Analogues of α‐Campholenal (= (1R)‐2,2,3‐Trimethylcyclopent‐3‐ene‐1‐acetaldehyde) as Building Blocks for (+)‐β‐Necrodol (= (1S,3S)‐2,2,3‐Trimethyl‐4‐methylenecyclopentanemethanol) and Sandalwood‐like Alcohols

To complete our panorama in structure–activity relationships (SARs) of sandalwood‐like alcohols derived from analogues of α‐campholenal (= (1R)‐2,2,3‐trimethylcyclopent‐3‐ene‐1‐acetaldehyde), we isomerized the epoxy‐isopropyl‐apopinene (?)‐ 2d to the corresponding unreported α‐campholenal analogue (+)‐ 4d (Scheme 1). Derived from the known 3‐demethyl‐α‐campholenal (+)‐ 4a , we prepared the saturated analogue (+)‐ 5a by hydrogenation, while the heterocyclic aldehyde (+)‐ 5b was obtained via a Bayer‐Villiger reaction from the known methyl ketone (+)‐ 6 . Oxidative hydroboration of the known α‐campholenal acetal (?)‐ 8b allowed, after subsequent oxidation of alcohol (+)‐ 9b to ketone (+)‐ 10 , and appropriate alkyl Grignard reaction, access to the 3,4‐disubstituted analogues (+)‐ 4f,g following dehydration and deprotection. (Scheme 2). Epoxidation of either (+)‐ 4b or its methyl ketone (+)‐ 4h , afforded stereoselectively the trans‐epoxy derivatives 11a,b , while the minor cis‐stereoisomer (+)‐ 12a was isolated by chromatography (trans/cis of the epoxy moiety relative to the C₂ or C₃ side chain). Alternatively, the corresponding trans‐epoxy alcohol or acetate 13a,b was obtained either by reduction/esterification from trans‐epoxy aldehyde (+)‐ 11a or by stereoselective epoxidation of the α‐campholenol (+)‐ 15a or of its acetate (?)‐ 15b , respectively. Their cis‐analogues were prepared starting from (+)‐ 12a . Either (+)‐ 4h or (?)‐ 11b , was submitted to a Bayer‐Villiger oxidation to afford acetate (?)‐ 16a . Since isomerizations of (?)‐ 16 lead preferentially to β‐campholene isomers, we followed a known procedure for the isomerization of (?)‐epoxyverbenone (?)‐ 2e to the norcampholenal analogue (+)‐ 19a . Reduction and subsequent protection afforded the silyl ether (?)‐ 19c , which was stereoselectively hydroborated under oxidative condition to afford the secondary alcohol (+)‐ 20c . Further oxidation and epimerization furnished the trans‐ketone (?)‐ 17a , a known intermediate of either (+)‐β‐necrodol (= (+)‐(1S,3S)‐2,2,3‐trimethyl‐4‐methylenecyclopentanemethanol; 17c ) or (+)‐(Z)‐lancifolol (= (1S,3R,4Z)‐2,2,3‐trimethyl‐4‐(4‐methylpent‐3‐enylidene)cyclopentanemethanol). Finally, hydrogenation of (+)‐ 4b gave the saturated cis‐aldehyde (+)‐ 21 , readily reduced to its corresponding alcohol (+)‐ 22a . Similarly, hydrogenation of β‐campholenol (= 2,3,3‐trimethylcyclopent‐1‐ene‐1‐ethanol) gave access via the cis‐alcohol rac‐ 23a , to the cis‐aldehyde rac‐ 24 .     

