19012-97-6Relevant academic research and scientific papers
Concise Synthesis of Chromene/Chromane-Type Aryne Precursors and Their Applications
Xu, Yuan-Ze,Tian, Jia-Wei,Sha, Feng,Li, Qiong,Wu, Xin-Yan
, p. 6765 - 6779 (2021/05/06)
The gram-scale synthesis of 5,6-, 6,7-, and 7,8-chromene/chromane-type aryne precursors and their applications in regioselective transformation to other functional derivatives is reported. Chromene/chromane-type arynes are generated under mild conditions, which can further undergo [2 + 2], [3 + 2], and [4 + 2] cycloaddition reactions, nucleophilic addition reactions, and σ-insertion reactions to produce structurally novel substituted chromenes and chromanes. The excellent regioselectivity of the reaction is facilitated by the oxygen-containing guiding groups at the ortho-position of the triple bond, which can be removed or switched to other functional groups including alkenyl, aryl, heteroaryl, and arylamino groups.
Enantioselective reduction of 4-chromanone and its derivatives by selected filamentous fungi
Janeczko, Tomasz,Dmochowska-Gladysz, Jadwiga,Szumny, Antoni,Kostrzewa-Suslow, Edyta
, p. 278 - 282 (2013/10/22)
Biotransformation of 4-chromanone and its derivatives in the cultures of three biocatalysts: Didymosphaeria igniaria, Coryneum betulinum and Chaetomium sp. is presented. The biocatalysts were chosen due to their capability of enantiospecific reduction of low-molecular-weight ketones (acetophenone and its derivatives and α- and β-tetralone). The substrates were reduced to the respective S-alcohols with high enantiomeric excesses, according to the Prelog's rule. In the culture of Chaetomium sp. after longer biotransformation time an inversion of configuration of the formed alcohols was also observed. The highest yield of transformation was observed for 6-methyl-4-chromanone. In all the tested cultures, the higher was the molecular weight of a chromanone, the lower conversion percent was observed.
Enantioselective syntheses of decursinol angelate and decursin
Lim, Jongdoo,Kim, Ik-Hwan,Kim, Hyeon Ho,Ahn, Kyung-Seop,Han, Hogyu
, p. 4001 - 4003 (2007/10/03)
The practical enantioselective syntheses of decursinol angelate and decursin were achieved in eight steps from resorcinol. The stereochemistry was addressed using the catalytic asymmetric epoxidation of 7-acetoxy-2,2-dimethylchromene by chiral (salen)Mn complexes as the key step.
Natural product-like combinatorial libraries based on privileged structures. 1. General principles and solid-phase synthesis of benzopyrans
Nicolaou,Pfefferkorn,Roecker,Cao,Barluenga,Mitchell
, p. 9939 - 9953 (2007/10/03)
Herein we report a novel strategy for the design and construction of natural and natural product-like libraries based on the principle of privileged structures, a term originally introduced to describe structural motifs capable of interacting with a variety of unrelated molecular targets. The identification of such privileged structures in natural products is discussed, and subsequently the 2,2-dimethylbenzopyran moiety is selected as an inaugural template for the construction of natural product-like libraries via this strategy. Initially, a novel solid-phase synthesis of the benzopyran motif is developed employing a unique cycloloading strategy that relies on the use of a new, polystyrene-based selenenyl bromide resin. Once the loading, elaboration, and cleavage of these benzopyrans was established, this new solid-phase method was then thoroughly validated through the construction of six focused combinatorial libraries designed around natural and designed molecules of recent biological interest.
REGIOSELECTIVE PRENYLATION OF PHENOLS BY PALLADIUM CATALYST: SYNTHESES OF PRENYLPHENOLS AND CHROMANS
Tsukayama, Masao,Kikuchi, Makoto,Kawamura, Yasuhiko
, p. 1487 - 1490 (2007/10/02)
The palladium-catalyzed coupling reaction of iodophenols (1) with 2-methyl-3-butyn-2-ol gave alkynylphenols (2).Catalytic hydrogenation of 2 over Raney nickel and the subsequent dehydration of the resultant alkylphenols (3) gave regioselectively the desired prenylphenols (4).Dehydration of alkylphenols (3f-h) gave chromans (7).
