Díaz Romina A. TorresLiliana R. Orelli 《Tetrahedron letters》2011,52(41):5238-5240
In this Letter we present a method for the synthesis of N-acyl-N′-arylhexahydropyrimidines 1, by ring closure of N-acyl-N′-aryl-1,3-propanediamines 3 with formaldehyde. Cyclodehydrations were performed in aqueous medium under microwave irradiation, and led to high yields of the desired compounds in remarkably short reaction times. The method also allowed for the synthesis of hitherto unreported N-acyl-N′-arylhexahydro-1,3-diazepines 2. The acyclic tetramethylenic precursors 4 were synthesized by selective functionalization of N-arylputrescines. 相似文献