- Amberlyst-15: A reusable heterogeneous catalyst for the dehydration of tertiary alcohols
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Tertiary alcohols react under mild conditions in the presence of Amberlyst-15 (dry) (solid-supported sulfonic acid) to give predominantly the most stable alkene in very good yield. The dehydration of tertiary alcohol functionality occurs without observation of rearrangement and polymerization products, and with outstanding substrate tolerance, which include the NHCBz, NHBoc, OSEM, OTBDMS, OBOM and ethylene ketal functional groups. Amberlyst-15 (dry) can be easily recovered from the reaction medium and reused for five cycles, maintaining the catalytic efficiency. In addition, the dehydration can occur under continuous operation.
- Frija, Luís M.T.,Afonso, Carlos A.M.
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experimental part
p. 7414 - 7421
(2012/09/22)
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- Thermal isomerization of (+)-cis- and (-)-trans-pinane leading to (-)-β-citronellene and (+)-isocitronellene
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Catalyzed and uncatalyzed rearrangement reactions of terpenoids play a major role in laboratory and industrial-scale synthesis of fine chemicals. Herein, we present our results on the thermally induced isomerization of pinane (1). Investigation of the thermal behavior of (+)-cis- (la) and (-)-trans-pinane (1b) in a flow-type reactor reveals significant differences in both reactivity and selectivity concerning the formation of (-)-β-citronellene (2) and (+)-isocitronellene (3) as main products. Possible explanations for these results are discussed on the basis of reaction mechanism and groundstate geometries for 1a and 1b. To identify side reactions caused from ene cyclizations of 2 and 3, additional pyrolysis experiments were conducted that enabled the identification of almost all compounds in the network of C 10H18-hydrocarbon products formed from 1.
- Stolle, Achim,Ondruschka, Bernd,Bonrath, Werner,Netscher, Thomas,Findeisen, Matthias,Hoffmann, Markus M.
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experimental part
p. 6805 - 6814
(2009/08/07)
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- Photochemical Transformations VI: Organic Iodides (Part 5) - Templet Effect of Transition Metal Ions on Photocyclization of Some Olefinic Acyclic Terpene Iodides
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Photocyclization of citronellyl iodide in the presence of certain transition metal salts especially CuCl, results in a significant increase (from 16percent to 35percent) in the yield of the cyclization products.Similar results have been obtained with geranyl and neryl iodides (11, 17).This enhancement of cyclization/elimination ratio is sought to be explained in terms of a templet effect of the transition metal ion.
- Subbarao, Kanury V.,Damodaran, N. P.,Dev, Sukh
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p. 1008 - 1011
(2007/10/02)
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- INVESTIGATION OF COMPOUNDS OF THE MENTHANE SERIES. XVI. REDUCTION OF o- AND p-ISOPROPENYLTOLUENES WITH CALCIUM HEXAAMMONIATE
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In the reduction of o- and p-isopropenyltoluenes with calcium hexaammoniate in the presence of protic and aprotic solvents 1,2-addition of hydrogen mostly occurs with the formation of o- and p-cymenes and o- and p-menthatrienes, which under the reaction conditions give the products from 1,2- and 1,4-addition of hydrogen.
- Bazyl'chik, V. V.
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p. 1847 - 1851
(2007/10/02)
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- APPLICATION OF 1H NMR AND 13C NMR FOR ESTABLISHING THE SPATIAL STRUCTURE OF STEREOISOMERIC o- AND p-MENTHANE, o- AND p-MENTHENES, AND ISOPROPYLCYCLOHEXANE.
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An attempt to establish the spatial structure of stereoisomeric o- and p-menthanes, 8-o- and 8-p-menthenes, and isopropylcyclohexane on the basis of an analysis of the **1H NMR and **1**3C NMR spectra is described.
- Bazyl'chik,Samitov,Ryabushkina
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p. 543 - 548
(2007/10/02)
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- PHOTOCHEMICAL TRANSFORMATIONS-II ORGANIC IODIDES-II: CITRONELLYL IODIDE, 2,3-DIHYDRO-6(Z)-FARNESYL AND 2,3-DIHYDRO-6(E)-FARNESYL IODIDES
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Experimental parameters governing ?-electrons participation during photolysis of citronellyl iodide have been investigated.Photoproducts resulting from irradiation of 2,3-dihydro-6(Z)- and 2,3-dihydo-6(E)-farnesyl iodides have been characterised.
- Saplay, K. M.,Sahni, Ranjana,Damodaran, N. P.,Dev, Sukh
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p. 1455 - 1461
(2007/10/02)
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