11‐Vertex arachno‐Clusters with an NB10, SNB9, and SeNB9 Skeleton

One of the two bridging protons of the aza‐nido‐decaboranes RNB₉H₁₀X can be removed by certain bases to give nido‐anions [RNB₉H₉X]^– [R/X = H/H ( 1 a ), Ph/H ( 1 b ), p‐MeC₆H₄/H ( 1 c ), Bzl/H ( 1 d ), H/N₃ ( 1 ′ a )]; the stericly demanding base 1,8‐bis(dimethylamino)naphthalene (“proton sponge”, ps) is ideal. In the case of tBu anion, the deprotonation (→ C₄H₁₀) may be accompanied by a hydridation (→ C₄H₈), yielding the arachno‐anions [RNB₉H₁₁X]^– ( 2 a , b , d , 2 ′ a ); these are the main products, when stericly non‐demanding bases like H^– are applied. The Lewis acid BH₃ is added to 1 a and 1 ′ a to give the aza‐arachno‐undecaborates HNB₁₀H₁₂X [X = H ( 3 a ), N₃ (in position 2) ( 3 ′ a )]. Thia‐ and selenaaza‐arachno‐undecaborates, [S(RN)B₉H₁₀]^– ( 4 b , c ) and [Se(RN)B₉H₁₀]^– ( 4 ′ b , c ), are obtained from 1 b , c by the addition of sulfur or selenium, respectively. The methylation of the anions 4 c and 4 ′ c gives the thia‐ and selenaazaarachno‐undecaboranes (MeS)(RN)B₉H₁₀ ( 5 c ) and (MeSe)(RN)B₉H₁₀ ( 5 ′ c ), respectively. The action of HBF₄ on the arachno‐borates [HNB₁₀H₁₂X]^– ( 3 a , 3 ′ a ) leads to a mixture of nido‐HNB₉H₁₀X and nido‐HNB₁₀H₁₁X by the elimination of BH₃ or H₂, respectively; the aza‐nido‐decaborane predominates in the case of 3 ′ a and the aza‐nido‐undecaborane in the case of 3 a . The action of HBF₄ on the anion 4 c yields the hypho‐undecaborate [S(RN)B₉H₁₀F₂]^– ( 6 c ). The structures of the products are elucidated on the basis of ¹H and ¹¹B NMR spectra, supported by 2D COSY and HMQC techniques. Two types of 11‐vertex‐arachno structures and an 11‐vertex‐hypho structure are found for the products. The crystal structures of 5 c and [Hps] 6 c · CH₂Cl₂ are reported.     

Synthesis and crystallographic studies of two new 1,3,5‐triazines

The synthesis and characterization of two new 1,3,5‐triazines containing 2‐(aminomethyl)‐1H‐benzimidazole hydrochloride as a substituent are reported, namely, 2‐{[(4,6‐dichloro‐1,3,5‐triazin‐2‐yl)amino]methyl}‐1H‐benzimidazol‐3‐ium chloride, C₁₁H₉Cl₂N₆⁺·Cl^? ( 1 ), and bis(2,2′‐{[(6‐chloro‐1,3,5‐triazine‐2,4‐diyl)bis(azanediyl)]bis(methylene)}bis(1H‐benzimidazol‐3‐ium)) tetrachloride heptahydrate, 2C₁₉H₁₈ClN₉²⁺·4Cl^?·7H₂O ( 2 ). Both salts were characterized using single‐crystal X‐ray diffraction analysis and IR spectroscopy. Moreover, the NMR (¹H and ¹³C) spectra of 1 were obtained. Salts 1 and 2 have triclinic symmetry (space group P) and their supramolecular structures are stabilized by hydrogen bonding and offset π–π interactions. In hydrated salt 2 , the noncovalent interactions yield pseudo‐nanotubes filled with chloride anions and water molecules, which were modelled in the refinement with substitutional and positional disorder.     

