A new method for the synthesis of dinaphtho[1,2‐b;2′,1′‐d]thiophenes and selenophenes

Naphthalene‐1‐sulfonic acid dimethylamides were treated with n‐BuLi and elemental sulfur or selenium to afford dinaphtho[1,2‐b:2′,1′‐d]thiophenes and selenophenes, respectively. This is the first example of making two C S/Se bonds and a C C bond in a single step at room temperature and also demonstrates a useful method for the synthesis of both thiophenes and selenophenes on naphthalene. In the case of the reactions of elemental selenium, diselenides were also obtained along with dinaphtho[1,2‐b:2′,1′‐d]selenophenes. The structure of dinaphtho[1,2‐b:′,1′‐d]thiophene was characterized by X‐ray crystallography as a representative molecule. © 2007 Wiley Periodicals, Inc. Heteroatom Chem 18:239–248, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20291     

The synthesis of dinaphthothiophenes

The synthesis of dinaphtho[1,2-b:2′,3′-d]thiophene ( 6 ), dinaphtho[2,1-b:2′,3′-d]thiophene ( 15 ), dinaphtho-[1,2-b:1′,2′-d]thiophene ( 20 ), dinaphtho[2,1-b:1′,2′-d]thiophene ( 26 ), dinaphtho[2,3-b:2′,3′-d]thiophene ( 37 ) and dinaphtho[1,2-b:2′,1′-d]thiophene ( 45 ) has been accomplished.     

Donor–acceptor semiconducting polymers for organic solar cells

This review describes the synthesis and photovoltaic performance of donor–acceptor (D–A) semiconducting polymers that have been reported during the last decade. 9,9‐Dialkyl‐2,7‐ fluorene, 2,7‐carbazole, cyclopenta[2,1‐b:3,4‐b′]dithiophene, dithieno[3,2‐b:2′,3′‐d]silole, dithieno[3,2‐b:2′,3′‐d]pyrrole, benzo[1,2‐b:4,5‐b′]dithiophene, benzo[1,2 b:4,5 b′]difuran building blocks, and their D–A copolymers are described in this review. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013     

An Efficient Synthesis of Spiro‐oxindole Derivatives by Three‐Component Reactions in Water

An efficient synthesis of (3S)‐1,1′,2,2′,3′,4′,6′,7′‐octahydro‐9′‐nitro‐2,6′‐dioxospiro[3H‐indole‐3,8′‐[8H]pyrido[1,2‐a]pyrimidine]‐7′‐carbonitrile is achieved via a three‐component reaction of isatin, ethyl cyanoacetate, and 1,2,3,4,5,6‐hexahydro‐2‐(nitromethylidene)pyrimidine. The present method does not involve any hazardous organic solvents or catalysts. Also the synthesis of ethyl 6′‐amino‐1,1′,2,2′,3′,4′‐hexahydro‐9′‐nitro‐2‐oxospiro[3H‐indole‐3,8′‐[8H]pyrido[1,2‐a]pyrimidine]‐7′‐carboxylates in high yields, at reflux, using a catalytic amount of piperidine, is described. The structures were confirmed spectroscopically (IR, ¹H‐ and ¹³C‐NMR, and EI‐MS data) and by elemental analyses. A plausible mechanism for this reaction is proposed (Scheme 2).     

A Facile,Atom‐Economical,and One‐Pot Pseudo Four‐Component Synthesis of Isoxazolylspiro[diindeno[1,2‐b;2′,1′‐e]pyridine‐11,3′‐indoline]‐2′,10,12‐triones Catalyzed by pTSA

A facile, atom‐economical, and one‐pot pseudo four‐component method for the synthesis of isoxazolylspiro[diindeno[1,2‐b ;2′,1′‐e ]pyridine‐11,3′‐indoline]‐2′,10,12‐trione derivatives ( 14 ) is described. Prominent advantages of this new method are operational simplicity, excellent yields with high purity, short reaction time, easy workup, and mild conditions.     

