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  • 1
    Electronic Resource
    Electronic Resource
    Chinazolincarbonsäuren, 10. Mitt. Synthese von 1-Methyl-2,4-dioxo-chinazolin-3-yl-essigsäure, 2,4-Dioxo-chinazolin-1-yl-essigsäuren, 2,4-Dioxo-1,3-chinazolindiessigsäuren und deren Estern (1987)
    Springer
    Monatshefte für Chemie 118 (1987), S. 71-79 
    Details
    ISSN: 1434-4475
    Keywords: Quinazolinyl-acetic acids ; 3,1-Benzoxazine-2,4-dione ; 2-Alkoxy-carbonylmethylamino-benzamides
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract 2,4-Dioxo-quinazolin-1-yl-acetic acid esters (2) were prepared by the reaction of either 3,1-benzoxazine-2,4-diones (1) with urea in the melt or in solution or of the substituted anthranilic acid ester4 with potassium cyanate in acid solution. The anthranilamides5 with trichloromethyl chloroformate (diphosgene) gave also2. Alkaline hydrolysis of2 affords the 2,4-dioxo-quinazolin-1-yl-acetic acids (3), which were independently obtained by the sequence5 →6 →7. 2,4-Dioxo-1,3-quinazolinediacetic acids (11) were synthesized from1 and glycine ester. Reaction of8 with ethyl chloroformate gave9 and treatment of the latter with KOH furnished the potassium salt10, which was converted to11 by acids. Quinazoline-2,4-dione (12) with ethyl bromoacetate yielded13 and with chloroacetonitrile14. 13 was hydrolyzed to11. 14 could not be converted into11. 1-Methyl-3,1-benzoxazine-2,4-dione (15) was transformed under similar conditions into 1-methyl-2,4-dioxo-quinazolin-3-yl-acetic acid (16).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00810042
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  • 2
    Electronic Resource
    Electronic Resource
    Chinazolincarbonsäuren, 5. Mitt.: Synthese von 1,4-Dihydro-chinazolin-4-on-1-yl-essigsäuren und Estern (1986)
    Springer
    Monatshefte für Chemie 117 (1986), S. 499-509 
    Details
    ISSN: 1434-4475
    Keywords: 3,1-Benzoxazine-2,4-dione ; Alkoxycarbonylmethylaminobenz-amides ; Amidines
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract 1,4-Dihydro-quinazoline-4-on-1-yl-acetic acids5 were prepared by reaction of 3,1-benzoxazine-2,4-diones1 with ammonia to2. Cyclisation of2 gave4 and their hydrolysis lead to5. 2-Substituted quinazolinones9 could be obtained by reaction of2 with acid chlorides or by reaction of1 with amidines. Quinazolinone8 was synthesized in a similar way. The substituted 2-aminobenzamide10 showed a reaction behaviour different from that of2.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00810899
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  • 3
    Electronic Resource
    Electronic Resource
    Chinazolincarbonsäuren. VII. MitteilungVI. Mitteilung: [1].. Ein einfacher Zugang zu (4-Oxo-3,4-dihydrochinazolin-3-yl)-alkansäuren, (4-Oxo-3,4-dihydro-1,2,3-benzotriazin-3-yl)-alkansäuren und deren Estern (1985)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 68 (1985), S. 892-899 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Quinazoline Carboxylic Acids. An Easy Route to (4-Oxo-3,4-dihydroquinazolin-3-yl)-alkanoic Acids, (4-Oxo-3,4-dihydro-1,2,3-benzotriazin-3-yl)-alkanoic Acids and their EstersA new route was found for the synthesis of (4-Oxo-3,4-dihydroquinazolin-3-yl)-alkanoic acids (8) and (4-Oxo-3,4-dihydro-1,2,3-benzotriazin-3-yl)-alkanoic acids (6) by cyclization of the N-(2-aminobenzoyl)amino acids 5 with HCOOH or HNO2. 2H-3,1-Benzoxazine-2,4(1H)-diones (1) reacted with glycine esters to 2, which were cyclized by HNO2 to the esters 4. Ester 4 was hydrolyzed to 6 (X = CH2). Diones 1 reacted with the most common amino acids (as the ammonium salt of tertiary amine) to amino-alkanoic acids 5, which were cyclized with orthoformate to 7 or 8 depending on the reaction conditions.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19850680410
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  • 4
    Electronic Resource
    Electronic Resource