Three different fluoro‐ or chloro‐substituted 1′‐deoxy‐1′‐phenyl‐β‐D‐ribofuranoses

Crystal structures are reported for three fluoro‐ or chloro‐substituted 1′‐deoxy‐1′‐phenyl‐β‐D‐ribofuranoses, namely 1′‐deoxy‐1′‐(2,4,5‐trifluorophenyl)‐β‐D‐ribofuranose, C₁₁H₁₁F₃O₄, (I), 1′‐deoxy‐1′‐(2,4,6‐trifluorophenyl)‐β‐D‐ribofuranose, C₁₁H₁₁F₃O₄, (II), and 1′‐(4‐chlorophenyl)‐1′‐deoxy‐β‐D‐ribofuranose, C₁₁H₁₃ClO₄, (III). The five‐membered furanose ring of the three compounds has a conformation between a C2′‐endo,C3′‐exo twist and a C2′‐endo envelope. The ribofuranose groups of (I) and (III) are connected by intermolecular O—H...O hydrogen bonds to six symmetry‐related molecules to form double layers, while the ribofuranose group of (II) is connected by O—H...O hydrogen bonds to four symmetry‐related molecules to form single layers. The O...O contact distance of the O—H...O hydrogen bonds ranges from 2.7172 (15) to 2.8895 (19) Å. Neighbouring double layers of (I) are connected by a very weak intermolecular C—F...π contact. The layers of (II) are connected by one C—H...O and two C—H...F contacts, while the double layers of (III) are connected by a C—H...Cl contact. The conformations of the molecules are compared with those of seven related molecules. The orientation of the benzene ring is coplanar with the H—C1′ bond or bisecting the H—C1′—C2′ angle, or intermediate between these positions. The orientation of the benzene ring is independent of the substitution pattern of the ring and depends mainly on crystal‐packing effects.     

2, 4‐Dimethylpenta‐1, 3‐dien‐ und 2, 4‐Dimethylpentadienyl‐Komplexe des Rhodiums und Iridiums

2, 4‐Dimethylpenta‐1, 3‐diene and 2, 4‐Dimethylpentadienyl Complexes of Rhodium and Iridium The complexes [(η⁴‐C₇H₁₂)RhCl]₂ ( 1 ) (C₇H₁₂ = 2, 4‐dimethylpenta‐1, 3‐diene) and [(η⁴‐C₇H₁₂)₂IrCl] ( 2 ) were obtained by interaction of C₇H₁₂ with [(η²‐C₂H₄)₂RhCl]₂ and [(η²‐cyclooctene)₂IrCl]₂, respectively. The reaction of 1 or 2 with CpTl (Cp = η⁵‐C₅H₅) yields the compounds [CpM(η⁴‐C₇H₁₂)] ( 3a : M = Rh; 3b : M = Ir). The hydride abstraction at the pentadiene ligand of 3a , b with Ph₃CBF₄ proceeds differently depending on the solvent. In acetone or THF the “half‐open” metallocenium complexes [CpM(η⁵‐C₇H₁₁)]BF₄ ( 4a : M = Rh; 4b : M = Ir) are obtained exclusively. In dichloromethane mixtures are produced which additionally contain the species [(η⁵‐C₇H₁₁)M(η⁵‐C₅H₄CPh₃)]BF₄ ( 5a : M = Rh; 5b : M = Ir) formed by electrophilic substitution at the Cp ring, as well as the η³‐2, 4‐dimethylpentenyl compound [(η³‐C₇H₁₃)Rh{η⁵‐C₅H₃(CPh₃)₂}]BF₄ ( 6 ). By interaction of 2, 4‐dimethylpentadienyl potassium with 1 or 2 the complexes [(η⁴‐C₇H₁₂)M(η⁵‐C₇H₁₁)] ( 7a : M = Rh; 7b : M = Ir) are generated which show dynamic behaviour in solution; however, attempts to synthesize the “open” metallocenium cations [(η⁵‐C₇H₁₁)₂M]⁺ by hydride abstraction from 7a , b failed. The new compounds were characterized by elemental analysis and spectroscopically, 4b and 5a also by X‐ray structure analysis.     

