NOPR Collection:

Direct observation and structural investigation of galactomannans by transmission electron microscope

Sat, 01 Apr 2000 00:00:00 GMT

Title: Direct observation and structural investigation of galactomannans by transmission electron microscope Authors: Yongli, Yang; Shoujun, Guo; Kun, Sun; Ji, Zhang; Tianzhen, Ju; Jian, Yao Abstract: Galactomannans isolated from the seeds of Ceratonia siliqua, Itelicise tetragonoloba and Sophora japonica have been studied directly by transmission electron microscope and the fine structures of these galactomannans investigated. Although all the three types of galactomannans are linear, they can be distinguished from one another easily under transmission electron microscope. The results indicate that the fine structures of galactomannans vary with their origin. Generally, galactomannan from guar is non block-type, their α--galactose side-chains are disposed basically regular; but not unifonnly. Unlike guar gum, the galactomannans from sophora bean gum and locust bean gum have block-type dispositions which are composed of alternately distributed smooth zone and hair zone but the smooth zone of locust bean gum is longer than that sophora bean gum. Page(s): 313-316

Steroidal alkaloids from Veratrum taliense

Sat, 01 Apr 2000 00:00:00 GMT

Title: Steroidal alkaloids from Veratrum taliense Authors: Zhou, C X; Tan, R X; Ye, W C; Min, Z D Abstract: Phytochemical reinvestigation of the roots and rhizomes of Veratrum taliense yield three known (solanidine,veramiline-3-O-β--glucopyranoside and stenophylline B-3-O-β--glucopyranoside) and two novel steroidal alkaloids. The structures of the new compounds have been established by a combination of spectroscopic methods as 3- angeloylzygadenine-β-N-oxide and (20S, 25S)-22,26-epiminocholesta-5,22-diene-3β,12α-diol (named veramitaline). The chemotaxonomic significance of the isolates are discussed briefly. Page(s): 283-286

A novel naphthalene glucoside from Cassia javanica stem bark

Sat, 01 Apr 2000 00:00:00 GMT

Title: A novel naphthalene glucoside from Cassia javanica stem bark Authors: Sanghi, Rashmi; Singh, Rahul; Singh, J Abstract: A new glucoside, 3-carbomethoxynaphtho [1,2-b]-3',3'dimethylpyran-4-O-,β-glucopyranoside has been isolated from the stem bark of Cassia javanica. Page(s): 321-322

Synthesis and antimicrobial activity of 2-substituted-6-chloro-8-nitro-4-trichloromethyl-4H-1,3,2-benzodioxaphosphorin 2-oxides

Sat, 01 Apr 2000 00:00:00 GMT

Title: Synthesis and antimicrobial activity of 2-substituted-6-chloro-8-nitro-4-trichloromethyl-4H-1,3,2-benzodioxaphosphorin 2-oxides Authors: Srinivasulu, D; Reddy, C Devendranath Abstract: A series of 2-aryloxy/2-arylthio-6-chloro-8-nitro-4-trichloromethyl-4H-1,3,2-benzodioxaphosphorin 2-oxides 3 have been synthesized by-reacting 2-(2,2,,2-trichloro-1-hydroxyethyl)-4-chloro-6-nitrophenol 1 with different arylphosphorodichloridates 2 in the presence of triethylamine at 70-80°C. Some of these compounds are prepared by reacting the monochloride, 2-chloro- 6-chloro-8-nitro-4-trichloromethyl-4H-1, 3, 2-benzodioxaphosphorin 2-oxide 4, in situ with substituted phenol and thiols 5. The monochloride is prepared by condensing 2-(2,2,2-trichloro-1-hydroxyethyl)- 4-chloro-6-nitrophenol with phosphorus oxychloride. IR, ¹H, ¹³C and ³¹P NMR and mass spectral data have been discussed. Some of these compounds have been screened for their antibacterial and antifungal activities. Page(s): 317-320