Facile one-pot synthesis of photochromic pyrans

[reaction: see text]. Photochromic pyrans, including [3H]naphtho[2,1-b]pyrans, [2H]naphtho[1,2-b]pyrans, indeno-fused naphtho[1,2-b]pyrans, and heteroannulated pyrans, were synthesized in excellent yields through a facile one-pot procedure by reaction of propargyl alcohol and naphthol or phenol derivatives in the presence of 5 mol % PPTS and 2 equiv of (MeO)3CH. Symmetrical and nonsymmetrical bispyrans can also be prepared using the protocol.     

Reaction of dichloroketene and sulfenc with N,N-disubstituted 2-aminomethylene-1 -indanones. Synthesis of indeno[ 1,2-b ] pyran and lndeno[2,l-e] -1,2-oxathiin derivatives

The 1,4-cycloaddition of dichloroketene to N,N-disubstituted 2-aminomethylcnc-l-indanones afforded N,N-disubstituted 4-ainino-3,3-dichloro-3,4-dihydro-2-oxoindeno[1,2-b ]pyrans only in the case of full or partial aromatic N-substitution. The diphenylamino adduct gave 3-chloro-4-diphenylamino-2-oxoindeno[ 1,2-b]pyran by dehydrochlorination with DBN. The 1,4-cycloaddition with sulfene occurred only in the case of 2-diethylaininomethylene-1-indanone to give 4-diethylamino-3,4-dihydroindeno[2, 1-e]-1,2-oxathiin 2,2-dioxide, a derivative of a new hetero-cyclic system.     

Heterocycles containing nitrogen and sulfur. Part 49. Synthesis of derivatives of new heterocyclic systems: 1,2-Dioxocyclopenta(hexa)[g]oxazolidino-[3,2-f] pyrimido[4,5-b][1,4]thiazine, 1,2-dioxocyclopenta(hexa)-[g] imidazolidino[3,2-f]pyrimido[4,5-b][1,4]thiazine, and 1,2-oxazino[5,4-g]pyrimidino[4,5-b][1,4]thiazine

The reaction of 4-methoxy-5-amino-6-mercaptopyrimidine with 2-oxo-1-chlorocyclopentyl(hexyl)glyoxalate esters gave derivatives of the previously unknown tetracyclic systems 1,2-dioxocyclopenta (hexa)[g]oxazolidino[3,2-f]pyrimido[4,5-b][1,4]thiazines, which are transformed by ammonium acetate into derivatives of 1,2-dioxocyclopenta(hexa) [g]imidazolidino[3,2-f]pyrimido[4,5-b]-[1,4] thiazines. Derivatives of the new tricyclic 1-oxazino [5,4-g]pyrimido[4,5-b][1,4]thiazine system were obrtained by reaction of 6-carbethoxy-7-acetylpyrimido [4,5-b] [1,4] thiazines with hydroxylamine.     

Benzopentalenonaphthalenones from the intramolecular capture of a merocyanine derived from a naphthopyran

Novel, highly coloured benzopentalenonaphthalenones result from a cascade process initiated by the thermally-induced ring-opening of diarylmethanol substituted 2H-naphtho[1,2-b]pyrans in the presence of acid.     

Efficient synthesis of fused perhydrofuro[2,3-b]pyrans (and furans) by ring opening of 1,2-cyclopropanated sugar derivatives

[structure: see text]. An efficient method has been developed for the construction of fused perhydrofuro[2,3-b]pyrans by diastereoselective ring opening of 1,2-cyclopropanated sugar derivatives. The methodology has been successfully applied to the synthesis of fused perhydrofuro[2,3-b]pyrano-gamma-butyrolactone derivatives.     

Selective construction of indeno[1,2-b]phenothiazine and indeno[2,1-c]phenothiazine via tandem annulation reaction

AcOH promoted annulation reaction of 2-arylideneindane-1,3-diones with methyl 2-(benzo[b][1,4]thiazin-3-ylidene)acetate in refluxing ethanol afforded pentacyclic tetrahydroindeno [1,2-b]phenothiazine in satisfactory yields and with high diastereoselectivity according to the unexpected tandem annulation process. When the above reaction was carried out in refluxing acetic acid, isomeric dihydroindeno [1,2-b]phenothiazines and dihydroindeno [2,1-c]phenothiazines were obtained in comparable yields according to alternate tandem annulation process.     

