Zur Synthese von Octahydrochinazolinonen und deren Reaktion mit Persäure

The Synthesis of Octahydroquinazolinones and their Reaction with Peracid By reaction of cyclohexanone-2-carboxamide with ammonia and aldehydes, octahydroquinazolinones 2a–f , and with Schiff bases octahydroquinazolinones 3a–c are formed. 2-Hydroxycyclohexanone-2-carboxamide forms with ammonia and butyraldehyde the hydroxyocta-hydroquinazolinone 4 . Compound 2e reacts with monoperoxiphthalic acid to the hydroxyoxaziridine 5e which reacts with alkali hydroxide to compound 6. 8 yields with peroxy acid the hydroperoxy epoxide 9 .     

Synthese und Reaktionen von 2.1-Benzisothiazolinonen-(3)

Synthesis and Reactions of 2,1-Benzisothiazolin-3-ones Dependent on the substituent group at the nitrogen the sodium salts of thioanthranilic acids 3 , availabel from isatoic anhydrides 1 and sodium hydrogen sulphide, yield on oxidation 2,1-benzisothiazolin-3-ones 4 or bis-anthranoyl disulphides 5 . The latter are cyclized under special conditions to yield 4 . From 4 and oxalyl chloride, 3-chloro-2,1-benzisothiazolium chlorides 7 are available which give with hydrogen sulphide the thiones 6 and with dimethyl aniline the polymethines 9 . The dyestuffs 9 can also be prepared from the 3-methylthio-2,1-benzisothiazolium salts 8 , obtainable by alkylation of compounds 6 .     

Synthese und Reaktionen von N-Phthalimido-keten-S,S-acetalen

Synthesis and Reactions of N-Phthalimido-ketene-S,S-acetals N-substituted phthalimido derivatives 1a – f react in the presence of bases (NaH, t-BuONa) with carbon disulfide to the N-phthalimido-ketene-S,S-acetals 3 , 4 , 5 and 6 , respectively. 2-Amino-ketene-S,S-acetals 7a – c are formed by reaction of 3a , b or 5a with hydrazine hydrate. 3c produces with phenylhydrazine the pyrazole 8 , and with piperidine and pyrrolidine the E/Z mixture of the corresponding ketene-S, N-acetals 9a , b . 1c is transformed into 10a – c (E/Z-mixture)by treatment with phenylisothiocyanate under basic condition followed by alkylation.     

Synthese von 2-[Benzazolyl-(2)]-3,3-bis-(alkylthio)-acrylnitrilen und Umsetzungen mit N-Nucleophilen

Synthesis of 2-[Benzazolyl-(2)]-3,3-bis-(alkylthio)-acrylnitriles and Their Reactions with N-Nucleophiles The reactions of benzazolyl-(2)-acetonitriles 1 (1H-benzimidazolyl-, 1-methylbenzimidazolyl-, benzoxazolyl- and benzothiazolyl-) with carbon disulfide in the presence of sodium hydride in dimethylsulfoxide and methylation yield the 2-[benzazolyl-(2)]-3,3-bis-(alkylthio)-acrylonitriles 3 – 5 reacting with amines to the keten-S,N-acetals 6 – 9 . If dinucleophilic reagents are used heterocyclic systems 10 – 14 are formed.     

Reaktionen von Heteroaryliminotriphenylphosphoranen mit Heterokumulenen: Synthese und Cycloadditionen α-N-Heteroaryl-substituierter Carbodiimide

Reactions of Heteroaryliminotriphenylphosphoranes with Heterocumulenes: Synthesis and Cycloaddition Reactions of α-N-Heteroaryl-substituted Carbodiimides N-α-Heteroaryl-substituted iminotriphenylphosphoranes react with phenylisocyanate, phenylisothiocyanate, and carbon disulfide to symmetrical and unsymmetrical α-heteroaryl-carbodiimides. These can not be isolated as monomeres because they behave as 1.3-diazabutadienes predominantly and form 4+2-cycloadducts. The monomeric intermediates cyclodimerize to the 1.3.5-triazines 5 resp. 14 or react by the same scheme both with phenylisocyanate and with phenylisothiocyanate to give the 1.3.5-triazines 4 , resp. 12 . In competition with this reaction a 2+2-cycloaddition takes place, hence there follow numerous by-products. The structure of 1.3.5-triazines is determined from hydrolysis to guanidines 6 and on the basis of spectroscopic methods.     

Neue Synthese von substituierten 4-Amino-chinazolinen und deren Heteroanalogen

New Synthesis of Substituted 4-Amino-quinazolines and Their Heteroanaloga N-Chloracetyl-anthranilonitriles react with potassium thiocyanate in the presence of alcohol to the (4-aminoquinazolin-2-yl-thio)-acetic acid ester ( 5 ). In the presence of water or primary amine the acetic acid derivative ( 6 ) or the acetic acid amide derivatives ( 7 ) are obtained. 2,4-Diaminoquinazolines ( 8 ) arise if vigorous reaction conditions are employed. With 2-chloracetylamino-cyclopent-1-en-carbonitrile as starting material the pyrimidines ( 11 ) are formed from the reaction with potassium thiocyanate. Analogously, (4-pyrimidyl-2-yl-seleno)-acetic acid ester ( 12 ) and (thiazolo[4,5-d]pyrimid-2-yl-seleno)-acetic acid derivatives ( 16 ) can be prepared with potassium selenocyanate. N-Chloracetyl derivatives of 5-membered heterocycles with enamino-nitrile structure ( 13 , 15 , 18 , 20 ) react with potassium thiocyanate to yield thieno[2,3-d]-, thiazolo[4,5-d]-, pyrrolo[2,3-d]-, furo[2,3-d]- and pyrazolo[4,3-d]pyrimidines ( 14 , 16 , 19a , 19b , 21 ).     

