Mass spectrometric studies of cis- and trans-1a,3-disubstituted-1, 1-dichloro-4-formyl-1a ,2,3,4-tetrahydro-1H-azirino [ 1,2-a] [1,5] benzodiazepines

The mass spectrometric behaviour of four cis- and trans-la, 3-disubstituted -1,1 -dichloro-4-formyl-1a,2,3,4-tetrahydro-1H-azirino[1, 2-a] [1,5] benzodiazepines has been studied with the aid of mass-analysed ion kinetic energy spectrometry and exact mass measurements under electron impact ioniza-tion. All compounds show a tendency to eliminate a chlorine atom from the aziridine ring, and then eliminate a neutral propene or styrene from the diazepine ring to yield azirino[ 1, 2-6][1,3]benzimidazole ions. These azmno[1,2-a] [1,5]-benzodiazepines can also eliminate HCl, or Cl plus HG simultaneously to undergo a ring enlargement rearrangement to yield 1,6-benzodiazocine ions, which further lose small molecular fragments, propyne or phenylacetylene, with rearrangement to give quinoxaline ions.     

An efficient synthesis of novel pyridothieno-fused thiazolo[3,2-α]pyrimidinones via Pictet–Spengler reaction

An efficient method for the synthesis of novel pyrido[3',2':4',5']thieno[3',2':2,3]pyrido [4,5:d][1,3]thiazolo[3,2-a]pyrimidine-4-one derivatives(5) has been developed using a Pictet–Spengler reaction between 2-(3-aminothieno[2,3-b]pyridin-2-yl)thiazolo[3,2-a] pyrimidin-5-one(3), which could be obtained from the condensation of 7-(chloromethyl)-5H-thiazolo[3,2-a]pyrimidin-5-one(1) with3-cyanopyridine-2-thione(2) via Thorpe–Ziegler isomerization, and aromatic aldehydes under NH_2SO_3 H as catalysis in good yields.     

Reaction of 2,3-Dihydro-1,5-benzothiazepines and Phenylacetyl Chloride in the Presence of Triethylamine： A New Aspect on the Formation Mechanism of Dihydro-1,3-oxazin-4-one Derivatives

2a,4-Disubstituted 2,2a,3,4-tetrahydro-2-phenyl-1H-azeto[2,1-d][ 1,5]benzothiazepin-1-ones, as well as 2-substi-tuted 2,3-dihydro-3-phenylacetyl-2-styryl-benzothiazoles and 4a,6-disubstituted 3- .benzyl-4a,5-d/hydro-2-phenyl-1H,6H-[1,3]oxazino[2,3-d][1,5]benzothiazepin-1-ones, were obtained from the reaction of 2,4-disubstituted 2,3-dihydro-1,5-benzothiazepines with phenylacetyl chloride in the presence of triethylamine. The mechanism for the formation of 4a,5-dihydro-1H,6H-[1,3]oxazino[2,3-d][1,5]benzothiazepin-1-ones, 2,3-dihydro-1,3-oxazin-4-one derivatives, was suggested.     

Highly regioselective synthesis of dicyano-8a,10,11-trihydropyrrolo[1,2-a][1,10]phenanthrolines via a domino-Knoevenagel-cyclization

1,10-Phenanthrolinium N-ylides,can react with malonitrile and aromatic aldehydes via a domino-Knoevenagel cyclization to afford a new class of trihydropyrrolo[1,2-a][l,10]phenanthroline derivatives as stable helical compounds in a simple,mild,and efficient protocol in excellent yields.     

Crystal Structure of 1,1-Dichloro-3-Dichloromethyl-1a-3-Dipenyl-1a,2,3,4-Tetrahydro-1H-Azirino[1,2-a][1,5]benzodiazepine (C23H18Cl4N2)

The crystal structure of the title compound, 1,1-dichloro-3-dichloro-3-dichloromethyl-1a,3-diphenyl-1a,2,3,4-tetrahydro-1H-azirino[1,2-a][1,5]benzodiazepine (C23H18Cl4N2, Mr=464.22) was crystallizedin triclinic, space group P1, with cell dimensions a=9.621(7), b=9.694(9), c=12.669(6) , α=107.99(5)°, β=101.42(5)°, γ=69.94(6)°, V=1050.2(4)3, Z=2, Dc=1.468 g/cm3, CuKα(λ=1.5418). F(000)=1816, μ=2.44 mm-1. The structure was solved by direct methods and refined by full-matrix least-squares method, and the final crystallographic discrepancy factor is 0.063 for 2555observed reflections. The molecular backbone is a tricyclic system with the central seven-membered 1,5-diazepine ring in twisted boat-like conformation and cis-fused to both aziridine ring and benzene ring.     

