Exploring the Sea Urchin Neuropeptide Landscape by Mass Spectrometry

Neuropeptides are essential cell-to-cell signaling messengers and serve important regulatory roles in animals. Although remarkable progress has been made in peptide identification across the Metazoa, for some phyla such as Echinodermata, limited neuropeptides are known and even fewer have been verified on the protein level. We employed peptidomic approaches using bioinformatics and mass spectrometry (MS) to experimentally confirm 23 prohormones and to characterize a new prohormone in nervous system tissue from Strongylocentrotus purpuratus, the purple sea urchin. Ninety-three distinct peptides from known and novel prohormones were detected with MS from extracts of the radial nerves, many of which are reported or experimentally confirmed here for the first time, representing a large-scale study of neuropeptides from the phylum Echinodermata. Many of the identified peptides and their precursor proteins have low homology to known prohormones from other species/phyla and are unique to the sea urchin. By pairing bioinformatics with MS, the capacity to characterize novel peptides and annotate prohormone genes is enhanced.

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Practical synthesis of four different pseudoenantiomeric organocatalysts with both cis- and trans-substituted 1,2-cis-cyclohexanediamine structures from a common intermediate

A new and convenient approach has been deviced for the practical synthesis of structurally robust, four different pseudoenantiomeric amino Tf-amido organocatalysts with the unique cis- and trans-substituted 1,2-cis-cyclohexanediamine structures. These pseudoenantiomeric organocatalysts are easily prepared by the Diels-Alder strategy of 2-phenyl-1,3-butadiene and maleic anhydride, and their chemical behavior was investigated by their application to asymmetric aldol synthesis for the practical synthesis of both enantiomeric aldols.     

A green protocol for one pot synthesis of benzosuberone tethered thiadiazolopyrimidine-6-carboxylates using PEG-400 as potent anti-proliferative agents

A new concise and facile method was explored to synthesize a collection of new benzosuberone based thiadiazolo [3,2-a] pyrimidine-6-carboxylates using polyethylene glycol (PEG), which could be regarded as the derivatives of the hybrid scaffolds of bioactive natural benzosuberone and heterocyclic thiadiazolo[3,2-a]pyrimidine. The structures of the synthesized compounds were characterized by ¹H, ¹³C NMR, MS and IR; and their anti-proliferative activity was evaluated against four human cancer cell lines; A549, SKNSH, HeLa and MCF-7. Among the tested compounds, compound 8k showed the most prominent activity against all the cell lines and these results may lay the foundation for further design of novel anti-proliferative agents.     

Propargylamine (secondary) as a building block in indole synthesis involving ultrasound assisted Pd/Cu-catalyzed coupling-cyclization method: Unexpected formation of (pyrazole)imine derivatives

Propargylamine (secondary) has been explored as a building block in synthesizing indoles via an ultrasound assisted Pd/Cu-catalyzed coupling-cyclization method. Indoles containing a pyrazole moiety at C-2 attached via the –CH₂NH– linker (designed as potential anti-tubercular agents) were synthesized first and then generality/scope of the methodology was expanded by synthesizing other indoles. Unexpected formation of imine side products in first cases helped in synthesizing related (pyrazole)imines via a Cu catalyzed ultrasound assisted aerobic oxidation of precursor amines.     

非负载纳米多孔钯催化喹啉及其衍生物的化学选择性氢化反应:H_2分子异裂（英文）

纳米多孔金属是近十年发展起来的一类具有三维通孔结构的新型功能材料,其由纳米尺度的细孔和韧带构成,具有极大的比表面积;它还是一种无毒无载体的宏观材料,并且易制备、易回收和重复利用,因此作为高效的非均相催化剂已逐渐引起人们的重视.1,2,3,4-四氢喹啉是许多医药、农药、染料和天然产物的重要骨架.通过喹啉及其衍生物的选择性加氢反应制备1,2,3,4-四氢喹啉,具有原子利用率高和原料易得等优点.在过去,已经开发了许多类型的均相和非均相催化体系,并成功地用于催化喹啉及其衍生物的选择性加氢反应.尽管非均相催化体系具有诸多优点,但仍存在H_2压力(10–50 atm)和反应温度(60–150℃)相对较高的缺点.因此,开发更加温和条件下的喹啉及其衍生物的选择性加氢反应具有重要意义.此外,在喹啉及其衍生物的加氢反应过程中,H_2分子在非均相催化剂表面的裂解模式,即均裂还是异裂尚不清楚.因此,本文采用新型非均相催化剂纳米多孔钯,研究了喹啉及其衍生物的选择性加氢反应,在相对较低的H_2压力(2–5 atm)和温度(室温–50℃)下实现了目标反应,高收率、高选择性地得到1,2,3,4-四氢喹啉化合物.在最佳反应条件下,对底物的适用范围进行了考察.结果表明,各种含喹啉结构单元的化合物均能顺利发生反应,产物收率在62%–95%.而且该反应对甲基、甲氧基、羟基、酯基、醛基、酰胺基、卤素(F,Cl和Br)等官能团具有较好的兼容性.苯环上取代基的电子效应对反应有一定的影响,吸电子基有利于目标反应的进行.反应完成后,纳米多孔钯催化剂很容易回收,且循环使用多次后,仍未见催化活性降低.扫描电镜和透射电镜结果发现,循环使用后的纳米多孔钯催化剂结构没有发生明显改变,表明其结构稳定.浸出实验结果证明,没有钯原子浸出到反应液中,表明该纳米多孔钯催化反应属于多相催化过程.喹啉的选择性氢化反应被放大到克级的规模时,目标产物的收率仅略有降低,说明该方法具有很好的实用性.通过动力学实验发现,随着反应的进行,反应速率不断加快,表明反应过程中生成的乙胺和1,2,3,4-四氢喹啉同样扮演着路易斯碱性添加剂的角色,促进了反应的进行.通过反应机理研究,揭示了H–H键在纳米多孔钯表面发生了异裂,原位形成的Pd–H物种作为弱亲核试剂,对目标反应的选择性控制起到了至关重要的作用.     

