3,9‐Bis(dicyanomethylene)‐2,4,8,10‐tetrathiaspiro[5.5]undecane

The title compound, 2,2′‐(2,4,8,10‐tetra­thia­spiro­[5.5]­undec­ane‐3,9‐diyl­idene)­bis­(propane­di­nitrile), C₁₃H₈N₄S₄, has been designed and synthesized for use as a potential new organic molecular electronic material. The spiro‐annulated structure has twofold symmetry and is formed by two equal push–pull ethyl­ene units, with the cyclo­alkyl­thio groups as electron donors and the cyano groups as electron acceptors. The intermolecular S?N non‐bonded separation within a layer in the lattice is 3.296 (6) Å, indicating a strong intermolecular interaction between the cyano groups and the S atoms, while the S atoms in two neighbouring mol­ecules have a shortest S?S contact of 3.449 (3) Å. In addition, attractive C—H?N and C—H?S interactions bridge adjacent mol­ecules either within a layer or between layers. In short, these four types of intermolecular interactions combine to form an extended three‐dimensional network in the lattice, resulting in a highly ordered array of molecular packing.     

A novel synthetic route to N‐protected 1‐aminoalkylphosphonates

Dialkyl and dithioalkyl N‐protected 1‐aminoalkylphosphonates were synthesized using reactions of benzyl carbamate, aldehydes and chlorophosphites, or dithioalkyl chlorophosphite, respectively. This represents a novel synthetic method for 1‐aminoalkylphosphonates. © 2000 John Wiley & Sons, Inc. Heteroatom Chem 11:417–421, 2000     

Synthesis and reactions of 3,9-diisocyanates and diisothiocyanates in the 2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5] undecane series

The synthesis of several novel phosphorus-containing isocyanates and isothiocyanates is reported. These compounds are spiranes with two six-membered dioxaphosphorinane rings in their respective molecule. The phosphorus-bonded isocyanato and isothiocyanato groups are capable of undergoing addition reactions with active hydrogen atom-containing compounds.     

A novel and direct synthetic route to substituted 1,5‐dihydro‐4H‐[1]benzopyrano[4,3‐b]pyridine‐4,5‐diones

The condensation of 4‐hydroxy‐6‐methyl‐2H‐pyran‐2‐one and substituted 2‐hydroxybenzaldehydes with ammonium acetate gave the title heterocycles. Synthesis of 1,5‐dihydro‐2‐methyl‐4H‐[1]naphtho‐[1′,2′:5,6]pyrano[4,3‐b]‐pyridine‐4,5‐dione is also described. A reaction mechanism is discussed.     

A synthetic approach to bicyclo[6.2.1]undecane ring systems

A synthesis of a functionalized bicyclo[6.2.1]undecane, N-(7-hydroxymethyl-bicyclo[6.2.1]undeca-3,5,9-trien-2-yl)-4-methyl-benzenesulfonamide, is described. Starting with a [6+4] cycloaddition between cyclopentadiene and cycloheptatrienone, the final product was prepared in five steps with an overall 37% yield. The remarkable resistance to hydrolysis of an intermediate lactam was overcome by tosylating the amide and reducing with LiAlH₄.     

A novel synthetic route to 6-oxabicyclo[3.1.1]heptane skeleton

6-Oxabicyclo[3.1.1]heptane skeleton is synthesized starting from bicyclo[2.2.1]heptane skeleton, in which as a key reaction, Baeyer-Villiger oxidation of the tricyclic oxetane (19) is involved.     

A convenient route to synthesize 1,2,4‐triazolo[1,5‐a]pyrimidine derivatives and their one and two‐photon absorption spectral properties

A convenient method for synthesizing α‐(1,2,4‐triazolo[1,5‐a]pyrimidine‐2‐sulfonyl)methane derivatives, 3 and 4 , by the well known Knoevenagel reaction, in one step, is described. The two chromophores are stilbene‐type chromophores containing the same D‐π‐A structures and end‐capped with aromatic group as their donors. Measured with femtosecond multipass Ti:sapphire amplifier as irradiation source (pumped by the laser at 800 nm), the two chromophores show efficient two‐photon induced orange red fluorescence emission. The experimental results indicate that the numbers of branches of the two chromophores affect their one‐photon properties and two‐photon up‐conversion emission behaviors, and with the increasing numbers of branches, their wavelengths of λ^abs_max, λ^spf_max and λ^tpf_max exhibit bathochromic shifts.     

Using Diels-Alder reactions to synthesize [2]rotaxanes under solvent-free conditions

Diels-Alder reactions of the terminal alkyne units of SiO₂-supported [2]pseudorotaxanes with 1,2,4,5-tetrazine derivatives proceed efficiently through solid-to-solid contact to provide both asymmetric and symmetric [2]rotaxanes incorporating either 24- or 25-membered-ring macrocycles.     

A new route to pyrimido[1,6‐a]benzimidazole derivatives

Cyclocondensation of orthophenylendiamines with 3‐bromopropionic acid in PPA afforded 2‐vinylbenzimidazoles which were subsequently converted to their corresponding 2‐(1,2‐dibromoethyl)‐1H‐benzimidazoles on treatment with bromine. Reaction of these compounds with aryl nitriles or aryl isocyanates in basic chloroform yielded 1‐arylpyrimido[1,6‐a]benzimidazoles and 2‐arylpyrimido[1,6‐a]‐benzimidazol‐3‐ones respectively.     

