Synthesis and reactions of alkyl 3-bromomethyl-3-(2-furyl)-2-propenoates with sulfur containing nucleophiles

1980 ◽  
Vol 45 (1) ◽  
pp. 142-149 ◽  
Author(s):  
Katarína Špirková ◽  
Jaroslav Kováč ◽  
Václav Konečný ◽  
Miloslava Dandárová ◽  
Marta Černayová
Keyword(s):  
Nmr Spectra ◽  
H Nmr ◽  
Nucleophilic Displacement ◽  
Displacement Reactions ◽  
Sulfur Containing

Preparation and nucleophilic displacement reactions of alkyl 3-bromomethyl-3-(2-furyl)-2-propenoates with sulfur containing nucleophiles is described. The UV, IR and 1H-NMR spectra of the synthesized compounds are interpreted.

Synthesis and Photochemical Trasformations of 19-Phenylsulfonyl Provitamin D Analogue

1998 ◽  
Vol 63 (10) ◽  
pp. 1597-1612
Author(s):  
Piotr Grzegorzewski ◽  
Izabela Koladkiewicz ◽  
Jacek W. Morzycki ◽  
Rafal R. Sicinski
Keyword(s):  
Double Bond ◽  
Uv Irradiation ◽  
Efficient Method ◽  
Nmr Spectra ◽  
Complex Mixture ◽  
The Other ◽  
Allylic Oxidation ◽  
H Nmr ◽  
Nucleophilic Displacement ◽  
Displacement Reactions

The synthesis of provitamin D analogue 19-(phenylsulfonyl)androsta-5,7-diene-3β,17β-diyl 3-acetate 17-pivalate (20) has been accomplished from 19-hydroxyandrost-5-ene-3β,17β-diyl 3-acetate 17-pivalate. 19-(Phenylsulfonyl)androst-5-ene-3β,17β-diyl 3-acetate 17-pivalate (10), a precursor of 20, was first obtained in low yield in the nucleophilic displacement reactions of 19-halogenated-5-ene steroids with sodium benzenesulfinate. Then a more efficient method has been used, which involves protection of the double bond as an epoxide. Introduction of the C(7)-C(8) double bond into olefin 10 has been also achieved in two ways. The first involved bromination-dehydrobromination and the other consisted of an allylic oxidation of olefin 10 leading to enone and the Bamford-Stevens reaction of its tosylhydrazone. UV irradiation of 5,7-diene 20 resulted in formation of a complex mixture of products. The structures of five isolated compounds were established on the basis of their 1H NMR spectra and mechanistic rationale.

Gas-Phase Ion Chemistry of Siloxide and Silamide Ions by Using the Flowing Afterglow. Unusual Rearrangements Involving SiO and SiS Bond Formation

1989 ◽  
Vol 42 (4) ◽  
pp. 489 ◽  
Author(s):  
RAJ Ohair ◽  
JC Sheldon ◽  
JH Bowie ◽  
R Damrauer ◽  
CH Depuy
Keyword(s):  
Gas Phase ◽  
Exchange Reactions ◽  
Ion Chemistry ◽  
Simple Correlation ◽  
Flowing Afterglow ◽  
Gas Phase Ion Chemistry ◽  
Nucleophilic Displacement ◽  
Displacement Reactions ◽  
Gas Phase Ion ◽  
Sulfur Containing

Siloxide ions undergo O/S exchange reactions with suitable sulfur-containing neutrals, e.g. H3SiO-+CS2 → H3SiS-+COS. Silamide ions similarly undergo NR/O and NR/S exchange reactions together with nucleophilic displacement reactions, e.g. Me3SiNMe + CO2 → Me3SiO-+MeNCO →No simple correlation between rate and mechanism is observed for all the studied reactions.

Synthesis of cyclopentane analogs of (2′- and 3′-deoxy-erythro-pentofuranosyl and ribofuranosyl)-2-thiouracil nucleosides

1986 ◽  
Vol 64 (8) ◽  
pp. 1620-1629 ◽  
Author(s):  
Lucjan J.J. Hronowski ◽  
Walter A. Szarek
Keyword(s):  
Sulfur Atom ◽  
Nmr Spectra ◽  
Aqueous Ammonia ◽  
Synthetic Route ◽  
Nmr Spectrum ◽  
H Nmr ◽  
Synthetic Intermediates ◽  
Derivatives Of ◽  
Sulfur Containing ◽  
Sulfur Containing Compounds

