A study of reactions of 5-substituted furfurylidene derivatives with secondary amines

1985 ◽  
Vol 50 (2) ◽  
pp. 459-469 ◽  
Author(s):  
Katarína Špirková ◽  
Rudolf Kada ◽  
Jaroslav Kováč ◽  
Viera Knoppová ◽  
Miroslav Dzuroška ◽  
...  
Keyword(s):  
Nmr Spectra ◽  
Secondary Amines ◽  
H Nmr ◽  
Kinetics Of

The paper describes preparation of 5-bromo-, 5-nitro-, 5-phenylsulphonyl-, and 5-phenylthio-2-furfurylidene derivatives and investigation of their reactions with N-phenylpiperazine, morpholine, piperidine, and pyrrolidine. Kinetics of the reactions have been followed, and UV, IR, and 1H NMR spectra of the compounds produced are interpreted.

New Substituted Difurylchalcones

1992 ◽  
Vol 57 (10) ◽  
pp. 2203-2207 ◽  
Author(s):  
Katarína Špirková ◽  
Štefan Stankovský
Keyword(s):  
Nmr Spectra ◽  
Knoevenagel Condensation ◽  
Secondary Amines ◽  
H Nmr ◽  
Nucleophilic Reactions

Preparation of 1-(5-substituted-2-furyl)-2-phenylsulfonyl-2-furoyl ethylenes (IIa-IId) using the Lehnert modification of Knoevenagel condensation, as well as substitution nucleophilic reactions of the 1-(5-bromo-2-furoyl)-2-phenylsulfonyl-2-furoyl derivative (IIa) with the corresponding phenolate, thiophenolate and secondary amines are described. IR, UV and 1H NMR spectra of final products are presented.

Synthesis of Optically Active N6-Alkyl Derivatives of (R)-3-(Adenin-9-yl)-2-hydroxypropanoic Acid and Related Compounds

2003 ◽  
Vol 68 (5) ◽  
pp. 931-950 ◽  
Author(s):  
Marcela Krečmerová ◽  
Miloš Buděšínský ◽  
Milena Masojídková ◽  
Antonín Holý
Keyword(s):  
Nmr Spectra ◽  
Enantiomeric Purity ◽  
Optically Active ◽  
Secondary Amines ◽  
H Nmr ◽  
Alkyl Derivatives ◽  
Optically Pure ◽  
Derivatives Of ◽  
Related Compounds

Reaction of ethyl (R)-oxiranecarboxylate (2a) with various nucleobases (adenine, 6-chloropurine, thymine, cytosine, N6-benzoyladenine, 4-methoxy-5-methylpyrimidin-2(1H)-one and 4-methoxypyrimidin-2(1H)-one) afforded ethyl 3-substituted-2-hydroxypropanoates 4-10. Enantioselectivity of this reaction is dependent on the type of the base: 6-chloropurine, N6-benzoyladenine, 4-methoxy-5-methylpyrimidin-2(1H)-one, thymine and cytosine gave optically pure R enantiomers. In other cases, partial or complete racemization occurred. Optically pure ethyl (R)-3-(6-chloropurin-9-yl)-2-hydroxypropanoate (5a) was hydrolyzed to give (R)-3-(6-chloropurin-9-yl)-2-hydroxypropanoic acid (11). Reactions of 11 with various primary or secondary amines led to N6-substituted (R)-3-(adenin-9-yl)-2-hydroxypropanoic acids 14-19. Enantiomeric purity was determined from 1H NMR spectra measured in the presence of (-)-(R)-1-(9-anthryl)-2,2,2-trifluoroethan-1-ol.

Stereochemistry and kinetics of amines addition to acetylenic esters

1991 ◽  
Vol 69 (9) ◽  
pp. 1445-1449 ◽  
Author(s):  
Saber M. Sharaf ◽  
Samir K. El-Sadany ◽  
Ezzat A. Hamed ◽  
Abdel-Hamid A. Youssef
Keyword(s):  
Key Words ◽  
Nucleophilic Addition ◽  
Nmr Spectra ◽  
Acetylenic Esters ◽  
H Nmr ◽  
Rate Limiting Step ◽  
Limiting Step ◽  
Rate Limiting ◽  
Kinetics Of ◽  
Step Mechanism

The reactions of a series of methyl para-substituted phenylpropiolates 1a–e with piperidine, morpholine, and diethylamine in methanol and dimethylformamide (DMF) have been studied and their rates measured. The products were methyl β-(N,N-dialkylamino)-p-substituted cinnamates 2–4a–e. 1H NMR spectra were used to determine the configuration of the products. The ρ values in methanol ranged between 0.34 and 1.24 whereas in DMF they were between 0.85 and 1.88. The values of ΔS≠ favor a bimolecular rate-limiting step mechanism. Key words: nucleophilic addition to acetylenic esters.