A study of nitrogen- and sulfur- containing heterocycles

The reaction of 3-amino-6-chloro-2-mercaptopyridine with phenacyl halides has been studied, and a number of 3-aryl-7-chloro-2H-pyrido-[2,3-b]-1,4-thiazines have been synthesized. Two types of intermediate compounds have been isolated: 2-amino-6-chloro-2-phenacyl-thiopyridines and 3-aryl-7-chloro-3-hydroxy-1,2-dihydropyrido[2,3-b]-1,4-thiazines.     

Chromene chromium carbene complexes in the syntheses of naphthopyran and naphthopyrandione units present in photochromic materials and biologically active natural products

The carbene complex 5-(2,2-dimethyl-2H-chromene)methoxylmethylene chromium pentacarbonyl will undergo a benzannulation reaction with phenylacetylene, 1-pentyne, 3-hexyne, and trimethylsilylacetylene to give 7-hydroxy-10-methoxy-3H-naphtho[2.1-b]pyrans as the primary product. These compounds are difficult to obtain pure due to their sensitivity to air. If the benzannulation reaction is performed in conjunction with protection of the phenol function at C-7, then good to excellent yields of 7-alkoxy-10-methoxy-3H-naphtho[2.1-b]pyrans are afforded. If the 7-hydroxy products are captured by triflic anhydride, then the resulting aryl triflate can be used to access 3H-naphtho[2.1-b]pyrans bearing C-7 carbon substituents. The 7-hydroxy products can be oxidized to 3H-naphtho[2,1-b]pyran-7,10-diones which are stable. The chromenyl carbene complex reacts with 1,6-bis(triisopropylsilyl)-1,3,5-hexatriyne to give a 2,3-dihydro-2,2-dimethylbenzo[de]chromene, a product type that has not been seen before in the reaction of Fischer carbene complexes with alkynes. A mechanism is proposed for this process that involves alpha,beta-hydride elimination from a chromacyclobutane intermediate. Chromenyl tungsten complexes react with alkynes to give products that result from cyclization without CO insertion.     

A study of nitrogen- and sulfur- containing heterocycles

The reaction of 3-amino-6-chloro-2-mercaptopyridine with phenacyl halides has been studied, and a number of 3-aryl-7-chloro-2H-pyrido-[2,3-b]-1,4-thiazines have been synthesized. Two types of intermediate compounds have been isolated: 2-amino-6-chloro-2-phenacyl-thiopyridines and 3-aryl-7-chloro-3-hydroxy-1,2-dihydropyrido[2,3-b]-1,4-thiazines.For part VI, see [3].     

Synthesis of a 4H-anthra[1,2-b]pyran derivative and its antimicrobial activity

The five-step synthesis of the new 4H-anthra[1,2-b]pyran derivative 1 is reported. The key steps in this approach included a Marschalk alkylation of 1,4-dihydroxyanthraquinone followed by a Baker-Venkataraman reaction and then an acid-catalyzed cyclization of ring A to form the 4H-anthra[1,2-b]pyran system. Two compounds, the 4H-anthra[1,2-b]pyran 1 and the anthraquinone derivative 6 were evaluated for antimicrobial activity and showed moderate antialgal, antifungal, and antibacterial activities.     

Sequential approach to the synthesis of 'U and Z' shaped polycyclic heteroarenes

The synthesis of three new classes of heteroarenes, built through the sequential fusion of naphthalene, benzo/naphtho[b]oxepine and thiochromene rings with pyran and pyrimidine ring systems to give 'U and Z' shaped structural frameworks is reported. The methodology is based on the synthesis of pyran fused intermediates, 1-methylthio-3-oxo-5,6-dihydro-3H-benzo[f]chromene-2-carbonitrile (3), 4-methylthio-2-oxo-5,6-dihydro-2H-benzo/naphtho[b]pyrano[2,3-d]oxepine-3-carbonitriles (10, 20) and 4-methylthio-2-oxo-2,5-dihydrothiochromeno[4,3-b]pyran-3-carbonitriles (15) from the reaction of 2-tetralone, benzo/naphtho[b]oxepin-5-ones and thiochromen-4-ones with methyl 2-cyano-3,3-dimethylthioacrylate respectively. Further condensation of intermediates 3, 10, 20 and 15 with amidines led to the formation of tetracyclic 'U' shaped 4-amino-2-aryl-7,8-dihydro-5-oxo-5H-naphtho[2,1-b]pyrimido[4,5-d]pyrans (8) and 'Z' shaped 4-amino-2-aryl-5-oxo-12,13-dihydro-5H-benzo/naphtho[b]oxepino[5,4-b]pyrimido[4,5-d]pyrans (12, 22) and 4-amino-2-aryl-5-oxo-5,12-dihydrothiochromeno[4,3-b]pyrimido[4,5-d]pyrans (17). Compound 12f forms a chain of dimers through N-HO interactions as indicated by the X-ray structure analysis, and the quantum chemical calculations performed at the MP2 level indicate that this interaction energy is 10 kJ mol(-1).     

