On the oxidation of 2-t-Butyl-p-cresol

1978 ◽  
Vol 31 (4) ◽  
pp. 907 ◽  
Author(s):  
FR Hewgill ◽  
GB Howie
Keyword(s):  
Acid Solution ◽  
Ferric Chloride ◽  
Silver Oxide ◽  
Quinone Methide ◽  
Alkaline Solutions ◽  
Aromatic Rings ◽  
Methyl Group

While oxidation of alkaline solutions of 2-t-butyl-p-cresol by ferricyanide or silver oxide gives the ortho-para-coupled Pummerer's ketone (6), ferric chloride in slightly acid solution gives the ortho- coupled biphenyldiol (5). With ddq in methanol the cresol is further oxidized, again through ortho coupling, to the lactone (10), in which one of the aromatic rings has been cleaved, and to the dibenzo-furan (9). Minor products, both monomeric and dimeric, in which the methyl group has been oxidized via the quinone methide, were also identified.

scholarly journals (E)-2-Methyl-6-{[(5-methylpyridin-2-yl)imino]methyl}phenol

IUCrData ◽  
2017 ◽  
Vol 2 (1) ◽  
Author(s):  
Md. Azharul Arafath ◽  
Farook Adam ◽  
Mohd. R. Razali
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Dihedral Angle ◽  
Title Compound ◽  
Zigzag Chain ◽  
Aromatic Rings ◽  
Methyl Group ◽  
Compound C

In the title compound, C14H14N2O, the dihedral angle between the aromatic rings is 5.54 (9)°. The conformation is reinforced by an intramolecular O—H...N hydrogen bond, which closes anS(6) ring. The pyridine N atom and methyl group lie to opposite sides of the molecule. In the crystal, the molecules are linked into a zigzag chain propagating in [0-11] by weak C—H...O hydrogen bonds.

scholarly journals Methyl (E)-2-({2-[(E)-(hydroxyimino)methyl]phenoxy}methyl)-3-(4-methylphenyl)acrylate

2012 ◽  
Vol 68 (6) ◽  
pp. o1617-o1617
Author(s):  
G. Ganesh ◽  
J. Srinivasan ◽  
E. Govindan ◽  
M. Bakthadoss ◽  
A. SubbiahPandi
Keyword(s):  
Double Bond ◽  
Hydrogen Bonds ◽  
Title Compound ◽  
Crystal Packing ◽  
Aromatic Rings ◽  
Methyl Group ◽  
Compound C ◽  
Benzene Rings ◽  
The Mean ◽  
Centrosymmetric Dimers

In the title compound, C19H19NO4, the dihedral angle between the mean planes through the benzene rings is 82.18 (7)°. The C=N double bond is trans-configured. The molecules are linked into centrosymmetric dimers via pairs of O—H...N hydrogen bonds with the motif R 2 2(6). The crystal packing also features C—H...O interactions. The methyl group attached to one of the aromatic rings is disordered over two almost equally occupied positions [occpancy ratio = 0.51 (4):0.49 (4)].

scholarly journals Relative substituent orientation in the structure ofcis-3-chloro-1,3-dimethyl-N-(4-nitrophenyl)-2-oxocyclopentane-1-carboxamide

2014 ◽  
Vol 70 (9) ◽  
pp. 121-123
Author(s):  
Matthias Zeller ◽  
Jonas Warneke ◽  
Vladimir Azov
Keyword(s):  
Hydrogen Bond ◽  
Crystal Packing ◽  
Membered Ring ◽  
Amide Group ◽  
Aromatic Rings ◽  
Methyl Group ◽  
Compound C ◽  
The Mean ◽  
Graph Set ◽  
Intramolecular Hydrogen

The structure of the title compound, C14H15ClN2O4, prepared by reaction of a methacryloyl dimer with nitroaniline, was determined to establish the relative substituent orientation on the cyclopentanone ring. In agreement with an earlier proposed reaction mechanism, the amide group and the methyl group adjacent to the chloro substituent adopt equatorial positions and relativecisorientation, whereas the Cl substituent itself and the methyl group adjacent to the amide have axial orientations relative to the mean plane of the five-membered ring. The conformation of the molecule is stabilized by one classical N—H...O (2.18 Å) and one non-classical C—H...O (2.23 Å) hydrogen bond, each possessing anS(6) graph-set motif. The crystal packing is defined by several non-classical intramolecular hydrogen bonds, as well as by partial stacking of the aromatic rings.

scholarly journals The structure of surface films. Part XVIII. ─The effect of alkalinity in the underlying solution on films of fatty acids