A Convenient Synthesis of Octahydro-pyrazino [ 1,2- a ] pyrazine

The recent research results suggest that a series of octahydro-pyrazino[ 1,2-a ]pyrazines are useful as antiallergic agents.[1] Gubert et al. [2] developed a route from 1,4-dibenzyl-2-ethoxycarbonylpiperazine for the synthesis of this ring system. Under their conditions, this ring system was obtained with a low overall yield in six steps. Optimization of synthetic route to this ring system is still desirable. In this paper, we presented an efficient synthesis of octahydropyrazino[1,2-a]pyrazine by a new and efficient method starting from 1,3-dichloro-2-propanol and N-tosylated diethylenetriamine. The structure of title compound was determined by spectroscopy and X-ray diffraction technique.     

Cycloaddition of benzoheteroazepine II Reactions and conformations of cycloadducts on1,5-benzothiazepines and 1,5-benzodiazepines with nitrile imine and nitrile oxides

Benzodiazepine and benzothiazepine derivatives have been well known as therapeutically important compounds. Four new tricyclic heterocyclic compounds, 3a,4,5,11-tetrahydro-3H-1,2,4-triazolo[4,3-d] [1, 5]benzothiazepines (3), 3a,4,5,11-tetrahydro-3H,6H-1,2,4-triazolo[4,3-d][1,5]benzodiazepine (4), 3a, 4,5,11-tetrahydro-1,2,4-oxadiazolo[4,5-d] [1,5]benzothiazepines (5, 6) and 3a,4,5,11-tetrahydro-6H-1, 2,4-oxadiazolo[4, 5-d] [ 1, 5 ] benzodiazepines (7,8), have been synthesized by 1,3-dipolar cycloaddition reactions of 2, 3-dihydro-1, 5-benzothiazepines and 2, 3-dihydro-1H-1, 5-benzodiazepine with benzonitrile N-phenylimine and benzonitrile oxides, respectively. The conformations of some cycloadducts and cycloaddition mechanism are described.     

One-pot synthesis of pyrrolo[1,2-a]quinoxaline and pyrrolo[1,2-a]pyrazine derivatives via the three-component reaction of 1,2-diamines,ethyl pyruvate and α-bromo ketones

A simple synthetic protocol has been developed involving the three-component reaction between 1,2-diamines, ethyl pyruvate and a-bromo ketones in the presence of Fe Cl3 as a catalyst. A number of pyrrolo[1,2-a]quinoxaline and pyrrolo[1,2-a]pyrazine derivatives were synthesized in excellent yields using this protocol.     

An efficient synthesis of 1-oxo-1,2-dihydrobenzo[b][1,6]naphthyridine-4-carbonitriles

Ethyl α-(dimethylaminomethylene)-2-cyanomethyl-4-phenylquinoline-3-carboxylate(2) as new synthons directed to 1-oxo-1,2-dihydrobenzo[b][1,6]naphthyridine-4-carbonitriles was obtained by the condensation of ethyl 2-cyanomethyl-4-phenylquinoline-3-carboxylate(1) and N,N-dimethylformamide dimethyl acetal(DMFDMA).Reaction of this enamine with primary amines(3) in HOAc-DMF at120 ℃then affords 2-substituted 1-oxo-1,2-dihydrobenzo[b][1,6]naphthyridine-4-carbonitrile derivatives(4) in good yields by a tandem addition-elimination-cyclization reaction.     

7-Deazapurines:Synthesis of new pyrrolo[2,3d]pyrimidin-4-onescatalyzed by a Brφnsted-acidic ionic liquid as a green and reusable catalyst

<正>Some new 2-aryl-3,7-dihydro-4H-pyrrolo[2,3-d]pyrimidin-4-ones have been prepared through cyclocondensation of 2-amino 1H-pyrrole-3-carboxamides with aromatic aldehydes followed by air oxidation in the presence of 3-methyl-1-(4-sulfonic acid)butylimidazolium hydrogen sulfate[(CH_2)_4SO_3HMIM][HSO_4],a Br(?)nsted-acidic ionic liquid,as a green and reusable catalyst in solvent-free conditions.     

