Chemical Constituents from the Root Bark of Formosan Zanthoxylum Ailanthoides

Two new N‐isobutylamides, hydroxy lanyuamide I ( 1 ) and hydroxy lanyuamide II ( 2 ), together with one hundred and ten known compounds, have been isolated from the root bark of Formosan Zanthoxylum ailanthoides. These known compounds include twenty coumarins, twenty‐one benzo[c]phenanthridines, ten quinoline derivatives, one aporphine, one purine, seven amides, twelve benzenoids, one lactone, four flavonoids, nine lignans, eight steroids, two chlorophylls, eleven terpenoids and three other compounds, which were determined by means of spectral analyses.     

Reductive Coupling Reaction of Aryliminomethylferrocenes with Triethyl Orthoformate Induced by Low‐valent Titanium

Reductive coupling reaction of aryliminomethylferrocenes FcCH = NAr[(1, Ar=QHs (a), p‐ClC₆H₄ (b), p‐BrC₆H₄ (c), p‐CH₃C₆H₄ (d), m‐ClC₆H₄ (e)] with triethyl orthoformate (2) in Zn‐TiCl₄ system gave three kinds of products: 1, 3‐diaryl‐4, 5‐diferrocenyl imidazolidines (3), N, N‐disubstituted formamides (4), and 1, 2‐diferrocenyl ethylene (5). ¹H NMR spectra proved that all the compounds 3 obtained were dl‐isomers. All the new compounds 3 and 4 were characterized by elemental analysis, ¹H NMR, ¹³C NMR (for 3) and IR spectra. The molecular structure of 3c was determined by X‐ray diffraction.     

Two New Dammarane‐Type Bisdesmosides from the Fruit Pedicels of Panax notoginseng

Two new dammarane‐type triterpenoidal saponins, notoginsenosides FP₁ ( 1 ) and FP₂ ( 2 ), were isolated from the fruit pedicels of Panax notoginseng, along with 22 known compounds. Their structures were elucidated on the basis of spectroscopic evidences and chemical methods. The known compounds were identified as ginsenosides Rg₁ ( 3 ), Re ( 4 ), Rb₃ ( 5 ), Rc ( 6 ), Rd ( 7 ), Rb₂ ( 8 ), Rb₁ ( 9 ), F₂ ( 10 ), and F₁ ( 11 ); as notoginsenosides R₁ ( 12 ), Fa ( 13 ), and Fc ( 14 ); as vina‐ginsenoside R₇ ( 15 ); as gypenosides IX ( 16 ), XVII ( 17 ), and XIII ( 18 ), and as chikusetsusaponin‐L₅ ( 19 ), quercetin 3‐O‐β‐D ‐glucopyranosyl‐(1→2)‐β‐D ‐galactopyranoside ( 20 ), kaempferol 3‐O‐β‐D ‐glucopyranosyl‐(1→2)‐β‐D ‐galactopyranoside ( 21 ), benzyl‐β‐primeveroside ( 22 ), (S)‐tryptophan ( 23 ), and icariside B₆ ( 24 ). Compounds 15, 19 and 22 – 24 are reported for the first time from the title plant.     

New Steroids and a New Alkaloid from the Gorgonian Isis minorbrachyblasta: Structures,Cytotoxicity, and Antilarval Activity

Two new polyoxygenated steroids, (1α,3β,7α,11α,12β)‐gorgost‐5‐ene‐1,3,7,11,12‐pentol 12‐acetate ( 1 ) and 11‐O‐acetyl‐22‐epihippuristanol ( 2 ), and a new alkaloid, 2,3,5,6,11,11b‐hexahydro‐2‐hydroxy‐1H‐indolizino[8,7‐b]indole‐2‐carboxylic acid ( 3 ), together with three known compounds, 22‐epihippuristanol ( 4 ), hippuristanol ( 5 ), and tryptamine ( 6 ), were isolated from the EtOH/CH₂Cl₂ extracts of the South China Sea gorgonian Isis minorbrachyblasta. The structures of the new compounds were determined by spectroscopic methods. Compound 1 showed weak cytotoxicity against A549, HONE1, and HeLa cancer cell lines and strong antilarval activity towards Bugula neritina larvae with an EC₅₀ value of 5.8 μg/ml. Compound 5 showed moderate cytotoxicity against A549, HONE1, and HeLa cell lines, and the epimer mixture 4 / 5 (weight ratio 3 : 2) exhibited potent cytotoxicity against A549 and HONE1 cell lines with IC₅₀ values of 4.2 and 4.8 μg/ml, which indicated that epimers 4 and 5 might have a synergistic effect on their cytotoxicity against A549 and HONE1 cell lines.     

