Bicyclic molecule

About: Bicyclic molecule is a research topic. Over the lifetime, 29587 publications have been published within this topic receiving 451252 citations. The topic is also known as: bicyclic molecule.

Bicyclic nucleosides, oligonucleotides, process for their preparation and intermediates

Abstract: Compounds of the formula I in the form of the racemates or enantiomers thereof, ##STR1## in which R 1 and R 2 independently of one another are hydrogen or a protective group, and B is a purine or pyrimidine radical or an analogue thereof, can be used as antiviral active ingredients or for the preparation of biologically active oligonucleotides.

Carbon cluster cations with up to 84 atoms: structures, formation mechanism, and reactivity

Abstract: Carbon clusters are generated by laser desorption. Mass-selected beams are then pulse injected into an ion chromatography (IC) device. This device temporally and spatially separates the beam into its isomeric components. Arrival time distributions (ATDs) are then measured at the detector. From these distributions, accurate mobilities are obtained for each isomeric component, along with the the fractional abundance of each isomer. Different isomer structures are calculated using quantum chemical methods. A Monte Carlo technique uses these structures to obtain accurate theoretical mobilities. Comparison of theory with experiment allows unambiguous structural assignment of the various families of isomers present in the cluster beam. The results indicate that, for carbon cluster cations, linear structures exist up to C[sub 10[sup +]]. Several families of planar ring systems begin with monocyclic rings (ring I), which first appear at C[sub 7[sup +]], and persist beyond C[sub 40[sup +]]. Bicyclic rings (ring II) are first observed at C[sub 21[sup +]] and persist beyond C[sub 40[sup +]], followed by tricyclic rings (ring III, initiated at C[sub 30[sup +]]) and tetracyclic rings (ring IV, initiated at C[sub 40[sup +]]). A 3-dimensional family we label as 3-D rings begins at C[sub 29[sup +]], whose structure is not yet unambiguouslymore » assigned. This family never exceeds 5% of the ions at any cluster size. Finally, the first fullerene is observed at C[sub 30[sup +]], with this family dominating above C[sub 50[sup +]]. 32 refs., 14 figs., 4 tabs.« less

Bicyclic compounds capable of inhibiting tyrosine kinases of the epidermal growth factor receptor family

Abstract: Epidermal growth-factor inhibitors of formula (I), wherein: 1) Y and Z are both C (carbon), both N or one N and the other C, in which case the ring structure is a linearly fused 6,6 (5 or 6) tricycle, or 2) one of Y and Z is C=C, C=N, whereupon the other one of Y or Z is simply a bond between the two aromatic rings, then the ring structure is a nonlinear 6,6 (5 or 6) tricycle, or 3) one of Y and Z is N, O or S, whereupon the other one of Y or Z is simply a bond between the two aromatic rings, then the ring structure is a fused 6,5 (5 or 6) tricycle; A, B, D and E can all be carbon, or up to two of them can be nitrogen, whereupon the remaining atoms must be carbon, or any two contiguous positions in A-E can be a single heteroatom, N, O or S, forming a five membered fused ring, in which case one of the two remaining atoms must be carbon, and the other can be either carbon or nitrogen. X = O, S, NH or NR9, such that R9 = lower alkyl, OH, NH?2?, lower alkoxy or lower monoalkylamino m = 0-3, and Ar is phenyl, thienyl, furanyl, pyrrolyl, pyridyl, pyrimidyl, imidazolyl, pyrazinyl, oxazolyl, thiazolyl, naphthyl, benzothienyl, benzofuranyl, indolyl, quinolinyl, isoquinolinyl and quinazolinyl.