Studies with Heterocyclic β‐Enaminoniriles: A Simple Route for the Synthesis of Polyfunctionally Substituted Thiophene,Imidazo[1,2:1′,6′]pyrimido[5,4‐b]thiophene and Thieno[3,2‐d]pyrimidine Derivatives

Reaction of 3,5‐diaminothiophene‐2‐carbonitrile derivatives 3a‐c with ethoxycarbonylmethyl isothiocyanate and/or N‐[bis(methylthio)methylene]glycine ethyl ester led to formation of 7‐substituted‐8‐amino‐5‐thioxo‐6H‐imidazo[1,2:1′,6′]pyrimido[5,4‐b]thiophene‐2(3H)‐one derivatives 6a‐c and 7‐substituted‐8‐amino‐5‐(methylthio)imidazo[1,2:1′,6′]pyrimido[5,4‐b]thiophene‐2(3H)‐one 7a‐c , respectively. Also, the synthetic potential of the β‐enaminonitrile moiety in 3a‐c has been explored; it proved to be a promising candiate for the synthesis of 1,6‐disubstituted‐2,4‐diamino‐7,8‐dihydro‐8‐oxopyrrolo[1,2‐a]thieno[2,3‐e]pyrimidine derivatives 10a‐f and pyrido[2′,3′:6,5]pyrimido[3,4‐a]benzimidazole derivatives 12a,b .     

An approach to novel fused triazole or tetrazole derivatives starting from benzimidazo[1,2‐a]quinazoline‐5(7H)‐one and 5,7‐dihydro‐5‐oxopyrido[3′,2′:5,6]pyrimido[1,2‐a]benzimidazole

The synthetic potential of the title compounds benzimidazo[1,2‐a]quinazoline‐5(7H)‐one 2a and 5,7‐dihydro‐5‐oxopyrido[3′,2′:5,6]pyrimido[1,2‐a]benzimidazole 2b for the construction of novel polyhetero‐cyclic frameworks is reported. Compounds 2a,b , by conversion into their thio analogues 3a,b , were used for the synthesis of tetrazole ( 5a,b ) and triazole ( 7a,b ) derivatives, as well as for an unexpected synthesis of tri‐azoles 8a,b , isomers of 7a,b , resulting from the occurrence of a Dimroth rearrangement.     

Cyclodextrins in polymer synthesis: free radical polymerization of cyclodextrin complexes with oxazoline‐functionalized vinyl monomers as guest molecules in aqueous medium

The synthesis of five new oxazoline functionalized vinyl monomers N‐[4‐(4′,5′‐dihydrooxazol‐2‐yl)phenyl]acrylamide ( 3 a ), N‐[4‐(4′,5′‐dihydrooxazol‐2‐yl)phenyl]‐2‐methylacrylamide ( 3 b ), N‐{10‐[4‐(4′,5′‐dihydrooxazol‐2‐yl)phenylcarbamoyl]decyl}‐2‐acrylamide ( 5 a ), N‐{10‐[4‐(4′,5′‐dihydrooxazol‐2‐yl)phenylcarbamoyl]decyl}‐2‐methylacrylamide ( 5 b ) and N‐[4‐(4′,5′‐dihydrooxazol‐2‐yl)‐phenyl]‐4‐vinylbenzamide ( 7 ) is described. With an equimolar amount of 2,6‐dimethyl‐β‐cyclodextrin (DMCD) these monomers formed hydrophilic inclusion complexes 3 a,b‐DMCD , 5 a,b‐DMCD and 7‐DMCD . These complexes were polymerized radically in an aqueous medium. Resulting polymers P‐(3 a, b) , P‐(5 a, b) and P‐(7) precipitated during the polymerization due to unthreading of the cyclodextrin from the growing polymer chain. The remaining oxazoline moiety offers possibilities of further modification of the polymers, e. g. grafting in a cationic ring opening polymerization with commercially available alkyloxazolines.     

Chiral (Diphosphonite)platinum Complexes in Asymmetric Hydroformylation

The chiral diphosphonite ligand (11bR,11′bR)‐4,4′‐(9,9‐dimethyl‐9H‐xanthene‐4,5‐diyl)bis[dinaphtho[2,1‐d:1′,2′‐f][1,3,2]dioxaphosphepin] ((R,R)‐XantBino; (R)‐ 1 ), based on a rigid xanthene backbone, was applied in the Pt/Sn‐catalyzed hydroformylation of styrene ( 4a ), 4‐methylstyrene ( 4b ), vinyl acetate ( 4c ), and allyl acetate ( 4d ), by using a Pt/Sn ratio of 1 : 1. High ee of up to 80% were observed, along with good regioselectivities towards the desired branched aldehydes. For styrene, an interesting inversion in the stereoselection process was observed at elevated temperatures, and a mechanism is proposed considering the temperature dependence of the regioselectivity. The complex [PtCl₂{(S,S)‐XantBino}] ((S)‐ 2 ) was characterized by X‐ray crystal‐structure analysis, revealing an unusual out‐of‐plane ligand coordination of the metal fragment. The complex [PtCl(SnCl₃){(R,R)‐XantBino}] ((R)‐ 3 ) was characterized by means of ³¹P‐NMR spectroscopy.     

