13732-88-2Relevant academic research and scientific papers
The synthesis and properties of vinyl substituted naphthopyrans and their styrene copolymers
Blackwell, Catherine J.,Gabbutt, Christopher D.,Guthrie, James T.,Heron, B. Mark
, p. 408 - 420 (2012/08/28)
A comprehensive series of mono-, di- and tri-bromo-3H-naphtho[2,1-b]pyrans was synthesised by the traditional union of a 2-naphthol with an alkynol. The bromine atom(s) in these naphthopyrans was readily replaced by a vinyl group using a Suzuki coupling reaction with vinyl boronic anhydride pyridine complex. The efficiency of the Suzuki vinylation reaction decreases with the increasing number of bromine atoms to be substituted. The vinylnaphthopyrans served as styrene analogues and readily underwent a thermally initiated free radical addition co-polymerisation with styrene to efficiently afford low molecular weight poly(styrene-co-naphthopyrans). The photochromic response of the bromonaphthopyrans and vinylnaphthopyrans followed the established colour-structure relationships for photochromic naphthopyrans. The photochromic response of toluene solutions of the poly(styrene-co-naphthopyrans) was characterised by a hypsochromic shift of the λmax relative to that recorded for the vinylnaphthopyran monomers. Increased half-lives were noted for the copolymers derived from the bis- and tris-vinylnaphthopyrans where some degree of crosslinking was expected. A further hypsochromic shift in λmax resulted for the thin films of the poly(styrene-co- naphthopyrans). Of particular note was the behaviour of the 3-(2-vinylphenyl)-3- phenylnaphthopyran which gave the typical yellow colour of the photomerocyanine coupled with the predictable large half-life. However, all photochromism of this naphthopyran was lost upon polymerisation suggesting that an alternative pathway supervenes in the expected polymerisation sequence.
Synthesis of sparteine-like chiral diamines and evaluation in the enantioselective lithiation-substitution of N-(tert-butoxycarbonyl)-pyrrolidine
Hermet, Jean-Paul R.,Porter, David W.,Dearden, Michael J.,Harrison, Justin R.,Koplin, Tobias,O'Brien, Peter,Parmene, Jerome,Tyurin, Vladimir,Whitwood, Adrian C.,Gilday, John,Smith, Neil M.
, p. 3977 - 3988 (2007/10/03)
Three chiral diamines were synthesised and evaluated as sparteine surrogates in the lithiation-substitution of N-(tert-butoxycarbonyl)pyrrolidine. The synthesis and attempted resolution of sparteine-like diamines {(1S*, 2R*, 8R*)-10-methyl-6,10-diazatricyclo [6.3.1.02,6]dodecane and (1S*, 2R*, 9R*)-11-methyl-7,11-diazatricyclo[7.3.1.02,7]tridecane} (via inclusion complex formation) are reported. Unfortunately, it was only possible to resolve the diazatricyclo-[7.3.1.02,7] tridecane compound. An alternative route to (1R,2S,9S)-11-methyl-7,11-diazatricyclo[7.3.1.02.7]tridecane starting from the natural product, (-)-cytisine, is described. This simple three-step route furnished gram-quantities of a (+)-sparteine surrogate. X-ray crystallography of an intermediate in the route, (1R,5S,12S)-3-methoxycarbonyl-decahydro-1,5-methanopyrido [1,2-a][1,5]diazocin-8-one, enabled the stereochemistry of all of the tricyclic diamines described in this paper to be unequivocally established. Two other diamines, starting from (S)-proline and resolved 2-piperidine ethanol, were prepared using standard methods. These diamines lacked the bispidine framework of (-)-sparteine and were found to impart vastly inferior enantioselectivity. It was concluded that, for the asymmetric lithiation-substitution of N-Boc pyrrolidine, a rigid bispidine framework and only three of the four rings of (-)-sparteine are needed for high enantioselectivity. Furthermore, it is shown that diamine (1R,2S,9S)-11-methyl-7,11-diazatricyclo [7.3.1.02,7]tridecane is the first successful (+)-sparteine surrogate.
Optically active propargyl alcohol derivative and a method for preparation of the same
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, (2008/06/13)
An optically active propargyl alcohol derivative of the formula (I) STR1 wherein X=phenyl or thienyl and R=lower alkyl, halogenated methyl, phenyl or substituted phenyl having at least one lower alkyl radical and or halogen atom, is prepared by contacting a racemic modification of l- and d-isomers of the formula (I) with l-brucine in an organic solvent, by separating the resultant deposited diastereomer from a solution containing the resultant other diastereomer in the organic solvent, by decomposing each diastereomer with an aqueous mineral acid solution in the presence of an organic solvent capable of dissolving the corresponding optically active isomer dissociated from the diastereomer and incompatible with water so as to allow the optically active isomer to be dissolved in the water-incompatible organic solvent, and by recovering the optically active isomer from the solution thereof.
