Erwin Haug

Beiträge zur Synthese von Orthocarbonsäureamiden

The formamidinium salts 11a, c as well as the nitrile 12 react with sodiumhydride/dimethylamine in the presence of trimethylborate to give the ortho formic acid amide 3a. The orthoamides 6a and 16 can be prepared from the iminium salts 15 and 14, resp. by the same procedure. Treatment of the azavinylogous formamidinium salt 15 with sodiumhydride and piperidine or morpholine in the presence of trime-thylborate affords the orthoamides 6c and 6d, resp. By transamination of the azavinylogous aminalester 5a are accessible the orthoamides 6b—d. The vinylogous orthocarbonic acid derivative 17 can be obtained from the salt 14 and sodium alcoholates. The action of sodiumhydride, dimethylamine and trimethylborate on the iminium salt 18 produces a mixture of the orthocarbonic acid derivatives 7a, 8a, 9a. When the guanidinium salt 20 is treated with the same reagents the ortho-amides 3a and 10a are obtained. The reduction of the salt 20 with sodiumhydride in the presence of several activating reagents (e.g. tetrabutyl orthotitanate, aluminiumisopropylate, trimethylborate) affords the orthoamide 3a. The reduction of the iminium salts 18 and 24 does not proceed clean, giving mixtures of various orthoformic acid derivatives. The form-amidine 25 can be prepared by reduction of the salt 15 with sodiumhydride/trimethylborate with good yields. By the action of the corresponding carbanions on the guanidinium salt 20 can be obtained the carboxylic acid orthoamides 26—33. By the same procedure the orthoamides of alkyne carboxylic acids 36a—h, j—n are accessible.

Eine neue, breit anwendbare Synthese für aromatische Aldehyde

Diformamide (1) reacts with activated aromatic compounds like toluene, anisole, m-xylene, 1,2-dimethoxybenzene in the presence of AlCl3 to give N-(diarylmethyl)-formamides 2a—d, the corresponding aromatic aldehydes 3—6 are formed as by-products in low yields. From N,N-dimethylaniline and 1/AlCl3 the triphenylmethane derivative 7 can be obtained. The reaction of anisole with N-methyl-diformamide (9) affords the formamide 10. The mixture of formamide, P4O10 and AlCl3 reveals to be a reagent which is capable to formylate toluene and anisole, resp. Triformamide (14)/AlCl3 is an effective formylating system which allows the preparation of aromatic aldehydes (e.g.3,4,17—32) from the corresponding aromatic hydrocarbons. Aluminiumchloride can be replaced by borontrichloride. The yields of the formylation reactions depend strongly from the reaction conditions (molar ratio: aromatic hydrocarbon/AlCl3/14; solvent, reaction temperature). The scope of the reaction covers nearly complete those of the Gattermann-Koch-, Gattermann- and Vilsmeier—Haack-reaction.

Orthoamide. LIV [1] Beiträge zur Chemie azavinyloger Orthoamid-Derivate der Ameisensäure

