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  • 1995-1999  (11)
  • 1975-1979  (6)
  • 1940-1944
  • 1900-1904  (1)
  • 1996  (11)
  • 1977  (6)
  • 1900  (1)
  • Organic Chemistry  (7)
  • Crystal Structure  (5)
  • Microbial biomass  (4)
  • Computational Chemistry and Molecular Modeling
  • Life and Medical Sciences
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  • 1995-1999  (11)
  • 1975-1979  (6)
  • 1940-1944
  • 1900-1904  (1)
Year
Keywords
  • 1
    Electronic Resource
    Electronic Resource
    Ergosterol and microbial biomass relationship in soil (1996)
    Springer
    Biology and fertility of soils 22 (1996), S. 299-304 
    Details
    ISSN: 1432-0789
    Keywords: Microbial biomass ; Fungal biomass ; Ergosterol ; Fumigation extraction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Ergosterol and microbial biomass C were measured in 26 arable, 16 grassland and 30 forest soils. The ergosterol content ranged from 0.75 to 12.94 μg g-1 soil. The geometric mean ergosterol content of grassland and forest soils was around 5.5 μg g-1, that of the arable soils 2.14 μg g-1. The ergosterol was significantly correlated with biomass C in the entire group of soils, but not in the subgroups of grassland and forest soils. The geometric mean of the ergosterol: microbial biomass C ratio was 6.0 mg g-1, increasing in the order grassland (5.1), arable land (5.4) and woodland (7.2). The ergosterol:microbial biomass C ratio had a strong negative relationship with the decreasing cation exchange capacity and soil pH, indicating that the fungal part of the total microbial biomass in soils increased when the buffer capacity decreased. The average ergosterol concentration calculated from literature data was 5.1 mg g-1 fungal dry weight. Assuming that fungi contain 46% C, the conversion factor from micrograms ergosterol to micrograms fungal biomass C is 90. For soil samples, neither saponification of the extract nor the more effective direct saponification during extraction seems to be really necessary.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00334573
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  • 2
    Electronic Resource
    Electronic Resource
    The problem of pretreatment and unintentional variations in the fumigation-extraction method for time-course measurements in the field (1996)
    Springer
    Biology and fertility of soils 22 (1996), S. 167-170 
    Details
    ISSN: 1432-0789
    Keywords: Analytical variations ; Root intenference ; Root pre-extraction ; Fumigation-extraction ; Microbial biomass
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A control soil stored at 4°C was analyzed 38 times by fumigation-extraction during a period of 11 months to correct for variations caused by the analytical procedure. The difference in extractable C between fumigated and unfumigated samples oscillated around the average without a positive or negative trend. When data from contemporaneously extracted field samples were corrected with control soil data the variations were lowered. The deviations between corrected and uncorrected biomass C values had maxima of ±12%. Data obtained for seven dates using pre-extraction, wet-sieving, and centrifuging were compared with data obtained by the conventional procedure without any pretreatment. A negative difference from data obtained without pretreatment was found when the soil water content was decreased to 6%. The largest positive difference (+38%) was found in May during the period of highest root growth.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00384450
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  • 3
    Electronic Resource
    Electronic Resource
    The problem of pretreatment and unintentional variations in the fumigation-extraction method for time-course measurements in the field (1996)
    Springer
    Biology and fertility of soils 22 (1996), S. 167-170 
    Details
    ISSN: 1432-0789
    Keywords: Key words Analytical variations ; Root interference ; Root pre-extraction ; Fumigation-extraction ; Microbial biomass
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A control soil stored at 4°C was analyzed 38 times by fumigation-extraction during a period of 11 months to correct for variations caused by the analytical procedure. The difference in extractable C between fumigated and unfumigated samples oscillated around the average without a positive or negative trend. When data from contemporaneously extracted field samples were corrected with control soil data the variations were lowered. The deviations between corrected and uncorrected biomass C values had maxima of ±12%. Data obtained for seven dates using pre-extraction, wet-sieving, and centrifuging were compared with data obtained by the conventional procedure without any pretreatment. A negative difference from data obtained without pretreatment was found when the soil water content was decreased to 6%. The largest positive difference (+38%) was found in May during the period of highest root growth.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00384450
