Isomerizations akin to the Dimroth rearrangement. IV. Formation of simple s-Triazolo[1,5-c]pyrimidines via their [4,3-c] isomers

1978 ◽  
Vol 31 (11) ◽  
pp. 2505 ◽  
Author(s):  
DJ Brown ◽  
T Nagamatsu
Keyword(s):  
Acetic Acid ◽  
Glacial Acetic Acid ◽  
Methyl Groups ◽  
Dimroth Rearrangement ◽  
Methyl Group ◽  
Alkyl Groups ◽  
Ring Fission

Pyrimidin-4-ylhydrazines and simple orthoesters are used in combination (1) to give N-ethoxyalkyl-idene-N'-pyrimidinylhydrazines (2) and thence s-triazolo[4,3-c]pyrimidine (3a) and its 3-, 5-, 7- or 8-alkylated derivatives (3b-s). In glacial acetic acid, these undergo rearrangement into the corresponding s-triazolo[1,5-c]pyrimidines (5) via the acylaminoalkenyltriazoles (4); in aqueous buffers, these reactions stop at the triazoles (4) except in the presence of a 7-methyl group which stimulates completion of the sequence. The ring-fission step, (3) → (4), is retarded markedly by 5- and/or 8-methyl groups but accelerated slightly by 3- and/or 7-alkyl groups; the slower ring-fission of triazolo[1,5-c]-pyrimidines (5) to the same triazoles (4) is retarded by 2-, 5- or 8-alkylation and precluded totally by a 7-methyl group. The recorded u.v. and N.M.R. spectra afford a ready means of distinguishing between the systems (3)-(5).

THE ANAEROBIC DISSIMILATION OF D-GLUCOSE-1-C14, D-ARABINOSE-1-C14, AND L-ARABINOSE-1-C14 BY AEROBACTER AEROGENES

1954 ◽  
Vol 32 (1) ◽  
pp. 147-153 ◽  
Author(s):  
A. C. Neish ◽  
F. J. Simpson
Keyword(s):  
Carbon Dioxide ◽  
Acetic Acid ◽  
Lactic Acid ◽  
Carboxyl Groups ◽  
Methyl Groups ◽  
Carboxyl Group ◽  
Complete Conversion ◽  
Aerobacter Aerogenes ◽  
Methyl Group ◽  
Ethanol Acetic Acid

D-Glucose-1-C14, D-arabinose-1-C14, and L-arabinose-1-C14 were dissimilated anaerobically by Aerobacter aerogenes. The major products (2,3-butanediol, ethanol, acetic acid, lactic acid, formic acid, and carbon dioxide) were isolated and the location of C14 determined. The products from glucose were all labeled, mainly in the methyl groups, in agreement with the hypothesis that they were derived from methyl-labeled pyruvate formed by the reactions of the classical Embden–Meyerhof scheme for glycolysis. The products from both pentoses appeared to have been formed from pyruvate labeled in both the methyl and carboxyl groups with twice as much C14 in the methyl group as in the carboxyl group. This result may be explained quantitatively by a hypothesis assuming complete conversion of pentose to triose via a heptulose.

Condensation of Schiff bases with 2-oxazolin-5-ones: simultaneous introduction of arylidene and amino moieties

1982 ◽  
Vol 60 (3) ◽  
pp. 317-322 ◽  
Author(s):  
Arya K. Mukerjee ◽  
Pradeep Kumar
Keyword(s):  
Acetic Acid ◽  
Schiff Bases ◽  
Sodium Acetate ◽  
Glacial Acetic Acid ◽  
Methyl Group

Schiff bases condense with 2-oxazolin-5-ones having a C-4 methylene and/or C-2 methyl group, and the reaction in glacial acetic acid, containing freshly fused sodium acetate, produces 4-arylidene- and/or 2-styryl-2-imidazoline-5-ones as a result of simultaneous introduction of arylidene and amino moieties.

