STUDIES IN ISOUREAS AND ISOUREIDES: III. THE IONIZATION CONSTANTS OF SOME ISOUREAS

1933 ◽  
Vol 8 (5) ◽  
pp. 458-462 ◽  
Author(s):  
Steward Basterfield ◽  
J. W. Tomecko
Keyword(s):  
Double Bond ◽  
Phenyl Group ◽  
Ionization Constants ◽  
Primary Amines

The ionization constants of seven isoureas have been measured. The values for simple alkyl isoureas increase definitely from methyl to n-propyl, the n-butyl-isourea showing no further increase. Isobutyl-isourea has a decidedly greater constant than the n-butyl compound. Introduction of the phenyl group into ethyl-isourea lowers the value of the constant as would be expected. The presence of a double bond in the radical also produces a similar effect as shown by a comparison of the values for n-propyl- and allyl-isoureas. Cyclohexyl-isourea has a constant slightly higher than those of n-propyl and n-butyl-isoureas. Some comparison with a series of primary amines is made.

Réactions avec le diazométhane d'esters cinnamylidène maloniques ou cyanacétiques méthylés ou phénylés en γ des groupements fonctionnels et des malononitriles correspondants. Thermolyse des pyrazolines obtenues

1977 ◽  
Vol 55 (22) ◽  
pp. 3942-3950 ◽  
Author(s):  
J. Martelli ◽  
R. Carrié
Keyword(s):  
Double Bond ◽  
Phenyl Group

The syntheses of cinnamylidene malonic or cyanacetic esters, bearing a methyl or a phenyl group in the position γ to the withdrawing groups, were achieved. The configurations of the various isomers were established and the conformations are discussed. Diazomethane adds exclusively to the α,β double bond of these dipolarophiles in only one orientation. The thermolysis of the resulting 1-pyrazoline was studied.

scholarly journals Bridge effect of the C=C, C=N and N=N bonds on the long distance electronic charge transfer ofpara‒substituted stilbenoid compounds

2000 ◽  
Vol 14 (4) ◽  
pp. 259-267 ◽  
Author(s):  
Manuel A. Leiva ◽  
Raul G. E. Morales
Keyword(s):  
Charge Transfer ◽  
Double Bond ◽  
Molecular System ◽  
Chemical Shifts ◽  
Phenyl Group ◽  
Point Of View ◽  
Electronic Charge ◽  
Orbital Theory ◽  
Long Distance ◽  
C Nmr

By means of13C‒NMR spectroscopy and ab initio molecular orbital theory calculations, we have analyzed the bridge effect of the C=C, C=N and N=N bonds on the long distance charge transfer of4‒dimethylamino‒4'‒nitrostilbenoid compounds in the ground electronic state.After a complete spectral assignment of the13C‒NMR signals in these molecular compounds, we have characterized the effect of the nitrogen centres on the molecular bridge by means of the chemical shifts of the carbon centres, the theoretical charge densities and the dipolar moments.From an electronic molecular point of view, our results describe two main properties of the double bond bridge. The first is related to the local charge accumulation capacity given by the type of the atomic centres and the structural orientation of the double bond bridge, and the second property is related to the modulation of the electronic charge distribution through the molecular system by the electrical polarization of the bridge.Other complementary experimental evidences have permit us to establish new local molecular domains of the bridge effect in these stilbenoid compounds by means of linear correlations between13C‒NMR chemical shifts of the aromatic carbon centres of the acceptor‒phenyl group and the molecular polarity of the species under study.

