Chemistry of Fenchonesulfonic Acid Derivatives

1995 ◽  
Vol 50 (2) ◽  
pp. 283-288 ◽  
Author(s):  
Gabriele Wagner ◽  
Uwe Verfürth ◽  
Rudolf Herrmann
Keyword(s):  
Acetic Anhydride ◽  
Thionyl Chloride ◽  
Sulfonic Acid ◽  
Reaction Rate ◽  
Enantiomeric Excess ◽  
Methyl Group ◽  
Close Analogy ◽  
Chiral Sulfoxides ◽  
Mndo Calculations ◽  
Nmr Techniques

(1 S) - (+)-Fenchone is sulfonated by SO3 or H2SO4/acetic anhydride in the bridgehead methyl group. This could be confirmed by NMR techniques (INADEQUATE). The fenchonesulfonic acid obtained is converted (SOCl2/NH3) to the cyclic fenchonesulfonimide, which can be oxidized to the corresponding oxaziridine, in close analogy to 10-camphorsulfonimide. Improved procedures for this reaction sequences are given. During the treatment of the sulfonic acid with thionyl chloride, a byproduct with a rearranged bicyclic skeleton is observed whose structure has been determined by ozonolytic degradation and NMR techniques. A possible mechanism for this rearrangement is suggested, based on MNDO calculations of the intermediate carbocations. The fenchonesulfonyloxaziridine oxidizes sulfides to chiral sulfoxides with appreciable enantiomeric excess, but very low reaction rate. A comparison with camphor-derived oxaziridines having similar steric requirements is made.

scholarly journals Isolation of Rhodococcus sp. Strain ECU0066, a New Sulfide Monooxygenase-Producing Strain for Asymmetric Sulfoxidation

2008 ◽  
Vol 75 (2) ◽  
pp. 551-556 ◽  
Author(s):  
Ai-Tao Li ◽  
Jian-Dong Zhang ◽  
Jian-He Xu ◽  
Wen-Ya Lu ◽  
Guo-Qiang Lin
Keyword(s):  
Enzyme Activity ◽  
Asymmetric Synthesis ◽  
Bacterial Strain ◽  
Enantiomeric Excess ◽  
Good Activity ◽  
Rich Medium ◽  
Practical Application ◽  
Chiral Sulfoxides ◽  
Good Potential ◽  
Rhodococcus Sp

ABSTRACT A new and efficient sulfide monooxygenase-producing strain, ECU0066, was isolated and identified as a Rhodococcus sp. that could transform phenylmethyl sulfide (PMS) to (S)-sulfoxide with 99% enantiomeric excess via two steps of enantioselective oxidations. Its enzyme activity could be effectively induced by adding PMS or phenylmethyl sulfoxide (PMSO) directly to a rich medium at the early log phase (6 h) of fermentation, resulting in over 10-times-higher production of the enzyme. This bacterial strain also displayed fairly good activity and enantioselectivity toward seven other sulfides, indicating a good potential for practical application in asymmetric synthesis of chiral sulfoxides.

Reaction of adamantanone, diamantanone, and their derivatives with thionyl chloride

1987 ◽  
Vol 52 (8) ◽  
pp. 2028-2034 ◽  
Author(s):  
Josef Janků ◽  
Jiří Burkhard ◽  
Luděk Vodička
Keyword(s):  
Hydrogen Chloride ◽  
Carbonyl Group ◽  
Chlorine Atom ◽  
Thionyl Chloride ◽  
Reaction Rate ◽  
Axial Position ◽  
Chlorine Atoms

In reaction of adamantanone, diamantanone, and their chloro or oxo derivatives with thionyl chloride the oxo group is replaced with two chlorine atoms under formation of geminal dichloro derivatives. The presence of a chlorine atom or an oxo group in both ketones reduces the reaction rate. The reaction rate decreases with decreasing distance between the substituent and the carbonyl group. Ketones with chlorine atom in α- or β-axial position do not react with thionyl chloride. The reaction is accelerated by hydrogen chloride whereas in the presence of pyridine no reaction was observed.

Isotope exchange reactions of the hydrogen H-5 of selected pyrimidine derivatives and the preparation of tritium-labeled pyrimidines

2011 ◽  
Vol 76 (12) ◽  
pp. 1567-1577 ◽  
Author(s):  
Martin Dračínský ◽  
Petr Jansa ◽  
Tomáš Elbert
Keyword(s):  
Exchange Reaction ◽  
Isotope Exchange ◽  
Reaction Rate ◽  
Tritiated Water ◽  
Solvent Composition ◽  
Exchange Reactions ◽  
Pyrimidine Derivatives ◽  
Isotope Exchange Reaction ◽  
Nmr Techniques ◽  
Tracer Experiments

The hydrogen-to-deuterium isotope exchange reaction of hydrogen in position 5 of pyrimidine derivatives was studied using NMR techniques. The dependence of the reaction rate on the pH and on the solvent composition was explored. In tracer experiments using tritiated water, the application of this exchange reaction was tested for the preparation of pyrimidine derivatives labeled by tritium.

scholarly journals Nitration of the tetramethylbenzenes in acetic anhydride. Formation and rearomatization of adducts

1976 ◽  
Vol 54 (11) ◽  
pp. 1795-1806 ◽  
Author(s):  
Alfred Fischer ◽  
David R. A. Leonard
Keyword(s):  
Acetic Anhydride ◽  
Side Chain ◽  
Methyl Group ◽  
Nitro Derivatives

Nitration of the tetramethylbenzenes in acetic anhydride at temperatures below –50 °C gives the l-acetoxy-4-nitro and 5-acetoxy-2-nitro adducts from the 1,2,3,4 isomer, the 5-acetoxy-2-nitro adduct from the 1,2,3,5 isomer, and the l-acetoxy-4-nitro adduct from the 1,2,4,5 isomer as well as the expected nitro derivatives. Corresponding nitritonitro adducts are also formed as well as side-chain (benzylic) derivatives: nitrates and phenylnitromethanes. Rearomatization of the tertiary acetate adducts leads to aryl acetates, benzylic derivatives, or nitroarenes, depending upon the acidity of the solvent. In the benzylic derivatives the methyl group substituted is that ipso to the acetate in the precursor adduct, that para to the most activated ipso position of the arene.