Synthesis,crystal structures and anti‐inflammatory activity of fluorine‐substituted 1,4,5,6‐tetrahydrobenzo[h]quinazolin‐2‐amine derivatives

Two fluorine‐substituted 1,4,5,6‐tetrahydrobenzo[h]quinazolin‐2‐amine (BQA) derivatives, namely 2‐amino‐4‐(2‐fluorophenyl)‐9‐methoxy‐1,4,5,6‐tetrahydrobenzo[h]quinazolin‐3‐ium chloride, ( 8 ), and 2‐amino‐4‐(4‐fluorophenyl)‐9‐methoxy‐1,4,5,6‐tetrahydrobenzo[h]quinazolin‐3‐ium chloride, ( 9 ), both C₁₉H₁₉FN₃O⁺·Cl^?, were generated by Michael addition reactions between guanidine hydrochloride and the α,β‐unsaturated ketones (E)‐2‐(2‐fluorobenzylidene)‐7‐methoxy‐3,4‐dihydronaphthalen‐1(2H)‐one, C₁₈H₁₅FO₂, ( 6 ), and (E)‐2‐(4‐fluorobenzylidene)‐7‐methoxy‐3,4‐dihydronaphthalen‐1(2H)‐one, ( 7 ). Because both sides of α,β‐unsaturated ketones ( 6 ) or ( 7 ) can be attacked by guanidine, we obtained a pair of isomers in ( 8 ) and ( 9 ). Single‐crystal X‐ray diffraction indicates that each isomer has a chiral C atom and both ( 8 ) and ( 9 ) crystallize in the achiral space group P2₁/c. The chloride ion, as a hydrogen‐bond acceptor, plays an important role in the formation of multiple hydrogen bonds. Thus, adjacent molecules are connected through intermolecular hydrogen bonds to generate a banded structure. Furthermore, these bands are linked into an interesting 3D network via hydrogen bonds and π–π interactions. Fortunately, the solubilities of ( 8 ) and ( 9 ) were distinctly improved and can exceed 50 mg ml^?1 in water or PBS buffer system (pH 7.4) at room temperature. In addition, the results of an investigation of anti‐inflammatory activity show that ( 8 ) and ( 9 ), with o‐ and p‐fluoro substituents, respectively, display more potential for inhibitory effects on LPS‐induced NO secretion than starting ketones ( 6 ) and ( 7 ).     

Microwave‐Assisted Synthesis of 10‐(Phthalimidoalkyl)‐halosubstitutedpyrido [3,2‐b][1,4]‐benzothiazine in Dry Media

N‐Alkylation of 10H‐9‐fluoropyrido[3,2‐b][1,4]‐benzothiazine 5a, 10H‐7‐fluoropyrido[3,2‐b][1,4]‐benzothiazine 5b, and 10H‐7‐chloropyrido[3,2‐b][1,4]‐benzothiazine 5c with different N‐(bromoalkyl)phthalimides using anhydrous K₂CO₃ and tetrabutylammonium bromide (TBAB) under dry conditions with microwave irradiation leads to the formation of 10‐(phthalimidoalkyl)‐halosubstitutedpyrido[3,2‐b][1,4]‐benzothiazine (6a–f) along with some unidentified product. Compound 5a is a new azaphenothiazine derivative and was obtained from hitherto unknown 2‐acetylamino‐3‐fluorophenyl‐3′‐nitro‐2′‐pyridylsulfide 4a via Smiles rearrangement. Compound 4a is required for the synthesis and has been prepared starting from 2‐amino‐3‐fluorobenzenethiol 1a in three steps.     