Tandem Hydroformylation/Reductive Amination of 3‐Allyl‐2‐methylquinazolin‐4(3H)‐one

The 3‐allyl‐2‐methylquinazolin‐4(3H)‐one ( 1 ), a model functionalized terminal olefin, was submitted to hydroformylation and reductive amination under optimized reaction conditions. The catalytic carbonylation of 1 in the presence of Rh catalysts complexed with phosphorus ligands under different reaction conditions afforded a mixture of 2‐methyl‐4‐oxoquinazoline‐3(4H)‐butanal ( 2 ) and α,2‐dimethyl‐4‐oxoquinazoline‐3(4H)‐propanal ( 3 ) as products of ‘linear’ and ‘branched’ hydroformylation, respectively (Scheme 2). The hydroaminomethylation of quinazolinone 1 with arylhydrazine derivatives gave the expected mixture of [(arylhydrazinyl)alkyl]quinazolinones 5 and 6 , besides a small amount of 2 and 3 (Scheme 3). The tandem hydroformylation/reductive amination reaction of 1 with different amines gave the quinazolinone derivatives 7 – 10 . Compound 10 was used to prepare the chalcones 11a and 11b and pyrazoloquinazolinones 12a and 12b (Scheme 4).     

The Orthogonal (e,e,e)‐Tris‐Adduct of 9,10‐Dimethylanthracene with C60‐Fullerene: A Hidden Cornerstone of Fullerene Chemistry. Preliminary Communication

Tris(9′,10′‐dimethyl[9,10]ethanoanthracene[11′,12′: 1,9;11″,12″: 16,17;11′′′,12′′′: 30,31])[5,6]fullerene C₆₀, the orthogonal (e,e,e)‐tris‐adduct of C₆₀ and 9,10‐dimethylanthracene, was obtained from [4+2]‐cycloaddition (Diels–Alder reaction) at room temperature. The thermally unstable orange red (e,e,e)‐tris‐adduct was purified by chromatography and was isolated in the form of red monoclinic crystals. Its C₃‐symmetric addition pattern was established spectroscopically. Its structure could be further investigated by single crystal X‐ray diffraction. The (e,e,e)‐tris‐adduct of C₆₀ and 9,10‐dimethylanthracene has earlier been suggested as intermediate and reversibly formed critical component in ‘template directed’ addition reactions of C₆₀. This previously elusive compound has now been isolated and structurally characterized.     

First Total Synthesis of N‐(3‐Guanidinopropyl)‐2‐(4‐hydroxyphenyl)‐2‐oxoacetamide

The first total synthesis of the α‐oxo amide‐based natural product, N‐(3‐guanidinopropyl)‐2‐(4‐hydroxyphenyl)‐2‐oxoacetamide ( 3 ), isolated from aqueous extracts of hydroid Campanularia sp., has been achieved. The α‐oxo amide 12 , prepared via the oxidative amidation of 1‐[4‐(benzyloxy)phenyl]‐2,2‐dibromoethanone ( 9a ) with 4‐{[(tert‐butyl)(dimethyl)silyl]oxy}butan‐1‐amine ( 10a ), has been used as the key intermediate in the total synthesis of 3 as HBr salt. On the way, an expeditious total synthesis of polyandrocarpamide C ( 2c ), isolated from marine ascidian Polyandrocarpa sp., was carried out in four steps.     

Stereo‐Inversion in the (4R)‐γ‐Decanolactone Synthesis by Saccharomyces cerevisiae: (2E,4S)‐4‐Hydroxydec‐2‐enoic Acid Acts as a Key Intermediate