Synthesis of 1,1-diacetates catalysed by silica-supported boron sulfonic acid under solvent-free conditions and ambient temperature

2014 ◽  
Vol 68 (4) ◽  
Author(s):  
Sami Sajjadifar ◽  
Sobhan Rezayati
Keyword(s):  
Acetic Anhydride ◽  
Ambient Temperature ◽  
Sulfonic Acid ◽  
Acid Catalyst ◽  
Solvent Free ◽  
Solvent Free Conditions ◽  
Brønsted Acid Catalyst ◽  
Ready Availability ◽  
Salient Features ◽  
Direct Condensation

Abstract1,1-Diacetates derivatives were prepared using the direct condensation of aldehydes with acetic anhydride in the presence of silica-supported boron sulfonic acid (SiO2/B(SO4H)3) as a tri-functional inorganic Brønsted acid catalyst under solvent-free conditions at ambient temperature. The salient features of this methodology are: (i) cheaper process ready availability of the catalyst; (ii) versatility; (iii) high regio-selectivity of the procedure and recyclable property of the catalyst.

Side chain nitration of polymethylbenzenes in nitric acid-acetic anhydride mixtures

1973 ◽  
Vol 26 (4) ◽  
pp. 775 ◽  
Author(s):  
DJ Blackstock ◽  
A Fischer ◽  
KE Richards ◽  
GJ Wright
Keyword(s):  
Gas Chromatography ◽  
Nitric Acid ◽  
Acetic Anhydride ◽  
Side Chain ◽  
Methyl Group ◽  
Product Distributions

Product distributions resulting from nitration of polymethylbenzenes in nitric acid-acetic anhydride mixtures have been determined by gas chromatography. Nitration of a methyl group occurs in all the substrates studied; such nitration occurs only at a methyl group para to the methyl most activated to ipso nitration. These results support the view that side chain nitration occurs through the diene intermediates which lead to ring acetoxylation.

Tetracyclic triterpenes. VIII. The skeletal rearrangement of 3β-acetoxy-9α,11α-epoxy-5α-lanostan-7-one: 13- and 10-methyl group migration

1985 ◽  
Vol 63 (6) ◽  
pp. 1280-1286 ◽  
Author(s):  
Zdzisław Paryzek ◽  
Roman Wydra
Keyword(s):  
Acetic Anhydride ◽  
Spectral Data ◽  
Boron Trifluoride ◽  
Boron Trifluoride Etherate ◽  
Major Product ◽  
Chemical Transformations ◽  
Skeletal Rearrangement ◽  
Methyl Group ◽  
Group Migration

The boron trifluoride etherate catalyzed rearrangement of 3β-acetoxy-9α, 11α-epoxy-5α-lanostan-7-one (1) in acetic anhydride resulted in formation of 19(10 → 9β)abeo compounds 2 and 4 along with 18(13 → 12β)abeo compound 5, as the major product. These structures are supported by spectral data and chemical transformations. The possible mechanism of the rearrangement is discussed.

scholarly journals 2-Substituted agelasine analogs: Synthesis and biological activity, and structure and reactivity of synthetic intermediates

2011 ◽  
Vol 83 (3) ◽  
pp. 645-653 ◽  
Author(s):  
Heidi Roggen ◽  
Lars Bohlin ◽  
Robert Burman ◽  
Colin Charnock ◽  
Jenny Felth ◽  
...  
Keyword(s):  
Significant Variation ◽  
Density Functional ◽  
Natural Bond Orbital ◽  
Nbo Analysis ◽  
Atomic Charges ◽  
Functional Theory ◽  
Methyl Group ◽  
H Nmr ◽  
Nmr Techniques ◽  
Synthetic Intermediates

2-Substituted N-methoxy-9-methyl-9H-purin-6-amines were synthesized either from their corresponding 6-chloro-9-methyl-9H-purines or 2-chloro-N-methoxy-9-methyl-9H-purin-6-amine. Great diversity in the amino/imino tautomeric ratios was observed and calculated based on 1H NMR. The tautomers were identified by 1D and 2D 1H, 13C, and 15N NMR techniques, and showed significant variation both in 13C and 15N shift values. Comparison of the tautomeric ratios with Hammett F values revealed that as the field/inductive withdrawing abilities of the 2-substituent increased, the ratio of amino:imino tautomers was shifted toward the amino tautomer. Computational chemistry exposed the significance of hydrogen bonding between solvent and the compound in question to reach accurate predictions for tautomeric ratios. B3LYP/def2-TZVP density functional theory (DFT) calculations resulted in quantitatively more accurate predictions than when employing the less expensive BP86 functional. N-7-Alkylation of the 2-substituted N-methoxy-9-methyl-9H-purin-6-amines showed that when the field/inductive withdrawing ability of the 2-substituent reached a certain point the reactivity drastically dropped. This correlated with the atomic charges on N-7 calculated using a natural bond orbital (NBO) analysis. Biological screening of the final 2-substituted agelasine analogs indicated that the introduction of a methyl group in the 2-position is advantageous for antimycobacterial and antiprotozoal activity, and that an amino function may improve activity against several cancer cell lines.

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