82275-93-2Relevant academic research and scientific papers
Allene-based Electrophile-mediated Cyclisations: Efficient Synthesis of Medium Ring Azacycles
Shaw, Robert W.,Gallagher, Timothy
, p. 3549 - 3556 (2007/10/02)
While AgI- and PdII-based electrophiles have limited application in cyclisation of allenic amines leading to 7-membered and larger azacycles, these rings may be obtained using iodine as the electrophilic trigger.Iodination of the N-b
RING-CLOSURE REACTIONS. XXIV. KINETICS OF FORMATION OF MEDIUM - AND LARGE-RING N-TOSYLAZACYCLOALKANES. ROLE OF RING STRAIN ON MEDIUM-RING FORMATION
Galli, Carlo,Gargano, Patrizia,Mandolini, Luigi
, p. 653 - 658 (2007/10/02)
The kinetics of closure of N-tosylazacycloalkanes from the anions derived from N-tosyl-ω-bromoalkylamines have been investigated in 99percent aqueous Me2SO.Rate constants and effective molarities (EM) have now been obtained for the ring sizes 8-13, 17, an
Nuclear Magnetic Resonance as a Means of Assessing Structure versus Reactivity Relationships in Alicyclic Compounds
Cerichelli, Giorgio,Galli, Carlo,Lillocci, Claudio,Luchetti, Luciana
, p. 725 - 728 (2007/10/02)
Proton-carbon-13 coupling constants (J13C,H) have been measured for three series of N-substituted azacycloalkanes.Structural features of the alicyclic compounds, as revealed by this and other n.m.r.techniques, reflect the strain present in the ring and can be used as a guide to predict ring-closure reactivity.Deviations from such structure versus reactivity relationships are found with highly strained small rings.Hence, it must be stressed that meaningful trends in the behaviour of ring compounds can only be revealed when large homologous series are examined.Literature X-ray structural studies are also exploited in order to comment on the situation in small rings and on their peculiar ring-closure tendency.It is suggested that, although some of the experimental features and behaviour can be accounted for in terms of strain, others, in the case of three-membered rings, are to be attributed to the presence of ?-aromaticity.Because of this, these three-membered ring compounds can efficiently gain stabilization by resonance interaction with exocyclic conjugative substituents: n.m.r. evidence is given on this point.
RING-CLOSURE REACTIONS. XX. AN EFFICIENT SYNTHESIS OF MANY-MEMBERED AZACYCLOALKANES
Gargano, Patrizia,Mandolini, Luigi
, p. 31 - 34 (2007/10/02)
An efficient cyclization of N-tosyl-ω-bromoalkylamines to N-tosylazacycloalkanes in the presence of a combination of EtOK/K2CO3 in Me2SO solution is described.This base-solvent system permitted the high-dilution conditions favourable to cyclization to be attained with a conveniently high rate of feed of the bifunctional reactants into the reaction medium.Yields are very good for the large rings, and still satisfactory, although significantly lower, for the medium-sized rings.