Electrophile‐Induced Nucleophilic Substitution of the nido‐Dicarbaundecaborate Anion nido‐7,8‐C2B9H12− by Conjugated Heterodienes

Substitution of the dicarbaundecaborate anion nido‐7,8‐C₂B₉H₁₂^? ( 1 ) by precise hydride abstraction followed by nucleophilic attack usually leads to symmetric products 10‐R‐nido‐7,8‐C₂B₉H₁₁. However, thioacetamide (MeC(S)NH₂) as nucleophile and acetone/AlCl₃ as hydride abstractor gave asymmetric 9‐[MeC(NHiPr)S]‐nido‐7,8‐C₂B₉H₁₁ ( 2 ), whereas N,N‐dimethylthioacetamide (MeC(S)NMe₂) gave the expected symmetric 10‐[MeC(NMe₂)S]‐nido‐7,8‐C₂B₉H₁₁ ( 4 ). For the formation of 2 , acetone and thioacetamide are assumed to give the intermediate MeC(S)N(CMe₂) ( 3 ), which then attacks 1 with formation of 2 . Similarly, reaction of acetyliminium chloride [MeC(O)NH(CPh₂)]Cl ( 5 ) with 1 in THF gave a mixture of 9‐ and 10‐substituted [MeC(NHCHPh₂)O]‐nido‐7,8‐C₂B₉H₁₁ ( 6 and 7 , respectively). These reactions are the first examples in which compounds (here heterodienes) that unite the functionalities of both hydride acceptor and nucleophilic site react with 1 in a bimolecular fashion. Furthermore, the analogous reaction of 1 and 5 (in an equilibrium mixture with acetyl chloride and benzophenone imine) in MeCN afforded 10‐[MeC(NCPh₂)NH]‐nido‐7,8‐C₂B₉H₁₁ ( 8 ) and MeC(O)NHCHPh₂ ( 9 ).     

Synthesis of Novel Pyrimido[4,5‐b]quinolin‐4‐ones with Potential Antitumor Activity

The 5,6,7,8,9,10‐hexahydro‐2‐methylthiopyrimido[4,5‐b]quinolines 4a , 4b , 4c , 4d , 5a , 5b , 5c , 5d and their oxidized forms 6a , 6b , 6c , 6d , 7a , 7b , 7c , 7d were obtained from the reaction of 6‐amino‐2‐(methylthio)pyrimidin‐4(3H)‐one 2 or 6‐amino‐3‐methyl‐2‐(methylthio)pyrimidin‐4(3H)‐one 3 and α,β‐unsaturated ketones 1a , 1b , 1c , 1d using BF₃.OEt₂ as catalyst and p‐chloranil as oxidizing agent. Some of the new compounds were evaluated in the US National Cancer Institute (NCI), where compound 5a presented remarkable activity against 46 cancer cell lines, with the most important GI₅₀ values ranging from 0.72 to 18.4 μM from in vitro assays.     

Hydroboration of Alkenes and Alkynes with Aza‐nido‐decaboranes

The 6‐aza‐nido‐decaboranes RNB₉H₁₁ ( 1a—d ; R = H, Ph, 4‐C₆H₄Me, 4‐C₆H₄Cl) act as 1, 2‐hydroboration agents via their 9‐BH vertex, giving products RNB₉H₁₀R′. The boranes 1a, b and 3‐hexyne yield the 9‐(1‐ethyl‐1‐butenyl)‐6‐aza‐nido‐decaboranes 2a, b (R′ = CEt = CHEt). 2, 3‐Dimethyl‐2‐butene is hydroborated by 1a—d under formation of the 9‐(1, 1, 2‐trimethylpropyl)‐6‐aza‐nido‐decaboranes 3a—d (R′ = —CMe₂ —CHMe₂). With the boranes 1a—c and (trimethylsilyl)ethene, a 85:15 mixture of the products (RNB₉H₁₀)CH₂CH₂(SiMe₃)( 4a—c ) and their chiral isomers (RNB₉H₁₀)CH(SiMe₃)CH₃ ( 5a—c ) is obtained. The action of BH₃(SMe₂) on the mixtures 4b/5b or 4c/5c results in a closure of the nido‐NB₉ skeleton of 4b or 4c , respectively, with a closo‐NB₁₁ skeleton of the products RNB₁₁H₁₀R′ ( 6b or 6c;R′ = CH₂CH₂(SiMe₃)); R′ is found in position 7 of 6b, c . All products of the type 2—6 are characterised by NMR.     