Studies of Chromenes. Part 9. Syntheses of Chromenequinones
Brown, Philip E.,Lewis, Robert A.,Waring, Mark A.
, p. 2979 - 2988 (2007/10/02)
Syntheses of 2,2-dimethylchromene-5,8-quinone, 2,2-dimethylchromene-6,7-quinone, and 6,7-dimethoxy-2,2-dimethylchromene-5,8-quinone are described.Being easily bioreductible to electron-rich chromenes these compounds, and their oxirane derivatives, are of
PHOTOCHEMISTRY OF 7-ACETOXYBENZOPYRAN DERIVATIVES. SYNTHESIS OF EUPATORIOCHROMENE AND ENCECALIN
Miranda, Miguel A.,Primo, Jaime,Tormos, Rosa
, p. 7593 - 7600 (2007/10/02)
The photolysis of the 7-acetoxybenzopyran derivatives 1a-5a has been carried out.Chromen 1a was found to undergo extensive photopolymerization.Chromanone 2a underwent a rather inefficient photo-Fries rearrangement to the 6- and 8- acetyl derivatives 2b and 2c.Diacetoxychromene 3a gave the unsaturated ketone 8 as the main product, besides its deacetylation analogue 9 and chromanone 11.Diacetoxychroman 4a afforded a mixture of four C-acetyl products: 1b, 1c, 2b and 2c, together with chromene 1a and chromanone 2a.Finally, irradiation of chroman 5a gave rise to a mixture of the two possible photo-Fries products 5b (43percent) and 5c (52percent).The mechanistic implications of the above results are discussed, with special emphasis on the photoreactivity of the phenyl ester as compared with that of the pyran ring, the enol ester and the benzyl ester moieties.The synthetic applications of these transformations are illustrated with the preparation of eupatoriochromene 1b and encecalin 1e.
REACTION OF 2H-1-BENZOPYRANS WITH ORGANOMETALLIC REAGENTS. SYNTHESIS OF 4-(α,γ-DIALKYL-β-4-METHOXYPHENYLALLYL)RESORCINS
Alberola, Angel,Andres, Celia,Ortega, Alfonso Gonzales,Pedrosa, Rafael,Vicente, Martina
, p. 393 - 400 (2007/10/02)
The stereoselective synthesis of E- and Z-4-(α,γ-dialkyl-β-4-methoxyphenylallyl)resorcins was accomplished by reaction of 2-alkyl-7-hydroxy-4'-methoxyisoflavenes with organoaluminum and organomagnesium reagents.This way leads to better yields than the reduction of 2,4-dialkyl-7-hydroxy-4'-methoxyisoflavenes.The influence of substituents at different positions on the reduction was studied on model 2H-1-benzopyrans.
The Synthesis of the Epoxide and some other possible Metabolites of Precocene I
Jennings, Richard C.,Ottridge, Anthony P.
, p. 1733 - 1738 (2007/10/02)
The synthesis of precocene I epoxide, 3,4-epoxy-7-methoxy-2,2-dimethylchroman (8), is described.This compound is the highly reactive metabolite responsible for the biological effects of the precocenes.The syntheses of some other oxygenated derivatives of precocene I, which are themselves possible metabolites, are also described.
CYCLODEHYDROGENATION OF ORTHO-(3,3-DIMETHYLALLYL)PHENOLS WITH TRITYL TETRAFLUOROBORATE
Barua, P.,Barua, N. C.,Sharma, R.P.
, p. 5801 - 5804 (2007/10/02)
Trityl tetrafluoroborate has been shown to effect the cyclodehydrogenation of o-(3,3-dimethylallyl)phenols in an efficient manner.