Orthoamides. LIV. Contributions to the Chemistry of Azavinylogous Orthoformic Acid Amide Derivatives The azavinylogous aminalester 3 reacts with primary amines to give amidines 5 and 6. In the reaction of 3 with aniline the azavinylogous amidine 7 is produced additionally to the amidine 5c. Ethylendiamine is formylated at both aminogroups, the bis-amidine 8 thus formed is transformed to the salts 9a,b. Benzoxazole and benzimidazole can be prepared from 3 and o-aminophenol and o-phenylenediamine, resp. carboxylic acid amides, urea, thiourea, aromatic acid hydrazides 17 and the sulfonylhydrazide 19 are formylated by 3 at nitrogen to give N-acylated formamidines 14, 16, 18, 20. From 3 and aliphatic acid hydrazides 17 and alkylhydrazines, resp., can be obtained 1,2,4-triazole 21 and 1-alkyl-1,2,4-triazoles 22a,b, resp. N,N-dimethylcyanacetamide (32) reacts with 3 and the orthoamide 4a, resp., to give a mixture of the formylated compound 34 and the amidine 33. The reaction conditions are of low influence on the ratio in which 33 and 34 are formed. The orthoamide 4b and 32 react to afford a mixture of the amidine 35 and the enamine 36. Hydrogensulfide acts on 3 giving N,N-dimethylthioformamide (37). From 3 and 1-alkynes 41 can be prepared the amidines 42. Hydrolysis of 42b affords phenylpropiolaldehyde (43). The alkylation of the aminalester 3 gives rise to the formation of vinylogous amidiniumsalts 1c and 1d, resp., additionally is formed the amide acetal 2a. The salt 1dcan also be prepared from 3 and borontrifluoride-ether. Iodide reacts with N,N-dimethylformamide acetals 12a,b in an unclear, complicated manner giving orthoesters 53, N,N-dimethylformamide, alkyliodides, alcohols, ammoniumiodides 46 and carbondioxide. The action of halogens on 3 affords the salts 1a,b,c,e,f depending on the chosen stoichiometric ratio. Aromatic aldehydes are suited for trapping azavinylogous carbenes formed on thermolysis of 3 — 1,3-oxazoles 69 are the reaction products. From 3 and propionaldehyde the amidine 65 can be obtained with low yield. Carbondisulfide transforms 3 to the azavinylogous salt 66. The preparation of the azavinylogous orthoamide 4ais described. The thermolysis of 3 and 4a, resp., gives rise to the formation of the triaminopyrimidine 67. Treatment of 1a with lithiumdiisopropylamide affords the triaminopyrazine 68, which can also be obtained by thermolysis of 3 in the presence of sodium hydride. Azavinylogous carbenes are thought to be the intermediates.

Orthoamide, LVII [1]. Lassen sich aromatische Aldehyde nach Fries aus Arylformiaten hersteilen? / Orthoamides, LVII [1]. Can Aromatic Aldehydes be Prepared from Aryl Formates via the Fries Rearrangement?

The aromatic hydroxyaldehydes 3a-3g, 5a-5f, 8 , 10 can be prepared by the action of BCl3, BBr3 or trifluoromethanesulfonic acid, on the aryl formates 1a-1f, 4a-e, 7, 9 via Fries rearrangement. BBr3 is more effective than BCl3. The activating ability of BBr3 can be improved by addition of FeCl3. Rearrangements which are induced by trifluoromethanesulfonic acid can give rise to the formations of regioisomers, which might be different from the products formed when the reaction is performed with Lewis acids. The yields of the aldehydes are lowered by subsequent condensation reactions. This view was confirmed by the isolation of a condensation product, which was characterized as a dibenzo[a,j]xanthene derivative 6 by crystal structure analysis. For the Fries rearrangement of formyl groups a new mechanism is proposed. 2-Hydroxy-1-naphthaldehyde 5c can be obtained in good yield from formic acid, BBr3, and 2 -naphthol.

Orthoamide und Iminiumsalze, LXXXI [1]. Orthoamid-Derivate der 1,3-Dimethylparabansäure / Orthoamides and Iminium Salts LXXXI [1]. Orthoamide Derivatives of 1,3-Dimethylparabanic Acid

1,3-Dimethyl-5-imino-imidazolidine-2,4-dione (7a) undergoes thiolysis (H2S) to give the corresponding imidazolidine-2,4-dione-5-thione derivative 6. The 5-N-methylimino analogue 7b can be obtained from 7a by methylation. Further methylation of 7b affords the crude iminium salt 8c from which the heterocyclic orthoamide derivatives 10, 11 can be prepared. The heterocyclic amide acetal 9a can be obtained from 7a and dimethyl sulfate in methanol and subsequent addition of sodium methanolate in a one-pot reaction. The aminal ester 10 is converted to the amide acetal 9a on treatment with hydrogen chloride in methanol Graphical Abstract Orthoamide und Iminiumsalze, LXXXI [1]. Orthoamid-Derivate der 1,3-Dimethylparabansäure / Orthoamides and Iminium Salts LXXXI [1]. Orthoamide Derivatives of 1,3-Dimethylparabanic Acid

Orthoamide, LX [1]. N,N,N’,N’-Tetraformylhydrazin – ein breit anwendbares Formylierungsmittel für aromatische Verbindungen / Orthoamide, LX [1]. N,N,N’,N’-Tetraformylhydrazine – a Formylation Agent for Aromatic Compounds of Wide Scope

Keywords The reagent system formed from N,N,N’,N’-tetraformylhydrazine (3) and aluminum chloride allows the formylation of aromatic compounds. The scope of the method is comparable with the Olah formylation and the Groß-Rieche procedure, since benzene and fluorobenzene can be formylated. Two formyl groups are transferred from 3 to the aromatic nuclei when a molar ratio 4:1:4 (aluminum chloride/3/aromatic compound) is chosen.