    Studies on the Carbon Zip Reaction of 2-Oxocycloalkane-1-carbonitriles (1985)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 68 (1985), S. 1986-1997 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: As a part of continuing interest in the zip reaction, we present the results on a carbon ring-enlargement reaction of activated ketones with a CN group as a charge stabilizer. Two series of (1-cyano-2-oxocy-cloalkyl)alkanoates were prepared from 8- and 12-membered cyano-ketones 1 and 2, respectively, namely the propanoates 3 and 4, the butanoates 6, 8 and 9 as well as the pentanoates 12 and 15. While treatment with t-BuOK of the former two homologous esters resulted in both ring enlargement and competitive transesterification, the pentanoates 12 and 15 afforded mostly the diastereoisomeric mixtures of bicyclic alcohols 20a-c and 31a,b, respectively, which remained intact on further exposure to base. It was shown that - apart from the base used (t-BuOK) vs. Li(i-Pr)2N - the distribution of products was greatly influenced by the ring size of substrates. This is further illustrated by treatment of ketones 34 and 35 with t-BuOK. While the former rearranged smoothly to diketone 36, no reaction at all took place with the latter. The behavior of the substrates is discussed in terms of steric and energetic reasons.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19850680723
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  • 5
    Electronic Resource
    Electronic Resource
    Synthese von 12-Cyano-15-hexadecanolid durch Ringerweiterung von 1-(3′-Hydroxybutyl)-2-oxocyclododecan-1-carbonitril (1985)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 68 (1985), S. 2115-2118 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis of 12-Cyano-15-hexadecanolide by Ring Enlargement of 1-(3′-Hydroxybutyl)-2-oxocyclododecane-1-carbonitrileIn the presence of Bu4NF, 2-oxocyclododecane-1-carbonitrile (1) reacted with acrylaldehyde to form the corresponding aldehyde 2 which was methylated, e.g. with CH3 Ti[OCH(CH3)2]3. The resulting 1-(3′-hydroxybutyl)-2-oxocyclododecane-1-carbonitrile (5) was converted to 12-cyano-15-hexadecanolide (6) in nearly quantitative yield under the influence of Bu4NF.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19850680804
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  • 6
    Electronic Resource
    Electronic Resource
    Synthese und Reaktionsverhalten 2′-substituierter IsoflavoneHerrn Prof. Dr. Dr. h.c. Klaus Schreiber zum 65. Geburtstag. (1992)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 75 (1992), S. 457-470 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis and Behaviour of Isoflavones Substituted in 2′-PositionThe protected chalcones 6-8 prepared from acetophenone and benzaldehydes rearranged to the dimethoxypropanone derivatives 9-11 in the presence of trimethyl orthoformate by Tl(NO3)3. 3 H2O. These compounds could be cyclized to the isoflavones 12-14 in high yields (Scheme 2). The conversion of these isoflavones to the corresponding isoflavanes (model compounds of the phytoalexin glabridin; see Scheme 1) was the main goal of this work. Hydrogenation of 13 and 14 gave the isoflavanes 15 and 16, respectively and their deprotection the racemic natural product 4′-O-demethylvestitol (17). Reduction of 13 and 14 yielded different compounds depending on the reducing agent (Scheme 3). The saturated alcohols 20-23 could be obtained with NaBH4 or LiBH4. They were transferred into the racemic 9-O-demethylmedicarpin (24) and haginin D (25) under acidic conditions. The ketones 26-28 (Scheme 4) were obtained in high yields by reduction of 12-14 with DIBAH. Deprotection of 26 yielded the racemic 2,3-dihydrodaidzein (29). Compounds 13 and 27 as well as 20 and 22 showed different behaviour under reduction conditions with Li in liquid ammonia. An efficient method for the introduction of the MeOCH2O and the MeOCH2CH2OCH2 protecting groups into hydroxylated benzaldehydes and acetophenones (Scheme 5) is described. The appropriate experimental conditions depend on the regioselectivity and on the number of the protected groups. The protected aldehydes, especially those with a protected ortho OH group, show an extraordinary ionization behaviour in chemical-ionization mass spectrometry (isobutane; Scheme 6).