Synthesis and Characterization of 1,3,2‐Bis (arylamino) phospholidine, 2‐oxide Derivatives: Crystal Structures of $\rm Cl(O)\overline{PN(p-Me-C_{6}H_{4})CH_{2}CH_{2}N}(p-Me-C_{6}H_{4})$ and $\rm ((CH_{2}C_{6}H_{5})(O)\overline{PN(p-Me-C_{6}H_{4})CH_{2}CH_{2}N}(p-Me-C_{6}H_{4})$

Using phosphoryl chloride as a substrate, a family of 1,3,2‐bis(arylamino) phospholidine, 2‐oxide of the general formula ; (X=Cl, 6a ; X=NMe₂, 1b ; X=N(CH₂C₆H₅)(CH₃), 2b ; X=NHC(O)C₆H₅, 3b ; X=4Me‐C₆H₄O, 4b ; X=C₆H₅O, 5b ; X=NHC₆H₁₁, 6b ; X=OC₄H₈N, 7b ; X=C₅H₁₀N, 8b ; X=NH₂, 9b ; X=F, 10b and Ar=4Me‐C₆H₄) was prepared and characterized by ¹H, ¹⁹F, ³¹P and ¹³C NMR and IR spectroscopy, and elemental analysis. A general and practical method for the synthesis of these compounds was selected. The structures of 6a and 2b were determined by single‐crystal X‐ray diffraction techniques. The low temperature NMR spectra of 2b revealed the restricted rotation of P‐N bond according to two independent molecules in crystalline lattice.     

Synthesis of 10‐Aryl‐10H‐naphtho[1,8a,8‐fg]indazol‐7‐ones

3‐Hydroxy‐2‐[1‐(arylhydrazono)ethyl]‐1H‐phenalen‐1‐ones 3 , obtained from 2‐acetyl‐3‐hydroxy‐1H‐phenalen‐1‐one ( 1 ) and arylhydrazines 2 , cyclize under acidic conditions to 8‐methyl‐10‐aryl‐10H‐naphtho‐[1,8a,8‐fg]indazol‐7‐ones 4 . Indazoles 4 are also obtained from 2‐acetyl‐3‐hydroxy‐1H‐phenalen‐1‐one ( 1 ) and arylhydrazines 2 in a one‐pot reaction. 2‐Acetyl‐3‐azido‐1H‐phenalen‐1‐one ( 6 ) does not give 8‐methyl‐9‐arylamino‐9H‐naphtho[1,8a,8‐fg]indazol‐7‐ones via azide decomposition but gives again by nucleophilic replacement of the azide moiety in 6 the indazole 4 .     

Synthesis of Benzimidazoles by Phosphine‐Mediated Reductive Cyclisation of ortho‐Nitro‐anilides

Heating ortho‐nitro‐anilides 1 – 3 and 2‐methyl‐N‐(3‐nitropyridin‐2‐yl)propanamide ( 5 ) with 4 equiv. of a phosphine led to the 2‐substituted benzimidazoles 6 – 8 and to the imidazo[4,5‐b]pyridine 10 , respectively, in yields between 45 and 85%. Heating 1 with (EtO)₃P effected cyclisation and N‐ethylation, leading to the 1‐ethylbenzimidazole 6b . The slow cyclisation of the N‐pivaloylnitroaniline 2b allowed isolation of the intermediate phosphine imide 11 that slowly transformed into the 1H‐benzimidazole 7b . The structure of 11 was established by crystal‐structure analysis. While the N‐methylated ortho‐nitroacetanilide 3 cyclised to the 1,2‐dimethyl‐1H‐benzimidazole ( 8 ), the 2‐methylpropananilide 4 was transformed into 1‐methyl‐3‐(1‐methylethyl)‐2H‐benzimidazol‐2‐one ( 9 ).     

