Of acetylenedicarboxylates

The rate of permanganate oxidation of acetylenedicarboxylic acid to CO2 at pH 0.25-5.0 requires the use of the stopped-flow method, which yielded simple... 

Esters of acetylenedicarboxylic acid 1023 are commercially readily available, are very reactive as dipolarophiles, and the carboxylic groups in products of their reactions can be easily converted to many other functionalities. Therefore, they are often the first choice as substrates for 1,3-dipolar cycloaddition to azides 1024 (Huisgen reaction). The reactions are carried out at room or elevated temperature, and the yields of 1,2,3-triazoles 1025 are usually high to quantitative (Equation 22). Several products obtained in this way are presented as structures 1026-1034. Some details about the reactions leading to these products are given in Table 10. 

Further studies on 1,3-dipolar addition reactions of diazophosphonates have been recorded,122 and work on 2-diazo-l-hydroxyalkylphosphonates also continues.123 The ester (155 R = H) reacts with esters of acetylenedicarboxylic acid without liberation of nitrogen to give stereoisomeric C-phosphorylated pyrazolines, which can be decomposed with both phosphorus-carbon and carbon-carbon bond fission, affording mixtures containing dimethyl acetylphosphonate, dimethyl hydrogen phosphonate, and tri(alkoxycarbonyl)pyrazolines. In the reaction between the same diazophosphonate and diazomethane, the latter conceivably acts as a basic catalyst for proton transfer in a series of steps which includes phosphonate-phosphate isomerization. The importance of a labile proton is demonstrated by the fact that the ester (155 R = Me) does not react in the manner described above. 

Dihydronaphthalen-1,4-iwmes from Isoindoles The naphthalen-l,4-imine derivatives 91-99 have been obtained by addition of acetylenedicarboxylic esters to the appropriate isoindoles. 3- ss Some such adducts react further with acetylenic esters (see Sections III, G and H), so that A -ethyl- and A-n-butylisoindole give 1 2 adducts with dimethyl aoetylenedicarboxylate instead. iV-Methylisoindole appears to be exceptional in giving an oily 2 1 adduct, for which structure (100) was suggested on analogy with the 2 1 adduct obtained from l,3-diphenylbenz[c]furan and acetylenedicarboxylic acid. ... 

The potassium acid salt of acetylenedicarboxylic acid is commercially obtainable from the National Aniline Division, Allied Chemical and Dye Corporation, New York, New York. Directions for the preparation of the free acid are given in earlier volumes.2-3... 

The same general method has been used by the submitters to prepare diethyl acetylenedicarboxylate. In this case absolute ethanol was used, and the ether extract was dried over anhydrous magnesium sulfate. The yield of diethyl ester from 100 g. of the acid potassium salt of acetylenedicarboxylic acid was 57-59 g. (51-53%) b.p. 96-98°/8 mm. n 1.4397. 

We were not able to obtain any cycloadduct from unactivated 2-azadienes 139 and esters of acetylenedicarboxylic acid. However, we found that 139 did cycloadd to typical electron-poor dienophiles such as esters of azodicarboxylic acid and tetracyanoethylene (Scheme 62). Thus, diethyl and diisopropyl azodicarboxylates underwent a concerted [4 + 2] cycloaddition with 139 to afford in a stereoselective manner triazines 278 in 85-90% yield (86CC1179). The minor reaction-rate variations observed with the solvent polarity excluded zwitterionic intermediates on the other hand, AS was calculated to be 48.1 cal K 1 mol-1 in CC14, a value which is in the range of a concerted [4 + 2] cycloaddition. Azadienes 139 again reacted at room temperature with the cyclic azo derivative 4-phenyl-1,2,4-triazoline-3,5-dione, leading stereoselectively to bicyclic derivatives 279... 

Dibromofumaric Acid (called Dibromofumar-saure in Ger), HOOC.CBr CBr.COOH mw 273.89, O 23.37% crysts (from w), mp 225°, bp - dec 230° readily sol in aic eth was obtd with other products by introducing bromine into an aq soln of acetylenedicarboxylic acid... 

The ultraviolet absorption spectra have been used to distinguish between the tautomers obtained by addition of dimethyl acetylene-dicarboxylate to pyridines. The 4/f-quinolizines show a band around 265 mfi. which is missing from the spectra of the 9a/f-quinolizines. Acheson and Taylor26 have successfully used this information to settle the constitution of the stable and labile adducts obtained by the action of acetylenedicarboxylic esters on pyridines. The ultraviolet spectra of the stable adducts formed by the above methods show... 

Enaminonitriles (154) easily react with esters of acetylenedicarboxylic acid or propiolic acid. The first step is an electrophilic attack of the reactant on the /3-position of the enamine, and this is followed by cyclization with... 

A small number of pyrroles undergo addition of acetylenedicarboxylic acid across the 2,5 positions, yielding adducts similar to those derived from cyclopentadiene. For instance, 1-benzylpyrrole (1) gives some 4,69,70 but it is not known if the product is formed via a species such as 2 or by a concerted addition. 