Three new carbocyclic analogs of nucleosides having the 2-thiouracil base have been synthesized. The cyclopentyl groups in these nucleosides are (±)-{(1β,3α,4β)-3-hydroxy-4-(hydroxyrnethyl)cyclopentyl} (see 31), (±)-{(1β,2α,4β)-2-hydroxy-4-(hydroxymethyl)cyclopentyl} (see 32), and (±)-{(1β,2α,3α,4β)-2,3-dihydroxy-4-(hydroxymethyl)cyclopentyl} (see 33). The nucleosides were prepared by coupling the appropriate hydroxy derivatives of cis-3-aminocyclopentanemethanol with 3-ethoxypropenoyl isothiocyanate (21) followed by cyclization in 15 N aqueous ammonia to give the 2-thiouracil nucleosides. In addition a modified and shortened synthetic route is described for the synthesis of (±)-(1β,2α,3α,4β)-4-amino-2,3-dihydroxy-cyclopentanemethanol (19). The 1H nmr spectra at 200 MHz of all of the synthetic intermediates, the 2-thiouracil nucleosides, and of the corresponding carbocyclic analogs of uracil nucleosides are discussed. It is shown that each nucleoside has a characteristically unique 1H nmr spectrum and that in general the protons in the sulfur-containing compounds resonate at lower fields than those in the corresponding oxygen-containing compounds. The magnitude of this downfield shift is inversely related to the number of bonds separating a particular proton from the sulfur atom.

Regioselective eliminations in reactions of carbohydrate derivatives with superoxide, or with borohydride in 2-propanol

1981 ◽  
Vol 59 (2) ◽  
pp. 333-338 ◽  
Author(s):  
Vanga S. Rao ◽  
Arthur S. Perlin
Keyword(s):  
Transition State ◽  
Sodium Borohydride ◽  
Nmr Spectra ◽  
Enol Ether ◽  
Proton Abstraction ◽  
H Nmr ◽  
Potassium Superoxide ◽  
Nucleophilic Displacement ◽  
Selective Displacement ◽  
Reaction Routes

The reaction between 2,3,4,6-tetra-O-benzyl-1,5-di-O-mesyl-D-glucitol (2) and potassium superoxide resulted in the loss of H-4 and the 5-mesyloxy (as well as 1-mesyloxy) substituent, and an almost quantitative conversion into enol ether 4, i.e., 1,3,4,5-tetra-O-benzyl-3-dehydro-2-deoxy-L-threo-hex-2-enitol. When the reaction was performed with 8, in which the 1-O-mesyl group (of 2) is replaced by O-(methoxy)trityl, the outcome was wholly different: an olefin was formed through the removal of a primary (H-6) rather than a secondary (H-4) proton, and nucleophilic displacement also took place. Results similar to those for 8 were obtained with the 2-epimer of 2, i.e., 2,3,4,6-tetra-O-benzyl-1,5-di-O-mesyl-D-mannitol (12). It is suggested that selective displacement of the 1-O-mesyl group of 2 by superoxide generates a 1-peroxy anion (6) that abstracts H-4 intramolecularly, promoting concomitant loss of the 5-mesyloxy group. The transition state for proton abstraction within anion 6 appears to be more stable than that of the corresponding anion in the manno series, accounting for the different reaction routes for 2 and 12. Elimination occurred also in the reduction of 2,3,4,6-tetra-O-benzyl-D-glucopyranose with sodium borohydride in 2-propanol, en route to 2, affording 2,4,6-tri-O-benzyl-2-dehydro-3-deoxy-D-threo-hex-2-enitol (21). The lH nmr spectra of alditol derivatives 2, 8, and 12 show that these molecules depart substantially from extended zigzag conformations, in contrast to configurationally related peracetylated acyclic derivatives.

Reaktionen koordinierter Liganden, V / Reactions of Coordinated Ligands, V

1977 ◽  
Vol 32 (12) ◽  
pp. 1449-1454 ◽  
Author(s):  
Othmar Stelzer ◽  
Hans-Bernhard Eikmeier ◽  
Gerd Johannsen
Keyword(s):  
Thermal Decomposition ◽  
Functional Groups ◽  
Nmr Spectra ◽  
Ir And Nmr Spectra ◽  
Azide Ion ◽  
Nucleophilic Displacement ◽  
Displacement Reactions

The azidophosphine complexes cis-Mo(CO)4(R2PN3)2 (R = Me, Ph) may be obtained by nucleophilic displacement reactions of chlorine by azide ion in complexes cis-Mo(CO)4(R2PCl)2. The thermal decomposition and Staudinger reactions were studied. Silylation of NH- or NH2-functional groups in aminophosphine and hydrazinophosphine complexes with Me3SiCl, Me2SiCl2 or Me2SiCl-SiClMe2 leads to a series of monodentate or bidentate silylaminophosphine complexes, e.g. (CO)4Mo(R2PNHSiMe3)2, (CO)4Mo-(R2PNH)2SiMe2, (CO)4Mo(R2PNH)2(SiMe2)2, (CO)4Mo[R2PN(SiMe3)(SiMe3)NPR2] or (CO)4Mo[R2P-N(SiMe3)SiMe2-SiMe2-N(SiMe3)PR2].The structures of these complexes are discussed on the basis of their IR and NMR spectra.