Reactions of t-Boc-Protected Amines with Difluorocarbene

Synthesis ◽  
2019 ◽  
Vol 51 (12) ◽  
pp. 2579-2583 ◽  
Author(s):  
Andrii Gerasov ◽  
Alexander Shivanyuk ◽  
Volodymyr Fetyukhin ◽  
Oleg Lukin
Keyword(s):  
Double Bond ◽  
Secondary Amines ◽  
Primary Amines ◽  
Primary And Secondary Amines

The reactions of t-Boc-protected secondary and primary amines with difluorocarbene generated from trimethylsilyl (fluorosulfonyl)difluoroacetate [Me3SiOC(O)CF2SO2F] (TFDA) in toluene at 110 °C results in the replacement of t-Bu by difluoromethyl in the t-Boc group. This reaction can be carried out in the presence of CH2Br and COOMe moieties in the structure of the protected amine. In the example of a t-Boc-protected amine containing a C=C double bond, replacement of the t-Bu group and/or cyclodifluoropropanation takes place. Difluoromethyl esters are shown to react with primary and secondary amines yielding the corresponding ureas.

scholarly journals Crystal structure of (3E)-3-[(4-nitrophenoxy)methyl]-4-phenylbut-3-en-2-one

2014 ◽  
Vol 70 (9) ◽  
pp. o1020-o1021 ◽  
Author(s):  
Julio Zukerman-Schpector ◽  
Stella H. Maganhi ◽  
Paulo J. S. Moran ◽  
Bruno R. S. de Paula ◽  
Paulo R. Nucci ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Double Bond ◽  
Torsion Angle ◽  
Title Compound ◽  
Crystal Packing ◽  
Phenyl Group ◽  
Aromatic Rings ◽  
Compound C ◽  
Centroid Distance ◽  
Phenyl Rings

In the title compound, C17H15NO4, the conformation about the C=C double bond [1.348 (2) Å] isEwith the ketone group almost co-planar [C—C—C—C torsion angle = 7.2 (2)°] but the phenyl group twisted away [C—C—C—C = 160.93 (17)°]. The terminal aromatic rings are almost perpendicular to each other [dihedral angle = 81.61 (9)°] giving the molecule an overall U-shape. The crystal packing feature benzene-C—H...O(ketone) contacts that lead to supramolecular helical chains along thebaxis. These are connected by π–π interactions between benzene and phenyl rings [inter-centroid distance = 3.6648 (14) Å], resulting in the formation of a supramolecular layer in thebcplane.

scholarly journals Crystal structure of (E)-13-{4-[(Z)-2-cyano-2-(3,4,5-trimethoxyphenyl)ethenyl]phenyl}parthenolide methanol hemisolvate

2014 ◽  
Vol 70 (10) ◽  
pp. o1092-o1093 ◽  
Author(s):  
Narsimha Reddy Penthala ◽  
Shobanbabu Bommagani ◽  
Venumadhav Janganati ◽  
Sean Parkin ◽  
Peter A. Crooks
Keyword(s):  
Crystal Structure ◽  
Double Bond ◽  
Title Compound ◽  
Heck Reaction ◽  
Lactone Ring ◽  
Phenyl Group ◽  
Exocyclic Double Bond ◽  
Reaction Conditions ◽  
Compound C ◽  
Methyl Phenyl

The title compound, C33H35NO6[systematic name: (Z)-3-(4-{(E)-[(E)-1a,5-dimethyl-9-oxo-2,3,7,7a-tetrahydrooxireno[2′,3′:9,10]cyclodeca[1,2-b]furan-8(1aH,6H,9H,10aH,10bH)-ylidene]methyl}phenyl)-2-(3,4,5-trimethoxyphenyl)acrylonitrile methanol hemisolvate], C33H35NO6·0.5CH3OH, was prepared by the reaction of (Z)-3-(4-iodophenyl)-2-(3,4,5-trimethoxyphenyl)acrylonitrile with parthenolide [systematic name: (E)-1a,5-dimethyl-8-methylene-2,3,6,7,7a,8,10a,10b-octahydrooxireno[2′,3′:9,10]cyclodeca[1,2-b]furan-9(1aH)-one] under Heck reaction conditions. The molecule is built up from fused ten-, five- (lactone) and three-membered (epoxide) rings with a {4-[(Z)-2-cyano-2-(3,4,5-trimethoxyphenyl)ethenyl]phenyl}methylidene group as a substituent. The 4-[(Z)-2-cyano-2-(3,4,5-trimethoxyphenyl)ethenyl]phenyl group on the parthenolide exocyclic double bond is oriented in atransposition to the lactone ring to form theEisomer. The dihedral angle between the benzene ring of the phenyl moiety and the lactone ring mean plane is 21.93 (4)°.

