Hetero-Diels-Alder reaction of some 1,3-diaza-1,3-butadienes with ketenes. Synthesis of functionalized pyrimido[1,2-b]-benzothiazoles and 1,3,4-thiadiazolo-[3,2-a]pyrimidines

Summary Reaction of 1,3-diaza-1,3-butadienes (1a–c) with various ketenes and chloroketenes results in the formation of substituted 4-oxo-pyrimido[2,1-b]benzothiazoles (4a–d) and 1,3,4-thiadiazolo[3,2-a]pyrimido-4-ones (4e,f). Reaction of 1,3-diaza-1,3-butadienes1d,e with ketenes and chloroketenes leads to the 2-morpholine-substituted compounds7 and15, respectively. All reactions proceedvia formation of [4+2] cycloadducts that eliminate methylthiol, methylsulfenyl chloride, or morpholine.

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Hetero-Diels-Alder-Reaktion einiger 1,3-Diaza-1,3-butadiene mit Ketenen. Synthese funktionalisierter Pyrimido[1,2-b]benzothiazole und 1,3,4-Thiadiazolo[3,2-a]pyrimidine

Zusammenfassung Die Reaktion der 1,3-Diaza-1,3-butadiene1a–c mit verschiedenen Ketenen und Chlorketenen führt zu substituierten 4-Oxo-pyrimido[2,1-b]benzothiazolen (4a–d) und 1,3,4-Thiadiazolo[3,2-a]pyrimido-4-onen(4e,f). Die 1,3-Diaza-1,3-butadiene1d,e ergeben mit Ketenen und Chlorketenen die 2-Morpholin-substituierten Verbindungen7 und15. Alle Reaktionen verlaufen über [4+2]-Cycloaddukte, die Methylthiol, Methylsulfenylchlorid oder Morpholin eliminieren.

     

Carbon-phosphorus bond formation and transformation in the reaction of 1,2-diaza-1,3-butadienes with alkyl phenylphosphonites

The reaction of 1,2-diaza-1,3-butadienes with dialkyl phenylphosphonites under solvent-free conditions proceeds via zwitterionic intermediate and gives, by precipitation, the stable ylidic α-phosphanylidene-hydrazones that, in turn, can be transformed into the corresponding 3-phenyl-2H-1,2,3λ⁵-diazaphospholes. The latter compounds are converted by hydrolytic cleavage in methanol-water (95:5) into E-hydrazonophosphonates that are useful for the preparation of the corresponding β-ketophosphonates and 4-[alkoxy(phenyl)phosphoryl]-1,2-diaza-1,3-butadienes. These peculiar 1,2-diaza-1,3-butadienes, bearing an alkoxy(phenyl)phosphoryl group on the carbon atom in position 4 are also able to add different nucleophiles, such as methanol or thiourea, giving 2-[alkoxy(phenyl)phosphoryl]-2-methoxyhydrazones and 5-phosphinate-substituted thiazol-4-ones, respectively.     

Synthesis and properties of 1,3-diaza-2-phospholo[4,5-d]pyrimidines

Reaction of 5-amino-4-alkyl(aryl or aralkyl)aminopyrimidines with PCl₅ gives 2,2-dichloro-3-alkyl(aryl or aralkyl)-1,3-diaza-2-phospholo[4,5-d]pyrimidines, which on treatment with piperidine or morpholine are converted into the corresponding 2,2-diamino derivatives. The latter, on boiling in water or aqueous alcohol, give the dipiperidides or dimorpholides of the corresponding 5-pyrimidylamidophosphoric acids.Translated from Khimiya Geterotsiklicheskikh Soedinenii, Vol. 6, No. 5, pp. 710–712, May, 1970.     

Synthesis of 1H,3H-imidazo[1,5-c]thiazole-5,7-[6H,7aH]-dione and 7,8-dihydro-5-H-imidazo[1,5-c][1,3]thiazine-1,3-[2H,8aH]-dione and derivatives

1H,3H-Imidazo[1,5-c]thiazole-5,7-[6H,7aH]-dione and the corresponding 7-thione derivatives as well as 7,8-dihydro-5H-imidazo[1,5-c][1,3]thiazine-1,3-[2H,8aH]-dione and the corresponding 3-thione derivatives were synthesized starting from L -cysteine and DL -homocysteine thiolactone, respectively. The second group of bicyclic compounds represents a new heterocyclic ring system. The structures of the compounds were confirmed by spectroscopic studies and elemental analyses.     