THE ANAEROBIC DISSIMILATION OF D-GLUCOSE-1-C14, D-ARABINOSE-1-C14, AND L-ARABINOSE-1-C14 BY AEROBACTER AEROGENES

1954 ◽  
Vol 32 (3) ◽  
pp. 147-153 ◽  
Author(s):  
A. C. Neish ◽  
F. J. Simpson
Keyword(s):  
Carbon Dioxide ◽  
Acetic Acid ◽  
Lactic Acid ◽  
Carboxyl Groups ◽  
Methyl Groups ◽  
Carboxyl Group ◽  
Complete Conversion ◽  
Aerobacter Aerogenes ◽  
Methyl Group ◽  
Ethanol Acetic Acid

D-Glucose-1-C14, D-arabinose-1-C14, and L-arabinose-1-C14 were dissimilated anaerobically by Aerobacter aerogenes. The major products (2,3-butanediol, ethanol, acetic acid, lactic acid, formic acid, and carbon dioxide) were isolated and the location of C14 determined. The products from glucose were all labeled, mainly in the methyl groups, in agreement with the hypothesis that they were derived from methyl-labeled pyruvate formed by the reactions of the classical Embden–Meyerhof scheme for glycolysis. The products from both pentoses appeared to have been formed from pyruvate labeled in both the methyl and carboxyl groups with twice as much C14 in the methyl group as in the carboxyl group. This result may be explained quantitatively by a hypothesis assuming complete conversion of pentose to triose via a heptulose.

Orientation in the Crossed Aldol Condensation of Chloral with Unsymmetrical Aliphatic Ketones

1971 ◽  
Vol 49 (10) ◽  
pp. 1588-1597 ◽  
Author(s):  
Eberhard Kiehlmann ◽  
Pui-Wah Loo
Keyword(s):  
Acetic Acid ◽  
Sodium Acetate ◽  
Marked Effect ◽  
Aldol Condensation ◽  
Condensation Product ◽  
Reaction Conditions ◽  
Methyl Group ◽  
Aliphatic Ketones ◽  
Alkyl Groups ◽  
Methylene Group

The reactivity of a series of 14 aliphatic ketones in the crossed aldol condensation with chloral has been studied in glacial acetic acid and in dimethoxyethane. The reaction is irreversible and not accompanied by dehydration of the resulting 1,1,1-trichloro-3-hydroxy-4-alkanones. Except for butanone, condensation occurs preferentially at the least-hindered position of an unsymmetrical ketone. The α-methyl/α-methylene condensation product ratio obtained from ketones of the general formula RCH2COCH3 is higher in acetic acid than in dimethoxyethane as solvent when sodium acetate is used as catalyst. The steric size and chain length of the alkyl groups of methyl alkyl ketones have a marked effect on the reactivity of the α-methyl group toward chloral. Condensation at the α-methylene group results in the formation of diastereomeric ketols which epimerize under the preparative reaction conditions.

scholarly journals The first spontaneous resolution of a sulfoxide: Dianin's compound analogue, (R)-4-(4-hydroxyphenyl)-2,2,4-trimethylthiachroman-1-oxide

2018 ◽  
Vol 74 (11) ◽  
pp. 1633-1636
Author(s):  
James H. Gall ◽  
J. Derek White ◽  
David D. MacNicol ◽  
Christopher S. Frampton
Keyword(s):  
Crystal Structure ◽  
Acetic Acid ◽  
Glacial Acetic Acid ◽  
Crystal Structure Analysis ◽  
Spontaneous Resolution ◽  
Orthorhombic Space Group ◽  
Aromatic Substituent ◽  
Methyl Group ◽  
Dianin's Compound ◽  
Initial Crystal

The title sulfoxide, C18H20O2S, was prepared by controlled oxidation of thia-Dianin's compound using hydrogen peroxide in glacial acetic acid. On recrystallization from glacial acetic acid, it was found to form unsolvated, spontaneously resolved crystals, the initial crystal structure analysis revealing the presence of both sulfoxide epimers in the crystal. On multiple recrystallization a single epimer was observed, with crystallization occurring in the unchanged orthorhombic space group P212121, with Z′ = 1. The molecule possesses a distal conformation, referring to the juxtaposition of the p-hydoxyphenyl substituent with respect to its syn-related methyl group, with the sulfoxide oxygen atom anti to the aromatic substituent. The molecular packing features O—H...O hydrogen bond chains running parallel to the b axis of the unit cell.

