4-hydroxy-2-quinolones. 114. Synthesis and structure of 6-R-5-hydroxy-2,4-dioxo-2,3,4,6-tetrahydrobenzo-[<Emphasis Type="Italic">c</Emphasis>][2,7]naphthyridine-1-carbonitriles

Hydration of ethyl 1-R-4-dicyanomethyl-2-oxo-1,2-dihydroquinoline-3-carboxylate gives the corresponding substituted cyanoacetamides which are readily and quantitatively cyclized to 6-R-5-hydroxy-2,4-dioxo-2,3,4,6-tetrahydrobenzo[c][2,7]naphthyridine-1-carbonitriles in the presence of aqueous base. For Communication 113 see [1]. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 726–735, May, 2007.     

Propanal in the Syntheses of Alkyl-substituted 3-Cyano-2-piperidone, 3-Cyano-2,5,6,7-tetrahydropyrindin-2(1H)-one, and 3-Cyanopyridine-2(1H)-thione

Condensation of propanal with cyanothioacetamide and morpholine gave 3-cyano-4-ethyl-5-methyl-6-morpholino-2-piperidone, the structure of which was studied by X-ray analysis. Reaction of propanal with cyanothioacetamides and cycloalkanone enamines gave 3-cyano-4-ethyl-2,5,6,7-tetrahydropyrindin-2(1H)-one and 3-cyano-4-ethyl-5,6-hexamethylenepyridine-2(1H)-thione. The latter was used for the preparation of substituted 2-benzyloxycarbonylmethylthiopyridine and 3-amino-2-benzyloxycarbonylthieno[2,3-b]pyridine. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 1053–1059, July, 2005.     

Novel Cyanoketene N,S‐Acetals and Pyrazole Derivatives using Potassium 2‐Cyanoethylene‐1‐thiolates

Novel ketene N,S‐acetals 3 were readily prepared by the reaction of cyanoacetamide or cyanothioacetamide with phenylisothiocyanate in the presence of potassium hydroxide, followed by alkylation of the produced salts with methyl iodide. The reaction of compounds 3 with hydrazines afforded different substituted pyrazoles 6.     

Spectrofluorometric Determination of Cephalexin in Pharmaceutical Preparations and Spiked Human Urine Using 2‐Cyanoacetamide

A simple, accurate, sensitive, and validated method was developed for the spectrofluorometric determination of cephalexin. The method involves the reaction of cephalexin with 2‐cyanoacetamide in presence of 33% ammonia solution. The formed fluorescent product exhibited maximum fluorescence intensity at λ 439 nm, after excitation at λ 339 nm. Different experimental parameters affecting the derivatization reaction were carefully studied and incorporated in the procedure. Under the described conditions, the proposed method was linear over the concentration range 0.04–0.4 µg/mL. The average percent found was 99.6±0.9%. The LOD was 7.76 ng/mL. The proposed method was applied for determination of cephalexin in pharmaceutical preparations as well as in spiked human urine. A mechanism of the reaction is postulated.     

Reaction of 2,3-Dichloro-1,4-naphthoquinone with Some Active Methylene Compounds in Different Basic Media

Reaction of 2,3-dichloro-1,4-naphthoquinone with some active methylene compounds, such as malononitrile and cyanoacetamide, under various basic conditions has been investigated. A mechanism for these reactions is proposed.     

4-Hydroxy-2-quinolones 119. Reaction of ethyl 1-R-4-chloro-2-oxo-1,2-dihydroquinoline-3-carboxylate with malononitrile

In acid medium ethyl 1-R-4-dicyanomethyl-2-oxo-1,2-dihydroquinoline-3-carboxylates are hydrated in the ketenimine tautomer form exclusively to the corresponding quinolylcyanoacetamides. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 856–863, June, 2007.     

KF／Al2O3催化下的Knoevenagel缩合反应

ＫＦ／Ａｌ＿２Ｏ＿３催化下的Ｋｎｏｅｖｅｎａｇｅｌ缩合反应戴桂元，史达清，周龙虎（徐州师范学院化学系徐州２２１００９）关键词Ｋｎｏｅｖｅｎａｇｅｌ缩合反应，氟化钾／氧化铝，芳香醛，氰乙酸乙酯，氰乙酰胺Ｋｎｏｅｖｅｎａｇｅｌ缩合反应一般在碱催化下进行，...     

Efficient synthesis of new butenolides by subsequent reactions: application for the synthesis of original iminolactones, bis-iminolactones and bis-lactones

We have developed the synthesis of twenty four new iminolactones, bis-iminolactones and bis-lactones by subsequent esterification-condensation or addition-condensation reactions according to two strategies from α-hydroxyketones. The X-ray diffraction data of a bis-iminolactone is described and present an interesting helical column packing.     

Imidazole‐catalyzed Three‐component Cascade Reaction for the Facile Synthesis of Highly Substituted 3,4‐Dihydropyridin‐2‐one Derivatives

A novel one‐pot protocol for the synthesis of valuable 3,4‐dihydropyridin‐2‐ones from the condensation of aldehyde with cyanoacetamide and 1,3‐dicarbonyl compounds in the presence of imidazole was developed. A series of aldehydes and 1,3‐dicarbonyl compounds were employed to examine the scope of substrates for this protocol. This reaction proceeded through the formation of one ring and four new bonds (two C? C, one C? N, one C?C) via the sequence involving Knoevenagel condensation, Michael addition and intramolecular cyclization with moderate to excellent yields. All new compounds were characterized by IR, ¹H NMR, ¹³C NMR and HRMS.