Reactions of αω-dodecatrienediylnickel with dimethyl acetylenedicarboxylate and methyl propiolate

1978 ◽  
pp. 480-483 ◽  
Author(s):  
Raymond Baker ◽  
Peter C. Bevan ◽  
Richard C. Cookson ◽  
Alison H. Copeland ◽  
Andrew D. Gribble
Keyword(s):  
Dimethyl Acetylenedicarboxylate ◽  
Methyl Propiolate

ChemInform Abstract: REACTIONS OF αΩ-DODECATRIENEDIYLNICKEL WITH DIMETHYL ACETYLENEDICARBOXYLATE AND METHYL PROPIOLATE

1978 ◽  
Vol 9 (49) ◽  
Author(s):  
R. BAKER ◽  
P. C. BEVAN ◽  
R. C. COOKSON ◽  
A. H. COPELAND ◽  
A. D. GRIBBLE
Keyword(s):  
Dimethyl Acetylenedicarboxylate ◽  
Methyl Propiolate

scholarly journals Huisgen [3 + 2] Dipolar Cycloadditions of Phthalazinium Ylides to Activated Symmetric and Non-Symmetric Alkynes

Molecules ◽  
2020 ◽  
Vol 25 (19) ◽  
pp. 4416
Author(s):  
Vasilichia Antoci ◽  
Costel Moldoveanu ◽  
Ramona Danac ◽  
Violeta Mangalagiu ◽  
Gheorghita Zbancioc
Keyword(s):  
Reaction Time ◽  
Comparative Study ◽  
Cycloaddition Reaction ◽  
Environmentally Friendly ◽  
Dipolar Cycloaddition ◽  
Cycloaddition Reactions ◽  
Dimethyl Acetylenedicarboxylate ◽  
Thermal Heating ◽  
Dipolar Cycloadditions ◽  
Methyl Propiolate

We present herein a straightforward and efficient pathway for the synthesis of pyrrolophthalazine cycloadducts via Huisgen [3 + 2] dipolar cycloaddition reactions of phthalazinium ylides to methyl propiolate or dimethyl acetylenedicarboxylate (DMAD). A thoroughly comparative study concerning the efficiency of synthesis, conventional thermal heating (TH) versus microwave (MW) and ultrasound (US) irradiation, has been performed. The cycloaddition reactions of phthalazinium ylides to methyl propiolate occur regiospecific, with a single regioisomer being obtained. Under conventional TH, the cycloaddition reaction of phthalazinium ylides with DMAD occurs to a mixture of inseparable partial and fully aromatized pyrrolophthalazine cycloadducts, while MW or US irradiation are leading only to fully aromatized compounds, with the reactions becoming selective. A feasible mechanism for formation of fully aromatized compounds is presented. Besides selectivity, it has to be noticed that the reaction setup under MW or US irradiation offer a number of other certain advantages: higher yields, decreasing of the amount of used solvent comparative with TH, decreasing of the reaction time from hours to minutes and decreasing of the consumed energy; consequently, these reactions could be considered environmentally friendly.

Chemistry of cyclic aminooxycarbenes

1997 ◽  
Vol 75 (9) ◽  
pp. 1281-1294 ◽  
Author(s):  
Philippe Couture ◽  
John Warkentin
Keyword(s):  
Activation Energy ◽  
Phenyl Isocyanate ◽  
Dimethyl Acetylenedicarboxylate ◽  
Methyl Propiolate ◽  
Amide Rotation

A series of oxazolidin-2-ylidenes and one tetrahydro-1,3-oxazin-2-ylidene, generated by thermolysis of Δ3-1,3,4-oxadiazolines in benzene at 90 °C, were intercepted by insertion into the OH bond of phenols. In two cases the initial products rearranged to N-(2-aryloxyethyl)-N-methylformamides. The activation energy for rotation about the amide CN bond of those ultimate products was measured as 20.4 kcal/mol. The aminooxycarbenes reacted with two equivalents of methyl or phenyl isocyanate to give spiro-fused hydantoins. Major products from the reactions of the N-carbonyl carbenes with dimethyl acetylenedicarboxylate or with methyl propiolate were 2-oxazolines resulting from apparent acyl transfers from N to C in the proposed dipolar intermediates; minor products of 1:2 (carbene:trap) stoichiometry were also observed. Keywords: nucleophilic carbene, aminooxycarbene, oxadiazoline, amide rotation, oxazolidine.