Synthesis and Caracterization of some New 1H-3-aryl-7-etoxycarbonyl-6-methyl-pyrazolo[5,1-c][1,2,4]triazoles

2008 ◽  
Vol 59 (1) ◽  
pp. 41-44
Author(s):  
Maria-Daniela Sofei ◽  
Maria Ilici ◽  
Valentin Badea ◽  
Carol Csunderlik ◽  
Vasile-Nicolae Bercean
Keyword(s):  
Mass Spectrometry ◽  
Acetic Acid ◽  
Nmr Spectroscopy ◽  
Sodium Acetate ◽  
Glacial Acetic Acid ◽  
Ir And Nmr Spectroscopy

The synthesis of 1H-3-aryl-7-ethoxycarbonyl-6-methyl-pyrazolo[5,1-c][1,2,4]triazoles (2) was carried out by cyclization of 1H-5-arylidenehydrazino-4-ethoxycarbonyl-3-methyl-pyrazoles (1) in the presence of bromine using glacial acetic acid as solvent and sodium acetate as base. The new nine obtained compounds were characterized by IR and NMR spectroscopy and mass spectrometry.

Coordination state of cobalt(II) ions in solution and on a sulphonated organic polymer

1979 ◽  
Vol 44 (8) ◽  
pp. 2330-2337 ◽  
Author(s):  
Jindřiška Maternová ◽  
Anastas A. Andreev ◽  
Dimitrii M. Shopov ◽  
Karel Setínek
Keyword(s):  
Acetic Acid ◽  
Coordination Sphere ◽  
Glacial Acetic Acid ◽  
Organic Polymer ◽  
Octahedral Complex ◽  
Coordination State ◽  
Tetrahedral Symmetry ◽  
Liquid Acid ◽  
Homogeneous Phase ◽  
Bromide Ion

It was found spectroscopically that cobalt(II) acetate dissolved in glacial acetic acid forms the octahedral complex [Co(OAc)2(HOAc)4] which in the presence of bromide ions gives the octahedral [Co(OAc)Br(HOAc)4] and tetrahedral bromo(acetate)cobalt(II) complexes with the higher number of Br- ions. When attached to an organic polymer cobalt(II) ions are bonded in the form of octahedral [Co(H2O)6]2+ cations which form with acetic acid similar complexes as in homogeneous phase and are able to coordinate one bromide ion. Drying the copolymer possessing octahedral hexaaquocobalt(II) cations leads to tetrahedral aquocomplexes which are solvated by gaseous acetic acid and converted into the acetate complexes with the liquid acid. The latter contain the acid in the inner coordination sphere and have tetrahedral symmetry.

Kinetics of the Imidazolium Ring-Opening of mRNA 5'-cap Analogs in Aqueous Alkali

2006 ◽  
Vol 71 (4) ◽  
pp. 567-578 ◽  
Author(s):  
Alicja Stachelska ◽  
Zbigniew J. Wieczorek ◽  
Janusz Stępiński ◽  
Marzena Jankowska-Anyszka ◽  
Harri Lönnberg ◽  
...  
Keyword(s):  
Electrostatic Interaction ◽  
Ring Opening ◽  
Nucleophilic Attack ◽  
Amino Groups ◽  
Hydroxide Ion ◽  
Methyl Group ◽  
Structural Modifications ◽  
Alkyl Groups ◽  
Imidazolium Ring ◽  
Kinetics Of

Second-order rate constants for the hydroxide-ion-catalyzed imidazolium ring-opening of several mono- and dinucleosidic analogs of mRNA 5'-cap have been determined. Intramolecular stacking of the two nucleobases in the dinucleosidic analogs, m7GpppN (m7G = 7-methylguanosine, N = 5'-linked nucleoside), and electrostatic interaction between the N-alkylated imidazolium ring and phosphate moiety have been shown to shield the m7G moiety against the nucleophilic attack of hydroxide ion. In addition, the effect of methylation of the nucleobase amino groups and replacement of the 7-methyl group with other alkyl groups have been studied. The influence of all the structural modifications studied turned out to be modest, the cleavage rates of the most and least reactive analogs (with the exception of non-phosphorylated nucleosides) differing only by a factor of 5.

Sign in / Sign up

Export Citation Format

Share Document