When the 5-amino- or 5-alkoxytriazoline contains an electron-withdrawing group in the 4-position with no free hydrogen, photolysis leads to unstable aminoaziridines, readily hydrolyzable in air, to give amides via azomethine ylides. In the presence of acetylenedicarboxylic ester, photolysis yields a pyrroline and a pyrrole (Scheme 158).250... 

When (36) reacted with polymeric monoester of acetylenedicarboxylic acid, a polymeric adduct was obtained. Saponification of this resin... 

Furthermore, when aliphatic dicarboxylic acid compounds (41-46) were used as hosts, a 1 1 complex (47) of oxalic acid (41) with 1, and a 1 2 complex (48) of acetylenedicarboxylic acid (42) with 1 were obtained (Table 5). Although the... 

An alternative application of cobalt Mb has been reported by Willner and coworkers (92). They immobilized the reconstituted cobalt Mb on the functionalized electrodes and generated cobalt(I)-Mb by the electrochemical reduction of cobalt(II)-Mb. The hydrogenation of acetylenedicarboxylic acid smoothly occurred on the functionalized electrode, and the electrocatalytic reaction in H20 and D20 reveals a clear isotope effect, kH/kD = 2.7, indicating that the hydride transfer from cobalt(III)-hydride in Mb is the key reactive process. 

Diels-Alder Reaction. By means of the Diels-Alder reaction a considerable number of hydrobiphenyls have been prepared,486 from which it should be possible to obtain unsymmetrical biaryls by dehydrogenation. Only a few of the adducts have been converted to the completely aromatic compounds. o-Terphenyl has been prepared from the adduct of maleic anhydride and 3,4-diphenylcyclopentadienone,436 and p-terphenyl has been obtained in practically quantitative yield from the adduct of the methyl ester of acetylenedicarboxylic acid and 1,4-diphenylbutadiene.43d... 

Having sufficient amounts of these novel dienes in hand opens the field for further study. Cycloaddition of acetylenedicarboxylic acid dimethyl ester (ADDE) to [3]dendralene 7 in toluene first afforded the l l-adduct 43, which by a second addition of ADDE provided the expected 2 l-adduct 44. After this had been aromatized by treatment with DDQ to the naphthalene derivative 45, a double benzannulation could be carried out as described in Scheme 8 [13]. 

Electrolysis of 1,2-dibromofumaric and 1,2-dibromomaleic acid or the diesters produces a 90-100% yield of acetylenedicarboxylic acid or diester 302). For vie-dihalides with no radical or anion stabilizing group in the a position an E2B like elimination mechanism is strongly indicated, /.e., 2e-transfer and double bond formation in a synchronous process (Eq. (148)). 

Finally, benzenepolycarboxylates were obtained by ruthenium-catalyzed cross-benzannulation of acetylenedicarboxylates with allylic compounds [52] (Eq. 39). A ruthenacyclopentene is postulated to occur via oxidative coupling of one molecule of alkyne with allylic alcohol. Subsequent insertion of another molecule of alkyne gives the corresponding polysubstituted benzene derivatives. 

Several protocols using multi-component reactions to prepare multisubstituted furans were reported. One procedure was that using acetylenedicarboxylate, isocyanides, triphenylphosphine and an aromatic carboxylic acid <07SL1610>. The others include the reaction of acetylenedicarboxylate, isocyanides and nicotinic acid <07S2637>, of dibenzoylacetylene, amines and diketene <07T8083>, of alkyl isocyanides, aromatic aldehydes and 3-cyanoacetyl indoles <07TL8987>, and of naphthoquinone, isocyanides and aldehydes <07T10269>. 

Formation of the dianilide of acetylenedicarboxylic acid from still another reaction of 16d, photolysis in ether containing aniline, may involve prior reaction 49) of aniline with 16 d. The bis-anhydride (16f) of squaric acid also afforded an acetylene dicarb-... 

A 2-azirine structure has been assigned to a by-product of Umi reactitai of acetic anhydride with the triazoledicarbo lic add obtained from the treatmenti of acetylenedicarboxylic acid with, hydi-azoic acid (Eq. 80). 

Such a process would always lead to the formation of the cis isomer, whereas it is known that treatment of acetylenedicarboxylic acid HOOGCsGGOOH with bromine gives dibromomaleic and dibromofumaric acids, the cis and trans forms respectively. The formation of the dibromofumaric acid is more favoured from energy considerations, since the molecule is stabilized by the formation of two hydrogen bonds with the bromine atoms (for hydrogen bond formation between the hydrogen of a carboxyl group and a bromine atom, see Chapter 12). 

The hydrogenation of acetylenedicarboxylic acid dimethyl ester (80) and diphenylacetylene (83) with [RhH2(0C(==0)0H)(PPr 3)2] gives dimethyl fumarate (82) and fraws-stilbene (84), respectively. This complex also catalyzes an isomerization of ds-stilbene to fra s-stilbene, though hydrogenation of alkyne is about eight times faster than the isomerization. ... 

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