Condensed isoquinolines. 37.* Heterocyclization using 3-(arylamino)- and 3-(hetarylamino)isoquinolin-1(2H)-ones

The reaction of 3-NHR-isoquinolin-1(2H)-ones (R = Ar) with aromatic aldehydes in the presence of Me3SiCl or in acetic acid leads to the formation of derivatives of dibenzo[b,f][1, 8]naphthyridin-5(6H)- one and benzo[f]isoquino[3,4-b][1, 8]naphthyridine-5,9(6H,7H)-dione. The reaction for R = Het in the presence of Me3SiCl gives derivatives of 5H-pyrido[1',2':1,2]pyrimido[4,5-c]isoquinolin-5-one, benzo[f]isoquinoline[3,4-b][1,8]naphthyridine-5,9[6H,7H]-dione, and derivatives of new heterocyclic systems, 5H-pyrazino[1',2':1,2]pyrimido[4,5-c]isoquinolin-5-one, 5H-[1,3]thiazolo[3',2':1,2]pyrimido- [4,5-c]isoquinolin-5-one, 5-H-benzo[f]pyrazolo[3,4-b][1,8]naphthyridin-5-one, and isoquino[3,4-b]- [1,5]naphthyridin-5(6H)-one. The effect of the structure of substituent R and nature of the substituent in the benzaldehydes on the structure of the reaction products was studied.     

Synthesis of Fluoroalkylated Heterocycles via the Reaction of 3-(1-Hydropolyfluoroalkenyl)-1-oxo-2,4,1-benzoxazines with Dinucleophilic Reagents

The reaction of 3-(1-hydropolyfluoroalkenyl)-1-oxo-2,4,1-benzoxazines 1 with some dinucleophiles was inves-tigated.7-Fluoroalkyl-2,3-dihydro-1,4-diazepine[1,2-d]quinazolin-11-ones 2,2-fluoroalkylisoxazolo[3,2-b]quin-azolin-9-ones 3 and 2-fluoroalkylbenzoimidazoles 4 were obtained from the reaction of 1 with 1,2-diaminoethane,hydroxylamine hydrochloride and 1,2-diaminobenzene respectively.     

3-炔基咪唑并[1,2-b]哒嗪的简便合成

以咪唑并[1,2-b]哒嗪为原料,与N-碘代丁二酰亚胺在三氟乙酸/二氯甲烷中于室温进行碘代反应制得3-碘咪唑并[1,2-b]哒嗪(3);3与三甲基硅基乙炔在Pd(OAc)_2催化下经Sonogashira偶联反应制得3-三甲基硅基乙炔基咪唑并[1,2-b]哒嗪(4);4在碳酸钾作用下脱除三甲基硅基合成了3-炔基咪唑并[1,2-b]哒嗪,总收率61.2%,其结构经~1H NMR和HR-MS确证。     

First asymmetric synthesis of 3-alkoxycarbonyl-2-amino-4-aryl-4H-naphtho[1,2-b]pyrans

The first asymmetric synthesis of 3-alkoxycarbonyl-2-amino-4-aryl-4H-naphtho[1,2-b]pyrans, by Michael addition of 1-naphthol to chirally modified arylidenecyanoacetates 6 and 7 , is described. Good yields and low diastereomeric excesses have been obtained in the 1,4-conjugate additions. The absolute stereochemistry at C-4 in major isomers of pyrans 8 and 9 has been assigned as 5 by X-ray analysis of major pyran 8 .     

