Auf das Zentralnervensystem wirkende Substanzen, XXIV. Über Azetidindione‐(2.4), II

Testa, Emilio; Fontanella, Luigi

doi:10.1002/jlac.19626600113

Cited by 10 publications

(8 citation statements)

References 22 publications

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“…Similar correlations were observed for the ring cleavage reaction in cyclobutanones: in the mass spectrum of cyclo-butanone5 the charge remains mainly with the ketene fragment (IP ketene 9.6 eV and IP ethylene 10.5 eV) while for 2-methyl and 2,2-dimethyl substituted cyclobutanones53 the alkylene fragment (IP propylene 9.7 eV and IP isobutylene Compernolle, De Schryver / Electron Impact of Substituted Table I. 70 eV Mass Spectra of Azetidinediones I-VIII 3.3-Diisopropyl-2,4-azetidinedione (I) 39 (9), 40 (2), 41 (20), 42 (1), 43 (9), 51 (1), 53 (3), 55 (37), 56…”

Section: Resultsmentioning

confidence: 99%

Nonconcerted cycloreversion by electron impact of substituted 2,4-azetidinediones. Relations between the mass spectral and photochemical reactions

Compernolle¹,

Schryver²

1975

J. Am. Chem. Soc.

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The transition state for production of ketene ions and isocyanic acid or isocyanates from the molecular ions of substituted 2,4-azetidinediones (I-VIII) was studied for the metastable reaction occurring in the first field-free region of the mass spectrometer. The effect of 1 and 3 substituents upon the partitioning of the reverse activation energy between translational and internal energy of the reaction products indicates competition between reactions proceeding via primary fissions of the C-CO and N-CO bonds, producing acyclic intermediates a and b, respectively. Formation of ions a, which possibly rearrange to a five-membered cyclic structure c prior to decomposition, is enhanced by 3-phenyl and 3-isopropyl substituents, while a 1 -phenyl group promotes production of ions b. The activation energies for the consecutive steps in the reaction of the molecular ions generally very low, i.e., about 0.05-0.1 eV. A 0.9 eV activation energy, found for 1 -phenyl-3,3-diethyl-2,4azetidinedione (VII), is ascribed to the energetically favorable formation of a nonreactive molecular ion, having a resonance stabilized structure b. A striking analogy is found between the mass spectral and photochemical reactions; in the latter, intermediates of type a lead to ring-expansion products, stabilized by the addition of methanol, while intermediates of type b give rise to cycloreversion products.The photochemical reactions of 2,4-azetidinediones (I to VIII, Scheme I) in methanol recently have been investi-Scheme I.

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Section: Resultsmentioning

confidence: 99%

Nonconcerted cycloreversion by electron impact of substituted 2,4-azetidinediones. Relations between the mass spectral and photochemical reactions

Compernolle¹,

Schryver²

1975

J. Am. Chem. Soc.

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“…12 We wish to present a simple strategy for the general synthesis of 2,2-dialkyl-3-aminopropionic acids as an extension of the present ¢nding (Scheme B). This type of compound has been used 13 as intermediates to b-lactams and other biologically useful compounds. We have synthesized the protected 2,2-diethyl-3-aminopropionic acid 4 as an example starting from 2,2-diethylmalononitrile 1c.…”

Section: -93%mentioning

confidence: 99%

Clay-catalyzed Conversion of 2,2-Disubstituted Malononitriles to 2-Oxazolines: Towards Unnatural Amino Acids

1999

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“…Durch Hydrolyse der Cyanessigsaure-ester 5a-Sc mit konz. Schwefelsaure bei 90" [8] [9] wurden direkt die Malonsaure-monoamide 6a-c erhalten, die rnit Thionylchlorid in Pyridin cyclisiert wurden. Die gebildeten Malonimide 7a-c wurden rnit kalter 10proz.…”

Section: Synthese Derunclassified

“…61, F a x . 8 (1978 [8]. Letztere tritt auch im Spektrum des N -Methylderivates 8 auf, welches Carbonylbanden bei 1737 und 1810 cm-1 aufweist (vgl.…”