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  • 4
    Electronic Resource
    Electronic Resource
    Activity and biomass of soil microorganisms at different depths (1996)
    Springer
    Biology and fertility of soils 23 (1996), S. 38-42 
    Details
    ISSN: 1432-0789
    Keywords: Microbial biomass ; Depth profile ; Fumigation-extraction method ; Soil organic matter ; Dormant population
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract We measured microbial biomass C and soil organic C in soils from one grassland and two arable sites at depths of between 0 and 90 cm. The microbial biomass C content decreased from a maximum of 1147 (0–10 cm layer) to 24 μg g-1 soil (70–90 cm layer) at the grassland site, from 178 (acidic site) and 264 μg g-1 soil (neutral site) at 10–20 cm to values of between 13 and 12 μg g-1 soil (70–90 cm layer) at the two arable sites. No significant depth gradient was observed within the plough layer (0–30 cm depth) for biomass C and soil organic C contents. In general, the microbial biomass C to soil organic C ratio decreased with depth from a maximum of between 1.4 and 2.6% to a minimum of between 0.5 and 0.7% at 70–90 cm in the three soils. Over a 24-week incubation period at 25°C, we examined the survival of microbial biomass in our three soils at depths of between 0 and 90 cm without external substrate. At the end of the incubation experiment, the contents of microbial biomass C at 0–30 cm were significantly lower than the initial values. At depths of between 30 and 90 cm, the microbial biomass C content showed no significant decline in any of the four soils and remained constant up to the end of the experiment. On average, 5.8% of soil organic C was mineralized at 0–30 cm in the three soils and 4.8% at 30–90 cm. Generally, the metabolic quotient qCO2 values increased with depth and were especially large at 70–90 cm in depth.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00335816
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  • 5
    Electronic Resource
    Electronic Resource
    Nachschrift (1900)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 62 (1900), S. 134-134 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19000620107
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  • 6
    Electronic Resource
    Electronic Resource
    α-Heterosubstituierte Organyllithiumverbindungen durch Selen/Lithium-Austausch; gezielte Kopplung von Carbonyl-verbindungen (1977)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1977 (1977), S. 846-858 
    Details
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: α-Heterosubstituted Organyllithium Compounds by Selenium/Lithium-Exchange; Directed Coupling of Carbonyl CompoundsThe preparation of phenylseleno derivatives 1-4 and 6 is described. Se/Li-exchange with butyl- and tert-butyllithium removes the heteroatom free substituent from 1-3 and 8a; the sulfur derivative 10a undergoes the same transformation. The α-seleno- and α-thioalkyl-lithium derivatives 5 and 11 are generated in high yields from 4 and 6, respectively, as shown by their reactions with carbonyl compounds to give alcohols 12 and 16. According to scheme 1, the allylic alcohols 17, 18, and 20, as well as the olefin 21 and the epoxide 22 are obtained.
    Notes: Die Phenylselenderivate 1-4 und 6 wurden hergestellt.  -  Während beim Versuch der Transmetallierung von 1-3 sowie 8a mit Butyl- oder tert-Butyllithium stets der heteroatomfreie Substituent am Selen ausgetauscht wird, was auch beim Thioether 10a der Fall ist, entstehen aus 4 und 6 die α-Seleno- und α-Thioalkyllithiumderivate 5 bzw. 11. Dies wird durch deren Umsetzung zu den Alkoholen 12 und 16 bewiesen.  -  Nach Schema 1 wurden die Allylalkohole 17, 18 und 20, sowie das Olefin 21 und das Epoxid 22 synthetisiert.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.197719770514
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  • 7
    Electronic Resource
    Electronic Resource
    Synthesen mit α-metallierten Isocyaniden, XXXVIII. Trialkylmethyl-substituierte Glycine und Pyrrol-2,4-dicarbonsäureester aus 2-Isocyanacrylsäureestern und Carbanionen (1977)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1977 (1977), S. 1174-1182 
    Details
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Syntheses with 2-Metalated Isocyanides, XXXVIII. - Trialkylmethyl Substituted Glycines and Pyrrole-2,4-dicarboxylic Esters from 2-Isocyanoacrylic Esters and CarbanionsThe following Michael additions of carbanions to 2-isocyanoacrylic esters 2 are described: 1. The addition of Grignard compounds 4 to give 2-isocyano-2-(trialkylmethyl)ethanecarboxylic esters 5 which on hydrolysis form trialkylmethyl-substituted glycines (type 6 or 7); 2. the addition of ethyl lithioisocyanoacetate (8) to give 3-substituted diethyl pyrrole-2,4-dicarboxylates 11; and 3. the addition of diethyl sodiomalonate to form triethyl 1-isocyano-2,2-dimethylpropane-1,3,3-tricarboxylate (14).
