Alkaloids of Arundo donax. XIV. Crystal and Molecular Structure of N-Methyl-tetrahydro- β-carboline

An indole alkaloid of the N-methyl-tetrahydro--carboline series was isolated for the first time from Arundo donax, Poaceae. Its structure was solved by X-ray structure analysis.     

Uronic (hexenuronic) acid profile of ethanol–alkali delignification of giant reed Arundo donax L.

The effect of process variables on uronic acids (UAs) and hexenuronic acids (HexAs) in the annual crop Arundo donax L. during ethanol–alkali pulping has been examined. A substantial loss of UA moieties (up to 90%) was observed by the end of pulping (target kappa number 18) performed with 25% NaOH and 40% EtOH (by volume) within the temperature range of 130–150 °C. At the same time, the progressive formation of HexA in pulp was detected from the early phases of delignification. The proportion of HexA in the residual UA of the final pulp was found to be 84%, indicating almost complete conversion of 4-O-methylglucuronic acid side groups (MeGlcA) of heteroxylan into HexA. The kinetics of UA degradation and HexA formation has been described in terms of three consecutive first-order reaction stages. The overall rate of UA degradation was one order higher than the rate of UA conversion into HexA. The values of apparent activation energy were estimated as 68.6 and 94.7 kJ mol^–1, respectively. The reaction medium alkalinity was shown to be the controlling factor for UA and HexA stability during ethanol–alkali pulping. An increase in alkali charge from 5% to 35% (as NaOH) led to UA loss of 40%, but promoted HexA formation from 11.8 to 20.1 mol g^–1. The addition of organic solvent to the alkaline pulping solution had a similar effect, and about 10% of UA was lost and the content of HexA increased from 6.9 to 10.9 mol g^–1 with an increase in ethanol proportion in the liquor from 20% to 60%.     

Prof. Dr. E. Gorter, 19. Februar 1881 –17. Februar 1954

Ohne Zusammenfassung     

Über die roten Anile. 2. Mitt.

Zusammenfassung Bei der Spaltung des -(p-Dimethylaminophenylimino)--keto--(3,4,5-trimethoxyphenyl)-valeriansäurenitrils (V) mit Chlorwasserstoffsäure entsteht die -Keto--(3,4,5-trimethoxyphenyl)-buttersäure (VII) und nicht, wie infolge des Versagens einiger typischen -Ketocarbonsäurereaktionen vermutet wurde, die 3-Hydroxy-4,5,6-trimethoxy-indan-3-carbonsäure.1. Mitt.:J. Michalský undL. Sadílek, Mh. Chem.90, 171 (1959).     

Correctionto Chin .J .Chem .2002,20,851— 857

Ａｆｔｅｒｏｕｒａｒｔｉｃｌｅｔｉｔｌｅｄ“Ｈｙｄｒｏｔｈｅｒｍａｌｓｙｎｔｈｅｓｅｓ ,ｓｕｐｒａｍｏｌｅｃｕｌａｒｓｔｒｕｃｔｕｒｅｓａｎｄｔｈｅｔｈｉｒｄ ｏｒｄｅｒｎｏｎ ｌｉｎｅａｒｏｐｔｉｃａｌｐｒｏｐｅｒｔｉｅｓｏｆｔｈｒｅｅｃｏｐｐｅｒ(Ｉ)ｈａｌｉｄｅａｍｉｎｅｃｏｍ ｐｌｅｘｅｓｃｏｎｎｅｃｔｅｄｖｉａｓｅｃｏｎｄａｒｙｂｏｎｄｉｎｇｉｎｔｅｒａｃｔｉｏｎｓ”ｉｓｐｕｂｌｉｓｈｅｄｉｎＣｈｉｎｅｓｅＪｏｕｒｎａｌｏｆＣｈｅｍｉｓｔｒｙ 2 0 0 2 ,2 0 ,85 1— 85 7,ａｎａｄｖｉｃｅｆｒｏ…     

Über die roten Anile. 1. Mitt.

Zusammenfassung Durch Anwendung der vonF. Kröhnke ¹ ausgearbeiteten Methode zur Darstellung von -Keto-carbonsäuren konnte man über die roten Anile VIII die entsprechenden -Keto-(3,4,5-trimethoxyphenyl)-alkancarbonsäuren (IX, XI) gewinnen. Die erfolgreich durchgeführte Synthese des -(p-Dimethylaminophenylimino)--keto--(3,4,5-trimethoxyphenyl)-valeriansäurenitrils (VIIIc) läßt auch die geplante Synthese von -(p-Dimethylaminophenylimino)--keto--[2,3,4,4-tetramethoxydiphenylyl-(6)]-valeriansäurenitril und der entsprechenden -Keto-säure (V, [H statt Br]) als hoffnungsvoll erscheinen.     

RECIPROCAL A.C.OSCILLOPOLAROGRAM

In this paper a new electrochemical method“Reciprocal a.c.oscillololarography”is discussed.Both principle and experimental work aredescribed.     

仪器信息网www.instrument.com.cn全面改版

为使网站功能更科学、内容更丰富,在广泛征询本网用户意见的基础上,科学仪器最大的门户网站-仪器信息网(www.instrument.com.cn)近期做了全面改版·本次改版后,网站功能大大增强、信息量也大有增加,"网上仪器展"展出的仪器超过了7 000台,展出的耗材配件超过了8 000种,分析方法及资料超过2万篇·另外,还新增了以下栏目:"新品发布":专门展出近两年在中国市场正式上市的仪器新品·"促销仪器":及时发布厂家正在促销或优惠打折的仪器产品信息·"热点应用":针对社会上的热点问题,如欧盟的ROHS指令、日本肯定列表制度、松花江污染、假药检测等及…     

C.P.M.G.脉冲序列法用于抑制和消除水信号

大约0.3M的NH_4Al(SO_4)_2的重水溶液用作溶剂而令其活泼氢交换,结果水的横向弛豫时间T_2缩短,可用C.P.M.G.脉冲序列法消除水峰。以此为溶剂测定了葡萄糖的图谱,结果满意。     

Chin.J.Chem.设立"NHU-CJC Innovation Award"

新和成控股集团有限公司着力于中国学术期刊的大发展,提升我国期刊的国际影响力,与中国科学院上海有机化学研究所于2018年1月签署协议,自2018年至2022年,每年捐赠人民币二十万元,对投稿给Chin.J.Chem.原则性非常强的工作,由主编或副主编提名,经主编和副主编全体投票,获2/3同意,授予“新和成《中国化学》创新奖”(NHU-CJC Innovation Award),每位作者均将获得证书和奖金,相关工作将在Breaking Report栏目发表。     

Chin.J.Chem.设立"NHU-CJC Innovation Award"

正新和成控股集团有限公司着力于中国学术期刊的大发展,提升我国期刊的国际影响力,与中国科学院上海有机化学研究所于2018年1月签署协议,自2018年至2022年,每年捐赠人民币二十万元,对投稿给Chin.J.Chem.原创性非常强的工作,由主编或副主编提名,经主编和副主编全体投票,获2/3同意,授予"新和成《中国化学》创新