Methyl (2E,4R)‐4‐hydroxydec‐2‐enoate, methyl (2E,4S)‐4‐hydroxydec‐2‐enoate, and ethyl (±)‐(2E)‐4‐hydroxy[4‐²H]dec‐2‐enoate were chemically synthesized and incubated in the yeast Saccharomyces cerevisiae. Initial C‐chain elongation of these substrates to C₁₂ and, to a lesser extent, C₁₄ fatty acids was observed, followed by γ‐decanolactone formation. Metabolic conversion of methyl (2E,4R)‐4‐hydroxydec‐2‐enoate and methyl (2E,4S)‐4‐hydroxydec‐2‐enoate both led to (4R)‐γ‐decanolactone with >99% ee and 80% ee, respectively. Biotransformation of ethyl (±)‐(2E)‐4‐hydroxy(4‐²H)dec‐2‐enoate yielded (4R)‐γ‐[²H]decanolactone with 61% of the ²H label maintained and in 90% ee indicating a stereoinversion pathway. Electron‐impact mass spectrometry analysis (Fig. 4) of 4‐hydroxydecanoic acid indicated a partial C(4)→C(2) ²H shift. The formation of erythro‐3,4‐dihydroxydecanoic acid and erythro‐3‐hydroxy‐γ‐decanolactone from methyl (2E,4S)‐4‐hydroxydec‐2‐enoate supports a net inversion to (4R)‐γ‐decanolactone via 4‐oxodecanoic acid. As postulated in a previous work, (2E,4S)‐4‐hydroxydec‐2‐enoic acid was shown to be a key intermediate during (4R)‐γ‐decanolactone formation via degradation of (3S,4S)‐dihydroxy fatty acids and precursors by Saccharomyces cerevisiae.     

Synthesis of (1α)‐1,25‐Dihydroxyvitamin D3 with a β‐Positioned Seven‐Carbon Side Chain at C(12)

A convergent synthesis of an analogue of (1α)‐1,25‐dihydroxyvitamin D₃ ( 1b ) with a C₇ side chain at C(12), i.e., of 5 (Fig.), is described. A key step of the synthesis is the assembly of the triene system by a Pd^II‐catalyzed ring closure of an enol triflate (‘bottom’ fragment) followed by coupling of the resulting Pd^II intermediate with an alkenylboronate (‘upper’ fragment) (Scheme 2). The synthetic strategy allows isotopic labelling at the end of the synthesis.     

Synthesis of (4Z)‐4‐(Arylmethylidene)‐5‐ethoxy‐1,3‐oxazolidine‐2‐thiones by the Reaction of Ethyl (2Z)‐3‐Aryl‐2‐isothiocyanatoprop‐2‐enoates with Organolithium Compounds

A convenient one‐pot method for the preparation of (4Z)‐4‐(arylmethylidene)‐5‐ethoxy‐1,3‐oxazolidine‐2‐thiones 2 and 3 from ethyl (2Z)‐3‐aryl‐2‐isothiocyanatoprop‐2‐enoates 1 , which can be easily prepared from ethyl 2‐azidoacetate and aromatic aldehydes, has been developed. Thus, these α‐isothiocyanato α,β‐unsaturated esters were treated with organolithium compounds, including lithium enolates of acetates, to provide 5‐substituted (4Z)‐4‐(arylmethylidene)‐5‐ethoxy‐1,3‐oxazolidine‐2‐thiones, 2 , and 2‐[(4Z)‐(4‐arylmethylidene)‐5‐ethoxy‐2‐thioxo‐1,3‐oxazolidin‐5‐yl]acetates, 3 .     

Synthesis of Three‐, Five‐, and Six‐Membered Heterocycles Derived from New β‐Amino‐α‐(trifluoromethyl) Alcohols

Nucleophilic trifluoromethylation of α‐imino ketones 2 , derived from arylglyoxal, with Ruppert–Prakash reagent (CF₃SiMe₃) offers a convenient access to the corresponding O‐silylated β‐imino‐α‐(trifluoromethyl) alcohols. In a ‘one‐pot’ procedure, by treatment with NaBH₄, these products smoothly undergo reduction and desilylation yielding the expected β‐amino‐α‐(trifluoromethyl) alcohols 4 . The latter were used as starting materials for the synthesis of diverse trifluoromethylated heterocycles, including aziridines 5 , 1,3‐oxazolidines 8 , 1,3‐oxazolidin‐2‐ones 9 , 1,3,2‐oxazaphospholidine 2‐oxides 10 , 1,2,3‐oxathiazolidine 2‐oxides 11 , and morpholine‐2,3‐diones 12 . An optically active 5‐(trifluoromethyl)‐substituted 1,3‐oxazolidin‐2‐one 9g was also obtained.     