    Notes: Folgende Michael-Additionen von Carbanionen an 2-Isocyanacrylsäureester 2 werden beschrieben: 1. die Addition von Grignard-Verbindungen 4 zu 2-Isocyan-2-(trialkylmethyl)-ethansäureestern 5, welche zu Trialkylmethyl-substituierten Glycinen (Typ 6 oder 7) hydrolysierbar sind, 2. die Addition von Lithioisocyanessigsäure-ethylester (8), die im Endeffekt 3-substituierte Pyrrol-2,4-dicarbonsäurediester 11 liefert und 3. die Addition von Natrium-malonsäureester an 2a, welche zu 1-Isocyan-2,2-dimethylpropan-1,3,3-tricarbonsäure-triethylester (14) führt.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.197719770714
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  • 8
    Electronic Resource
    Electronic Resource
    Synthesen mit α-metallierten Isocyaniden, XXXIX. 2-Imidazoline aus α-metallierten Isocyaniden und Schiff-Basen; 1,2-Diamine und 2,3-Diaminoalkansäuren (1977)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1977 (1977), S. 1183-1193 
    Details
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Syntheses with α-Metalated Isocyanides, XXXIX - 2-Imidazolines from α-Metalated Isocyanides and Schiff Bases; 1,2-Diamines and 1,2-Diaminoalkanoic acidsα-Metalated isocyanides 1 react with Schiff bases 5 to give via the intermediates 6 and 7 2-unsubstituted 2-imidazolines 8. The intermediate 2-metalated 2-imidazolines 7 can be trapped with electrophiles to give 2-substituted 2-imidazolines (for instance 9). - Alkyl 2-imidazoline-4-carboxylates 8f-o can be obtained alternatively from alkyl 2-isocyanoacrylates 11a,b and primary amines or ammonia. - On acides hydrolysis 2-imidazolines 8 give 1,2-diamines 13 or 2,3-diaminoalkanoic acids 14.
    Notes: α-Metallierte Isocyanide 1 reagieren mit Schiff-Basen 5 über die Zwischenstufen 6 und 7 zu 2-unsubstituierten 2-Imidazolinen 8. Die 2-metallierten Imidazoline vom Typ 7 können mit Elektrophilen zu 2-substituierten 2-Imidazolinen (z. B. 9) umgesetzt werden. - 2-Imidazolin-4-carbonsäureester 8f-o erhält man alternativ aus 2-Isocyanacrylsäureestern 11a,b und primären Aminen oder Ammoniak. - Die 2-Imidazoline 8 liefern bei der Hydrolyse 1,2-Diamine 13 oder 2,3-Diaminoalkansäuren 14.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.197719770715
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  • 9
    Electronic Resource
    Electronic Resource
    Dihydropyridine, III. Synthese von 2-Aminodihydropyridinen durch Michael-AdditionTeil eines Vortrages vor der Fachgruppe “Medizinische Chemie” der GDCh am 29 März 1974 in München. Herrn Prof. O. Bayer mit den besten Wünschen zum 75. Geburtstag gewidmet. (1977)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1977 (1977), S. 1895-1908 
    Details
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Dihydropyridines, III. - Synthesis of 2-Aminodihydropyridines via Michael AdditionMichael addition of amidinoacetic esters 4 to alkylidene- or aralkylideneacetoacetic esters 1 is followed by ring closure to give novel 2-amino-1,4-dihydropyridine-3,5-dicarboxylates 10. 2-Amino-1,4-dihydropyridine-3-carboxylates 20 are obtained by addition of 4 to α,β-un-saturated ketones 17. Reaction of 3-amino-3-dialkylaminoacrylic esters 25 with 1 leads to 2-dialkylamino-3,4-dihydropyridine-3,5-dicarboxylates 27. Condensation of aldehydes 21, 1,3-cyclohexanedione and 4 yields 2-amino-5-oxo-1,4,5,6,7,8-hexahydroquinoline-3-carboxylates 23.
    Notes: Die Michael-Addition der Amidinoessigsäureester 4 an Alkylidene- oder Aralkylidenacetessigsäureester 1 führt unter Ringschluß zu 2-Amino-1,4-dihydropyridin-3,5-dicarbonsäure-ester 10. An α, β-ungesättigte Ketoverbindungen 17 wird 4 zu den 1,4-Dihydropyridin-3-carbonsäureestern 20 addiert. 3-Amino-3-dialkylaminoacrylsäureester 25 liefern mit 1 unter analogen Bedingungen die 2-Dialkylamino-3,4-dihydropyridine 27. Die Aldehyde 21, 1,3-Cyclohexandion und 4 kondensieren zu den teilhydrierten 2-Amino-5-oxochinolin-3-carbon-säureestern 23.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.197719771111
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  • 10
    Electronic Resource
    Electronic Resource
    Synthese von (-)(1S, 7S)-exo-Brevicomin aus (+)-(2R, 3R)-Weinsäure-diethylester (1977)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1977 (1977), S. 732-736 
    Details
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis of (-1S, 7S)-exo-Brevicomine starting from (+)-(2R, 3R)-Diethyl TartrateThe sex attractant 4 of western pine beetle Dendroctonus brevicomis has been synthesised in high yield in optically active form starting from (+)-(2R, 3R)-diethyl tartrate by coupling dithiane 5c with the optically active bromide 2d.
    Notes: Der Sexuallockstoff 4 des Borkenkäfers Dendroctonus brevicomis wird in guter Ausbeute in optisch aktiver Form ausgehend von (+)-(2R, 3R)-Weinsäure-diethylester über die Kupplung des Dithianderivates 5c mit dem optisch aktiven Bromid 2d synthetisiert.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.197719770503
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