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  • 1
    Electronic Resource
    Electronic Resource
    Catalytic determination of nanogram amounts of Mn(II) by the aerial oxidative coupling reaction of 3-methyl-2-benzothiazolinone hydrazone with N,N-dimethylaniline (1985)
    Springer
    Microchimica acta 86 (1985), S. 273-282 
    Details
    ISSN: 1436-5073
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A new catalytic method for the determination of nanogram level of Mn(II) is developed, which is based on its catalytic effect on the aerial oxidative coupling reaction of 3-methyl-2-benzothiazolinone hydrazone (MBTH) withN, N-dimethylaniline (DMA) to form an indamine dye (λmax=590 nm) in the presence of 1,10-phenanthroline (phen) as an activator. A detection limit of 〈0.05 ng Mn(II)/ml can be achieved and as low as 10−9 M Mn(II) can easily be determined by measuring the absorbance of the dye at a fixed time (50 min at 30° C). The proposed method was successfully applied to the determination of manganese in natural waters by using 0.02–4 ml of water samples without preconcentration and separation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01197827
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  • 2
    Electronic Resource
    Electronic Resource
    Preparation and isolation of 2-methylamino-3-phenylpropanoic acid enantiomers using selective crystallization (1997)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 9 (1997), S. 386-389 
    Details
    ISSN: 0899-0042
    Keywords: optical resolution ; diastereomeric method ; molecular compound ; 2-chloro-3-phenylpropanoic acid ; 2-methylamino-3-phenylpropanoic acid ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: First, (RS)-2-chloro-3-phenylpropanoic acid [(RS)-CPP] was optically resolved using ethyl (S)-phenylalaninate as a resolving agent, aiming at preparation of optically active 2-methylamino-3-phenylpropanoic acid (MPP). The (R)-CPP obtained as the sodium salt monohydrate was reacted with methylamine to give (S)-2-methylamino-3-phenylpropanoic acid [(S)-MPP]. Next, the optical resolution of (RS)-MPP was also attempted via molecular compound formation with optically active mandelic acid (MAN). The molecular compound of (R)-MPP with (S)-MAN [(R)-MPP (S)-MAN] was obtained as the less soluble diastereomeric compound, while the (S)-MPP (S)-MAN compound was found to be the more soluble one. Recrystallization of (R)-MPP (S)-MAN compound from water, followed by treatment with acetone, gave optically pure (R)-MPP in 79% yield, based on a half amount of the starting (RS)-MPP. The (S)-MPP obtained from (S)-MPP (S)-MAN compound was again subjected to formation of molecular compound with (R)-MAN to give optically pure (S,)-MPP in 66% yield. Chirality 9:386-389, 1997. © 1997 Wiley-Liss, Inc.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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    Paper (German National Licenses)
  • 3
    Electronic Resource
    Electronic Resource
    Optical resolution by preferential crystallization of (RS)-2-amino-3-chloropropanoic acid hydrochloride (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 8 (1996), S. 197-200 
    Details
    ISSN: 0899-0042
    Keywords: optical resolution ; conglomerate ; preferential crystallization ; optically active 2-amino-3-chloropropanoic acid ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The racemic structures of (RS)-2-amino-3-chloropropanoic acid [(RS)-ACP] and (RS)-2-amino-3-chloropropanoic acid hydrochloride [(RS-ACP·HCl] were examined to obtain (R)- and (S)-ACP via optical resolution by preferential crystallization. The melting point, infrared spectrum, solubility, and ternary solubility diagram suggested that (RS)-ACP·HCl exists as a conglomerate and that (RS)-ACP forms a racemic compound. Optical resolution by preferential crystallization of (RS)-ACP·HCl was successfully achieved to yield (R)- and (S)-ACP·HCl. Optically pure (R)- and (S)-ACP were obtained from the purified (R)-and (S)-ACP·HCl, respectively. © 1996 Wiley-Liss, Inc.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Optical resolution by preferential crystallization of (2RS,3SR)-2-amino-3-chlorobutanoic acid hydrochloride (1997)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 9 (1997), S. 656-660 
    Details
    ISSN: 0899-0042
    Keywords: β-chloro-α-amino acid ; conglomerate ; successive optical resolution ; racemic structure ; (2RS,3SR)-ACB · HCl ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: (2RS,3SR)-2-Amino-3-chlorobutanoic acid hydrochloride [(2RS,3SR)-ACB · HCl] was found to exist as a conglomerate based on the melting point, infrared spectrum, and solubility. Optical resolution by preferential crystallization of (2RS,3SR)-ACB · HCl was achieved to yield both (2R,3S)- and (2S,3R)-ACB · HCl of 80-100% optical purities. The obtained (2R,3S)- and (2S,3R)-ACB · HCl were recrystallized, taking into account the solubility of (2RS,3SR)-ACB · HCl, to give efficiently optically pure (2R,3S)- and (2S,3R)-ACB · HCl. Treatment of the purified (2R,3S)- and (2S,3R)-ACB · HCl with triethylamine gave optically pure (2R,3S)- and (2S,3R)-2-amino-3-chlorobutanoic acid, respectively. Chirality 9:656-660, 1997. © 1997 Wiley-Liss, Inc.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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