Synthesis and crystal structure of cobalt(III) complex with a Schiff base and azide

The cobalt(III) complex, [Co(L)₂(N₃)₂]₂(ClO₄)₂, L being a Schiff base N-[phenyl(pyridin-2-yl)methylene]aniline has been synthesized and the crystal structure determined using X-ray crystallography. The complex crystallizes in triclinic system, space group P-1 with unit cell parameters a=10.9367(9) ?, b=18.0817(17) ?, c=20.1629(16) ?, α=111.341(2)°, β=91.622(2)°, γ=107.5030(10)°, V=3499.1(5) ?³ and Z=2. It crystallizes with two independent molecules in the asymmetric unit. The two cobalt atoms are hexa-coordinate and have a distorted octahedral geometry, satisfied by four nitrogen atoms from two molecules of the Schiff base and two nitrogen atoms from the monodentate azide group. The perchlorate ions are non-coordinating.     

SYNTHESIS, CHARACTERIZATION AND CATALYTIC ACTIVITY OF N,N''-BIS(3-ALLYL SALICYLIDENE)ETHYLENEDIAMINE COBALT(II) SCHIFF BASE COMPLEX ANCHORED ON A NEW POLYMER SUPPORT

A new chelating polymer support has been prepared by suspension copolymeriz a tion of synthesized N,N'-bis(3-allyl salicylidene)ethylenediamine monomer Schiff base (N,N'-BSEDA) with styrene (St) and divinylbenzene (DVB) using azobisisobutyronitrile (AIBN) as initiator in the presence of poly(vinyl alcohol). The content and complexation ability of monomer Schiff base (N,N'-BSEDA) for cobalt(II) ions in prepared crosslinked polymer beads have shown dependence on the amount of DVB used in reaction mixture. The amount of monomer Schiff base (N,N'-BSEDA) in crosslinked beads showed a substantial decreasing trend at high concentration of DVB in the reaction mixture (＞ 1.5 mol dm-3), hence the efficiency of complexation (EC%) and cobalt(II) ion loading (EL%) of polymer beads showed a decreasing trend. The structure of monomer Schiff base (N,N'-BSEDA) and its cobalt(II) complex on polymer support was elucidated by IR, UV and magnetic measurements. The catalytic activity of polymer bound cobalt(Ⅱ) Schiff base complex was evaluated by analyzing kinetic data of decomposition of hydrogen peroxide in the presence of either supported cobalt (II) complex or free cobalt(II) complex. The activation energy for the decomposition of hydrogen peroxide by polymer supported cobalt(II)complex was found to be low (33.37 kJ mol-l) in comparison with unsupported cobalt(II) complex (56.35 kJ mol-1). On the basis of experimental observations, reaction steps are proposed and a suitable rate expression derived.     

Structural and thermal studies on sisal fibre

Mechanical characteristics of sisal fibre, such as UTS and Young's modulus, have been determined. The thermal degradation of sisal fibre has been observed by running its DSC and TG/DTG.

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Zusammenfassung Die mechanischen Kennwerte (UTS, Young's Modul) von Sisalfasern wurden bestimmt. Der thermische Abbau von Sisalfasern wurde mittels DSC und TG/DTG untersucht.

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The authors wish to thank Dr. R. K. Tiwari, Dr. S. V. Prasad and Dr. M. Patel for their useful suggestions.     

Osmium(VIII) oxidation of arsenic(III) in aqueous sulphuric acid

The oxidation of As^III by Os^VIII or Os^VI in aqueous H₂SO₄ follows the rate law: