101001-06-3Relevant articles and documents
Etude RMN(1)H et radiocristallographique de la stereochemie de 3-aryl-9b-hydroxy-1,3,3a,9b-tetrahydro-4H-thienobenzopyrane-1-carboxylates d'ethyle. Configuration et conformation
Alhassan, M.,Robert, J. F.,Xicluna, A.,Ombetta, J. E.,Mercier, R.,Laude, B.
, p. 1109 - 1120 (1993)
The reaction of ethyl mercaptoacetate with some 3-arylidene-4-chromanones yields the corresponding ethyl 3-aryl-9b-hydroxy-1,3,3a,9b-tetrahydro-4H-thienobenzopyrane-1-carboxylates.In spite of the presence of four chirality centers, the reaction is diastereospecific and gives a single diastereoisomer whose configuration and conformation were specified by its PMR data.The cis-fused tetrahydrothiophenic and dihydropyranic cycles lie in half-chair conformation.The 9b-hydroxyl and the 3-aryl groups are in a cis equatorial and pseudoequatorial disposition.The ester group, also cis with the hydroxyl group, presents a hydrogen bond with the hydroxyl.In the presence of an ortho-substituent at the phenyl group (particularly a chlorine atom), this phenyl group undergoes a notable rotation as is pointed out by a radiocristallographic study.A comparative study between the NMR and radiogcristallographic data allows the confirmation of the maintenance of the same conformation in solid and dissolved states.
Rhodium-Catalyzed Asymmetric Transfer Hydrogenation/Dynamic Kinetic Resolution of 3-Benzylidene-Chromanones
Molina Betancourt, Ricardo,Phansavath, Phannarath,Ratovelomanana-Vidal, Virginie
supporting information, p. 1621 - 1625 (2021/03/08)
Straightforward access to enantiomerically enriched cis-3-benzyl-chromanols from (E)-3-benzylidene-chromanones was developed through Rh-catalyzed asymmetric transfer hydrogenation. This transformation allowed the reduction of both the CaC and CaO bonds and the formation of two stereocenters in high yields with excellent levels of diastereo- A nd enantioselectivities (up to >99:1 dr, up to >99% ee) in a single step through a dynamic kinetic resolution process using a low catalyst loading and HCO2H/DABCO as the hydrogen source.
Imidazolium ionic liquids as catalyst for synthesis of (E)-3- arylidene(thio)chroman-4-ones under microwave irradiation
Li, Hong-Ya,Li, Shu-Na,Wang, Quan,Wang, Shu-Xiang,Zhu, Bao-Cheng
, p. 635 - 637 (2013/02/23)
Use of imidazolium ionic liquids [Bmim][CF3COO] and [Bmim]OH as a catalyst for synthesis of 3-arylidene(thio)chroman- 4-ones by the condensation of (thio)chroman-4-ones and aromatic aldehydes under microwave irradiation conditions. A series of 3-arylidene(thio)chroman-4-ones were obtained as the only product and considerable increase of yield was founded within short time. The products 3-arylidene(thio)chromanones were assigned the (E)-configuration based on 1H NMR spectroscopic data.
Facile condensation of aromatic aldehydes with chroman-4-ones and 1-thiochroman-4-ones catalysed by amberlyst-15 under microwave irradiation condition
Mandal, Tapas K.,Pal, Rammohan,Mondal, Rina,Mallik, Asok K.
experimental part, p. 863 - 869 (2012/02/15)
Different aromatic aldehydes and cinnamaldehyde undergo crossaldol condensation with chroman-4-ones and 1-thiochroman-4-ones in the presence of amberlyst-15 under microwave irradiation in solvent free condition to afford rapidly the corresponding E-3-arylidene and E-3-cinnamylidene derivatives, respectively, in high yield. This process is simple, efficient and environmentally benign.
Novel synthesis of N-methyl spiropyrrolidines by 1,3-dipolar cycloaddition reaction of azomethine ylides
Subramaniyan,Jayashankaran,Raghunathan
, p. 2189 - 2193 (2007/10/03)
A series of novel N-methyl spiropyrrolidines have been synthesized in good yield by the cycloaddition reaction of azomethine ylides generated by a decarboxylative route from sarcosine and paraformaldehyde with conformationally locked s-trans enone functionality present in the (E)-3-arylidene-4-chromanone as dipolarophiles. The structure of the title compound was established by spectroscopic techniques. Copyright Taylor & Francis, Inc.
Synthesis of novel tricyclic heterocyclic compounds as potential anticancer agents using chromanone and thiochromanone as synthons
Hammam, Abou El-Fotooh G.,Fahmy,Amr, Abdel-Galil E.,Mohamed, Ashraf M.
, p. 1985 - 1993 (2007/10/03)
The arylmethylene of benzopyrane or benzothiopyrane 3,4 have been synthesized and condensed with hydrazine, guanidine and thiourea to yield pyrazole 5-8, aminopyrimidine 9,10 and thioxopyrimidine derivatives 11,12, respectively. Compounds 3 or 4 on treatment with malononitrile in the presence of ammonium acetate/acetic acid or in the presence of piperidine/ methanol to yield benzopyrano- and benzothiopyranopyridine 13,14 and benzopyrano- and benzothiopyrane 15,16, respectively. The oxirane of compound 3 is prepared and condensed with CS2 to yield the tricyclic system, thioxothienobenzopyrane 21. Ylidenemalononitrile for the ketone 1 and 2 are synthesized and condensed with aromatic aldehyde in presence of ammonium acetate/acetic acid to yield benzopyranopyridine and benzothiopyranopyridine derivatives 24,25, respectively, which are the isomer of compounds 13,14. Ylidenemalononitrile on condensation with phenylisothiocyanate yields benzo-pyrano- and benzothiopyranothioxopyridine 28,29, respectively.
Stereochemical studies of Michael-adducts obtained by reaction of the ethyl mercaptoacetate with substituted 3-benzylidenchroman-4-ones and of their cyclization into 4H-thienobenzopyran derivatives.
Robert, JF.,Alhassan, M.,Xicluna, A.,Ombetta, JE.,Mercier, MF.,et al.
, p. 788 - 797 (2007/10/02)
The reaction of ethyl mercaptoacetate with substituted 3-benzylidenechroman-4-ones gives mixtures of erythro and threo diastereoisomers.In one case, the erythro-isomer was isolated and its structure specified by NMR and crystallographic studies.These studies allow us to analyse the mixtures of the other Michael adducts.The erythro-isomer does not cyclize directly but via an epimerization into the threo-isomer.This occurs under the influence of a basic reagent such as piperidine and gives a single diastereoisomer of a 4H-thienobenzopyran derivative.On the basis of the Cram, Felkin and Bassindale models, we propose a chelated transition state to explain both the remarkable stereoselectivity of the cyclization reaction and why it does not occur in the case of the Michael adduct issued from 3-ortho-nitrobenzylidenechroman-4-one. - - - 3-benzylidenechroman-4-ones / stereochemistry / stereoselectivity / 1H NMR spectroscopy / Michael adducts / 4-H-thienobenzopyran
