Reaction of 2-Tetrafluoropropoxy-5,6-benzo-1,3,2-dioxaphosphorinan-4-one with Pyruvonitrile

The reaction of pyruvonitrile with 2-tetrafluoropropoxy-5,6-benzo-1,3,2-dioxaphosphorinan-4-one results mainly in the enlargement of the starting heteroring to form 4-cyano-4-methyl-2-tetrafluoropropoxy-6,7-benzo-1,3,2⁵-dioxaphosphepin-5-one 2-oxide as a mixture of two diastereomers (14:1) along with minor amounts of 3-cyano-3-methyl-2-tetrafluoropropoxy-6,7-benzo-1,4,2⁵-dioxaphosphepin-5-one 2-oxide.     

Molecular and Solution Structure of 5,6-Benzo-1,3,2-dioxaphosphinin-4-one Derivatives

2-X-5,6-benzo-1,3,2-dioxaphosphinin-4-ones (X = N = C = O, Cl, NEt₂), regardless of their aggregative state, prefer one and the same conformation (flattened sofa); the exocyclic substituent occupies either an axial (N = C = O, NEt₂) or an equatorial (Cl) position.     

Synthesis and Photoisomerization of 3-Cyano-6,6-dimethyl-4-(4-nitrophenylvinyl)-5,6-dihydropyran-2-one

The condensation of 4-nitrobenzaldehyde with 3-cyano-4,6,6-trimethyl-5,6-dihydropyran-2-one leads to the formation of a crotonization product and a compound of the Michael adduct type. The main product of the photochemical conversion of (E)-3-cyano-6,6-dimethyl-4-(4-nitrophenylvinyl)-5,6-dihydropyran-2-one is the Z-isomer. Investigation of the photoisomerization of 3-cyano-6,6-dimethyl-4-(4-nitrophenylvinyl)-5,6-dihydropyran-2-one by the semiempirical AM1 method showed that in the ground state the E-isomer was thermodynamically more stable than the E-isomer. E-Z-photoisomerization is effected most probably through the lowest excited singlet state S₁.     

Reaction of 6-methyl-6-p-tolyl-4-ethoxy-5,6-dihydro-pyran-2-one1 with perchloric acid

6-Methyl-6-p-tolyl-4-ethoxy-5,6-dihydro-pyran-2-one (1) undergoes decarboxylative elimination with perchloric acid in ether to give 4-p-tolyl-3-penten-2-one (3), the structure of which has been confirmed through an unambiguous synthesis.

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Reaktion von 6-Methyl-6-p-tolyl-4-ethoxy-5, 6-dihydro-pyran-2-on mit PerchlorsäureKurze Mitteilung

Zusammenfassung Die Titelverbindung (1) ergibt mit Perchlorsäure unter decarboxylierender Eliminierung 4-p-Tolyl-3-penten-2-on (3). Die Struktur von3 wurde mittels eines eindeutigen Syntheseweges festgelegt.

     

Novel Fused Heterocycles: Synthesis and Activity of 5,6-Dihydro-7-thia-1,3,3a,5-tetraazainden-4-one and 1-Thia-3,4a,9-triazafluoren-4-one Derivatives

Summary.  Thiatetraazaindenone derivatives were synthesized by reaction of 3-substituted 1,2,4-triazole-5-thiols with N-substituted N-chloromethyl carbamoyl chlorides. A series of thiatriazafluorenone derivatives were also prepared by reaction of benzimidazole derivatives with the same substrate. Some of the new compounds show fungicidal, herbicidal, and insecticidal activity. Received February 14, 2000. Accepted (revised) April 11, 2000     

Novel Fused Heterocycles: Synthesis and Activity of 5,6-Dihydro-7-thia-1,3,3a,5-tetraazainden-4-one and 1-Thia-3,4a,9-triazafluoren-4-one Derivatives

 Thiatetraazaindenone derivatives were synthesized by reaction of 3-substituted 1,2,4-triazole-5-thiols with N-substituted N-chloromethyl carbamoyl chlorides. A series of thiatriazafluorenone derivatives were also prepared by reaction of benzimidazole derivatives with the same substrate. Some of the new compounds show fungicidal, herbicidal, and insecticidal activity.     

Synthesis of 5,6-dehydro-7-oxoisodrimenin from drim-8-en-7-one

The natural drimane sesquiterpenoid lactone 5,6-dehydro-7-oxoisodrimenin was synthesized from drim-8-en-7-one as well as from 7-oxoisodrimenin.     