Synthesis,stability and bonding situation of tris-, bis- and mono[9-(azuleno[1,2-b]thienyl)]methyl cations

Stable tris-, bis- and mono[9-(azuleno[1,2-b]thienyl)]methyl cations (7a, 8a and 9a) and their derivatives, with a 6-isopropyl substituent on each azuleno[1,2-b]thiophene ring (7b, 8b and 9b) were prepared by the hydride abstraction reaction of the corresponding methane derivatives. The bonding situation of these compounds including the methane derivatives was examined by analysis of the 3J(H,H) values for the seven-membered ring from the 1H NMR spectra. The methane derivatives exhibited a significant alternating pattern in the 3J(H,H) values, which indicated that the pi-system of the azulene core is perturbed by the fused thiophene ring, showing a tendency towards a localized heptafulvene substructure. The 3J(H,H) values of 7b and 8b in the seven-membered ring revealed that the alternating C-C bond lengths in the azulene core still existed. The cations 9a and 9b, which exhibited nearly equal 3J(H,H) values in the seven-membered ring, exhibit the development of a delocalized tropylium substructure in the azulene core. X-ray crystal analysis of 6-isopropylazuleno[1,2-b]thiophene revealed substantial bond-length alternation in the seven-membered ring. Significant bond-length equalization in the seven-membered ring was also confirmed by the X-ray crystal analysis of 9b. The stability of these carbocations was examined by measurement of the pKR+ values and the redox potentials, which revealed that the bond-length alternation in the azulene core does not significantly affect the stability of the carbocations.     

Triazolobenzodiazepine Derivative (III): Synthesis of s-Triazolo-[4,3-a]-benzimidazolo-[1,2-d][1,4]-benzodiazepines

A 7H-benzimidazolo-[1,2-d] [1,4]-benzodiazepin-6(5H)-one was isolated in high yield from a condensation reaction of 2-(o-aminophenyl)benzimidazole with bromoacetyl bromide. The reactivity of 7H-benzimidazolo-[1,2-d] [1,4]-benzodiazepin-6(5H)-one have been studied.     

Investigation of heterocycles containing nitrogen or sulfur. 47. Reactions of 1,2-dioxo-3a-alkyl-4,7-dichloroxazolidino [3,2-f]pyrido[2,3-b]-1,4-thiazines with saturated cyclic amines. synthesis and structure of derivatives of 1,2-dihydrothiazolo[5,4-b]pyridine

It has been established spectroscopically that 1-N-oxalamides of 2-acyl-5-chloro-1,2-dihydrothiazolo[5,4-b] pyridine are formed in the reaction of 4,7-dichloroxazolidino[3,2-f]pyrido[2,3-b]-1,4-thiazines with morpholine, piperidine and pyrrolidine. The products are a mixture of amide conformers in solution. The reaction intermediate 2-(1-chloro-2-oxobutylthio)-3-pyrrolidinooxamoyl-6-chloropyridine has been isolated and characterized. A proposed reaction scheme is presented.For Communication 46 see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1125–1132, August, 1993.     

Photochemical Synthesis and Characterization of 8,9-Dihydroacenaphtho-[1,2-b][1,4]Dioxins

The orange-red 8,9-dihydroacenaphtho[1,2-b] [1,4]dioxins were synthesized by the photo-Diels-Alder reaction of acenaphthenequinone with the corresponding alkenes. The products were characterized by spectroscopic and X-ray methods.     

Synthesis of 1,10-phenanthrolines fused with bicyclo[3.3.0]octane and bicyclo[3.3.1]nonane frameworks

Reactions of bicyclo[3.3.1]nonane-2,6-dione and bicyclo[3.3.0]octane-3,7-dione with 8-amino-7-quino-linecarbaldehyde under basic conditions led to fused nonplanar compounds with one or two 1,10-phenanthroline moieties. The novel heterocyclic systems bicyclo[3.3.1]nonano[2,3-b]bis[1,10]-phenanthroline, cis-bicyclo[3.3.0]octano[3,2-b:7,6-b']bis[1,10]phenanthroline, bicyclo[3.3.1]nona-no[2,3-b:6,7-b']bis[1,10]phenanthroline, and 8H-9,16-methanoindolo[2',3':5,6]cycloocta[1,2-b]bis-[1,10]-phenanthroline have been synthesized and characterized.