X+ transfer from the halonium ions of adamantylideneadamantane to acceptor olefins. The possibility of chiral induction in the transfer process

1997 ◽  
Vol 75 (12) ◽  
pp. 1844-1850 ◽  
Author(s):  
Alexei A. Neverov ◽  
Theresa L. Muise ◽  
R.S. Brown
Keyword(s):  
Nmr Spectra ◽  
Room Temperature ◽  
Reaction Rate ◽  
Methyl Groups ◽  
Kinetic Behavior ◽  
Methyl Group ◽  
Chiral Induction ◽  
H Nmr ◽  
Group 12 ◽  
Kinetics Of

The bromonium ion of adamantylideneadamantane (Ad=Ad-Br+) has been used to induce the bromocyclization of a 4-pentenyl glycoside (10) and a 5-hexenyl glycoside (11) in dichloroethane. The kinetics of these processes have been studied at 25 °C in the presence of varying [Ad=Ad] and, in the case of the transfer to 10, in the presence of pentanol. The second-order rate constants for bromocyclization of these two alkenes are (1.04 ± 0.06) × 10−1 M−1 s−1 and (5.34 ± 0.2) × 10−1 M−1 s−1, respectively, and in no case does added Ad=Ad or pentanol alter the reaction rate. The kinetic behavior is interpreted in terms of cyclization occurring directly from a 1:1 complex of Ad=Ad-Br+ and 10 or 11. The chiral induction for the bromocyclization of 10 promoted by AdAd-Br+ was measured at 20% e.e., the (−)-(S)-tetrahydrofurfuryl bromide being the dominant stereoisomer. Ad=Ad molecules substituted at one of the homoallylic carbons by an axial methyl group (12), or by two methyl groups (axial and equatorial), were synthesized and the 1H NMR spectra of their bromonium ions is given. These materials are not stable for prolonged times at room temperature. A limited kinetic study of the reaction of 12-Br+ and 4-pentenol indicated that the Br+ transfer is 500 times faster than the comparable transfer from Ad=Ad-Br+ to 4-pentenol. The possibility of using these materials to induce chiral bromocyclization is discussed. Keywords: bromonium ion, halonium, transfer, chiral, adamantylideneadamantane.

Transmission of polar effects arcoss the CH=CH link in styrylfuran system

1981 ◽  
Vol 46 (12) ◽  
pp. 3110-3114
Author(s):  
Viera Knoppová ◽  
Anton Beňo ◽  
Miloslava Dandárová ◽  
Jaroslav Kováč
Keyword(s):  
Thermodynamic Parameters ◽  
Substituent Effect ◽  
Nmr Spectra ◽  
Aldehyde Group ◽  
Point Of View ◽  
Polarographic Reduction ◽  
Transmission Coefficients ◽  
H Nmr ◽  
Polar Substituent ◽  
Kinetics Of

Transmission of polar substituent effect through the vinylidene grouping in 5-(4-X-styryl)-2-furaldehydes (X = H, Cl, Br, COOCH3, CN and NO2) was studied by polarographic reduction of the aldehyde group as well as by kinetics of their condensation with malononitrile. The obtained transmission coefficients π' were compared with the corresponding values for systems, containing other links between the benzene and furan nuclei. Thermodynamic parameters of the condensation with malononitrile were determined. The transmission of polar effects is discussed also from the point of view of 1H NMR spectra.