Synthesis of 3-methyl-substituted pyrazolotriazolopyrimidin-4-one and pyrazolothiazolopyrimidin-4-one derivatives

As a part of a research on anti-inflammatory analgesic compounds 3-methyl substituted pyrazolotria-zolopyrimidin-4-one and pyrazolothiazolopyrimidin-4-one derivatives were prepared by previously reported procedures. None of the compounds showed improved activity when compared with the previously reported unsubstituted analogs.     

Recyclization of the products of amidine addition to the substituted 5-amino-4-cyano-1,3-oxazole into new derivatives of 5,6-Diaminopyrimidin-4-one

The products of addition of amidines to accessible 5-arylamino-4-cyano-1,3-oxazoles at heating in acetic acid undergo recyclization and afford new derivatives of 6-amino-5-acylaminopyrimidin-4-one, whose structure was reliably established using X-ray diffraction studies.     

Synthesis of 5,6-dihydro-4H-thiopyran-4-ones

The anions of 1,4-diaryl-3-buten-2-ones 1 reacts with arylisothiocyanates, yielding intermediates 4 which can ring close to 5,6-dihydro-4H-thiopyran-4-ones 5 . Under similar reaction conditions ethyl 3-oxo-4-pentenoates 7 gives the 6-spiropyrans 9 . Methylation of 3 gives the S-methylated open form 6 .     

Behaviour of 5,6-dihydrothieno[2,3-h]cinnolin-3(2H)-one and 5,6-dihydrothieno[3,2-h]cinnolin-3(2H)-one towards hydrazine. Synthesis of thienocinnolinones and of 4-aminothienocinnolinones

The isomeric compounds 5,6-dihydrothieno[2,3-h]cinnolin-3(2H)-one ( 7a ) and 5,6-dihydrothieno-[3,2-h]cinnolin-3(2H)-one ( 7b ) rapidly tautomerise to the corresponding 1,4-dihydrothienocinnolinones 8a,b when kept in refluxing hydrazine hydrate. With longer reaction times the initially formed 8a,b dehydrogenate to the thienocinnolinones 9a,b which eventually are aminated to 4-aminothienocinnolinones 10a,b . This behaviour recalls that reported for the related 5,6-dihydrobenzocinnolin-3(2H)-one ( 1 ) which under the same conditions undergoes dehydrogenation to benzo[h]cinnolin-3(2H)-one ( 2 ) followed by 4-amination to 3 , but differs for the stability of the intermediates, for the mechanism of the final amination, and for the higher reaction rate. All these differences can be rationalised in terms of the heats of formation of the intermediates and products of the two series of transformations.     

Synthesis,steric structure,and biological activity of 5-methyl-2-(morpholin-4-ylamino)-5,6-dihydro-4H-1,3-thiazin-4-one

Russian Journal of General Chemistry - New 5,6-dihydro-1,3-thiazin-4-one derivatives have been synthesized by one-pot reaction of morpholin-4-amine and adamantan-1-amine with methacryloyl...     

水相中2-氨基-4-芳基-5,6-二氢化-4H-吡喃并[3,2-c]喹啉-5-酮衍生物的合成

以芳亚甲基丙二腈或2-氰基-3-芳基丙烯酸酯和4-羟基喹啉-2-酮为原料, 水为溶剂, 在TEBA(三乙基苄基氯化铵)催化下90 ℃, 合成了2-氨基-4-芳基-5,6-二氢化-4H-吡喃[3,2-c]喹啉-5-酮衍生物. 和其它方法相比, 该反应具有反应条件温和, 产率高(87%～96%)和环境友好等优点. 产物的结构通过熔点, IR, ¹H NMR和元素分析表征. 化合物3m的结构通过X单晶衍射分析确证.     

Semipinacol and protoadamantane-adamantane rearrangements of 5,6-dibromoadamantan-2-one and -2-ol

A number of new polybrominated adamantanes were formed by rearrangements and bromination of 2,2,6,6-tetrabromoadamantane under Friedel-Crafts conditions. Protoadamantane-4,10-dione, 10-acetoxyprotoadamantan-4-one, 1,2,6-triacetoxyadamantane and 5,6-diacetoxyadamantan-2-one were formed by successive semipinacol and protoadamantane-adamantane rearrangements of 5,6-dibromoadamantan-2-one and 5,6-dibromoadamantan-2-ol. This work may open up new pathways for the synthesis of 1,2,6-trisubstituted adamantanes.     

Synthesen des 4-Sulfanilamido-5,6-dimethoxypyrimidins

Zusammenfassung Es wird über 4 verschiedene Synthesen des 4-Sulfanilamido-5,6-dimethoxypyrimidins² berichtet.Frau Prof. Dr. Dr.E. Cremer zum Geburtstage in Verehrung gewidmet.14. Mitt.:H. Bretschneider, J. Dehler undW. Klötzer, Mh. Chem.95, 207 (1964).