3‐Cyano‐6‐hydroxy‐4‐methyl‐2‐pyridone: two new pseudopolymorphs and two cocrystals with products of an in situ nucleophilic aromatic substitution

Four crystal structures of 3‐cyano‐6‐hydroxy‐4‐methyl‐2‐pyridone (CMP), viz. the dimethyl sulfoxide monosolvate, C₇H₆N₂O₂·C₂H₆OS, (1), the N,N‐dimethylacetamide monosolvate, C₇H₆N₂O₂·C₄H₉NO, (2), a cocrystal with 2‐amino‐4‐dimethylamino‐6‐methylpyrimidine (as the salt 2‐amino‐4‐dimethylamino‐6‐methylpyrimidin‐1‐ium 5‐cyano‐4‐methyl‐6‐oxo‐1,6‐dihydropyridin‐2‐olate), C₇H₁₃N₄⁺·C₇H₅N₂O₂⁻, (3), and a cocrystal with N,N‐dimethylacetamide and 4,6‐diamino‐2‐dimethylamino‐1,3,5‐triazine [as the solvated salt 2,6‐diamino‐4‐dimethylamino‐1,3,5‐triazin‐1‐ium 5‐cyano‐4‐methyl‐6‐oxo‐1,6‐dihydropyridin‐2‐olate–N,N‐dimethylacetamide (1/1)], C₅H₁₁N₆⁺·C₇H₅N₂O₂⁻·C₄H₉NO, (4), are reported. Solvates (1) and (2) both contain the hydroxy group in a para position with respect to the cyano group of CMP, acting as a hydrogen‐bond donor and leading to rather similar packing motifs. In cocrystals (3) and (4), hydrolysis of the solvent molecules occurs and an in situ nucleophilic aromatic substitution of a Cl atom with a dimethylamino group has taken place. Within all four structures, an R₂²(8) N—H...O hydrogen‐bonding pattern is observed, connecting the CMP molecules, but the pattern differs depending on which O atom participates in the motif, either the ortho or para O atom with respect to the cyano group. Solvents and coformers are attached to these arrangements via single‐point O—H...O interactions in (1) and (2) or by additional R₄⁴(16) hydrogen‐bonding patterns in (3) and (4). Since the in situ nucleophilic aromatic substitution of the coformers occurs, the possible Watson–Crick C–G base‐pair‐like arrangement is inhibited, yet the cyano group of the CMP molecules participates in hydrogen bonds with their coformers, influencing the crystal packing to form chains.     

Semisynthesis and absolute configuration of a novel rearranged 19,20‐δ‐lactone (9βH)‐pimarane diterpene

Annonalide (3β,20‐epoxy‐3α,16‐dihydroxy‐15‐oxo‐7‐pimaren‐19,6β‐olide, C₂₀H₂₆O₆, 1 ) is the major (9βH)‐pimarane diterpene isolated from tubers of Cassimirella ampla, and it exhibits cytotoxic properties upon interaction with ctDNA. We have prepared new derivatives of 1 by modification of the (9βH)‐pimarane backbone and report here the semisynthesis and absolute configuration of a novel rearranged 19,20‐δ‐lactone (9βH)‐pimarane. Our approach was the reduction of the carbonyl groups of 1 with sodium borohydride, at positions C15 (no stereoselectivity) and C3 (stereoselective reduction), followed by rearrangement of the 6,19‐γ‐lactone ring into the six‐membered 19,20‐δ‐lactone ring in 4a (3β,6β,16‐trihydroxy‐7‐pimaren‐19,20β‐olide monohydrate, C₂₀H₃₀O₆·H₂O). The absolute structure of the new compound, 4a , was determined unambiguously with a Flack parameter x of −0.01 (11), supporting the stereochemistry assignment of 1 redetermined here. Besides the changes in the pattern of covalent bonds caused by reduction and lactone rearrangement, the conformation of one of the three fused cyclohexane rings is profoundly different in 4a , adopting a chair conformation instead of the boat shape found in 1 . Furthermore, the intramolecular hydrogen bond present in 1 is lost in new compound 4a , due to hydrogen bonding between the 3‐OH group and the solvent water molecule.     

