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The article describes various reactions of orthoamides of alkynecarboxylic acids with diols, ethanedithiol, and CH-acidic nitro compounds. This results in the formation of vinylogous cyclic urea acetals and vinylogous thio-ureas. Further reactions and products are also described, such as condensation with 3,5-dimethyl-4-nitroisoxazole and the formation of 1,1-diamino-butadiene derivatives. The article is dedicated to Professor Dr. Gerhard Müller on his 70th birthday. [Extracted from the article]

The article describes various chemical reactions in which orthoamides are reacted with other compounds. New compounds are synthesized, such as vinylogous guanidinium bromides and vinylogous guanidinium tetraphenylborates. Ketenimines are also synthesized from orthoamides and phosphonic acid esters. The structure of the ketenimines is described by polar resonance structures. Information is also provided on the yields and properties of the resulting compounds. Further investigations into the reactions and the resulting compounds are encouraged. [Extracted from the article]

The article describes various chemical reactions in which orthoamides are reacted with different compounds. Detailed information is provided on the yields and properties of the resulting products, including melting points, infrared spectra, and nuclear magnetic resonance spectra. The reactions are carried out in various variations and the results are analyzed. Specific measurements such as IR and NMR spectroscopy are also performed to confirm the structure of the products. [Extracted from the article]

N,N,N′,N′-Tetramethylurea diethylacetal reacts with CH2-acidic compounds as benzylcyanide, cyanoacetic acid derivatives malonodinitrile and nitromethane to give ketene aminals or ketene-O,N-acetales. Low polar solvents favour mostly the formation of ketenaminals. The yields of ketenaminals and ketene-O,N-acetals can be improved in some cases by addition of trimethylsilyldimethylamine. The reactions of the urea acetal with diethylmalonate, ore acetyl acetone, stops at the stage of the N,N′,N″-permethylated guanidinium salts with carbanionic counterions. The formation of bis(dimethylamino)methylene-diethylmalonate from the urea acetal and diethylmalonate can be initiated by addition of trimethylsilyldimethylamine/trimethylsilylcyanide. N,N,N′,N′,N″,N″-Hexamethylguanidinium cyanide is formed in the analogous reactions of the urea acetal with N,N-dimethylcyanacetamide or diethylsuccinate. The N,N′,N″-Hexamethyl-guanidinium nitrite can be obtained from the urea acetal and nitropropane. [ABSTRACT FROM AUTHOR]

[super 1]H, [super 2]H, and [super 11]B NMR spectroscopy and DFT calculations was used to study the mechanism of the Fries rearrangement of aryl formates promoted by boron trichloride by monitoring both the substrate and the Lewis acid. After the formation of a 1:1 substrate-Lewis acid adduct, the rearrangement proceeds in two steps beginning with the cleavage of the ester bond and the release of formyl chloride in situ, which in turn acts as a formylating agent introducing an aldehydic functionality into the aromatic ring.

A report on a binary ionic liquid electrolyte composed of 1-propyl-3-methylimidazolium iodide and 1-ethyl-3-methylimidazolium tricyanomethanide that reaches an unprecedented 7.4% power conversion efficiency under full air mass (AM) 1.5 sunlight, is presented. Ultramicroelectrode voltammetric, nanosecond laser transient absorbance, and photovoltaic measurements show that a high iodide concentration is required for dye regeneration to compete efficiently with charge recombination.

The 1,1-bis(dimethylamino)-1,3-butadienes (keten aminals) 11a–l are prepared from orthoamide derivatives of alkyne carbonxylic acids 9b, d, e, i and CH2-acidic compounds 10a–c, f–h, k, o. The C-silylated orthoamide derivative 9c shows an ambivalent behaviour towards CH-acidic compounds. Reactions of 9c with strong CH2-acidic compounds like the nitro alkanes 10m, n and strongly enolized carbonyl compounds as methyl acetoacetate, cyanoacetamide, dibenzoylmethane, 1,3-dimethylbarbituric acid proceed under desilylation to give the ketene aminals 11u–z. In contrast to these reactions, the C-silylated ketene aminals 11o–t are obtained from 9c and weaker CH2-acidic compounds as dimethyl malonate, cyanoacetic acid derivatives and benzylcyanides. CH2/NH2-acidic compounds [cyanoacetamide (10d) and N-ethyl-cyanoacetamide (10f)] react with the orthoamide derivatives 9b, e–g at the acidic carbon-hydrogen bond to give the ketene aminals 11ac, ad, af, ag, ai, which cyclize to the pyridones 14a–d, d–g on heating. From the reaction of the orthoamide 9d with cyanoacetamide the pyridone 14c results directly. The persubstituted pyridone derivative 19 is formed by the reaction of cyanoacetamide with a mixture of the isomeric orthoamides 15 and 16. The 5,5-diamino-2,4-pentadienamide 11v attacks the orthoamide 9a at C3/C1. In the product 20 a cross conjugated multiple bond system is formed which contains an 1-aza-2,3-diamino function and a further ketene aminal function. [ABSTRACT FROM AUTHOR]

From acetone and the orthoamide of phenylpropiolic acid (21b) N,N-dimethyl-phenylpropiolic acid amide (24) is formed. In contrast, the reaction of chloroacetone (28) with 21b results in the vinylogous guanidinium chloride 29. Unexpectedly, the Birckenbach-analogoue ethyl methyl ketone (34) reacts with the orthoamide 21b to give the push-pull-substituted butadiene 36. In contrast to this observation, the reaction of the Birckenbach-analogous acetophenones 30 with the orthoamides 21a–c delivers the push-pull-substituted 1,3,5-hexatrienes 31a–j. [ABSTRACT FROM AUTHOR]