NEW HETEROCYCLIC SYSTEM SYNTHESIS I REACTION OF DIHYDRO-1,5-BENZO-DIAZEPINES AND THIAZEPINES WITH (ETHOXYCARBONYL)CARBENES

Dihydro-1-benzoyl-1,5-benzodiazepines react with (ethoxycarbonyl)carbenes to give 4H-azirino-[1,2-a][1,5]-benzodiazepines and unexpected new tin9 system 1H-pyrrolo-[1,2-a][1,5]-benzodiazepines. Dihydro-1,5-benzothiazepines react with (ethoxycarbonyl)carbenes in cyclohexane to gire unexpected rin9 cleavage products ethyl (2E, 4E)-3-aryl-2-arylthiohexadienoates.     

Synthesis of (1H)-3,4-Dihydropyrrolo[2,1-c][1,4]oxazin-1-one Derivatives

It has been found that some acyl derivatives of 1,2,3,4-tetrahydro-1-indolizin-1-one 1and (1H)-3,4-dihydropyrrolo[1,2-a]pyrazin-1-one 2 show remarkable anti-inflammatory and analgesic activities1,2. The interest in extending the study of structure-activity relationships and search of new potent anti-inflammatory and analgesic agents led us to design and synthesize (1H)-3,4-dihydropyrrolo[2,1-c][1,4]oxazin-1-one 3 derivatives. NO 1 NNHO2 87654321ONO3 A few examples of the p…     

Tin(II) Chloride Dihydrate Catalyzed Groebke Condensation: An Efficient Protocol for the Synthesis of 3-Aminoimidazo[1,2-a]pyridines

The ability of tin(II) chloride dihydrate as a catalyst to promote the three-component condensation reaction from a diversity of aromatic aldehydes, 2-aminopyridines and isonitriles at room temperature is described. This methodology affords a number of 3-aminoimidazo[1,2-a]pyridines in the presence of tin(II) chloride dihydrate as a new and mild Lewis acid catalyst in the multi-component reaction in reasonable yields and short reaction time without any significant optimization of the reaction conditions.     

Crystal Structure and Herbicidal Activity of 5,7-Dimethoxy-(2,4-dichlorophenoxyacetyl- imino)-2H-1,2,4-thiadiazolo[2,3-a]pyrimidine

1 INTRODUCTION 2H-1,2,4-Thiadiazolo[2,3-a]pyrimidine compounds are a new series of ALS inhibiting agents besides sulfonylurea herbicide. Their herbicidal activity is similar to that of sulfonylurea herbicide, but be- cause of weak S–N bond existing in 2H-1,2,4-thiadi- azolo[2,3-a]pyrimidine ring, which is advantageous for the absorption and metabolism of vegetable, 2H- 1,2,4-thiadiazolo[2,3-a]pyrimidine herbicides have better selectivity[1～3]. At present, reports about the synthesis…     

Synthesis and spectroscopic characterization of novel2-amino-4,5,6,7-tetrahydro-3H-cyclopenta[d]pyrimidine and pyrimido[1,2-α]pyrimidine derivatives

2-Aminocyclopenta[d]pyrimidines 3a–c were achieved via a one-pot, three-component reactions of cyclopentanone 1, aromatic aldehyde and guanidine hydrochloride(1:2:1 molar ratio). Also, cyclization of 2,5-bis-(arylmethylidene)cyclopentanones 2 with guanidine hydrochloride(1:1 molar ratio) in methanol in the presence of sodium methoxide afforded cyclopenta-[d]pyrimidines 3. Compound 3c has been shown to be a useful building block for the synthesis of some novel pyrimido[1,2-a]pyrimidines 5, 7and 12. The structures of the newly synthesized compounds were confirmed on the basis of analytical and spectral data.     

Novel Synthesis of 1,2,3-Triazoles via 1,3-Dipolar Cycloadditions of Alkynes to Azides in Ionic Liquid^＋

2-Azido-3,5-dichloropyridine and 2-azido-5-chloro-3-fluoropyridine were given by reaction of sodium azide with 2,3,5-trichloropyridine, 3,5-dichloro-2-fluoropyridine or 5-chloro-2,3-difluoropyridine in ionic liquids. 1,3-Dipolar cycloaddition of 2-azido-3,5-dichloropyridine or 2-azido-5-chloro-3-fluoropyridine to alkynes in ionic liquids afforded the corresponding 1,4,5-trisubstituted [1,2,3]-triazoles in good yields and regioselectivities.     