Vinyl/Vinylene functionalized highly branched polyethylene waxes obtained using electronically controlled cyclohexyl‐fused pyridinylimine‐nickel precatalysts

A series of 8‐(2,6‐dibenzhydryl‐4‐R‐phenylimino)‐5,6,7‐trihydroquinoline ligands have been prepared in which the nature of 4‐R substitutions vary from electron withdrawing to electron donating. The treatment with NiCl₂.6H₂O or (DME)NiBr₂ afforded the corresponding complexes of nickel chloride (4‐R = Me Ni1 , Et Ni2 , ^tBu Ni3 , CHPh₂ Ni4 , Cl Ni5 , and F Ni6 ) and nickel bromide (4‐R = Me Ni7 , Et Ni8 , ^tBu Ni9 , CHPh₂ Ni10 , Cl Ni11 , and F Ni12 ). X‐ray diffraction study of complexes Ni3 , Ni6 , and Ni10 , revealed that Ni3.1/2H₂O and Ni6.H₂O adopted unsymmetrical and symmetrical chloride‐bridged dinuclear structures respectively, while Ni10.H₂O is found as mononuclear specie forming distorted‐square planer geometry. In the presence of either diethylaluminum chloride (Et₂AlCl) or modified methylaluminoxane (MMAO), all the nickel complexes ( Ni1–Ni12 ) displayed high activities (up to 1.91 × 10⁶ g(PE) mol (Ni)⁻¹h⁻¹. Highly branched polyethylene waxes with low molecular weights (M_w ≤ 2.6 kg/mol) and narrow molecular weights distributions (M_w/M_n ≤ 1.96) incorporated with vinylene and vinyl groups were obtained. The effects of 4‐R substitutions to the nickel chloride and bromide pre‐catalysts and reaction conditions on the catalytic performance and the properties of the resulting polyethylene were the subject of a detail investigation. The positive influences of using electron‐withdrawing 4‐R substitutions and bromides were observed. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56, 1269–1281     

Investigation of Some Functionalization Reactions of 4‐Benzoyl‐5‐phenyl‐1‐(4‐methoxyphenyl)‐1H‐pyrazole‐3‐carbonyl Chloride and Their Antimicrobial Activity

The 1H‐pyrazole‐3‐carboxylic acid 1 was converted via reactions of its acid chloride 3 with various asymmetrical disubstituted urea and alcohol derivatives into the corresponding novel 4‐benzoyl‐N‐(N′,N′‐dialkylcarbamyl)‐1‐(4‐methoxyphenyl)‐5‐phenyl‐1H‐pyrazole‐3‐carboxamide 4a , b and alkyl 4‐benzoyl‐1‐(4‐methoxyphenyl)‐5‐phenyl‐1H‐pyrazole‐3‐carboxylate 7a‐c , respectively, in good yields (57%‐78%). Friedel‐Crafts reactions of 3 with aromatic compouns for 15 min.‐2 h led to the formation of the 4‐3‐diaroyl‐1‐(4‐hydroxyphenyl)‐5‐phenyl‐1H‐pyrazoles 9a‐c , 4‐benzoyl‐1‐(4‐methoxyphenyl)‐3‐aroyl‐5‐phenyl‐1H‐pyrazoles 10a , b and than from the acylation reactions of 9a‐c were obtained the 3,4‐diaroyl‐1‐(4‐acyloxyphenyl)‐5‐phenyl‐1H‐pyrazoles 13a‐d . The structures of all new synthesized compounds were established by NMR experiments such as ¹H, and ¹³C, as well as 2D COSY and IR spectroscopic data, and elemental analyses. All the compounds were evaluated for their antimicrobial activities (agar diffusion method) against eight bacteria and two yeasts.     