Syntheses of dibenzo[c,e][1,2]diselenin and related novel chalcogenide heterocyclic compounds

Reaction of 2,2′-dilithio-1,1′-binaphthyl with selenium followed by air oxidation gives a mixture of dinaph-thoselenophene and dimer and oligomers of 2,2′-diseleno-1,1′-binaphthyl. 2,2′-Dilithio-1,1′-biphenyl reacts with selenium to afford dibenzo[c,e][1,2]diselenin. Structures of the dimeric 2,2′-diseleno-1,1′-binaphthyl and dibenzo[c,e][1,2]diselenin have been confirmed by X-ray crystallographic analyses. Similar reaction of 2,2′-dilithio-1,1′-binaphthyl with sulfur or tellurium gives a mixture of dinaphthothiophene and dinaphtho[2,1-c:-1′,2′-e][1,2]dithiin or a mixture of dinaphthotellurophene and oligomer of 2,2′-ditelluro-1,1′-binaphthyl, respectively. Dibenzotellurophene and oligomer of 2,2′-ditelluro-1,1′-biphenyl are obtained from reaction of 2,2′-dilithio-1,1′-biphenyl with tellurium.     

Novel regioselective synthesis of 3′H,4H‐spiro[chromene‐3,2′‐[1,3,4]thiadiazol]‐4‐one containing compounds

A variety of 3″,5″‐diaryl‐3″H,4′H‐dispiro[cyclohexane‐1,2′‐chromene‐3′,2″‐[1,3,4]thiadiazol]‐4′‐ones 3a‐c were synthesized regioselectively through the reaction of 4′H,5H‐trispiro[cyclohexane‐1,2′‐chromene‐3′,2″‐[1,3,4]oxadithiino[5,6‐c]chromene‐5″,1″′‐cyclohexan]‐4′‐one ( 1 ) with nitrilimines (generated in situ via triethylamine dehydrohalogenation of the corresponding hydrazonoyl chlorides 2a‐c ) in refluxing dry toluene. Single crystal X‐ray diffraction studies of 3a,b add support for the established structure. Similarly, 3′,5′‐diaryl‐2,2‐dimethyl‐3′H,4H‐spiro[chromene‐3,2′‐[1,3,4]thiadiazol]‐4‐ones 5a‐c were obtained in a regioselective manner through the reaction of 2,2,5′,5′‐tetramethyl‐4H,5′H‐spiro[chromene‐3,2′‐[1,3,4]oxadithiino[5,6‐c]chromen]‐4‐one ( 4a ) with nitrilimines under similar reaction conditions. On the other hand, reaction of 2,5′‐diethyl‐2,5′‐dimethyl‐4H,5′H‐spiro[chromene‐3,2′‐[1,3,4]oxadithiino‐[5,6‐c]chromen]‐4‐one ( 4b ) with nitrilimines in refluxing dry toluene afforded the corresponding 3′,5′‐diaryl‐2‐ethyl‐2‐methyl‐3′H,4H‐spiro[chromene‐3,2′‐[1,3,4]thiadiazol]‐4‐ones 5d‐f as two unisolable diastereoisomeric forms.     

Asymmetric Hydroformylation of Vinylfurans Catalyzed by {(11bS)‐4‐{[(1R)‐2′‐Phosphino[1,1′‐binaphthalen]‐2‐yl]oxy}dinaphtho[2,1‐d:1′,2′‐f]‐ [1,3,2]dioxaphosphepin}rhodium(I) [RhI{(R,S)‐binaphos}] Derivatives

The asymmetric hydroformylation of 2‐ and 3‐vinylfurans ( 2a and 2b , resp.) was investigated by using [Rh{(R,S)‐binaphos}] complexes as catalysts ((R,S)‐binaphos = (11bS)‐4‐{[1R)‐2′‐phosphino[1,1′‐binaphthalen]‐2‐yl]oxy}dinaphtho[2,1‐d:1′,2′‐f][1,3,2]dioxaphosphepin; 1 ). Hydroformylation of 2 gave isoaldehydes 3 in high regio‐ and enantioselectivities (Scheme 2 and Table). Reduction of the aldehydes 3 with NaBH₄ successfully afforded the corresponding alcohols 5 without loss of enantiomeric purity (Scheme 3).     