The reaction of steroid 2,4-dienes with acetylenes

1976 ◽  
Vol 54 (22) ◽  
pp. 3508-3516 ◽  
Author(s):  
Peter Yates ◽  
Françoise M. Walliser
Keyword(s):  
Diels Alder ◽  
The Other ◽  
Dimethyl Acetylenedicarboxylate ◽  
Methyl Propiolate ◽  
Lower Temperature

Reaction of 2,4-cholestadiene, 2,4-androstadien-17-one, or 3-trimethylsiloxy-2,4-cholestadiene with dimethyl acetylenedicarboxylate or methyl propiolate in boiling xylene results in the cleavage of rings A and B and the formation of 4-(2-arylethyl)-5-isopropenyl-7a-methyltetrahydroindane derivatives. They are considered to be formed via Diels–Alder addition of the acetylene to the steroid diene followed by a retro-Diels–Alder cleavage of the resulting bicyclo[2.2.2]octadiene system. Attempts to isolate the Diels–Alder adducts by carrying out the additions at lower temperature were unsuccessful, since no reaction occurred. However, when 2,4-androstadien-17-one was treated with dicyanoacetylene in boiling benzene, it was possible to isolate a mixture of two stereoisomeric Diels–Alder adducts containing the bicyclo[2.2.2]octadiene system in ring A; this was converted in boiling xylene to a retro-Diels–Alder product analogous to the products obtained with the other acetylenic dienophiles.

Annelated furans. XIV. Synthetic analogues of usnic acid

1973 ◽  
Vol 26 (5) ◽  
pp. 1093 ◽  
Author(s):  
JA Elix ◽  
D Tronson
Keyword(s):  
Chromium Trioxide ◽  
Usnic Acid ◽  
Triethyl Phosphite ◽  
Selenium Dioxide ◽  
Dimethyl Acetylenedicarboxylate ◽  
Synthetic Analogues ◽  
Methyl Propiolate ◽  
Oxidative Rearrangement

The cycloaddition of dimethyl acetylenedicarboxylate and methyl propiolate to 2-isopropenyl-3-methylbenzofurans afforded a convenient and versatile route to 9b-methyl-3,9b-dihydrodibenzofurans and 9b- methyl-1,9b-dihydrodibenzofurans, which are synthetic analogues of usnic acid. Selenium dioxide oxidation of dimethyl 4,9b-dimethyl-3,9b- dihydrobenzofuran-1,2-dicarboxylate (5; R1 = R2 = H) has been shown to proceed by oxidative rearrangement and demethylation to give a mixture of dimethyl 1-hydroxy-4,9b-dimethyl-1,9b-dihydrodibenzofuran-1,2- dicarboxylate (9), dimethyl 4-methyldibenzofuran-1,2-dicarboxylate (10), and dimethyl 6-(o-hydroxy-phenyl)-4,6-dimethyl-5-oxocyclohexa- 1,3-diene-1,2-dicarboxylate(8). Evidence concerning the mechanism of this reaction is discussed. Autoxidation of methyl 4,9b-dimethyl-3,9b- dihydrodibenzofuran-1-carboxylate (12) proceeded smoothly to give methyl 4a-hydroperoxy-4,9b-dimethyl-4a,9b-dihydrodibenzofuran-1- carboxylate (17) and methyl 4-methyldibenzofuran-1-carboxylate (16). Reduction of the hydroperoxide (17) with triethyl phosphite gave methyl 6-(o-hydroxyphenyl)-4,6-dimethyl-5-oxocyclohexa-1,3-diene-1-carboxylate (19), which could also be obtained by oxidation of the ester (12) with selenium dioxide. Methyl 4,9b-dimethyl-3-oxo-3,9b-dihydrodibenzofuran- 1-carboxylate (22) and the corresponding 4,4a-epoxide (23) were obtained together with the dibenzofuran (16) and the phenol (19), by oxidation of (12) with chromium trioxide.

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