Synthesis,crystal structure and activity evaluation of novel 3,4‐dihydro‐1‐benzoxepin‐5(2H)‐one derivatives as protein–tyrosine kinase (PTK) inhibitors

Four new 3,4‐dihydro‐1‐benzoxepin‐5(2H )‐one derivatives, namely (E )‐4‐(5‐bromo‐2‐hydroxybenzylidene)‐6,8‐dimethoxy‐3,4‐dihydrobenzo[b ]oxepin‐5(2H )‐one, ( 7 ), (E )‐4‐[(E )‐3‐(5‐bromo‐2‐hydroxyphenyl)allylidene]‐6,8‐dimethoxy‐3,4‐dihydrobenzo[b ]oxepin‐5(2H )‐one, ( 8 ), (E )‐4‐(5‐bromo‐2‐hydroxybenzylidene)‐6‐hydroxy‐8‐methoxy‐3,4‐dihydrobenzo[b ]oxepin‐5(2H )‐one, C₁₈H₁₅BrO₅, ( 9 ), and (E )‐4‐[(E )‐3‐(5‐bromo‐2‐hydroxyphenyl)allylidene]‐6‐hydroxy‐8‐methoxy‐3,4‐dihydrobenzo[b ]oxepin‐5(2H )‐one, ( 10 ), have been synthesized and characterized by FT–IR, NMR and MS. The structure of ( 9 ) was confirmed by single‐crystal X‐ray diffraction. Crystal structure analysis shows that molecules of ( 9 ) are connected into a one‐dimensional chain in the [010] direction through classical hydrogen bonds and these chains are further extended into a three‐dimensional network via C—H…O interactions. The inhibitory activities of these compounds against protein–tyrosine kinases (PTKs) show that 6‐hydroxy‐substituted compounds ( 9 ) and ( 10 ) are more effective for inhibiting ErbB1 and ErbB2 than are 6‐methoxy‐substituted compounds ( 7 ) and ( 8 ). This may be because ( 9 ) and ( 10 ) could effectively bind to the active pockets of the protein through intermolecular interactions.     

Pyrrole‐Modified Subporphyrins Bearing a Sulfur‐Containing Heterocyclic Unit

As new pyrrole‐modified subporphyrins (PMSubPs) bearing a sulfur‐containing heterocyclic unit, dithiazolosubporphyrin 5 , dithiazinosubchlorin 6 , and oxodithiazinosubchlorin 7 were synthesized from α‐fluorosubchlorophin 2 via α’‐selective nitration with Cu(NO₃)₂ followed by double S_N2 reaction with methyl 3‐mercaptopropionate as a key step. Oxidation of 5 with H₂O₂ in the presence of a tungsten catalyst afforded S,S‐dioxodithiazolosubporphyrin 8 and nitration of 5 with Cu(NO₃)₂·3H₂O gave β‐nitrodithiazolosubporphyrin 9 or β,β‐dinitrodithiazolosubporphyrins 10a and 10b depending on reaction conditions. In the solid‐states, the dithiazole units in 8 and 9 are almost planar but the dithiazine unit in 6 and the 2‐oxodithiazine unit in 7 are non‐planar. Compared to subchlorophin 1 , dithiazolosubporphyrin 5 possesses a significantly reduced diatropic ring current and a greatly perturbed absorption spectrum showing largely split Q‐like bands at 501 and 660 nm. These perturbed electronic and optical properties of 5 are considerably attenuated in 6 and 7 and completely vanished in 8 , suggesting the importance of disulfide bond for the large perturbation.     

7‐Halogenated 7‐Deazapurine 2′‐Deoxyribonucleosides Related to 2′‐Deoxyadenosine, 2′‐Deoxyxanthosine,and 2′‐Deoxyisoguanosine: Syntheses and Properties