A convenient and applicable route to synthesize 2‐(1‐alkynyl)phenylphosphonates

A convenient and applicable route has been developed to synthesize various 2‐(1‐alkynyl)‐ phenylphosphonates starting from easily available phenols via palladium‐catalyzed alkynyl‐dehydroxylation of 2‐hydroxylphenylphosphonates. © 2005 Wiley Periodicals, Inc. Heteroatom Chem 16:529–534, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20156     

A novel synthetic route for the synthesis of 4,6‐diaryl‐2‐methyl‐1,3‐benzoxazoles

A new synthetic route was developed for the synthesis of 4,6‐diaryl‐2‐methyl‐l,3‐benzoxazoles and their hydrogenated derivatives. The target compounds were obtained via the Neber rearrangement from 3,5‐diaryl‐2‐cyclohexen‐l‐ones. The formation of the isomers in the dihydro derivatives was explained by the [1,5] sigmatropic shift of hydrogen under thermal condition. DDQ was employed for the dehydrogenation of the dihydro benzoxazoles.     

A novel route to synthesize libraries of quinoxalines via Petasis methodology in two synthetic operations

This Letter reveals an innovative and facile procedure to prepare quinoxalines in two synthetic steps. The microwave assisted Petasis reaction is followed by the acid mediated unmasking of an internal amino nucleophile, cyclodehydration and oxidation to give collections of quinoxalines in good to excellent yields.     

A new synthetic approach to the bicyclo[5.3.1]undecane ring system in taxanes

The bicyclo[5.3.1]undecane derivative 19, which was referred to the A,b ring system of taxane diterpenes, was synthesized by a base-induced fragmentation reaction of the tricyclic diol monomesylate 18 derived highly stereoselectively from 5-methyl-1,3-cyclohexadione.     

Relative acidities and structure analysis of cis and trans isomers of 1,5‐oxazaspiro[5.5] undecane derivatives by multinuclear magnetic resonance

The relative acidities of the cis and trans isomers of a series of 1,5‐oxazaspiro[5.5]undecane derivatives were determined by measuring ΔpK in acid‐base titrations followed by ¹ H NMR. Relative structural stabilities were determined by measuring substituent chemical shift and γ‐gauche effects in ¹³C, ¹⁵N, and ¹⁷O NMR. Crystallographic characterization of a model spiro[5.5]undecane is presented to support the basicity in solid state. Copyright © 2010 John Wiley & Sons, Ltd.     

A new synthetic route to chloride selective [2]catenanes

A novel anion templation route has been developed to synthesise two new catenanes, which are observed to selectively complex chloride in protic solvent media.     

A convenient route to pyridones,pyrazolo[2,3‐a]pyrimidines and pyrazolo[5,1‐c]triazines incorporating antipyrine moiety

Condensation of 4‐aminoantipyrine with ethyl acetoacetate, ethyl benzoylacetate, and ethyl cyanoacetate furnished the corresponding ethyl 3‐(1,2‐dihydro‐1,5‐dimethyl‐2‐phenyl‐3‐oxo‐3H‐pyrazol‐4‐yl)aminoacrylate and 2‐cyano‐N‐[(1,2‐dihydro‐1,5‐dimethyl‐2‐phenyl‐3‐oxo‐3H‐pyrazol‐4‐yl)]acetamide derivatives. The aminoacrylates derivatives react with acetonitrile and sodium hydride to give 2‐amino‐6‐methyl‐1‐(1,2‐dihydro‐1,5‐dimethyl‐2‐phenyl‐3‐oxo‐3H‐pyrazol‐4‐yl)‐4‐pyridone. Reaction of the cyanoacetamide derivative with dimethylformamide‐dimethylacetal (DMF‐DMA) afforded 2‐cyano‐N‐[1,2‐dihydro‐1,5‐dimethyl‐2‐phenyl‐3‐oxo‐pyrazol‐4‐yl]‐2‐(N,N‐dimethylamino)methylene acetamide in high yield. Treatment of the latter with 5‐aminopyrazole derivatives afforded the corresponding pyrazolo[2,3‐a]pyrimidines. 2‐cyano‐N‐[(1,2‐dihydro‐1,5‐dimethyl‐2‐phenyl‐3‐oxo‐3H‐pyrazol‐4‐yl)]acetamide also reacts with heterocyclic diazonium salts to give the corresponding pyrazolo[5,1‐c]‐1,2,4‐triazine derivatives. © 2004 Wiley Periodicals, Inc. Heteroatom Chem 15:508–514, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20046     

9,9‐Dimethoxy‐7,11‐diphenyl‐2,4‐diazaspiro[5.5]undecane‐1,3,5‐trione monohydrate

Due to steric repulsions, the cyclo­hexane ring in the title compound, C₂₃H₂₄N₂O₅·H₂O, shows some bond‐length abnormalities and adopts a chair conformation. The pyrimidine and cyclo­hexane rings are approximately perpendicular to each other, and the phenyl rings are equatorial. C—H?π and N—H?O intermolecular interactions, as well as C—H?O inter‐ and intramolecular interactions, occur between the mol­ecules. In addition to van der Waals interactions, the water mol­ecule interacts with the pyrimidine­trione ring to stabilize the structure.