The orthoamides of alkyne carboxylic acids 4 react with acetophenones 5 – catalyzed by trialkylborates – to give ketene aminals 6, which can be transformed to 5-amino-5-hydrazino-penta-2,4-dien-1-ones 10 by treatment with 2,4-dinitro-phenylhydrazine. From acetophenone-phenylhydrazones 12 and orthoamides 4 1H-1,2-diazepines 18 (fett) are formed at room temperature, whereas 4-dimethylamino-pyridines 22 are obtained at elevated temperatures. The diazepine 18a is degraded to the pyridine-derivative 22b upon heating. The N-unsubstituted acetophenone-hydrazone 25 reacts with 4c to give amidrazone 26. The constitution of compounds 18a, 22a, 22b, 26 is established by crystal structure analyses. [ABSTRACT FROM AUTHOR]

The ketene aminals 9a-e can be prepared from the orthoamide of propiolic acid 6a and 2-methyl-5-phenacyl- 1,3,4-thiadiazoles 8a-e under mild conditions. The crystal structure analyses of 9b and 9d reveal that compounds 9 can be regarded as 1,4-dipoles (push-pullsubstituted butadienes). Surprisingly, the analogous reactions of the orthoamides 6b,c with the thiadiazoles 8a-c give rise to the formation of 1,2-dihydro-pyridin-2-thiones 13a-j. The constitution of the compounds 13 was confirmed by crystal structure analyses of the compounds 13c,f,g,i. [ABSTRACT FROM AUTHOR]

β-Ionone and camphor were ethynylated to give the alkynols 14, 16, 17 which can be transformed to the alkynolethers 5b, 5i, 5j, 5k, 5l, 5m by treatment with dimethylsulfate and chlorotrimethylsilane, respectively. From the alkynolethers 5h, 5i, 5j/5k, 5l/5m the orthoamide derivatives 4h, 4i, 4j/4k, 4l/4m can be prepared by treatment with N,N,N′,N′,N″,N″-hexamethylguanidinium chloride (8) in the presence of sodium hydride. The orthoamides 4h, 4i react with the sulfonamide 30 under condensation yielding the N-sulfonylated acrylamidines 31, 32. From the orthoamide 4h and p-nitroaniline the propiolamidine 29 could be obtained. The orthoamides 4j/4k and 4l/4m, react with benzamidine to give the pyrimidines 33, 34, respectively. In the reaction of malonodinitrile (9a) with the orthoamides 4i and 4j/4k, mixtures of 1,1-diamino-1,3-butadienes 36, 38 and 1,3-diamino-1,3-butadienes 37 and 39 are produced, respectively. From CH2-acidic compounds as ethylcyanacetate (9b), diethyl-malonate (9c) and nitromethane (9d) and the orthoamide 4i the 1,1-diamino-1,3-butadienes 36b–d were produced. The pyridone derivative 40 can be prepared from cyanoacetamide (9e) and the orthoamide 4i. The condensation of the orthoamides 4j/4k with cyanoacetamide (9e) affords a mixture of the pyrimidone 41 and the nicotinonitrile 42. [ABSTRACT FROM AUTHOR]

The preparation of the vinylogue guanidinium salt 10c is described. The reaction of the vinylogue orthocarbonic acid amide derivative 12 with CH2-acidic compounds 14a–s affords the ketene aminals 15a–s. At room temperature the succinimide 19a is deprotonated by 12 to give the vinylogue salt 10e. The bis-ketene aminal 20 is formed in the reaction of 19a with 12 at elevated temperatures. Succinic acid esters 21 do not react cleanly with the orthoamide 12, but mixtures of ketene aminals 23 and bis-ketene aminals 22 are formed. From succinodinitrile (24) and 12 the bis-ketene aminal 25 could be obtained, which is also accessible by the action of the salt 10c with 24 in the presence of sodium hydride. [ABSTRACT FROM AUTHOR]

β-Ionone and camphor were ethynylated to give the alkynols 14, 16, 17 which can be transformed to the alkynolethers 5b, 5i, 5j, 5k, 5l, 5m by treatment with dimethylsulfate and chlorotrimethylsilane, respectively. From the alkynolethers 5h, 5i, 5j/5k, 5l/5m the orthoamide derivatives 4h, 4i, 4j/4k, 4l/4m can be prepared by treatment with N,N,N′,N′,N″,N″-hexamethylguanidinium chloride (8) in the presence of sodium hydride. The orthoamides 4h, 4i react with the sulfonamide 30 under condensation yielding the N-sulfonylated acrylamidines 31, 32. From the orthoamide 4h and p-nitroaniline the propiolamidine 29 could be obtained. The orthoamides 4j/4k and 4l/4m, react with benzamidine to give the pyrimidines 33, 34, respectively. In the reaction of malonodinitrile (9a) with the orthoamides 4i and 4j/4k, mixtures of 1,1-diamino-1,3-butadienes 36, 38 and 1,3-diamino-1,3-butadienes 37 and 39 are produced, respectively. From CH2-acidic compounds as ethylcyanacetate (9b), diethyl-malonate (9c) and nitromethane (9d) and the orthoamide 4i the 1,1-diamino-1,3-butadienes 36b–d were produced. The pyridone derivative 40 can be prepared from cyanoacetamide (9e) and the orthoamide 4i. The condensation of the orthoamides 4j/4k with cyanoacetamide (9e) affords a mixture of the pyrimidone 41 and the nicotinonitrile 42. [ABSTRACT FROM AUTHOR]