1933 ◽  
Vol 142 (847) ◽  
pp. 401-415 ◽  
Keyword(s):  
Fatty Acids ◽  
Acid Solution ◽  
Aqueous Solutions ◽  
Complete Solution ◽  
Alkaline Solutions ◽  
Carboxyl Group ◽  
Surface Films ◽  
Electrolytic Dissociation ◽  
End Groups ◽  
Monomolecular Films

Historical . It has been known for some time that extensive changes occur in monomolecular films of fatty acids on aqueous solutions, as the alkalinity or acidity is varied. These changes are of at least tow kinds; changes in the packing of the molecules in the coherent types of film, and changes in the lateral adhesion between molecules have already been described. Thus Adam found changes in the packing of the molecules in the condensed films on changing from neutral to acid solution; and also a change from condensed to gaseous or vapour expanded films, on changing from natural to strongly alkaline solutions. The second of those effects was considered to be due to a decrease in the lateral adhesion between the molecules, caused by the development of similar electric charges on the end groups, through electrolytic dissociation of the carboxyl group on alkaline solutions. On alkaline solutions, it has previously been noted that the films contract spontaneously; Adam called this "solution," but did not examine it in detail; Lyons and Rideal believed it to be not a complete solution, but the formation of a bimolecular layer two molecules thick; Zocher and Stiebel, by ultramicroscopic examintion, concluded that this disappearance of the film was due to a partial collapse into thick, localized aggregates, not into a uniform bimolecular film.

scholarly journals N-[2-(Methylsulfanyl)phenyl]-2-sulfanylbenzamide

2012 ◽  
Vol 68 (8) ◽  
pp. o2400-o2400
Author(s):  
Chang-Chih Hsieh ◽  
Hon Man Lee ◽  
Yih-Chern Horng
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Intramolecular Hydrogen Bond ◽  
Title Compound ◽  
Aromatic Rings ◽  
Intermolecular Hydrogen Bonds ◽  
Methyl Group ◽  
Interplanar Angle ◽  
Compound C ◽  
Intramolecular Hydrogen

In the title compound, C14H13NOS2, the S atom with the methyl group is involved in an intramolecular hydrogen bond with the amido H atom. In the crystal, the sulfanyl H atoms form intermolecular hydrogen bonds with the O atoms, connecting the molecules into zigzag chains along thecaxis. The two aromatic rings exhibit a small interplanar angle of 16.03 (9)°.

scholarly journals The mechanism of tyrosinase-catalysed oxidative decarboxylation of α-(3,4-dihydroxyphenyl)-lactic acid

1991 ◽  
Vol 277 (3) ◽  
pp. 849-853 ◽  
Author(s):  
M Sugumaran ◽  
H Dali ◽  
V Semensi
Keyword(s):  
Lactic Acid ◽  
Enzyme Reaction ◽  
Quinone Methide ◽  
Oxidative Decarboxylation ◽  
Mushroom Tyrosinase ◽  
Mechanistic Studies ◽  
Methyl Group ◽  
Enzymic Oxidation ◽  
Steady State Kinetic ◽  
State Kinetic

Mushroom tyrosinase, which is known to catalyse the conversion of o-diphenols into o-benzoquinones, has been shown to catalyse the oxidative decarboxylation of 3,4-dihydroxymandelic acid [Sugumaran (1986) Biochemistry 25, 4489-4492]. To account for this unusual reaction, a quinone methide intermediate has been proposed. Since all attempts to trap this intermediate ended in vain, mechanistic studies were designed to support the formation of this transient product. Replacement of the alpha-proton in 3,4-dihydroxymandelic acid with a methyl group generates alpha-(3,4-dihydroxyphenyl)-lactic acid, the enzymic oxidation of which should produce 3,4-dihydroxyacetophenone as the end product if the oxidative decarboxylation proceeds through the quinone methide intermediate. Accordingly, chemically synthesized alpha-(3,4-dihydroxyphenyl)-lactic acid on enzymic oxidation produced 3,4-dihydroxyacetophenone as the major isolatable product. Non-steady-state kinetic analysis of the enzyme reaction attested to the transient formation of the conventional quinone product. Thus the enzymic oxidation of alpha-(3,4-dihydroxyphenyl)-lactic acid seems to generate the conventional quinone, which, owing to its instability, is rapidly decarboxylated to yield the transient quinone methide. The coupled dieneonephenol re-arrangement and ketol-enol tautomerism transforms the quinone methide into 3,4-dihydroxyacetophenone.