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19920750205
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  • 7
    Electronic Resource
    Electronic Resource
    Chinazolincarbonsäuren. XII. MitteilungXI. Mitteilung: [1].. Synthese von [2-(Ethoxycarbonyl)-3,4-dihydro-4-oxochinazolin-3-yl]-, [2-(Ethoxycarbonyl)chinazolin-4-yloxy]- und (5,6,7,8-Tetrahydro-2-phenylchinazolin-4-ylthio)alkansäure-estern (1986)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 69 (1986), S. 1017-1024 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Quinazolinecarboxylic Acids. Synthesis of Alkyl [2-(Ethoxycarbonyl)-3,4-dihydro-4-oxoquinazolin-3-yl]-, [2-(Ethoxycarbonyl)quinazolin-4-yloxy]- and (5,6,7,8-Tetrahydro-2-phenylquinazolin-4-ylthio)alkanoatesThe [(2-aminobenzoyl)amino]alkanoic acids and their esters 1 showed a different reaction behaviour with diethyl oxalate. Compound 1 (n = 2,3) was converted into the quinazolinylalkanoates 3. o-Aminohippurate yielded with ethyl (chloroformyl)formate a mixture of the amide 4 and the cyclized quinazolinone 7b. Ethyl 3,4-dihydro-4-oxoquinazoline-2-carboxylate (6) reacted with 2-bromoalkanoates, in the presence of NaH, to the [2-(ethoxycarbonyl)-3,4-dihydro-4-oxoquinazolin-3-y1]acetates 7 in the case of alkyl bromoacetate, and to the O-alkylated derivatives 8 with the ethyl 2-bromopropionate and -butyrate. 2-Aminobenzamide (5) gave with ethyl 3-(chloroformyl)-2-propenoate and methyl 3-(chloroformyl)propionate the amides 9 or 11, respectively, and not the expected quinazolinones. The cyclized product 12 was obtained from 11 and ethyl bromoacetate. Tetrahydroquinazolin-4(3H)-thione 14 was synthesized by the reaction of 13 with NH3, and it was alkylated at the S-atom with bromoalkanoates to 15. The hydrazide 16 was synthesized from 15b with hydrazine hydrate.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19860690509
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  • 8
    Electronic Resource
    Electronic Resource
    Mass spectroscopy of natural products. 20 - Quinazoline carboxylic acidsFor Part 19 see D. Voigt and G. Dube, J. Prakt. Chem., in press. 4 - Comparative positive and negative ion mass spectroscopic studies of 3,4-dihydroquinazolin-4-on-3-ylalkanoic acids and 3,4-dihydro-1,2,3-benzotriazin-4-on-3-ylalkanoic acidsFor Part 3 see Ref. 5. (1985)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 20 (1985), S. 184-188 
    Details
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The mass spectroscopic behaviour of 3,4-dihydroquinazolin-4-on-3-ylalkanoic acids and 3,4-dihydro-1,2,3-benzotriazin-4-on-3-ylalkanoic acids was studied under positive and negative ionization. The differences in fragmentation both between the ionization modes and between the two heterocyclic systems are discussed by using some 15N-labelled derivatives.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/oms.1210200303
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