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A bicyclic analogues

The synthesis of 8-epi-castanospermine (31), a bicyclic analogue of (5), was reported [48,73], but no biological data were given. [Pg.165]

A very powerful inhibitor, which is a bicyclic analogue of (33), is 6-acetamido-6-deoxycastanospermine (49), a compound synthesized from castanospermine and tested by Liu and co-workers [99]. This compound, amongst many other 6-modified castanospermine derivatives, was also prepared by the Furneaux team [100]. Furthermore, by controlled ring-contraction of suitably substituted castanospermine derivatives, these workers gained access to 8-acetamido-8-deoxyaustraline (50), a byciclic analogue of l-acetamido-l,2,5-trideoxy-2,5-imino-D-mannitol (44). This ring contraction reaction, which proceeds via a tricyclic aziridinium intermediate, is based on the same principle as the approach by Peter et al. to compound (45) [95]. [Pg.170]

The same authors also reported the synthesis of the bicyclic analogue 391. Synthesis of a closely related zwitterionic compound, the imidazolium salt 392 <2005TL5325>, was reported by Lakner et al. Ring closure to 393 has also been described <1999J(P1)2929>. [Pg.1005]

A series of 7-diazabicycloalkyl quinolones has been prepared and found to exhibit excellent broad spectrum activity against important veterinary pathogenic bacteria [105], The structures of several of these interesting bicyclic analogues (76) as well as MIC data are summarized in Table 6.28. Compound (76e) (danofloxacin), which also exhibits excellent p.o. and s.c. activity in a mouse protection model for Pasteurella multocida [ 106], is undergoing development for use in veterinary medicine. It has been shown to exhibit excellent bioavailability properties in cattle, swine and poultry [107] and is efficacious in models for the treatment of respiratory diseases in food-producing animals [108],... [Pg.285]

Millar and co-workers reported the synthesis of a number of energetic pyrimidines, pyrazines and their bicyclic analogues, including 2,5-diamino-3,6-dinitropyrazine (185) and the quina-zoline (186)." ... [Pg.319]

Less active derivatives might therefore be desirable in some cases. In this context, Paulsen and co-workers synthesized a range of chain-extended as well as bicyclic analogues of 1-deoxyfuconojirimydn, amongst others the 6-C-ethyl (54) and 6-C-methyl derivatives as well as l-deoxy-6,7,8-a-tri-epi-castanosper-mine (55). All of these derivatives exhibited considerable inhibitory activities towards a-L-fucosidase and were slightly to appreciably less active than the parent compound [107]. In an attempt to design a simple synthesis of 1-deoxy-... [Pg.171]

These compounds, at present hypothetical, contain a cr-tervalent sulfur atom. Theoretical studies were performed16 for models of compounds 122-126 the first two are, in a sense, analogues of bicyclic compounds. In view of their formal similarity with the cyclazines,133 and their positive charge, the tricyclic compounds 124-126 shall be called cyclothiolia. ... [Pg.38]

The arrangement of the material in this chapter follows closely that for the bicyclic analogues it is ordered first by the mutual relationship of the fused rings, second by the number of heteroatoms and finally by the size of the heterocyclic ring. We define adjacent as in (1) and non-adjacent fused rings as in (2). Rings of type (3) form a class of pen -annulated heterocyclic systems which are of growing importance. [Pg.657]

The it energy of a non-classical conjugated hydrocarbon can be compared directly with that of a classical analogue by the PMO method.14 Consider an even monocyclic polyene. This can be formed by fusion of methyl with an odd AH with one atom less. These components can also be fused to form an acyclic polyene. Comparison gives the aromatic energy of the cyclic system by difference. In this way we find that rings with An + 2 atoms are more stable, and those with An atoms less stable, than analogous acyclic compounds. The same method can be used for the bicyclic systems XVII, XIX, XXI, XXII, XXIII. The procedure is indicated below... [Pg.121]

The water-promoted hydrolyses of a bicyclic amide, l-azabicyclo[2.2.2]octan-2-one (87), and a planar analogue, l,4-dimethylpiperidin-2-one (88), were studied using density functional theory in conjunction with a continuum dielectric method to introduce bulk solvent effects. The aim of these studies was to reveal how the twisting of the C-N bond affects the neutral hydrolysis of amides. The results predict important rate accelerations of the neutral hydrolysis of amides when the C-N bond is highly twisted, the corresponding barrier relaxation depending on the specific reaction pathway and transition state involved.85... [Pg.72]

Acetals result from oxidative coupling of alcohols with electron-poor terminal olefins followed by a second, redox-neutral addition of alcohol [11-13]. Acrylonitrile (41) is converted to 3,3-dimethoxypropionitrile (42), an intermediate in the industrial synthesis of thiamin (vitamin Bl), by use of an alkyl nitrite oxidant [57]. A stereoselective acetalization was performed with methacrylates 43 to yield 44 with variable de [58]. Rare examples of intermolecular acetalization with nonactivated olefins are observed with chelating allyl and homoallyl amines and thioethers (45, give acetals 46) [46]. As opposed to intermolecular acetalizations, the intramolecular variety do not require activated olefins, but a suitable spatial relationship of hydroxy groups and the alkene[13]. Thus, Wacker oxidation of enediol 47 gave bicyclic acetal 48 as a precursor of a fluorinated analogue of the pheromone fron-talin[59]. [Pg.296]

A theoretical study of the mechanism of ruthenium-catalyzed formation of pyran-2-one and the corresponding sulfur and selenium analogues 8 from acetylene and CX2 (X = O, S, Se) has been reported (Equation 3) <2004NJC153>. This cyclotrimerization reaction has been experimentally carried out using carbon disulfide as a substrate <2002JA28>. The proposed mechanism involves formation of a bicyclic metal carbene intermediate. Formation of this intermediate seems to be particularly unfavorable energetically in the case of carbon diselenide. [Pg.959]


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See also in sourсe #XX -- [ Pg.489 ]




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