ChemInform Abstract: Intramolecular Cyclization of O-Alkyl-N-(3-phenylpropenoyl)thiocarbamates Catalyzed by Boron Trifluoride.

ChemInform ◽  
1990 ◽  
Vol 21 (26) ◽  
Author(s):  
M. DZURILLA ◽  
P. KUTSCHY ◽  
D. KOSCIK ◽  
S. TOMA
Keyword(s):  
Intramolecular Cyclization ◽  
Boron Trifluoride

Synthesis and Antifungal Activity of New Indolylthiazinone Derivatives

1998 ◽  
Vol 63 (1) ◽  
pp. 94-102 ◽  
Author(s):  
Milan Dzurilla ◽  
Peter Kutschy ◽  
Jalpa P. Tewari ◽  
Martin Ružinský ◽  
Stanislav Šenvický ◽  
...  
Keyword(s):  
Antifungal Activity ◽  
Intramolecular Cyclization ◽  
Boron Trifluoride ◽  
Alternaria Brassicicola ◽  
Alternaria Brassicae

New 6-(indol-3-yl)-5,6-dihydro-4H-1,3-thiazin-4-one derivatives were prepared by boron trifluoride catalyzed intramolecular cyclization of N'-substituted N-[3-(indol-3-yl)propenoyl]thioureas and by the reaction of 3-(indol-3-yl)propenoyl isothiocyanate with sodium hydrogensulfide. Antifungal activity of the prepared compounds was studied using the fungi Alternaria brassicae and Alternaria brassicicola.

Intramolecular cyclization of O-alkyl-N-(3-phenylpropenoyl)thiocarbamates catalyzed by boron trifluoride

1990 ◽  
Vol 55 (3) ◽  
pp. 710-717 ◽  
Author(s):  
Milan Dzurilla ◽  
Peter Kutschy ◽  
Dušan Koščík ◽  
Štefan Toma
Keyword(s):  
Methyl Ester ◽  
Intramolecular Cyclization ◽  
Alkyl Group ◽  
Boron Trifluoride ◽  
Intramolecular Rearrangement

2-Alkoxy-6-phenyl-5,6-dihydro-4H-1,3-thiazin-4-ones, 6-phenyl-1,3-perhydrothiazine-2,4-dione and S-methyl N-(3-phenylpropenoyl)thiocarbamate are the products of intramolecular rearrangement of O-alkyl N-(3-phenylpropenoyl)thiocarbamates catalyzed by boron trifluoride; their formation depends on the nature of the alkyl group. The rearrangement was shown to proceed intermolecularly by investigating the reaction of O-methyl N-(3-phenylpropenoyl)thiocarbamate to an S-methyl ester by the method of a crossover experiment.

Cyclization of 17-ethylenedioxy-3α,5-cyclo-6,7-seco-5α-androstane-6,7-diol

1979 ◽  
Vol 44 (1) ◽  
pp. 128-144 ◽  
Author(s):  
Helena Velgová ◽  
Dietrich Zeigan ◽  
Günther Engelhardt ◽  
Antonín Trka
Keyword(s):  
Acetic Anhydride ◽  
Intramolecular Cyclization ◽  
Boron Trifluoride ◽  
Boron Trifluoride Etherate ◽  
Mass Spectrometric ◽  
Cyclic Ethers ◽  
Mass Spectrometric Data ◽  
Spectrometric Data ◽  
H Nmr ◽  
C Nmr

Intramolecular cyclization of 17-ethylenedioxy-3α,5-cyclo-6,7-seco-5α-androstane-6,7-diol (I) on treatment with p-toluenesulphonyl chloride in pyridine gives 17-ethylenedioxy-3α,5-cyclo-B-homo-7-oxa-5α-androstane (III) and 17-ethylenedioxy-3,5-methylene-6-oxaandrostane (II). The cyclic ethers II and III after deketalization and treatment with boron trifluoride etherate in acetic anhydride yield 3β,7-dihydroxy-6,7-secoandrost-5-en-17-one (XIV) along with a small quantity of 3β,5-cyclo-A-homo-6-oxa-5β-androstane-17-one (XIII). Proof of the structures in question is based on IR, 1H NMR, 13C NMR and mass spectrometric data.