Reaktionen mit Cyclobutendionen. LII. Reaktionen von 4-Hydroxy-3-phenyl-cyclobut-(3)-en-onen-(1) mit Arylhydrazinen

Reactions of Cyclobutendiones. LII. Reaction of 4-Hydroxy-3-phenyl-3-cyclobuten-1-ones with Arylhydrazines In the reaction of hydroxycyclobutenones of the typ 1 – 4 with arylhydrazines 5 an unexpected reaction behaviour is found. The major products are hydrazones of different structure, the well known hydroxy-cyclopropane-carboxylicacid hydrazines 6 [1] are byproducts. The direction of the reaction depends on the substituents X, on the different substituted arylhydrazines and the solvents.     

Synthese und Reaktionen von β-Campholenverbindungen

Synthesis and Reactions of β-Campholene Compounds In contrast to the well known α-campholenic ( B ) and fencholenic compounds ( C ) little is known about β-campholenic derivatives ( A ) because of their difficult accessibilitiy. β-Campholenic compounds ( A ) can be obtained: (1) by Baeyer-Villiger oxidation of camphor via lactone 7 and β-dihydrocampholenic lactone ( 5 ); (2) by Beckmann fragmentation of camphor oxime via α-( 2 ) and β-campholenic nitril ( 3 ) and the lactone 5 ; and ( 3 ) by acid catalysed rearrangement of α-campholenic derivatives ( B , 17a , b ). The β-analogous brahmanol ( 14 ) can be synthesized by the reaction of the β-campholenic bromide ( 11 ) with methyl diethyl malonate or by rearrangement of brahmanol.     

Synthesen auf der Basis von 2-Oxoglutarsäure. III [1] Synthese und Reaktionen von (E)-2-Oxoglutaconsäuredimethylester

Organic Syntheses Based on 2-Oxoglutaric Acid. III. Synthesis and Reactions of Dimethyl (E)-2-oxoglutaconate Dimethyl (E)-2-oxoglutaconate 1 obtained by dehydrobromination of dimethyl 3-bromo-2-oxoglutarate reacts with o-phenylendiamine to form the quinoxalin-2(1H)-one 2 , and with phenylhydrazine to yield the 4,5-dihydropyrazole 3 . Furthermore, a Doebner-von Miller-type reaction affords the 8-carboxy quinoline derivative 4 . Finally, addition of bromine leads diastereoselectively to the racemate of dimethyl 3S,4R- and 3R,4S-dibromo-2-oxoglutarate 5 .     

Reaktionen von Malonsäureethylesteraniliden mit Heterokumulenen

Reactions of Malonanilic Acid Ethyl Esters with Heterocumulenes Malonanilic acid ethyl esters 1 react with carbon disulfide in the presence of sodium hydride to give disodium salts 2 . Treatment of 2 with an alkylation reagent yields the openchain or cyclic ketene S,S-acetals 3 and 4 , respectively. Adding only one equivalent of methyl iodide to 2 and acidifying the reaction mixture lead to the dithioesters 5 . Reaction of 3 with amines or o-amino-thiophenol yields S,N- and N,N-acetals only in some cases. S,N-acetals 6 are further available by addition of phenyl isothiocyanate to 1 whereas N,N-acetals are synthesized, too, by chlorination of 3 and reaction with amines. Acidifying of 11 gives the thioacetoanilides 12 . Some more reactions (oxidation of 3a , d and saponification/decarboxylation of 4a ) are discussed.     

Synthese und Photochemie von Sydnonazomethinen-(4)

Synthesis and Photochemistry of Sydnonazomethines-(4) Sydnon-4-aldehydes 1 – 3 react with prim. amines or N-sulfinylanilines to sydnon-azomethines. The i.r.-spectra are discussed. Sydnonazomethines undergo a photoinduced E/Z-isomerisation, at room temperature; a rapid thermic back-reaction (Z/E-isomerisation) takes place, however. The photostationary states at −75°C are analyzed. The rate constants of the thermic back-reaction at 18°C are measured by means of flash-photolysis. The quantum yields for the E/Z-isomerisation (at −75°C) and the photolytic decomposition have the value of >0,1 and <10⁻³ respectivly.     

Synthese und physiko-chemisches Verhalten von Lecithinen mit verzweigten Fettsäureresten

Synthesis and Physico-chemical Behaviour of Lecithins with Branched Fatty Acid Chains Branched fatty acids widely occur as components of the lipids of microorganisms, plants and animals. For studying the biophysical and biochemical behaviour of lecithins with branched fatty acyl, we synthesized three series of glycerophosphocholines. For this purpose fatty acids (palmitic, stearic acid) with a methyl group in different positions and α-branched fatty acids with alkyl residues of different lenght were synthesized and incorporated into 1,2-diacyl-, 1-acyl-2-O-hexadecyl- and 1-O-hexadecyl-2-acyl-glycerophosphocholines. The resulted lecithins were characterized biophysical (differential scanning calorimetry, X-ray diffraction) and biochemical (interaction with phospholipase A₂).