Synthesis and conformational analysis of stereoisomeric 1- and 2-methyl-2H,4H-1,6,7,11b-tetrahydro-1,3-oxazino[4,3-a]isoquinolines☆

Sohár, Pàl; Lázár, László; Fülöp, Ferenc; Bernáth, G.; Kóbor, J.

doi:10.1016/s0040-4020(01)81586-6

Cited by 18 publications

(8 citation statements)

References 11 publications

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“…The 2Ј-methyl-substituted homocalycotomines 7 and 8 were prepared from the corresponding 1-isoquinolylacetone (Scheme 2). 8 The (1R*,2ЈR*) diastereomer 7 was obtained by sodium borohydride reduction of 6 at Ϫ5 ЊC. Compound 7 was readily converted to its (1R*,2ЈS*) counterpart 8 via epimerization.…”

Section: Resultsmentioning

confidence: 99%

“…[1][2][3][4][5][6][7] The hetero atoms, the substituents on the saturated rings and the configurations of the substituted carbon atoms have been demonstrated to exert pronounced effects on the conformation of these compounds. [7][8][9] The possibility of synthesis, and especially enantioselective synthesis, and the properties, e.g. the conformational behaviour, of the 1,2,3-oxathiazine ring system 10- 12 and some related heterocycles [13][14][15][16][17] are therefore of current interest.…”

Section: Introductionmentioning

confidence: 99%

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Synthesis and stereochemistry of stereoisomeric 1,2,3-oxathiazino[4,3-a]isoquinolines

Sohár

Forró

Lázár

et al. 2000

J. Chem. Soc., Perkin Trans. 2

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The ring-closures of homocalycotomine and its 1Ј-and 2Ј-methyl-substituted diastereomers 3, 4 and 7, 8 with thionyl chloride or with sulfuryl chloride led to 1,2,3-oxathiazino[4,3-a]isoquinoline derivatives 9-11 and 18, 19 or to 15, 17 and 22, 23, respectively. The relative configurations and the predominant conformations of the cis 1 -transcis 2 conformational equilibrium were studied by means of 1 H-and 13 C-NMR spectroscopy, with the application of DNOE, 2D HSC and 2D-COSY measurements. In good agreement with the liquid-phase results, the X-ray investigations revealed that 9 and 10 have the cis 1 , while 18 has the trans-anellated stereostructure.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Synthesis and stereochemistry of stereoisomeric 1,2,3-oxathiazino[4,3-a]isoquinolines

Sohár

Forró

Lázár

et al. 2000

J. Chem. Soc., Perkin Trans. 2

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“…1). In contrast, in the case of the cyclopentanefused six-membered 1,3-heterocycles, the cis isomers (46) are much more stable than the transfused counterparts (47). This is not at all obvious, because the Gibbs standard free energy difference between the analogous carbocycles, the cis-and trans-hydrindanes (48) and (49), is merely 1.3 kJ mol-l in favour of the trans isomer.…”

Section: Arylsubstituted Fusedskeleton Satu-rated 134xazines Isoindmentioning

confidence: 99%

Fused‐Skeleton Saturated Six‐Membered 1,3‐N,O, N,N and N,S Heterocycles. Fused‐Skeleton Aryl‐Substituted Saturated Isoindolones

Bernáth

1994

Bulletin des Soc Chimique

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In the introduction, a brief survey is given of the main types of fused-skeleton saturated six-membered 1,3-heterocycles serving as model compounds in our earlier investigations and as starting compounds in the present studies. The synthesis and conformational analysis of aryl-substituted fused-skeleton saturated 1 ,boxazines and of aryl-substituted hetero-condensed saturated isoindolones are treated. cis-trans isomerization in the saturated isoindolone moiety of the resulting tricyclic, tetracyclic and pentacyclic systems is discussed in connection with the ring-closure reactions of cis-and trans-1 ,Zdisubstituted 1,2-and 1,3-difunctional alicyclic compounds to give alicycle-fused six-membered 1,3-heterocycles. The cycloaddition reactions of dihydro-1,3 and 3,l-oxazines and the conformations of the alicycle-fused tetrahydrooxazine-azetidinone derivatives obtained are presented. Methods are given for the preparation of saturated thiazolo-and thiazino[2,3-b]quinazolinones. Unambiguous, mainly one-pot syntheses for the preparation of 1,3-heterocycles by a retro Diels-Alder method are discussed.

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“…refs 9-11) deal with the synthesis of the closely analogous 1,3-oxazino-and 1,3-thiazino [4,3-a]isoquinolines. As a continuation of our systematic studies [5][6][7][8][9][10][11][12][13][14][15] on isoquinoline-fused 1,3-heterocycles, we now report on the synthesis of 1,3-oxazino-and 1,3-thiazino [4,3-a]isoquinolines. These compounds are interesting from both pharmacological and stereochemical points of view.…”

Section: Introductionmentioning

confidence: 98%

Synthesis and stereochemistry of 4-arylimino-1,3-oxazino- and 1,3-thiazino[4,3,a]isoquinolines

Fülöp

Martinek

Bernáth

2002

Arkivoc

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Thioureas 2-5 were prepared from homocalycotomine and isocyanates. When 2 and 3 were treated with methyl iodide and then with alkaline, 9,10-dimethoxy-4-arylimino-1,6,7,11b-tetrahydro-2H,4H-1,3-oxazino[4,3-a]isoquinoline, 6 and 7 were formed. The corresponding 9,10-dimethoxy-4-arylimino-1,6,7,11b-tetrahydro-2H,4H-1,3-thiazino [4,3-a]isoquinolines 8 and 9 were synthesized from 4 and 5 treatment with hydrogen chloride. The predominant conformations and the conformational equilibria were studied by means of NMR spectroscopy and molecular modelling calculations. The 1,3-X,N heterocyclic ring attains a flattened twist conformation, due to the orbital interaction between the bridgehead nitrogen lone pair and the C=N double bond.

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Synthesis and conformational analysis of stereoisomeric 1- and 2-methyl-2H,4H-1,6,7,11b-tetrahydro-1,3-oxazino[4,3-a]isoquinolines☆

Cited by 18 publications

References 11 publications

Synthesis and stereochemistry of stereoisomeric 1,2,3-oxathiazino[4,3-a]isoquinolines

Synthesis and stereochemistry of stereoisomeric 1,2,3-oxathiazino[4,3-a]isoquinolines

Fused‐Skeleton Saturated Six‐Membered 1,3‐N,O, N,N and N,S Heterocycles. Fused‐Skeleton Aryl‐Substituted Saturated Isoindolones

Synthesis and stereochemistry of 4-arylimino-1,3-oxazino- and 1,3-thiazino[4,3,a]isoquinolines

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