Die Synthese von 2-Methyl-5-phenacyl-1,3,4-thiadiazolen / The Synthesis of 2-Methyl-5-phenacyl-1,3,4-thiadiazoles

Keywords 2,5-Dimethyl-1,3,4-thiadiazole (1a) reacts which aromatic carboxylic acid esters 8a - u in the presence of excessive sodium hydride under condensation to give sodium enolates which afford on hydrolysis the phenacyl-1,3,4-thiadiazoles 9a - u. The action of aromatic carboxylic acid chlorides on 1a in the presence of triethylamine gives rise to the formation of mixtures of diacylated thiadiazole derivatives 16 and 18. In some cases the pure 3-acyl-phenacylidene-2,3-dihydro-1,3,4-thiadiazoles 16 can be isolated. Generally the compounds 16 are rearranged on heating in higher boiling solvents to give the enolbenzoates 18. Hydrolysis of the diacylated thiadiazoles 16 and 18 yields the phenacylthiadiazoles 9a, c, d, g - j, v, w.

Orthoamide, LVIII . Kondensationsreaktionen von CH2-aciden Verbindungen mit Orthoamiden von Carbonsäuren und Alkincarbonsäuren / Orthoamides, LVIII . Condensation Reactions of CH2-Acidic Compounds with Orthoamides of Carboxylic Acids and Alkyne Carboxylic Acids

The orthoamide derivatives 1s and 2e were prepared from the guanidinium salt 7a and the appropriate carbanions. Cleavage of the orthoamide 2e with benzoyl chloride affords the amidinium salt 10a, which can be transformed into the amidinium salt 10b by an anion exchange reaction. The enamines 11a-i, 12a-c, 13a, b, 14a-c, 15a, b, 16, 17a, b, 18a, b, 19a, b, 20 were prepared by condensation of CH2-acidic compounds with the carboxylic acid orthoamides 2a-j. The orthoamide 2d reacts with 1-nitropropane to give the amidinium salt 27a which is transformed into the salt 27b. From benzyl cyanide and orthoamides 2g, i the enamines 30 and 32 were obtained. Similar condensation reactions were performed with the orthoamides of alkyne carboxylic acids 1b, 1c, 1d, 1e, 1p, 1s, giving the push-pull-butadiene derivatives 35a-f, 36a-f, 37a-j, 38a, b, 39a, b, 40a, b. Crystal structure analyses of the butadiene derivatives 37a, 39a, b, 40a, b and 42 were performed, showing that in 37a, 39b, 40a, b by far the shortest bond distance is between C-2 and C-3 of the butadiene system. In 39a the bonds between C1-C2, C2-C3 and C3-C4 are nearly of equal length, whereas in the 1,3-diene unit of 42 the shortest bonds are between C1-C2 and C3-C4.

Orthoamide, LIX. Formyl-aalen [Tris(diformylamino)methan] – ein neues Formylierungsmittel für aktivierte Aromaten/Orthoamides, LIX. Formyl-aalen [Tris(diformylamino)methane] – a New Formylating Reagent for Activated Aromatic Compounds

In the presence of strong Lewis acids such as aluminum chloride or boron trichloride, formyl-aalen [tris(diformylamino)methane] (3) acts as a formylating reagent for aromatic alkane compounds and aromatic ethers. The orthoamide 3 delivers three formyl groups for the formylation process. Thus toluene, cumene, tert-butylbenzene, hexylbenzene, ο-xylene, ρ-cymene, biphenyl, anisole, diphenylether and 1,3-dimethoxybenzene can be formylated in 1,2-dichloroethane. In these reactions, 3 and aluminum chloride should be used in a molar ratio of 1:6 to 1:9.