A series of 7‐fluorinated 7‐deazapurine 2′‐deoxyribonucleosides related to 2′‐deoxyadenosine, 2′‐deoxyxanthosine, and 2′‐deoxyisoguanosine as well as intermediates 4b – 7b, 8, 9b, 10b , and 17b were synthesized. The 7‐fluoro substituent was introduced in 2,6‐dichloro‐7‐deaza‐9H‐purine ( 11a ) with Selectfluor (Scheme 1). Apart from 2,6‐dichloro‐7‐fluoro‐7‐deaza‐9H‐purine ( 11b ), the 7‐chloro compound 11c was formed as by‐product. The mixture 11b / 11c was used for the glycosylation reaction; the separation of the 7‐fluoro from the 7‐chloro compound was performed on the level of the unprotected nucleosides. Other halogen substituents were introduced with N‐halogenosuccinimides ( 11a → 11c – 11e ). Nucleobase‐anion glycosylation afforded the nucleoside intermediates 13a – 13e (Scheme 2). The 7‐fluoro‐ and the 7‐chloro‐7‐deaza‐2′‐deoxyxanthosines, 5b and 5c , respectively, were obtained from the corresponding MeO compounds 17b and 17c , or 18 (Scheme 6). The 2′‐deoxyisoguanosine derivative 4b was prepared from 2‐chloro‐7‐fluoro‐7‐deaza‐2′‐deoxyadenosine 6b via a photochemically induced nucleophilic displacement reaction (Scheme 5). The pK_a values of the halogenated nucleosides were determined (Table 3). ¹³C‐NMR Chemical‐shift dependencies of C(7), C(5), and C(8) were related to the electronegativity of the 7‐halogen substituents (Fig. 3). In aqueous solution, 7‐halogenated 2′‐deoxyribonucleosides show an approximately 70% S population (Fig. 2 and Table 1).     

Three new dihydro‐β‐agarofuran sesquiterpenes from the seeds of Maytenus boaria

As part of a project studying the secondary metabolites extracted from the Chilean flora, we report herein three new β‐agarofuran sesquiterpenes, namely (1S,4S,5S,6R,7R,8R,9R,10S)‐6‐acetoxy‐4,9‐dihydroxy‐2,2,5a,9‐tetramethyloctahydro‐2H‐3,9a‐methanobenzo[b]oxepine‐5,10‐diyl bis(furan‐3‐carboxylate), C₂₇H₃₂O₁₁, ( II ), (1S,4S,5S,6R,7R,9S,10S)‐6‐acetoxy‐9‐hydroxy‐2,2,5a,9‐tetramethyloctahydro‐2H‐3,9a‐methanobenzo[b]oxepine‐5,10‐diyl bis(furan‐3‐carboxylate), C₂₇H₃₂O₁₀, ( III ), and (1S,4S,5S,6R,7R,9S,10S)‐6‐acetoxy‐10‐(benzoyloxy)‐9‐hydroxy‐2,2,5a,9‐tetramethyloctahydro‐2H‐3,9a‐methanobenzo[b]oxepin‐5‐yl furan‐3‐carboxylate, C₂₉H₃₄O₉, ( IV ), obtained from the seeds of Maytenus boaria and closely associated with a recently published relative [Paz et al. (2017). Acta Cryst. C 73 , 451–457]. In the (isomorphic) structures of ( II ) and ( III ), the central decalin system is esterified with an acetate group at site 1 and furoate groups at sites 6 and 9, and differ at site 8, with an OH group in ( II ) and no substituent in ( III ). This position is also unsubstituted in ( IV ), with site 6 being occupied by a benzoate group. The chirality of the skeletons is described as 1S,4S,5S,6R,7R,8R,9R,10S in ( II ) and 1S,4S,5S,6R,7R,9S,10S in ( III ) and ( IV ), matching the chirality suggested by NMR studies. This difference in the chirality sequence among the title structures (in spite of the fact that the three skeletons are absolutely isostructural) is due to the differences in the environment of site 8, i.e. OH in ( II ) and H in ( III ) and ( IV ). This diversity in substitution, in turn, is responsible for the differences in the hydrogen‐bonding schemes, which is discussed.     