Structural characterization of a modification subunit of a putative type I restriction enzyme fromVibrio vulnificusYJ016

2012 ◽  
Vol 68 (11) ◽  
pp. 1570-1577 ◽  
Author(s):  
Suk-Youl Park ◽  
Hyun-Ju Lee ◽  
Jung-Mi Song ◽  
Jiali Sun ◽  
Hyo-Jeong Hwang ◽  
...  
Keyword(s):  
Vibrio Vulnificus ◽  
Restriction Enzymes ◽  
Type I ◽  
Aromatic Rings ◽  
Recognition Sequence ◽  
Thermus Aquaticus ◽  
Methyl Group ◽  
Cofactor Binding ◽  
Adenine Ring ◽  
Adenine Base

In multifunctional type I restriction enzymes, active methyltransferases (MTases) are constituted of methylation (HsdM) and specificity (HsdS) subunits. In this study, the crystal structure of a putative HsdM subunit fromVibrio vulnificusYJ016 (vvHsdM) was elucidated at a resolution of 1.80 Å. A cofactor-binding site forS-adenosyl-L-methionine (SAM, a methyl-group donor) is formed within the C-terminal domain of an α/β-fold, in which a number of residues are conserved, including the GxGG and (N/D)PP(F/Y) motifs, which are likely to interact with several functional moieties of the SAM methyl-group donor. Comparison with the N6 DNA MTase ofThermus aquaticusand other HsdM structures suggests that two aromatic rings (Phe199 and Phe312) in the motifs that are conserved among the HsdMs may sandwich both sides of the adenine ring of the recognition sequence so that a conserved Asn residue (Asn309) can interact with the N6 atom of the target adenine base (a methyl-group acceptor) and locate the target adenine base close to the transferred SAM methyl group.

Polysulfonylamine, CLXXIII [1]. Intermolekulare Wechselwirkungen in kristallinen Di(organosulfonyl)aminen. – Teil 2 [2]. Strukturvergleich f ¨ur Di(4-X-benzolsulfonyl)amine mit X = Fluor, Chlor, Brom oder Methyl / Polysulfonylamines, CLXXIII [1]. Intermolecular Interactions in Crystalline Di(organosulfonyl) amines. Part 2 [2]. Comparing the Stuctures of Di(4-X-benzenesulfonyl)amines, where X is Fluorine, Chlorine, Bromine, or Methyl

2005 ◽  
Vol 60 (6) ◽  
pp. 645-658 ◽  
Author(s):  
Dagmar Henschel ◽  
Thomas Hamann ◽  
Oliver Moers ◽  
Peter G. Jones ◽  
Armand Blaschette
Keyword(s):  
Hydrogen Bonds ◽  
The Other ◽  
Halogen Bonds ◽  
Aromatic Rings ◽  
Methyl Group ◽  
X Ray ◽  
Rotation Axes ◽  
Halogen Compounds ◽  
The Face ◽  
Exchange Rule

Low-temperature X-ray structures of the following di(4-X-benzenesulfonyl)amines, HN(SO2-C6H4-X)2, are compared in order to study the effects of the 4-substituents on the molecular packings: X = F (1, monoclinic, C2/c, Z′ = 1), X = Cl (2, monoclinic, C2/c, Z′ = 1/2, N-H bonds lying on twofold rotation axes), X = Me (3, orthorhombic, Pbca, Z′ = 1), X = Br (4A, monoclinic, P21/c, Z′ = 1), X = Br (4B, monoclinic, P21/c, Z′ = 2). As a common feature, the molecules of the halogen compounds, including two polymorphs of 4, are associated into catemers by strong hydrogen bonds of the type N-H···O in 1, 4A and 4B or N-H(···O)2 in 2. These molecular chains are assembled in the crystal structures via different packing modes, which underline the well-known correlation between the atomic number of halogen atoms and their propensity to form halogen bonds. Thus, the structure of 1 is devoid of short C-F···O/N contacts, but close F···F contacts are tolerated, whereas in 2 each catemer is connected to four parallel congeners by long and bifurcated C-Cl(···O)2 bonds, and both polymorphs of 4 display layers in which the molecules are connected by N-H···O bonds in one and by relatively short and approximately linear C-Br···O interactions in the other dimension. Despite the alleged steric equivalence of methyl and chloro substituents (“chloro-methyl exchange rule”), the packing architecture of the methyl compound 3 is not related to any of the preceding structures. In this case, the N-H···O bonding leads to centrosymmetric cyclodimers, which pack in such a way that each methyl group is located between two oxygen atoms and above the face of an aromatic ring in a topology consistent with C-H···O and C-H···C(π) bonding. All the structures are pervaded by weak Car-H···O hydrogen bonds; moreover, 1 displays a short C-H···F hydrogen bond and a C-F···C(π) interaction, and π-stacking of aromatic rings is observed in 1, 3 and 4B

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