Kinetic and spectral studies on 5-phenoxy-2-furaldehydes and their condensation products

1981 ◽  
Vol 46 (2) ◽  
pp. 506-514 ◽  
Author(s):  
Viera Knoppová ◽  
Miloslava Dandárová ◽  
Jaroslav Kováč
Keyword(s):  
Substitution Reaction ◽  
Nmr Spectra ◽  
Furan Ring ◽  
Point Of View ◽  
Spectral Studies ◽  
Reaction Site ◽  
Cyclic Amines ◽  
H Nmr ◽  
Condensation Products ◽  
Kinetics Of

The base-catalyzed reaction of 5-(4- or 3-phenoxy)-2-furaldehydes (X = 4-OCH3, 4-CH3, 4-Cl, 4-NO2, 3-NO2, 4-Br, 4-COOC2H5, 3-NHCOCH3, 4-SCH3) with malonodinitrile in ethanol gave the corresponding condensation products. The course of the reaction has been monitored kinetically. The kinetics of the nucleophilic substitution reaction at the position 5 of the furan ring of the obtained 2-cyano-3-(5-X-phenoxy-2-furyl)acrylonitriles with secondary cyclic amines (piperidine, morpholine, pyrrolidine) has been studied. The effect of X across the oxygen bridge upon the reaction site is discussed from the point of view of kinetics of the reaction. 1H-NMR spectra of the starting aldehydes and of the formed condensation products have been measured.

New synthesis of 2-amino-4-oxopyrido[3,2-e]-1,3-thiazines and 1-alkyl(aryl)pyrido[3,2-e]-2-thiouracils

1983 ◽  
Vol 48 (11) ◽  
pp. 3315-3328 ◽  
Author(s):  
Dušan Koščík ◽  
Pavol Kristian ◽  
Jozef Gonda ◽  
Emília Dandárová
Keyword(s):  
Mass Spectra ◽  
Nmr Spectra ◽  
Secondary Amines ◽  
Primary Amines ◽  
Addition Reactions ◽  
Alkyl Aryl ◽  
H Nmr ◽  
New Synthesis ◽  
Subsequent Cyclization ◽  
C Nmr

Addition reactions of 2-chloronicotinoyl isothiocyanate with primary and secondary amines and subsequent cyclization of intermediate thioureas represent new synthesis of pyrido[3,2-e]thiouracil and pyrido[3,2-e]-thiazine derivatives. 2-Amino-4-oxopyrido[3,2-e]-1,3-thiazines are formed upon heating the reaction components in ethanol, whereas 1-alkyl(aryl)pyrido[3,2-e]-2-thiouracils are products of alkali-catalyzed reaction. In reaction with primary amines the corresponding thioureas were isolated as intermediates, whereas secondary amines reacted directly to give the pyridothiazine derivatives. Structure of the synthesized compounds was confirmed by their 13C NMR and mass spectra; also the IR and 1H NMR spectra are in accord with the suggested formulae.

Variable temperatures 1H NMR technique on the kinetics and thermodynamic parameters of equilibrium between the Z and E isomers in a stable phosphorus ylide involving an imidazole

RSC Advances ◽  
2016 ◽  
Vol 6 (52) ◽  
pp. 46345-46349 ◽  
Author(s):  
Elham Aghdaei ◽  
Sayyed Mostafa Habibi-Khorassani ◽  
Mehdi Shahraki
Keyword(s):  
Thermodynamic Parameters ◽  
1H Nmr ◽  
Nmr Spectra ◽  
Phosphorus Ylide ◽  
H Nmr ◽  
Kinetics Of ◽  
Kinetics And Thermodynamic

Analysis of 1H NMR spectra of a special ylide involving an imidazole at variable temperatures has been employed to study the kinetics of the interchangeable process in the equilibrium between the two Z- and E-isomers of a stable phosphorus ylide.

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.

Synthesis of 2-amino-5,7-dimethyl-4-oxopyrido[3,4-e]-1,3-thiazines

1983 ◽  
Vol 48 (12) ◽  
pp. 3426-3432 ◽  
Author(s):  
Dušan Koščík ◽  
Pavol Kristian ◽  
Ondrej Forgáč
Keyword(s):  
Spectral Data ◽  
Chlorine Atom ◽  
Mass Spectra ◽  
High Reactivity ◽  
Secondary Amines ◽  
Dimroth Rearrangement ◽  
H Nmr ◽  
New Synthesis ◽  
C Nmr

New synthesis of pyrido[3,4-e]-1,3-thiazines consisting in reaction of 2,6-dimethyl-4-chloronicotinoyl isothiocyanate with primary or secondary amines, or with benzaldehyde phenylhydrazone, is described. High reactivity of the chlorine atom does not allow isolation of the corresponding thioureas, arising as intermediates, except in the case of the benzylamino derivative. Structure of the products was unequivocally confirmed by their spectral data (IR, UV, 1H NMR, 13C NMR and mass spectra). The synthesized derivatives do not undergo the Dimroth rearrangement.

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