Syntheses, properties and structures of copper and nickel complexes of 6,7-dihydro-5H-1,4-dithiepin-2,3-dithiolate

The reaction of CuCl2-2H2O or NiCl2.6H2O with K2(C5H6S4) [potassium salt of 6,7-dihydro-5H-1,4-dithiepin-2,3-dithiolate] under nitrogen atmosphere resulted in the isolation of [Cu(C5H6S4)2]- or [Ni(C5H6S4)2]- as the tetrabutylammonium salt. Both complexes show characteristic IR and UV-Vis absorptions of transition metal dithiolenes. Cyclic voltammograms contain two waves indicating a two step electrochemical procedure [M(C5H6S4)2]0 = [M(C5H6S4)2]1-= [M(C5H6S4)2]2-. Single crystal structure study has been carried out on the nickel complex. Crystal of [Bu4N][Ni(C5H6S4)2] belongs to monoclinic space group P21/c with a=17.576(5), 6=10.883(2), c=17.773(4) A,B=91.07(2)0, Z=4, and o(calcd.)=1.348 g/cm3. Final result is R=0.059 for 2959 reflections. The NiS4 core exhibits square planar coordination with average Ni-S bond length of 2.134(5) A. There are not anion pairs in crystal. The anions stack along a and c axes while the cations intercalate in them. The nearest S-S contact is 4.429 A. The solid powder ESR s     

Two Copper Complexes Based on Derivatives of Imidazo[1,5-a]pyridine: Syntheses,Structures, and Catalytic Properties

The syntheses, crystal structures and catalytic activities of two copper complexes are reported. Reaction of CuC l, 3-(pyridin-2-yl)imidazo[1,5-a]pyridine and pyridine-4-formaldehyde under solvothermal conditions gave [Cu_4(L1)_2Cl_2][CuCl_2]_2(1, L1 = 1,1?-(pyridin-4-ylmethylene)bis(3-(pyridin-2-yl)imidazo[1,5-a]pyridine). The ligand L1 was generated in situ from the reaction of 3-(pyridin-2-yl)imidazo[1,5-a]pyridine and pyridine-4-formaldhyde. The tetranuclear [Cu_4(L1)_2Cl_2]~(2+) moiety displays McClellan Saddle-like configuration. Reaction of Cu(BF_4)_2×6H_2O with 1,1?-(pyridin-4-ylmethylene)bis(3-(pyridin-2-yl)imidazo[1,5-a]pyridine(L2) in glass tube generated [Cu(L2)(H_2O)_2]_2[BF_4]_2(SiF_6)×2H_2O(2). The structures of 1 and 2 were characterized by Xray single-crystal diffraction analysis. The catalytic activities of 1 and 2 toward ketalization reactions were studied. They both exhibited high activities for the ketalization of aliphatic ketones by ethylene glycol.     

Synthesis and characterization of a new Mo-Fe-S cluster compound containing MoO_3S_3 unit and mixed-valent Mo atoms [Et_4N]_2[Mo_2Fe(CO)_4(S,O-C_6H_4-1,2)_3Cl_2]

Reaction of [Mo3(CO)7(S,O-C6H4-1,2)3]2- with FeCl2 in MeCN at 60℃ affords a new Mo-Fe-S cluster complex containing MoO3S3 unit and mixed-valeut Mo atoms, [Et4N]2[Mo2Fe-(CO)4(O,S-C6H4-1,2)aCl2] (1). 1 is characterized by elemental analysis, IR, Mossbauer spectra, X-ray photoelectron spectra and mass spectra. And the structure of 1 is suggested as the structure which contains a [Mo(S,O-C6H4-1,2)3] unit of which the two of three sulfur atoms link to a Mo(CO)4-moiety and the three oxygen atoms are coordinated to a FeCl2 ligand.     

Study on the Ring Eulargment Reaction: Synthesis of 7,8,13, 13a-tetrahydroisoindolo[1,2-b][3]benzazepine and 5,6,8,9,14,14a-hexahydroisoquino[1,2-b][3]benzazepine

In our research on the ring enlargement of certain N-heterocycles, a general procedure for the ring enlargement with the insertion of an extra -CH2- was improved and shown in Scheme I1.Scheme IThe procedure had been carried out with such N-heterocycles as 2-methyl-1,2,3,4-tetrahydroisoquinoline2, tetrahydroberberine and strychnine3 with expected results. Thus, the procedure shown in Scheme I provides a new approach to the synthesis of larger N-heterocycles.Isoindolo[1,2-b][3]benzazepines a…