Ring transformations of heterocyclic compounds. XIX. Spiro[dihydropyridine‐indolines] novel heterocycles with two spiro‐condensed N‐containing subunits easy accessible by 1,3‐oxazinium ring transformation

The synthesis of hitherto unknown 1‐benzoyl‐1′,3′,3′‐trimethyl‐4,6‐diphenylspiro[1,2‐dihydropyridine‐2,2′‐indolines] 5 from 2,4,6‐triphenyl‐1,3‐oxazinium tetrafluoroborate ( 1b ) and 1,3,3‐trimethyl‐2‐methyleneindolines 2 (used as such or generated in situ from the corresponding 3H‐indolium salts 4 ) in the presence of triethylamine in anhydrous acetonitrile by a 3,6‐[C₃N+C₂] 1,3‐oxazinium ring transformation is reported. Structure elucidation is performed by an X‐ray structure determination of the spiro[dihydropyridine‐indoline] 5a . Spectroscopic data of the transformation products and their mode of formation are discussed.     

Synthesis and photovoltaic properties of thieno[3,4‐b]pyrazine or dithieno[3′,2′:3,4;2″,3″:5,6]benzo[1,2‐d]imidazole‐containing conjugated polymers

Novel conjugated polymers composed of benzo[1,2‐b:4,5‐b′]dithiophene and thieno[3,4‐b]pyrazine or dithieno[3′,2′:3,4;2″,3″:5,6]benzo[1,2‐d]imidazole units are synthesized by Stille polycondensation. The resulting polymers display a longer wavelength absorption and well‐defined redox activities. The effective intramolecular charge‐transfer and energy levels of all polymers are elucidated by computational calculations. Bulk‐heterojunction solar cells based on these polymers as p‐type semiconductors and [6,6]‐phenyl‐C₆₁‐butyric acid methyl ester (PC₆₁BM) as an n‐type semiconductor are fabricated, and their photovoltaic performances are for the first time evaluated. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 1067–1075     

Facile and simple synthesis of some new polyfunctionally heterocyclic derivatives incorporating 2‐imino‐2H‐chromene moiety

1,2‐Dihydro‐2‐imino‐6‐(2‐imino‐2H‐chromen‐3‐yl)‐1,4‐diphenyl‐pyridine‐3‐carbonitrile 4 has been synthesized and reacted with ethyl cyanoacetate to yield the new 5‐amino‐1,7‐dihydro‐2‐(2‐imino‐2H‐chromen‐3‐yl)‐7‐oxo‐1,4‐diphenyl‐1,8‐naphthyridine‐6‐carbonitrile 6 , which consider a good and available starting intermediate for synthesis of series of functionalized chromenes. So, the compound 6 was utilized as a key for the synthesis of some new pyrimido[5,4‐c][1,8]naphthyridinones, pyrido[2,3‐c][1,6]naphthyridinones, triazolo[3′,4′:1,6]triazino][5,4‐c][1,8]naphthyridinones, triazolo[2′,3′:1,6]pyrimido[4,5‐c][1,8]naphthyridinones, triazepino[6,5‐c][1,8]naphthyridinone, and triazino[5,4‐c][1,8]naphthyridinones. The structures of these compounds were established by elemental analysis, IR, MS, and NMR spectral analysis. J. Heterocyclic Chem., (2012).     

Annosqualine: a Novel Alkaloid from the Stems of Annona squamosa

Annosqualine (=(10′bR)‐1′,5′,6′,10′b‐tetrahydro‐9′‐hydroxy‐7′,8′‐dimethoxyspiro[cyclohexa‐2,5‐diene‐1,2′‐pyrrolo[2,1‐a]isoquinoline]‐3′,4‐dione; 1 ), a novel alkaloid with an unprecedented skeleton, and a new amide, dihydrosinapoyltyramine (=3‐(4‐hydroxy‐3,5‐dimethoxyphenyl)‐N‐[2‐(4‐hydroxyphenyl)ethyl]propanamide; 2 ), were isolated from the stems of Annona squamosa L., together with six known alkaloids. The structures of all compounds were elucidated spectroscopically by means of optical rotation, ¹H‐, ¹³C‐, and 2D‐NMR, and by EI‐MS, or by comparison with the spectral data of authentic samples. A possible biogenetical pathway towards annosqualine ( 1 ) is proposed.     