2,2‐Difluor‐1,3‐diaza‐2‐sila‐cyclopenten – Synthese und Reaktionen

2,2‐Difluor‐1,3‐diaza‐2‐sila‐cyclopentene – Synthesis and Reactions N,N′‐Di‐tert‐butyl‐1,4‐diaza‐1,3‐butadiene reacts with elemental lithium under reduction to give a dilithium salt, which forms with fluorosilanes the diazasilacyclopentenes 1 – 4 ; (HCNCMe₃)₂SiFR, R = F ( 1 ), Me ( 2 ), Me₃C ( 3 ), N(CMe₃)SiMe₃ ( 4 ). As by‐product in the synthesis of 1 , the tert‐butyl‐amino‐methylene‐tert‐butyliminomethine substituted compound 5 was isolated, R = N(CMe₃)‐CH₂‐CH = NCMe₃. 5 is formed in the reaction of 1 with the monolithium salt of the 1,4‐diaza‐1,3‐butadiene in an enamine‐imine‐tautomerism. 1 reacts with lithium amides to give (HCNCMe₃)₂SiFNHR, 6 – 12 , R = H ( 6 ), Me ( 7 ), Me₂CH ( 8 ), Me₃C ( 9 ), H₅C₆ ( 10 ), 2,6‐Me₂C₆H₃ ( 11 ), 2,6‐(Me₂CH)₂C₆H₃ ( 12 ). The reaction of 12 with LiNH‐2.6‐(Me₂CH)₂C₆H₃ leads to the formation of (HCNCMe₃)₂Si(NHR)₂, ( 13 ). In the presence of n‐BuLi, 12 forms a lithium salt which looses LiF in boiling toluene. Lithiated 12 adds this LiF and generates a spirocyclic tetramer with a central eight‐membered LiF‐ring ( 14 ), [(HCNCMe₃)₂Si(FLiFLiNR)]₄, R = 2,6‐(Me₂CH)₂C₆H₃. ClSiMe₃ reacts with lithiated 12 to yield the substitution product (HCNCMe₃)₂SiFN(SiMe₃) R, ( 15 ). The crystal structures of 1 , 5 , 6 , 9 , 11 , 13 , 14 are reported.     

Weak intermolecular interactions in isomorphous 5‐(2‐chloroethoxy)‐2,3‐dihydro‐1,4‐benzodioxine and 5‐(2‐bromoethoxy)‐2,3‐dihydro‐1,4‐benzodioxine: bonding or nonbonding interactions

The title compounds, C₁₀H₁₁ClO₃, (I), and C₁₀H₁₁BrO₃, (II), are isomorphous and effectively isostructural; all of the interatomic distances and angles are normal. The structures exhibit long intermolecular C—H...O and C—H...π contacts with attractive energies ranging from 1.17 to 2.30 kJ mol⁻¹. Weak C—H...O hydrogen bonds form C(3) and C(4) motifs, combining to form a two‐dimensional R₃⁴(12) net. No face‐to‐face stacking interactions are observed.     

Three novel topologically different metal–organic frameworks built from 3‐nitro‐4‐(pyridin‐4‐yl)benzoic acid

