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  • 1
    Electronic Resource
    Electronic Resource
    Holocene stromatolites and microbial laminites associated with lenticular gypsum in a marine-dominated environment, Ras El Shetan area, Gulf of Aqaba, Egypt (1998)
    Oxford UK : Blackwell Science Ltd, UK
    Sedimentology 45 (1998), S. 0 
    Details
    ISSN: 1365-3091
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences
    Notes: Field and petrographic investigations of Holocene evaporites in the Ras El Shetan area, Gulf of Aqaba, Egypt, indicate the presence of microbial mats either in the form of laminites or stromatolites. The morphology of microbial mats and gypsum crystal size characterize the following lithofacies: (1) slump-stromatolitic gypsarenite, (2) random gypsrudite, (3) stromatolitic gypsarenite, and (4) microbially laminated gypsrudite. These evaporite lithofacies are formed above pre-evaporitic mudstones rich in disrupted cyanobacterial filaments, burrows and cerithid gastropods. The morphology of the gypsum crystals is mainly lenticular, indicating enrichment of dissolved organic compounds in the depositional environment. The difference in size of the lenticular gypsum crystals is related to minor changes in salinity and temperature of the parent brine. Fluid inclusions in gypsum crystals indicate their formation at low temperature (〈50°C) in a seawater sourced brine that evaporated to gypsum saturation or higher. The brine salinities range from 10·62 to 12·99 equivalent wt% NaCl, and the brine densities range from 1·08 to 1·11 g/cm3. The change in morphology of the microbial mats (stromatolites and laminites) is related mainly to changes in water depth, from a very shallow salina to a coastal sabkha. Lenticular gypsum nucleated displacively in the microbial mats from saline, oxygenated groundwater that seeped from the sea through a barrier.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-3091.1998.00136.x
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  • 2
    Electronic Resource
    Electronic Resource
    Synthesis and reactions of new 4-chloro-2-methylpyrimidino[4′,5′:4,5]thiazolo[3,2-a]-benzimidazoles (1997)
    Springer
    Monatshefte für Chemie 128 (1997), S. 1133-1141 
    Details
    ISSN: 1434-4475
    Keywords: Pyrimidothiazolobenzimidazole ; Chlorination ; Nucleophilic substitution ; Condensation ; Pharmacological interest
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung 4-Chlor-2-methylpyrimidino[4′,5′:4,5]thiazolo[3,2-a]benzimidazol (3) wurde durch Chlorierung von2, welches auch direkt zu 2-Methylpyrimidino[4′,5′:5,4]thiazolo[3,2-a]-benzimidazol-4-thiol (4) umgesetzt werden kann, hergestellt. Nucleophile Substitution von3 mit Alkoholen, Phenolen, primären Aminen, sekundären Aminen, Natriumazid und Mercaptoessigsäure ergab die entsprechenden Derivate. Das Thiolderivat4 wurde mit Alkyl/Alkarylhalogeniden, Phenacylbromidderivaten, Bromaceton, Chloraniliden, Brommalonsäureester und Bromessigsäureethylester zu potentiell pharmakologisch interessanten Verbindungen umgesetzt.
    Notes: Summary 4-Chloro-2-methylpyrimidino[4′,5′:4,5]thiazolo[3,2-a]benzimidazole (3) was prepared by chlorination of2 which could also be converted directly to 2-methylpyrimidino[4′,5′:4,5]-thiazolo[3,2-a]benzimidazol-4-thiol (4). Nucleophilic substitution of3 with alcohols, phenols, primary amines, secondary amines, sodium azide, and mercaptoacetic acid gave the corresponding derivatives. The thiol derivative4 was reacted with alkyl/aralkyl halides, phenacyl bromide derivatives, bromoacetone, chloroanilides, bromomalonic ester, and ethyl bromoacetate to afford compounds of potential pharmacological interest.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00807563
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  • 3
    Electronic Resource
    Electronic Resource
    Synthesis and reactions of 2-(p-chloroanilino)-5- (D-galacto-1,2,3,4,5-pentahydroxypentyl)-1,3,4-thiadiazole (1986)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 328 (1986), S. 1-6 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Oxidative cyclization of D-galactose (p-chlorophenyl)thiosemicarbazone gave 2-(p-chloroanilino)-5-(D-galacto-1,2,3,4,5-pentahydroxypentyl)-1,3,4-thiadiazole (1), whose acetylation afforded 2-[N-acetyl-N-(p-chlorophenyl)]-amino-5-(D-galacto-1,2,3,4,5-pentacetoxypentyl)- 1,3,4-thiadiazole (3). Its periodate oxidation of the glycol groups gave 2-(p-chloroanilino)-1,3,4-thiadiazole-5-carboxaldehyde (4), which can be transformed into 1,2-[2-(p-chloroanilino)-1,3,4-thiadiazol-5-yl]-1-hydroxy-2-oxoethane. A number of hydrazones of the formyl thiadiazole was prepared and its reduction with sodium borohydride gave 2-(p-chloroanilino)-5-hydroxymethyl-1,3,4-thiadiazole (6), whose acetylation gave a mono-O-acetyl derivative (7). Oxidation of the formyl thiadiazole gave 2-(p-chloroanilino)-1,3,4-thiadiazole (9). The spectral data of the compounds were discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19863280102
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  • 4
    Electronic Resource
    Electronic Resource
    Mass spectral studies of some 2,3-disubstituted 4(3H)-quinazolinoness (1983)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 18 (1983), S. 364-365 
    Details
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/oms.1210180813
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