Chemical reactions of cycloalkanespirohydantoins. Part 3. Acid-catalyzed reaction of 4-hydroxy-2-imidazolidinones. Preparation of bis(1,3-diaza-2-oxospiro[4,5]decyl-4) ether

The use of N-carbamoyliminium ion initiated reactions for the generation of spiroimidazolidin-2-ones has been successfully exploited. N₃-Substituted-4-hydroxy-2-imidazolidinones have been treated under acid conditions to give the rearranged imidazolinones. Only in the case of N₃-dialkylaminomethyl-4-hydroxy-5-cyclohexanespiro-2-imidazolidinones upon treatment with trifluoroacetic anhydride/trifluoroacetic acid afforded a mixture containing bis(1,3-diaza-2-oxospiro[4,5]decyl-4) ether with the rearranged imidazolidinone.     

Structure elucidation of [1,3]oxazolo[4,5‐e][2,1]benzisoxazole and naphtho[1,2‐d][1,3]‐ and phenanthro[9,10‐d]oxazoles using gradient selected gHMBC,gHMQC and gHMQC‐TOCSY NMR techniques

Structure elucidation of compounds in the benzisoxazole series ( 1 – 6 ) and naphtho[1,2‐d][1,3]‐ ( 7 – 10 ) and phenanthro[9,10‐d][1,3]oxazole ( 11 – 14 ) series was accomplished using extensive 2D NMR spectroscopic studies including ¹H–¹H COSY, long‐ range ¹H–¹H COSY, ¹H–¹³C COSY, gHMQC, gHMBC and gHMQC‐TOCSY experiments. The distinction between oxazole and isoxazole rings was made on the basis of the magnitude of heteronuclear one‐bond ¹J_{C2, H2} (or ¹J_{C3, H3}) coupling constants. Complete analysis of the ¹H NMR spectra of 11 – 14 was achieved by iterative calculations. Gradient selected gHMQC‐TOCSY spectra of phenanthro[9,10‐d][1,3]oxazoles 11 – 14 were obtained at different mixing times (12, 24, 36, 48 and 80 ms) to identify the spin system where the protons of phenanthrene ring at H‐5, H‐6 and at H‐9 and H‐7 and H‐8 were highly overlapping. Copyright © 2003 John Wiley & Sons, Ltd.     

A convenient synthesis of 1,2,4-triazolo[4,3,2-o,p]-[1,3]diazocino[4,5-b]quinoxalines via a 1,3-dipolar cycloaddition reaction and a ring transformation

The reaction of 6-chloro-2-hydrazinoquinoxaline 4-oxide 5 with triethyl orthoformate gave 7-chloro-1,2,4-triazolo[4,3-a]quinoxaline 5-oxide 6. The reaction of compound 6 with phenyl isocyanate afforded 7-chloro-4-phenylamino-1,2,4-triazolo[4,3-a]quinoxaline 7 , while the reaction of compound 6 with phenyl isothiocyanate resulted in deoxygenation to provide 7-chloro-1,2,4-triazolo[4,3-a]quinoxaline 8. However, the reaction of compound 6 with allyl isothiocyanate effected the 1,3-dipolar cycloaddition reaction, but not deoxygenation, to furnish 9-chloro-4,5-dihydroisoxazolo[2,3-a][1,2,4]triazolo[3,4-c]quinoxalin-5-ylmethylisothiocyanate 9. Moreover, the reduction of compound 9 with iron/acetic acid resulted in ring transformation to give 11 -chloro-7-hydroxy-4-thioxo-4,5,6,7,8,9-hexahydro-1,2,4-triazolo[4,3,2- o,p][1,3]diazocino[4,5-b]quinoxaline 10 , whose acetylation afforded 5-acetyl-11-chloro-7-hydroxy-4-thioxo-4,5,6,7,8,9-hexahydro-1,2,4-triazolo[4,3,2-o,p][1,3]diazocino[4,5-b]quinoxaline 11.     