Conformational structure of ethylene glycol dibenzoate. Vibrational and NMR spectra

1981 ◽  
Vol 46 (8) ◽  
pp. 1913-1929 ◽  
Author(s):  
Bohdan Schneider ◽  
Pavel Sedláček ◽  
Jan Štokr ◽  
Danica Doskočilová ◽  
Jan Lövy
Keyword(s):  
Ethylene Glycol ◽  
Vibrational Spectra ◽  
Nmr Spectra ◽  
Coupling Constants ◽  
Conformational Structure ◽  
Infrared And Raman Spectra ◽  
H Nmr ◽  
Liquid States ◽  
Crystalline Forms ◽  
C Nmr

It was found that three crystalline forms of ethylene glycol dibenzoate can be prepared. Infrared and Raman spectra of these three forms, as well as of the glassy and liquid states, were measured. From 3JHH coupling constants obtained by analysis of the 13C satellite band of the -CH2- group in 1H NMR spectra, and from the 3JCH coupling constants of the -CO.O.CH2- fragment obtained by analysis of the carbonyl band in 13C NMR spectra it was found that in the liquid state the -CH2-CH2- group exists predominantly in the gauche conformational structure, and the bonds C-O-C-C assume predominantly a trans orientation. The results of the analysis of NMR and vibrational spectra were used for the structural interpretation of conformationally sensitive bands in vibrational spectra of ethylene glycol dibenzoate.

Preparation and absolute configuration at C(20) of 21-nor-5α-chol-22-en-24→20-olide derivatives

1981 ◽  
Vol 46 (4) ◽  
pp. 917-925 ◽  
Author(s):  
Vladimír Pouzar ◽  
Miroslav Havel
Keyword(s):  
Absolute Configuration ◽  
Nmr Spectra ◽  
Lithium Salt ◽  
H Nmr ◽  
Chemical Correlation ◽  
Unsaturated Lactones

Reaction of the aldehyde I with the lithium salt of 1-(2-tetrahydropyranyloxy)-2-propyne yielded the compounds II and IV. From the compound II the lactone XII was prepared via the intermediates III and X, the lactone XVIII was prepared from the substance IV via the intermediates V and XVI. The unsaturated lactones XII and XVIII were also prepared by sulfenylation and dehydrosulfenylation of the saturated lactones XIII and XIX. Based on chemical correlation and 1H-NMR spectra analyses of the compounds II and IV, the lactone XII was assigned the 20R-configuration whereas the lactone XVIII was allotted the 20S-configuration.

New type of addition to 5-substituted 4-arylidene-2-(4,5-dihydrofurfurylidene)-N,N-dimethyliminium bisperchlorates. Preparation of 4-substituted 5-(N,N-dimethylamino)-2-furancarbaldehydes

1986 ◽  
Vol 51 (3) ◽  
pp. 573-580 ◽  
Author(s):  
Tibor Gracza ◽  
Zdeněk Arnold ◽  
Jaroslav Kováč
Keyword(s):  
Nmr Spectra ◽  
Addition Reaction ◽  
H Nmr ◽  
Organic Bases ◽  
New Type

4-Arilidene-5-(N,N-dimethyliminium)-2-(4,5-dihydrofurfurylidene)-N,N-dimethyliminium bisperchlorate I undergoes a 1,4-addition reaction with organic bases under re-formation of the furan nucleus; this behaviour has been utilized in the preparation of new 4-substituted 5-(N,N-dimethylamino)-2-furancarbaldehydes II, III. The structure of the prepared compounds has been confirmed by 13C and 1H NMR spectra.

Preparation, properties and structure of some intermediate nido- and arachno-monocarbaboranes

1981 ◽  
Vol 46 (10) ◽  
pp. 2345-2353 ◽  
Author(s):  
Karel Baše ◽  
Bohumil Štíbr ◽  
Jiří Dolanský ◽  
Josef Duben
Keyword(s):  
Transition Metal ◽  
Metal Complexes ◽  
Transition Metal Complexes ◽  
Nmr Spectra ◽  
Liquid Ammonia ◽  
X Ray Diffraction ◽  
X Ray ◽  
H Nmr ◽  
Starting Compound

The 6-N(CH3)3-6-CB9H11 carbaborane reacts with sodium in liquid ammonia with the formation of 6-CB9H12- which was used as a starting compound for preparing the 4-CB8H14, 9-L-6-CB9H13 (L = (CH3)2S, CH3CN and P(C6H5)3), 1-(η5-C5H5)-1,2-FeCB9H10-, and 2,3-(η5-C5H5)2-2,31-Co2CB9H10- carboranes. The 4-CB8H14 compound was dehydrogenated at 623 K to give 4-(7)-CB8H12 carborane. Base degradation of 6-N(CH3)3-6-CB9H11 in methanol resulted in the formation of 3,4-μ-N(CH3)3CH-B5H10. The structure of all compounds was proposed on the basis of their 11B and 1H NMR spectra and X-ray diffraction was used in the case of the transition metal complexes.

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