Polycyclic N‐Heterocyclic Compounds. Part 81: Synthesis and Evaluation of Pentacyclic 1,2,4,5‐Tetrahydro[1]benzothieno[2′,3′:6,7]thiepino[4,5‐e]imidazo[1,2‐c]pyrimidine and Related Compounds as Potential Antiplatelet Aggregators

Dehydrative ring closure reactions were carried out on fused 4‐(2‐hydroxyethylamino) (or 2‐hydroxyethoxy or 2‐hydroxyethylthio)pyrimidines ( 2a , 2b , 2c ) to give fused 2,3‐dihydroimidazo[1,2‐c] (or 2,3‐dihydrooxazolo[3,2‐c] or 2,3‐dihydrothiazolo[3,2‐c])pyrimidines. This reaction produced the pentacyclic 1,2,4,5‐tetrahydro[1]benzothieno[2′,3′:6,7]thiepino[4,5‐e]imidazo[1,2‐c]pyrimidine ( 3a ) and 1,2,4,5‐tetrahydro[1]benzothieno[2′,3′:6,7]thiepino[4,5‐e]thiazolo[3,2‐c]pyrimidinium chloride ( 3c ) from the 2‐hydroxyethylamino‐derivative and 2‐hydroxyethylthio‐derivative, respectively. In contrast, 2‐hydroxyethoxy‐derivative ( 2b ) gave the rearrangement product, 3‐(2‐chloroethyl)‐5,6‐dihydro[1]benzothieno[3′,2′:2,3]thiepino[4,5‐d]pyrimidin‐4(3H)‐one ( 4 ). Effects of the synthesized compounds on collagen‐induced platelet aggregation were also evaluated.     

A Convenient Synthesis and Pharmacological Activity of Novel Annelated Pyrimidine Derivatives

Simple and convenient synthesis for a series of 2,3‐diglycosylpyrimidine 4 , pyrazolo[3,4‐d]pyrimidine 8 , ditetrazolo[1,5‐a;1′,5′‐c]pyrimidine 9 , 2,9a,10‐triazaanthracene 12 , thieno[2,3‐d]pyrimidine 14 , 1,3,5,7‐tetraazafluorene‐8‐one 15 , 1,3,5‐triazafluorene‐8‐one 16 , 1,3‐diazafluorene 21a,b derivatives have been synthesized via a sequence of heterocyclization reactions of suitably functionalized 6‐[5‐(4‐bromophenyl)ox‐azol‐4‐yl]‐4‐oxo‐2‐thioxo‐1,2,3,4‐tetrahydropyrimidine‐5‐carbonitrile ( 2 ) with different electrophiles and nucleophiles. The new compounds were prepared with the objective to study their pharmacological properties.     

Synthesis,structure and some reactions of 4a',5′,6′,7′,8′,8a'‐hexahydro‐4′H‐spiro[cyclohexane‐1,9′‐[1,2,4]triazolo[5,1‐b]‐quinazolines]

2′‐Substituted 5′,6′,7′,8′‐tetrahydro‐4′H‐spiro[cyclohexane‐1,9′‐[1,2,4]triazolo[5,1‐b]quinazolines] 3a‐d were synthesized by condensation of 3‐substituted 5‐amino‐1,2,4‐triazoles 1a‐d with 2‐cyclohexylidene cyclohexanone 2 in DMF. The compounds 3 were hydrogenated with sodium borohydride in ethanol to give 2′‐substituted cis‐4a',5′,6′,7′,8′,8a'‐hexahydro‐4′H‐spiro[cyclohexane‐1,9′‐[1,2,4]triazolo[5,1‐b]quinazolines] 4a‐d in high yields. The reactions of alkylation, acylation and sulfonylation of the compounds 4 were studied. The structure of the synthesized compounds was determined on the basis of NMR measurements including HSQC, HMBC, NOESY techniques and confirmed by the X‐ray analysis of 6 and 11b . The described synthetic protocols provide rapid access to novel and diversely substituted hydrogenated [1,2,4]triazolo[5,1‐b]quinazolines.     

Using Cyclopenta[2,1‐b:3,4‐c′]dithiophene‐4‐one as a Building Block for Low‐Bandgap Conjugated Copolymers Applied in Solar Cells

A novel electron‐accepting unit cyclopenta[2,1‐b:3,4‐c′]dithiophene‐4‐one (CPDTO‐c′), which is an isomer of CPDTO‐b′ was developed. CPDTO‐c′ can be incorporated into the D–A backbone through 5, 7 positions. The 2 position of CPDTO‐c′ can be easily functionalized with an electron‐withdrawing chain. By copolymerizing CPDTO‐c′ with four different donor units: benzo[1,2‐b:4,5‐b′]dithiophene (BDT), dithieno[3,2‐b:2′,3′‐d]silole (DTS), carbazole, and fluorene, four new conjugated copolymers P1 – P4 were obtained. All these polymers have good solubility and low‐lying HOMO energy levels (−5.41 ∼ −5.92 eV). Among them, P1 and P2 exhibit broad absorption and narrow optical bandgaps of 1.91 and 1.72 eV, respectively. Solar cells based on P1 /PC₇₁BM afforded a PCE up to 2.72% and a high V_oc up to ∼0.9 V.