A spectroscopic study of 1,3-dimethyl-2-(trimethylstannyl)-1,3-diaza-2-boracycloakanes

The vibrational spectra of 1,3-dimethyl-2-(trimethylstannyl)-1,3-diaza-2-boracyclopentane and the corresponding diazacyclohexane derivatives as well as those of some other 1,3-diaza-2-boracycloalkanes have been recorded. Boron-nitrogen valence vibrations are observed in the 1500±10 cm^?1 frequency region and boron-tin stretching is assigned near 760 cm^?1. These data are discussed in conjunction with the ¹¹B and ¹H NMR spectra of the various heterocycles and the tin Mössbauer spectra of the two boron-tin species.     

[1,3]Dioxolo[5,6][1]benzothieno[2,3-c]-quinolin-6(5H)-ones

Summary The reaction of 3,4-methylenedioxycinnamic acid (1) with thionyl chloride resulted in the formation of 7-chlorothieno[2,3-f]-1,3-benzodioxole-6-carbonyl chloride (2) and cinnamoyl chloride (3). Subsequent reaction of the former withp-substituted anilines led to the formation of 7-chloro-N-(p-substituted phenyl)-thieno[2,3-f]-1,3-benzodioxole-6-carboxamides (4a–c) which on photocyclization afforded 2-substituted [1,3]dioxolo[5,6][1]benzothieno[2,3-c]quinolin-6(5H)-ones (5a–c) in fairly good yields and high purity. The structures have been confirmed by IR,¹H NMR, and analytical methods.Accepted for presentation at the Hong Kong International Symposium on Heterocyclic Chemistry (August 13–16, 1995)     

Die Molekül-und Kristallstruktur des Bis[propylenthioacetals] des 2,4-Dioxo-3-[1,3],6o-[1,3,4,6],9o-[1,3]tribenzaspiro[5.5]undecaphanes

The crystal structure of the Bis[propylenthioacetale] of 2,4-Dioxo-3-[1,3],6 ^u -[1,3,4,6],9 ^u -[1,3]tribenzaspiro-[5.5]undecaphane has been determined by three-dimensional X-ray data (4312 reflections) and refined to anR-value of 0.035. The cell constants of the triclinic cell (P ) are:a=13.598 Å,b=11.195 Å,c=10.280 Å, =77.21°, =69.23°, =71.51°. The shape of the central benzene ring is found to be chair-like, the two terminal benzene rings boat-like.     

Chemie des 2-Aminospiro[indan-1,3′-pyrrolidin]-Systems

The chemistry of the 2-aminospiro[indan-1,3′-pyrrolidine]system 2-Aminospir[indan-1,3′-pyrrolidines] 1 are easily synthesized from the α-hydroxyiminoketones 6 and 19 (Schemes 2 and 3, and 6 respectively). Removal of the N-acetyl group in the intermediate 8 of the trans series induces transposition to the 3a-aminomethyl-indano[2,1-b]pyrrolidine system. The configurations of all compounds have been determined by ¹H-NMR. spectroscopy.     

One‐step ring‐closure procedure for 4,5‐dihydro‐1,3‐thiazino[5,4‐b]indole derivatives with Lawesson's reagent. The fifth dihydro‐1,3‐thiazino[b]indole isomer

We report a convenient approach for the synthesis of a new ring system: 4,5‐dihydro‐1,3‐thiazino[5,4‐b]indoles. The procedure involves the use of Lawesson's reagent in the presence of silica to achieve the one‐step ring‐closure reactions of 2‐benzoylamino‐3‐hydroxymethylindole intermediates to furnish 4,5‐dihydro‐2‐aryl‐1,3‐thiazino[5,4‐b]indoles. 2‐Phenylimino‐1,3‐thiazino[5,4‐b]indoles were obtained via the corresponding 3‐phenylthiourea‐2‐carboxylic acid ester derivatives by chemoselective reduction of the ester group, followed by ring closure under acidic conditions. The structures of the novel products were elucidated by IR, ¹H‐NMR, and ¹³C‐NMR spectroscopy, including 2D‐HMQC, 2D‐HMBC, and DEPT measurements. J. Heterocyclic Chem., (2011).     