The design and synthesis of metal–organic frameworks (MOFs) have attracted much interest due to the intriguing diversity of their architectures and topologies. However, building MOFs with different topological structures from the same ligand is still a challenge. Using 3‐nitro‐4‐(pyridin‐4‐yl)benzoic acid (HL) as a new ligand, three novel MOFs, namely poly[[(N,N‐dimethylformamide‐κO)bis[μ₂‐3‐nitro‐4‐(pyridin‐4‐yl)benzoato‐κ³O,O′:N]cadmium(II)] N,N‐dimethylformamide monosolvate methanol monosolvate], {[Cd(C₁₂H₇N₂O₄)₂(C₃H₇NO)]·C₃H₇NO·CH₃OH}_n, ( 1 ), poly[[(μ₂‐acetato‐κ²O:O′)[μ₃‐3‐nitro‐4‐(pyridin‐4‐yl)benzoato‐κ³O:O′:N]bis[μ₃‐3‐nitro‐4‐(pyridin‐4‐yl)benzoato‐κ⁴O,O′:O′:N]dicadmium(II)] N,N‐dimethylacetamide disolvate monohydrate], {[Cd₂(C₁₂H₇N₂O₄)₃(CH₃CO₂)]·2C₄H₉NO·H₂O}_n, ( 2 ), and catena‐poly[[[diaquanickel(II)]‐bis[μ₂‐3‐nitro‐4‐(pyridin‐4‐yl)benzoato‐κ²O:N]] N,N‐dimethylacetamide disolvate], {[Ni(C₁₂H₇N₂O₄)₂(H₂O)₂]·2C₄H₉NO}_n, ( 3 ), have been prepared. Single‐crystal structure analysis shows that the Cd^II atom in MOF ( 1 ) has a distorted pentagonal bipyramidal [CdN₂O₅] coordination geometry. The [CdN₂O₅] units as 4‐connected nodes are interconnected by L^? ligands to form a fourfold interpenetrating three‐dimensional (3D) framework with a dia topology. In MOF ( 2 ), there are two crystallographically different Cd^II ions showing a distorted pentagonal bipyramidal [CdNO₆] and a distorted octahedral [CdN₂O₄] coordination geometry, respectively. Two Cd^II ions are connected by three carboxylate groups to form a binuclear [Cd₂(COO)₃] cluster. Each binuclear cluster as a 6‐connected node is further linked by acetate groups and L^? ligands to produce a non‐interpenetrating 3D framework with a pcu topology. MOF ( 3 ) contains two crystallographically distinct Ni^II ions on special positions. Each Ni^II ion adopts an elongated octahedral [NiN₂O₄] geometry. Each Ni^II ion as a 4‐connected node is linked by L^? ligands to generate a two‐dimensional network with an sql topology, which is further stabilized by two types of intermolecular OW—HW…O hydrogen bonds to form a 3D supramolecular framework. MOFs ( 1 )–( 3 ) were also characterized by powder X‐ray diffraction, IR spectroscopy and thermogravimetic analysis. Furthermore, the solid‐state photoluminescence of HL and MOFs ( 1 ) and ( 2 ) have been investigated. The photoluminescence of MOFs ( 1 ) and ( 2 ) are enhanced and red‐shifted with respect to free HL. The gas adsorption investigation of MOF ( 2 ) indicates a good separation selectivity (71) of CO₂/N₂ at 273 K (i.e. the amount of CO₂ adsorption is 71 times higher than N₂ at the same pressure).     

CdII and CoII coordination polymers constructed from benzene‐1,4‐dicarboxylic acid and 2‐(pyridin‐3‐yl)‐1H‐benzimidazole ligands

In poly[aqua(μ₃‐benzene‐1,4‐dicarboxylato‐κ⁵O¹,O^1′:O¹:O⁴,O^4′)[2‐(pyridin‐3‐yl‐κN)‐1H‐benzimidazole]cadmium(II)], [Cd(C₈H₄O₄)(C₁₂H₉N₃)(H₂O)]_n, (I), each Cd^II ion is seven‐coordinated by the pyridine N atom from a 2‐(pyridin‐3‐yl)benzimidazole (3‐PyBIm) ligand, five O atoms from three benzene‐1,4‐dicarboxylate (1,4‐bdc) ligands and one O atom from a coordinated water molecule. The complex forms an extended two‐dimensional carboxylate layer structure, which is further extended into a three‐dimensional network by hydrogen‐bonding interactions. In catena‐poly[[diaquabis[2‐(pyridin‐3‐yl‐κN)‐1H‐benzimidazole]cobalt(II)]‐μ₂‐benzene‐1,4‐dicarboxylato‐κ²O¹:O⁴], [Co(C₈H₄O₄)(C₁₂H₉N₃)₂(H₂O)₂]_n, (II), each Co^II ion is six‐coordinated by two pyridine N atoms from two 3‐PyBIm ligands, two O atoms from two 1,4‐bdc ligands and two O atoms from two coordinated water molecules. The complex forms a one‐dimensional chain‐like coordination polymer and is further assembled by hydrogen‐bonding interactions to form a three‐dimensional network.     