Concise Synthesis of GB22 by Endo-Selective Siloxycyclopropane Arylation

2019 ◽  
Author(s):  
Hannah E. Burdge ◽  
Takuya Oguma ◽  
Takahiro Kawajiri ◽  
Ryan Shenvi
Keyword(s):  
Intramolecular Cyclization ◽  
Cross Coupling ◽  
Building Blocks ◽  
Ring Expansion ◽  
Dual Catalysis ◽  
Acid Labile

<div><div><div><p>The first synthesis of GB22 was accomplished by a con- cise, modular route. Two building blocks converged in a novel sp3-sp2 attached-ring coupling that used Ir/Ni dual-catalysis to reverse the regioselectivity of siloxycy- clopropane arylation. This cross-coupling proved general to access β-substituted tetralones via ring-expansion of indanone-derived siloxycyclopropanes. The congested, bridging rings of the GB alkaloids were completed using an aluminum-HFIP complex that effected intramolecular cyclization of an acid-labile substrate.</p></div></div></div>

Concise Synthesis of GB22 by Endo-Selective Siloxycyclopropane Arylation

2019 ◽  
Author(s):  
Hannah E. Burdge ◽  
Takuya Oguma ◽  
Takahiro Kawajiri ◽  
Ryan Shenvi
Keyword(s):  
Intramolecular Cyclization ◽  
Cross Coupling ◽  
Building Blocks ◽  
Ring Expansion ◽  
Dual Catalysis ◽  
Acid Labile

<div><div><div><p>The first synthesis of GB22 was accomplished by a con- cise, modular route. Two building blocks converged in a novel sp3-sp2 attached-ring coupling that used Ir/Ni dual-catalysis to reverse the regioselectivity of siloxycy- clopropane arylation. This cross-coupling proved general to access β-substituted tetralones via ring-expansion of indanone-derived siloxycyclopropanes. The congested, bridging rings of the GB alkaloids were completed using an aluminum-HFIP complex that effected intramolecular cyclization of an acid-labile substrate.</p></div></div></div>

Cyclopropyl→cyclobutyl rearrangement in intramolecular cyclization of 3,5-bridged B-secoandrostane-6,7(or 5,7)-diols and mass spectra of products

1982 ◽  
Vol 47 (8) ◽  
pp. 2280-2290 ◽  
Author(s):  
Helena Velgová ◽  
Jorga Smolíková ◽  
Antonín Trka ◽  
Antonín Vítek
Keyword(s):  
Intramolecular Cyclization ◽  
Mass Spectra ◽  
Acid Catalyzed

Acid-catalyzed intramolecular cyclization of 6,7-dihydroxy-3α,5-cyclo-6,7-seco-5α-androstan-17-one (VII), 5,7-dihydroxy-3,5-methylene-5,7-secoandrostan-17-one and 5,7-dihydroxy-3β,5-cyclo-5,7-seco-A-homo-5β-androstan-17-one (XIII) in benzene and dioxane was investigated. The main cyclization products were 3,5-methylene-6-oxaandrostan-17-one (I) and/or 3β,5-cyclo-6-oxa-A-homo-5β-androstan-17-one (VIII). In the case of VI and VII the ratio of I and VIII was solvent-dependent: in benzene more VIII was formed than in dioxane. The mass spectra of I and VIII were almost identical and corresponded to the structure VIII.

ChemInform Abstract: INTRAMOLECULAR CYCLIZATION IN REACTIONS OF BICYCLIC DIEPOXIDES WITH DIMETHYLAMINE

1985 ◽  
Vol 16 (9) ◽  
Author(s):  
L. I. KAS'YAN ◽  
N. S. ZEFIROV ◽  
N. V. STEPANOVA ◽  
L. E. SALTYKOVA ◽  
O. L. RYZHIK
Keyword(s):  
Intramolecular Cyclization
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