Section: Synthese Derunclassified

“…3 , 4 7 (10) 3 , 0 5 ( 9 ) 2,08 ( 9 ) 0 , 8 7 ( 8 ) 2,56 (10) 2 , 4 4 (10) 2,03 ( 9 ) 0 , 1 3 ( 8 ) 2,90 ( 1 2 ) 2 , 1 7 (10) 1 , 9 6 ( 9 ) -0,11 (8) 2,73 (10) 3,79 (10) 1,88 ( 8 ) 0 , O l (8) 2,55 (11) 2,713 (11) 2,33 (10) 0,15 (9) 2 , 3 1 (10) 2 , 5 0 (10) 2 , 1 7 ( 9 ) -0 , 1 7 (8) 2,70 (11) 2,41 (10) 2,20 (10) -0,47 ( 9 ) 4 , 8 4 ( 1 6 ) 2,58 (12) 3 , 4 5 (13) 0 , 4 6 (11) 3 , 1 8 (13) 5 , 0 3 (17) 3 , 0 7 (14) -0,66 ( 1 2 ) 3 , 2 1 (10) 4 , 0 7 (10) 2,32 (8) 0,46 ( 8 ) 5 , 2 7 (18) 7,68 (22) 3 , 1 3 (14) 0 , 9 0 (17) 4,15 (16) 5 , 7 0 (18) 4 , 7 1 (17) 0 , 8 9 ( 1 4 ) 2 , 9 7 ( 8 ) 4 , 5 9 (9) 3 , 8 8 ( 9 ) -1,14 ( 7 ) 2,76 (11) 3,45 (13) 3,30 (12) 1 4 ) 4 , 4 4 (17) 5 , 1 4 ( 1 7 ) 0 , 7 7 (13) 3 , 4 1 (13) 2,54 (11) 3,11 (12) -0 , 3 4 (10) 4 , 5 2 (16) 3 , 0 8 (13) 4 , 6 7 (15) -0 , 6 9 ( 1 2 ) 5 , 0 4 (10) 4 , 6 1 (10) 1 , 9 5 ( 7 ) 0 , 8 9 ( 8 ) 1 , 0 6 ( 8 ) 0 , 5 9 ( 7 ) 0 , 7 8 ( 8 ) -0 , 0 9 ( 8 ) 0 , 8 0 ( 8 ) -0,53 ( 8 ) 0 , 5 2 ( 7 ) -0,30 ( 7 ) 0 , 4 6 (8) 0 , O l (8) 0 , 6 4 ( 8 ) -0,09 (8) 0 , 6 2 (8) -0 , 2 1 (8) 1 , 0 3 ( 1 2 ) -0,04 (10) 0 , 1 6 (11) 0 , 2 9 ( 1 2 ) 1 , 1 7 ( 7 ) 0 , 4 0 (7) 1 , 4 5 (13) 2,32 (15) 2,57 (13) 0 , 2 9 (15) 0 , 8 6 ( 7 ) -1 , 3 0 (7) 1,18 (10) -0 , 3 1 (10) 0,89 (12) 0 , 2 1 (14) 0 , 9 6 (10) 0,08 ( 9 ) 1 , 2 9 (13) -0,92 (11) 1 , 2 5 ( 7 ) 0,Ol ( dabei, dass trotz des Winkels von 120,3" zwischen den beiden ccn-Ebenenn des Acylamidins die N (4), C (5)-Bindung vie1 kurzer (1,347 A) als eine normale C,N-Einfachbindung (ca. 1,47 A) ist und im ublichen Bereich von C,N-Bindungen in Amiden liegt.…”

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1, 5, 6, 7‐Tetrahydro‐2H‐[1,4]diazepin‐5,7‐dione aus Malonimiden und 3‐Dimethylamino‐2,2‐dimethyl‐2H‐azirin

Scholl

Bieri

Heimgartner

1978

Helvetica Chimica Acta

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1,5,6,7-Tetrahydro-2H-[1,4jdiazepin-5,7-diones from Malonimides and 3-Dimethylamino-2,2-dimethyl-2H-azirine SummaryReaction of the aminoazirine 1 with malonimides of type 7 in 2-propanol at room temperature leads to the 1,4-diazepine derivatives of type 9 (Scheme 3). The structure of 6,6-diethyl-3-dimethylamino-2,2-dimethyl-l, 5,6,7-tetrahydro-2 H-[ 1,4]diazepin-5,7-dione (9a) has been proved by single crystal X-ray analysis (Chapter 4). Rediiction of the 7-membered heterocycle 9a with sodium borohydride yields the perhyclro-[l,4]diazepin-5,7-dione 10, while 9a in ethanol at 60" undergoes a ring contraction to the 4 H-imidazole derivative l l a (Scheme 4): Mechanisms of these two reactions are discussed in comparison with previously reported reactions (Chapter 5).1. Einleitung. -Vor einiger Zeit haben wir iiber die Bildung 8gliedriger Heterocyclen aus 3-Dimethylamino-2,2-dimethyl-2 H-azirin (1) und Saccharin bzw.

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Auf das Zentralnervensystem wirkende Substanzen, XXIV. Über Azetidindione‐(2.4), II

Cited by 10 publications

References 22 publications

Nonconcerted cycloreversion by electron impact of substituted 2,4-azetidinediones. Relations between the mass spectral and photochemical reactions

Nonconcerted cycloreversion by electron impact of substituted 2,4-azetidinediones. Relations between the mass spectral and photochemical reactions

Clay-catalyzed Conversion of 2,2-Disubstituted Malononitriles to 2-Oxazolines: Towards Unnatural Amino Acids

1, 5, 6, 7‐Tetrahydro‐2H‐[1,4]diazepin‐5,7‐dione aus Malonimiden und 3‐Dimethylamino‐2,2‐dimethyl‐2H‐azirin

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