三元环氨基酸的合成工艺改进

以甘氨酸乙酯盐酸盐为原料,经酰氨化、脱水、成环、水解反应合成了三元环氨基酸,总收率达50.4%。其结构经1HNMR,13CNMR,IR和EI-MS确证。     

A Facile Synthesis of Bridged‐tricyclic Skeletons via Intramolecular Diels‐Alder Reaction of Cyclic 1,3‐Dienes Containing an α,β‐Unsaturated Ester

Intramolecular Diels‐Alder reaction (IMDA) precursors are easily available starting from addition of ester functionalized zinc‐copper reagents to cyclohexadienyl‐ and cycloheptadienylirontricarbonyl cation salts. The resulting cyclic 1,3‐dienes containing an α,β‐unsaturated ester functionality underwent smoothly IMDA reaction to afford bridged tricyclic compounds. Bridged heterotricyclic skeletons were also available via IMDA reaction of cyclic 1,3‐dienes bearing an imine or aldehyde functionality.     

NEW ACYCLIC AND FUSED TRICYCLIC PHOSPHORUS COMPOUNDS AFFORDED BY NOVEL CONDENSATION

Abstract

The condensation of 1 - (2-benzothiazolyl)-4-phenylsemicarbazide with (R₂ N)₂ PX(X [dbnd] R₂N. RO, Ph) proceeds with cleavage of the N—C(O) bond and formation of the title compounds which were also synthesized via similar treatment of 2-hydrazinobenzothiazole in good yields. Reactivities of (R, N), PX, spectroscopic properties of the products and preliminary mechanism of these reactions were discussed.     

The Synthesis and Chemistry of 1,3‐Bridged Polycyclic Cyclopropenes: 8‐Oxatricyclo[3.2.1.02,4]octa‐2,6‐dienes

Three 1,3‐bridged polycyclic cyclopropenes, exo‐8‐oxatricyclo[3.2.1.0^2,4]octa‐2,6‐diene ( 10 ), endo‐8‐oxatricyclo[3.2.1.0^2,4]octa‐2,6‐diene ( 11 ), and exo‐6,7‐benzo‐1,5‐diphenyl‐8‐oxatricyclo[3.2.1.0^2,4]octa‐2,6‐diene ( 12 ), have been synthesized by elimination of 2‐chloro‐3‐trimethylsilyl‐8‐oxatricyclo[3.2.1.0^2,4]‐oct‐6‐enes, 17 , 18 and 30 , which were generated from 1‐chloro‐3‐trimethylsilylcyclopropene with furan and diphenylisobenzofuran. We have demonstrated a facile route to synthesize the highly strained 1,3‐fused polycyclic cyclopropenes, 10 , 11 , and 12 . The stereochemistry of the Diels‐Alder reactions of cyclopropene 16 with furan and DPIBF are different. Cyclopropene 16 was treated with furan to form exo‐exo and endo‐exo adducts (5:2) and treated with DPIBF to generate an exo‐exo adduct. Compounds 10 , 11 and 12 undergo isomerization reactions to form benzaldehyde and phenyl 4‐phenyl‐[1]naphthyl ketone to release strain energies via diradical mechanisms.     

（±）-13-羟基-8（14）-松香烯的全合成

（±）-13-羟基-8（14）-松香烯的全合成;三环二萜;全合成;（±） 羟基 松香烯     

Determination of imipramine and trimipramine by capillary electrophoresis with electrochemiluminescence detection

The tricyclic antidepressants (TCA) imipramine (Imi) and trimipramine (Tri) were successfully analyzed by capillary electrophoresis (CE) coupling with Tris(2,2-bipyridyl) ruthenium(II)-based (Ru(bpy)₃²⁺) end-column electrochemiluminescence (ECL) detection. The addition of β-CD to the running buffer was found to enable baseline separation of the two analytes and the addition of acetonitrile (ACN) as an organic additive to improve the repeatability and sensitivity of the CE method. Under the optimized separation and detection conditions (50 mM PBS (pH = 7.0) and 2 mM Ru(bpy)₃²⁺ in the ECL detection cell, 20 mM Tris (pH = 2.0), 0.2 mM β-CD and 20% ACN (v/v) as running buffer), wide linear ranges of 0.1-5 μM and 0.1-5 μM were achieved, with the correlation coefficients of 0.9990 (n = 8) and 0.9980 (n = 8) for Imi and Tri, respectively. Detection limits 5 nM and 1 nM (S/N = 3) were obtained for Imi and Tri, respectively. The method was also successfully applied for the determination of Imi in pharmaceutical dosage form.     

New anti-bacterial halogenated tricyclic sesquiterpenes from Bornean Laurencia majuscula (Harvey) Lucas

Three new halogenated tricyclic sesquiterpenes, omphalaurediol (1), rhodolaurenones B (2) and C (3) were isolated together with nine known haloganated sesquiterpenes such as rhodolaurenone A (4), rhodolaureol (5), isorhodolaureol (6), (?)-laurencenone D (7), elatol (8), (+)-deschloroelatol (9), cartilagineol (10), (+)-laurencenone B (11) and 2-chloro-3-hydroxy-α-chamigren-9-one (12) from a population of Bornean red algae Laurencia majuscula. The structures of three new metabolites were determined based on their spectroscopic data (IR, 1D and 2D NMR, and MS). These compounds showed antibacterial activity against three human pathogenic bacteria (Escherichia coli, Salmonella typhi and Vibrio cholera).     

On the Laplacian integral tricyclic graphs

A graph is called Laplacian integral if all its Laplacian eigenvalues are integers. In this paper, we give an edge subdividing theorem for Laplacian eigenvalues of a graph (Theorem 2.1) and characterize a class of k-cyclic graphs whose algebraic connectivity is less than one. Using these results, we determine all the Laplacian integral tricyclic graphs. Furthermore, we show that all the Laplacian integral tricyclic graphs are determined by their Laplacian spectra.     

The Signless Laplacian Spectral Radius of Tricyclic Graphs with k Pendant Vertices

In this paper,we determine the unique graph with the largest signless Laplacian spectral radius among all the tricyclic graphs with n vertices and k pendant vertices.     

几类多圈图的拉普拉斯谱刻画

设图G是一个简单连通图. 如果任何一个与图G同拉普拉斯谱的图都与图G同构,则称图G是由其拉普拉斯谱确定的. 定义了双圈图\theta_{n}(p_1,p_2,\cdots,p_t) 和m 圈图H_n(m\cdot C_3;p_1,p_2,\cdots,p_t). 证明了双圈图\theta_{n}(p)和\theta_{n}(p,q),三圈图H_n(3\cdot C_3;p)和H_n(3\cdot C_3;p,q)分别是由它们的拉普拉斯谱确定的.