Synthesis of 6-alkylidene-2,3-benzo-1,4-diaza-7-oxabicyclo[4.3.0]non-2-enes by cyclization of 1,3-bis(silyl enol ethers) with quinoxalines

6-Alkylidene-2,3-benzo-1,4-diaza-7-oxabicyclo[4.3.0]non-2-enes were prepared by cyclization of 1,3-bis(silyl enol ethers) with quinoxaline.     

2,2-Difluor-1,2,3-trimethyl-1,3-diaza-2λ5-phospholidin

2,2-Difluoro-1,2,3-trimethyl-1,3-diaza-2λ⁵-phospholidine The title compound 1 is obtained in about 50% yield by oxidative fluorination of 1,2,3-trimethyl-1,3-diaza-2λ³-phospholidine, 6 , with IF₅. 1 is characterized by its nmr, mass, and ir spectra.     

(Fluorosilyl)ethylenediamines and fluorosilyl-1,3-diaza-2-silacyclopentanes

This paper presents the chemistry of ethylenediamines and fluorosilanes. The synthesis of thermally stable monosilyl (1-5)- and bis(fluorosilyl)ethylenediamines (6) is described. Starting with the dilithium salt of ethylenediamine and F₂Si(CMe₃)₂ the five-membered 1,3-diaza-2-silacyclopentane (8) is obtained. The reaction of tetra- and trifluorosilanes with dilithiated bis(silyl)ethylenediamines leads to the formation of 1,3-diaza-2-fluorosilylsilacyclopentanes (9-14). Fluorosilanes substitute 8 in 1 and 3 positions (15-28). A fluorosilyl-bridged five-membered ring (29) is isolated in the reaction of 1-trimethylsilyl-1,3-diaza-2-silacyclopentane, BuLi and MeSiF₃. In the synthesis of N-fluorosilyl-1,3-diaza-2-silacyclopentanes constitutional isomers were formed (30-33). Quantum-chemical calculations support the isomerisation mechanism. An iminosilane with an SiN double bond is the intermediate product of the rearrangement process.Crystal structures of 7, 13, 20 and 23 are reported.     

Synthesis,structural and conformational study of 6-hydroxy (or acyloxy) derivatives of the 1,3-dimethyl-1,3-diazoniatricyclo[3.3.1.13–7]decane system

1,3-Dimethyl-1,3-diazoniatricyclo[3.3.1.1^3–7]decan-6-ol, and his p-chlorobenzoxy and diphenylacetoxy derivatives have been synthesized and studied by ¹H and ¹³C nmr spectroscopy. The crystal structure of the alcohol 2a has been determined by X-ray diffraction. Each ring of the adamantane cage system is a nearly perfect chair. From the ¹H and ¹³C nmr data, several stereoelectronic effects have been deduced.     

New heterocyclic structures. [1,3]Thiazino[3,2-a]purine and [1,2,3]triazolo[4,5-d][1,3]thiazino[3,2-a]pyrimidine

Derivatives of two new molecular structures, namely, [1,3]thiazino[3,2-a]purine and [1,2,3]triazolo[4,5-d]-[1,3]thiazino[3,2-a]pyrimidine, were synthesized together with other heterocyclic compounds. Retrosynthetic analysis of their molecular skeletons suggested a simple way of obtaining 3,4-dihydro-7,8-diamino-2H,6H-pyrimido[2,1-b][1,3]thiazin-6-one, which is a useful intermediate for their synthesis. This intermediate and the thiazole homologue were obtained directly by reaction of 5,6-diamino-2,3-dihydro-2-thioxo-4(lH)-pyrimidi-none with 1,3- or 1,2-dibromoalkane, respectively.     