金属参与的N-酰基腙的偕二氟烯丙基化反应：高效合成偕二氟高烯丙基胺

金属铟参与醛衍生的N-酰基腙 1a-1q,4a-4g与3-溴-3,3-二氟丙烯 2 的反应,分别高效得到α, α-二氟高烯丙基肼 3a-3q,5a-5g。该反应条件温和,操作简便。硝基,酚羟基,苄氧基,α, β-不饱和醛的碳-碳双键等官能团对该反应具有良好的官能团兼容性。通过用锌粉代替铟粉, 酮衍生的N-酰基腙 6a-6d 也能发生偕二氟烯丙基化反应,以中等产率得到α, α-二氟高烯丙基肼 7a-7d。裂解肼3a的 N-N键顺利得到偕二氟高烯丙基胺 8,化合物 8 经丙烯酰化,随后进行RCM关环反应,可以方便的转化为偕二氟-γ-取代α, β-不饱和内酰胺 11。     

Synthesis and Structures of Two Isomeric 4‐Diazo‐2,3,4,5‐tetrahydrofuran‐3‐ones

The two regioisomeric 4‐diazo‐2,3,4,5‐tetrahydrofuran‐3‐ones 6 and 7 were prepared via the common intermediate 2,3,4,5‐tetrahydro‐2,2‐dimethyl‐5,5‐diphenylfuran‐3‐one ( 8 ). Diazo transfer with 2,4,6‐triisopropylbenzenesulfonyl azide yielded 6 , whereas 7 was obtained via oxidation of the monohydrazone 12 , which was prepared selectively from tetrahydrofuran‐3,4‐dione 11 . The crystal structures of 6 and 7 have been established by X‐ray crystallography.     

Chemoselectivity of the Reactions of Diazomethanes with 5‐Benzylidene‐3‐phenylrhodanine

The reactions of 5‐benzylidene‐3‐phenylrhodanine ( 2 ; rhodanine=2‐thioxo‐1,3‐thiazolidin‐4‐one) with diazomethane ( 7a ) and phenyldiazomethane ( 7b ) occurred chemoselectively at the exocyclic C?C bond to give the spirocyclopropane derivatives 9 and, in the case of 7a , also the C‐methylated products 8 (Scheme 1). In contrast, diphenyldiazomethane ( 7c ) reacted exclusively with the C?S group leading to the 2‐(diphenylmethylidene)‐1,3‐thiazolidine 11 via [2+3] cycloaddition and a ‘two‐fold extrusion reaction’. Treatment of 8 or 9b with an excess of 7a in refluxing CH₂Cl₂ and in THF at room temperature in the presence of [Rh₂(OAc)₄], respectively, led to the 1,3‐thiazolidine‐2,4‐diones 15 and 20 , respectively, i.e., the products of the hydrolysis of the intermediate thiocarbonyl ylide. On the other hand, the reactions with 7b and 7c in boiling toluene yielded the corresponding 2‐methylidene derivatives 16, 21a , and 21b . Finally, the reaction of 11 with 7a occurred exclusively at the electron‐poor C?C bond, which is conjugated with the C?O group. In addition to the spirocyclopropane 23 , the C‐methylated 22 was formed as a minor product. The structures of the products (Z)‐ 8, 9a, 9b, 11 , and 23 were established by X‐ray crystallography.     

3,17‐Dioxoandrost‐4‐en‐4‐yl acetate

The title compound, C₂₁H₂₈O₄, has a 4‐acetoxy substituent positioned on the steroid α face. The six‐membered ring A assumes a conformation intermediate between 1α,2β‐half chair and 1α‐sofa. A long Csp³—Csp³ bond is observed in ring B and reproduced in quantum‐mechanical ab initio calculations of the isolated molecule using a molecular‐orbital Hartree–Fock method. Cohesion of the crystal can be attributed to van der Waals interactions and weak C—H...O hydrogen bonds.