A dihydro‐β‐agarofuran sesquiterpene from Maytenus boaria

The natural compound (1S ,4S ,5S ,6R ,7R ,8R ,9R ,10S )‐6‐acetoxy‐4,9,10‐trihydroxy‐2,2,5a,9‐tetramethyloctahydro‐2H‐3,9a‐methanobenzo[b ]oxepin‐5‐yl furan‐3‐carboxylate, C₂₂H₃₀O₉, (I), is a β‐agarofuran sesquiterpene isolated from the seeds of Maytenus boaria as part of a study of the secondary metabolites from Chilean flora. The compound presents a central structure formed by a decalin system esterified with acetate at site 1 and furan‐3‐carboxylate at site 9. The chirality of the skeleton can be described as 1S ,4S ,5S ,6R ,7R ,8R ,9R ,10S , which is consistent with that suggested by NMR studies. Unlike previously reported structures of sesquiterpenes containing a pure dihydro‐β‐agarofuran skeleton, (I) exhibits a three‐dimensional hydrogen‐bonded network.     

Regioselective synthesis of pentacyclic polyheterocycles: Sequential [3,3] sigmatropic rearrangement of 4‐(4′‐aryloxybut‐2′‐ynyloxy)‐1‐phenyl‐1,8‐naphthyridin‐2(1H)‐ones

A number of 4‐aryloxymethyl‐6‐phenyl‐2H‐pyrano[3,2‐c][1,8]naphthyridin‐5(6H)‐ones ( 4a‐f ) are regioselectively synthesized in 72‐78% yield by the Claisen rearrangement of 4‐(4′‐aryloxybut‐2′‐ynyloxy)‐1‐phenyl‐1,8‐naphthyridin‐2(1H)‐ones ( 3a‐f ) in refluxing chlorobenzene for 4‐6 h. These products are then subjected to a second Claisen rearrangement catalyzed by anhydrous AlCl₃ at room temperature for 2 h to give hitherto unreported pentacyclic heterocycles ( 5a‐f ) in 78‐85% yield.     

Condensation of 1‐(Dicyanomethylene)acenaphthene‐2‐one with Aromatic Diamines

1‐(Dicyanomethylene)acenaphthene‐2‐one ( 1 ) reacts with 1,8‐diaminonaphthalene ( 2 ) to yield two products, identified as acenaphtho[1,2‐b]naphtho[1,8‐ef][1,4]diazepine ( 3 ) and (Z)‐2‐(8‐aminonaphthalen‐1‐ylamino)‐2‐(2‐oxoacenaphthylen‐1(2H)‐ylidene)acetonitrile ( 4 ). On the other hand, (2Z,2′Z)‐2,2′‐(hydrazine‐1,2‐diylidene)diacenaphthylen‐1(2H)‐one ( 6 ) was obtained during the condensation process of 1 with hydrazine hydrate ( 5 ). Reaction of 1 with 3,4‐diaminotoluene ( 8b ) produces 9‐methylacenaphtho[1,2‐b]quinoxaline ( 9b ) and (Z)‐2‐(2‐amino‐5‐methylphenyl‐amino)‐2‐(2‐oxoacenaphthylen‐1(2H)‐ylidene)acetonitrile ( 10b ). However, treatment of 5,6‐diamino‐pyrimidine‐2,4‐diol hemisulphate ( 11 ) with 1 affords acenaphtho[1,2‐g]pteridine‐9,11‐diol ( 12 ).     

Synthetische untersuchungen zum reaktionsverhalten von 2-phenyl-5-oxo-5H-naphtho[1,8-bc] thiophen — thia-pseudophenalenon

The reactivity of 2-phenyl-5-oxo-5H-naphtho[1,8-bc]thiophene ( 1 ) with the N-sulfonyl-heterokumulenes ( 2a-2c, 2d-2e. 2f-2k ) was of interest. We obtained the N-sulfonylimino-pseudophenalenones ( 5a-5k ). Phenylisocyanate and m-chlorophenylisocyanate reacted with 1 only in the presence of the Lewis acid anhydrous aluminum chloride to give the derivatives 6a and 6b . From diphenylketene ( 7 ) and 1 we obtained the pseudophenafulvene 8 , and from the fluorenketene ( 9 ) and 1 we obtained the pentapseudophenafulvalene 10 .