1,5-Dihydropyrrol-2-ones from (1,4-diaza-1,3-diene)tricarbonyliron and alkyne: III. Stereospecific ligand incorporation on formation of the [2.2.2]-Bicyclic intermediate

Examples of the [2.2.2.]-bicyclic intermediate formed in the reaction of (1,4-diaza-1,3-diene)tricarbonyliron complexes, (dad)Fe(CO)₃, with dimethyl acetylenedicarboxylate and an additional ligand L [L = ¹³CO, P(OMe)₃] have been isolated and characterized by elemental analysis, field desorption mass spectrometry and NMR (¹H, ¹³C, ³¹P) and IR spectroscopy. The ligand L which completes the octahedral coordination around the bridge head iron atom, is incorporated stereospecifically trans to the inserted carbonyl group of the [2.2.2] system. This is found to be the case with complexes of diazadienes of differing donor/acceptor abilities and also for the two electronically different ligands L. From the results it is concluded that a stereochemically rigid intermediate is initially formed, which for steric reasons and so in a kinetically controlled reaction, allows access of L to the iron from only one direction, consequently closing the [2.2.2] structure. Conclusive evidence that the reaction is kinetically controlled is provided by the isolation of two isomeric complexes (2b and 7, respectively) from the reactions of (dad)Fe(CO)₃ in the presence of P(OMe)₃, and of (dad)Fe[P(OMe)₃](CO)₂ from reaction in the presence of CO.     

Reactions of cyclic 1,3-dicarbonyl compounds with 1,2(1,4)-dihydro-1-methyl-2(4)-methylene-N-heterocycles. A new access to 6,12-methano-dibenz[d,g]-[1,3]oxazocinones

Summary The enamine-type methylene-N-heterocycles1–5 react with cyclic 2-ethoxymethylene-1,3-dicarbonyl compounds6 to give 2-[2-(hetarylidene)ethylidene]-1,3-dicarbonyl compounds7–14. The result of the reactions between 1,2-dihydro-1-methyl-2-methylene-quinoline (1a) and cyclic 1,3-dicarbonyl compounds depends on the nature of the dihydro intermediatesA/B. Dehydrogenation of keton intermediatesA results in 2-(1,2-dimethyl-4(1H)-quinolylidene)-1,3-dicarbonyl compounds17–21. Enol intermediatesB with 6-membered dicarbonyl ring form 6,12-methano-dibenz-[d,g][1,3]oxazocinones22–25.¹H NMR spectra and X-ray structure analysis prove the structure of23.

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Reaktionen cyclischer 1,3-Dicarbonylverbindungen mit 1,2(1,4)-Dihydro-1-methyl-2(4)-methylen-N-heterocyclen. Ein neuer Zugang zu 6,12-Methano- dibenz[d,g][1,3]oxazocinonen

Zusammenfassung Aufgrund ihres Enamincharakters reagieren die Methylen-N-heterocyclen1–5 mit cyclischen 2-Ethoxymethylen-1,3-dicarbonylverbindungen6 zu den 2-[2-(Hetaryliden)ethyliden]-1,3-dicarbonylverbindungen7–14. Das Ergebnis der Reaktionen zwischen 1,2-Dihydro-1-methyl-2-methylen-chinolin (1a) und cyclischen 1,3-Dicarbonylverbindungen hängt von der Natur der zwischenzeitlich entstehenden DihydroverbindungenA/B ab. Die Intermediat-KetoneA gehen durch Dehydrierung während der Reaktion in die 2-(1,2-Dimethyl-4(1H)chinolyliden)-1,3-dicarbonylverbindungen17–21 über. Die Intermediat-EnoleB mit sechsgliedrigem Dicarbonylring bilden in intramolekularer Reaktion die 6,12-Methano-dibenz[d,g][1,3]oxazocinone22–25, deren Struktur am Beispiel der Verbindung23 durch¹H-NMR sowie durch Röntgenkristallstrukturanalyse bewiesen wird.

     

Intramolecular 1,3-Dipolar Cycloaddition of Azomethine Ylides Leading to Pyrido[2,3-b]quinolines

A convenient six-step route to the previously unknown 1H-pyrrolo[2,3-f]benzo[b][1,8]naphthyridine ring system using an intramolecular 1,3-dipolar cycloaddition of nonstabilized azomethine ylides has been described.