scholarly journals Selective 1,2 addition of polar X‒H bonds to the Ga–P double bond of gallaphosphene L(Cl)GaPGaL

2022 ◽  
Author(s):  
Mahendra K. Sharma ◽  
Christoph Wölper ◽  
Stephan Schulz
Keyword(s):  
Double Bond ◽  
Ambient Temperature ◽  
Primary Amines

Gallaphosphene L(Cl)GaPGaL 1 (L = HC[C(Me)N(2,6-i-Pr2-C6H3)]2) reacts at ambient temperature with a series of polar X−H bonds, i.e. ammonia, primary amines, water, phenol, thiophenol, and selenophenol, selectively with 1,2 addition...

Conformational Aspects of Substituents in Enamines. X-Ray Structure Analyses and Quantum Chemical Calculations

1992 ◽  
Vol 47 (7-8) ◽  
pp. 869-876 ◽  
Author(s):  
Gerhard Raabe ◽  
Wolfgang Karl ◽  
Dieter Enders ◽  
Jörg Fleischhauer
Keyword(s):  
Molecular Structure ◽  
Double Bond ◽  
Ab Initio Calculations ◽  
Ab Initio ◽  
Quantum Chemical ◽  
Lone Pair ◽  
Phenyl Group ◽  
Careful Analysis ◽  
X Ray ◽  
Nitrogen Lone Pair

Abstract X-ray structure determination of the enamine (Z)-4-(6'-t-butoxycarbonyl-2',2'-dimethyl-5'-phenyl- 3'-hexen-3'-yl)morpholine (1) reveals that certain bulky groups may enforce a relative orientation of the molecular subunits without conjugative interaction between the nitrogen lone pair and the olefinic double bond. According to the results of quantum chemical ab initio calculations the experimentally found arrangement would be the least favourable one in the absence of such substituents. A careful analysis of the molecular structure of 1 shows that this unusual arrangement is due to the presence of both, the a- and the ß-substituent. In (E)-4-(3'-t-butoxycarbonylmethyl-1'-phenyl-1'-penten-1'-yl)morpholine (2) rather the nitrogen lone pair than the phenyl n system is in conjugation with the olefinic double bound. The results of ab initio calculations on model compounds show that conjugation of the double bond with the nitrogen lone pair is by 2 - 6 kcal/mol more favourable than conjugative interaction between the phenyl group and the C = C bond. Closer examination of the molecular structure of 2, however, led to the conclusion that it is predominantly the ß-substituent which forces the phenyl ring in a position where conjugation with the enamine double bond is not possible

Further examples of photocycloadditions of 1,3-diketonatoboron difluorides to olefins: a description of the reaction pattern and mechanism

1997 ◽  
Vol 75 (6) ◽  
pp. 720-726 ◽  
Author(s):  
Yuan L. Chow ◽  
Xianen Cheng ◽  
Shi S. Wang ◽  
Susan P. Wu
Keyword(s):  
Excited State ◽  
Double Bond ◽  
Phenyl Group ◽  
Adduct Formation ◽  
Reaction Pattern ◽  
Methyl Substituent ◽  
Cyclic Olefins ◽  
Dibenzoylmethanatoboron Difluoride

The photocycloaddition of dibenzoylmethanatoboron difluoride (DBMBF2) with conjugated nitriles, ketones, and esters occurs more slowly than that with simple olefins and with fair regioselectivity. For these electron-deficient olefins, the cyclic analogues react more slowly than the acyclic ones and the cyano analogues react more slowly than all others; also a β-methyl substituent reverses the regioselectivity in adduct formation. Benzoylacetonatoboron difluoride (BABF2) photocycloadds to simple cyclic olefins from the excited state isomer in which the double bond is conjugated with the phenyl group, and occurs more slowly than that of the corresponding reaction of DBMBF2. The efficiency and regiochemistry of these cycloadditions have been explained with respect to the exciplex as the immediate intermediate. Keywords: photocycloaddition, dibenzoylmethanatoboron difluoride, benzoylacetonatoboron difluoride, exciplex.

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