Studies in Vilsmeier-Haack reaction: Reaction of 3-methyl-1-phenyl-4-arylidene-5-pyrazolone

1989 ◽  
Vol 54 (3) ◽  
pp. 706-712 ◽  
Author(s):  
Ibrahim M. A. Awad ◽  
Khairy M. Hassan
Keyword(s):  
Double Bond ◽  
Vilsmeier Reaction ◽  
Methyl Group ◽  
Vilsmeier Reagent ◽  
Carbon Double Bond ◽  
Pyrazolone Derivatives

The 3-methyl group in Ia, b has been found to undergo diformylation by Vilsmeier reagent to give the aminoacrolein derivatives (IIa, b). Treatment of IIa, b with different reagents affords the related 1-phenyl-4-arylidene-5-pyrazolone derivatives with different heterocyclic systems in the 3-position. The Vilsmeier reaction on pyrazolopyrazole (XIII) have been utilized to prove chemically that new heterocyclic systems are formed only at the 3-position and no addition on the carbon-carbon double bond in the conjugated system O=C-C=C-(B) takes place.

Some Analogs of 4-(2',4'-Difluorobiphenyl-4-yl)-2-methyl-4-oxobutanoic Acid: Synthesis and Antiinflammatory Activity

1995 ◽  
Vol 60 (6) ◽  
pp. 1026-1033 ◽  
Author(s):  
Miroslav Kuchař ◽  
Václav Vosátka ◽  
Marie Poppová ◽  
Eva Knězová ◽  
Vladimíra Panajotovová ◽  
...  
Keyword(s):  
Double Bond ◽  
Antiinflammatory Activity ◽  
Acid Synthesis ◽  
Reaction Conditions ◽  
Methyl Group ◽  
Oxobutanoic Acid

Analogs of 4-(2',4'-difluorobiphenyl-4-yl)-2-methyl-4-oxobutanoic acid (I, flobufen), containing a double bond (II, IV, V, VII, VIII) or a methyl group in position 3 (VI) were prepared. Their antiinflammatory activity was evaluated and compared with that of flobufen. None of the mentioned analogs reached the activity of the standard. Isomerization of the unsaturated derivatives is connected with a shift of the double bond, Z-E transformation or lactonization. Reaction conditions and spectra of the compounds prepared are described.

Reactions of 4-Pyrones with Azomethine Ylides as a Chemo­selective Method for the Construction of Multisubstituted Pyrano[2,3-c]pyrrolidines

Synthesis ◽  
2021 ◽  
Author(s):  
Dmitrii L. Obydennov ◽  
Vyacheslav D. Steben’kov ◽  
Konstantin L. Obydennov ◽  
Sergey A. Usachev ◽  
Vladimir S. Moshkin ◽  
...  
Keyword(s):  
Double Bond ◽  
Ring Opening ◽  
Azomethine Ylides ◽  
Azomethine Ylide ◽  
Dipolar Cycloaddition ◽  
Computational Studies ◽  
Carbon Double Bond ◽  
Reactivity Indexes ◽  
Reaction Proceeds

Abstract4-Pyrones bearing electron-donating and electron-withdrawing groups react with nonstabilized azomethine ylides to form pyrano[2,3-c]pyrrolidines in moderate to good yields. The reaction proceeds chemoselectively as a 1,3-dipolar cycloaddition of the azomethine ylide at the carbon–carbon double bond of the pyrone activated by the electron-withdrawing substituent. The reactivity of 4-pyrones toward azomethine ylides was rationalized by computational studies with the use of reactivity indexes. The pyrano[2,3-c]pyrrolidine moiety could be modified, for example by a ring-opening transformation under the action of hydrazine to provide pyrazolyl-substituted pyrrolidines.

Cycloaddition reactions across the carbon-carbon double bond of thiirene 1,1-dioxide

1984 ◽  
Vol 49 (7) ◽  
pp. 1300-1302 ◽  
Author(s):  
Mitsuo Komatsu ◽  
Yasuo Yoshida ◽  
Masatoshi Uesaka ◽  
Yoshiki Ohshiro ◽  
Toshio Agawa
Keyword(s):  
Double Bond ◽  
Cycloaddition Reactions ◽  
Carbon Double Bond

ChemInform Abstract: Electrooxidative Fission of Carbon-Carbon Double Bond in a K2OsO2(OH)4/ HIO4 Double Mediatory System.

ChemInform ◽  
2010 ◽  
Vol 27 (5) ◽  
pp. no-no
Author(s):  
H. TANAKA ◽  
R. KIKUCHI ◽  
M. BABA ◽  
S. TORII
Keyword(s):  
Double Bond ◽  
Carbon Double Bond

Unusual carboncarbon double bond cleavage in thiophenohomotropone system promoted by ethanedithiol

1982 ◽  
Vol 23 (28) ◽  
pp. 2859-2862 ◽  
Author(s):  
Bernard Hanquet ◽  
Mohammed El Borai ◽  
Roger Guilard ◽  
Yves Dusausoy
Keyword(s):  
Double Bond ◽  
Bond Cleavage ◽  
Carbon Double Bond

scholarly journals Stereoselective total syntheses of (±)-sinularene and (±)-5-epi-sinularene: a general intramolecular Diels–Alder approach to tricyclic sesquiterpenes

1985 ◽  
Vol 63 (4) ◽  
pp. 993-995 ◽  
Author(s):  
Kazimierz Antczak ◽  
John F. Kingston ◽  
Alex G. Fallis
Keyword(s):  
Double Bond ◽  
Methyl Ester ◽  
Total Synthesis ◽  
Ring System ◽  
Diels Alder ◽  
Exocyclic Double Bond ◽  
Total Syntheses ◽  
Methyl Group ◽  
Secondary Hydroxyl ◽  
Selective Hydrogenolysis

Stereoselective total synthesis of (±)-sinularene and (±)-5-epi-sinularene are described. The sequence employs a "blocked" cyclopentadiene in which the cyclopropane unit also serves as a latent methyl group. Thus intramolecular [4 + 2] cycloaddition of the substituted methyl spiro[2.4]hepta-4,6-dien-1-yl)-2-pentenoate 11 affords 5-benzyloxy-6-isopropyl-8-carbomethoxytetracyclo[5.4.01,7.02,4.02,9]undec-10-ene (12) which after selective hydrogenolysis generates the tricyclo[4.4.01,6.02,8]decane (sinularene) ring system. Removal of the secondary hydroxyl function (Ph3P/CCl4/CH3CN; H2/Pd/C), reduction of the methyl ester (LiAlH4), and introduction of the exocyclic double bond (acetate pyrolysis, 550 °C) completes the synthesis of (±)-sinularene in 14 steps from cyclopentadiene. A parallel series of reactions employing the isopropyl epimer of 12 affords (±)-5-epi-sinularene.

Raman Spectra of Polyisoprene Rubbers

1970 ◽  
Vol 43 (2) ◽  
pp. 313-321 ◽  
Author(s):  
S. W. Cornell ◽  
J. L. Koenig
Keyword(s):  
Double Bond ◽  
Raman Spectra ◽  
Structure Type ◽  
Peak Height ◽  
Mixed Structure ◽  
Carbon Double Bond

Abstract The Raman spectra of cis-1,4-, trans-1,4-, and 3,4-polyisoprene are presented, and the frequencies are classified by configurational structure type. The stretching frequency of the carbon-carbon double bond vibrations are used to describe structure content. Only Raman bands characteristic of total 1,4 content and total vinyl content can be observed. Tentative values of structure content determined by both peak height and peak area are presented for two mixed structure rubbers.

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