Synthesis of Some C2‐Symmetric Bidentate Ligands and Their Complexes Derived from Feist's Acid

Various new C₂‐symmetric bidentate ligands, bearing phosphorus, nitrogen, and sulfur, were obtained in an efficient manner, starting from (±)‐trans‐3‐methylidenecyclopropane‐1,2‐dicarboxylic acid (Feist's acid; (±)‐trans‐ 3 ). The structures of the new bidentate ligands, di(tert‐butyl) (±)‐[(trans‐3‐methylidenecyclopropane‐1,2‐diyl)dimethanediyl]biscarbamate ((±)‐ 9 ), (±)‐(trans‐3‐methyldienecyclopropane‐1,2‐diyl)dimethanaminium dichloride ((±)‐ 10 ), (±)‐S,S′‐[(trans‐3‐methylidenecyclopropane‐1,2‐diyl)dimethanediyl] diethanethioate ((±)‐ 11 ), and (±)‐[(trans‐3‐methylidenecyclopropane‐1,2‐diyl)dimethanediyl]bis(diphenylphosphane) ((±)‐ 12 ), were fully characterized by standard spectroscopic techniques. These new classes of C₂‐symmetric bidentate ligands have the potential to be used in asymmetric catalysis.     

The structures of 1,4‐diaryl‐5‐trifluoromethyl‐1H‐1,2,3‐triazoles related to J147, a drug for treating Alzheimer's disease

J147 [N‐(2,4‐dimethylphenyl)‐2,2,2‐trifluoro‐N′‐(3‐methoxybenzylidene)acetohydrazide] has recently been reported as a promising new drug for the treatment of Alzheimer's disease. The X‐ray structures of seven new 1,4‐diaryl‐5‐trifluoromethyl‐1H‐1,2,3‐triazoles, namely 1‐(3,4‐dimethylphenyl)‐4‐phenyl‐5‐trifluoromethyl‐1H‐1,2,3‐triazole (C₁₇H₁₄F₃N₃, 1 ), 1‐(3,4‐dimethylphenyl)‐4‐(3‐methoxyphenyl)‐5‐trifluoromethyl‐1H‐1,2,3‐triazole (C₁₈H₁₆F₃N₃O, 2 ), 1‐(3,4‐dimethylphenyl)‐4‐(4‐methoxyphenyl)‐5‐trifluoromethyl‐1H‐1,2,3‐triazole (C₁₈H₁₆F₃N₃O, 3 ), 1‐(2,4‐dimethylphenyl)‐4‐(4‐methoxyphenyl)‐5‐trifluoromethyl‐1H‐1,2,3‐triazole (C₁₈H₁₆F₃N₃O, 4 ), 1‐[2,4‐bis(trifluoromethyl)phenyl]‐4‐(3‐methoxyphenyl)‐5‐trifluoromethyl‐1H‐1,2,3‐triazole (C₁₈H₁₀F₉N₃O, 5 ), 1‐(3,4‐dimethoxyphenyl)‐4‐(3,4‐dimethoxyphenyl)‐5‐trifluoromethyl‐1H‐1,2,3‐triazole (C₁₉H₁₈F₃N₃O₄, 6 ) and 3‐[4‐(3,4‐dimethoxyphenyl)‐5‐(trifluoromethyl)‐1H‐1,2,3‐triazol‐1‐yl]phenol (C₁₇H₁₄F₃N₃O₃, 7 ), have been determined and compared to that of J147 . B3LYP/6‐311++G(d,p) calculations have been performed to determine the potential surface and molecular electrostatic potential (MEP) of J147 , and to examine the correlation between hydrazone J147 and the 1,2,3‐triazoles, both bearing a CF₃ substituent. Using MEPs, it was found that the minimum‐energy conformation of 4 , which is nearly identical to its X‐ray structure, is closely related to one of the J147 seven minima.     

Synthesis and characterization of (pyrazolylethylphosphinite)nickel(II) complexes and catalytic activity towards ethylene oligomerization

Compounds (2‐(3,5‐dimethyl‐1H‐pyrazol‐1‐yl)ethyldiphenylphosphinite ( L1 ), 2‐(3,5‐di‐tert‐butyl‐1H‐pyrazol‐1‐yl)ethyldiphenylphosphinite ( L2 ) , and 2‐(3,5‐diphenyl‐1H‐pyrazol‐1‐yl)ethyldiphenylphosphinite ( L3 ) were prepared using the synthetic routes reported in literature. These compounds were reacted with [NiCl₂(DME)₂] or [NiBr₂(DME)₂] under appropriate reaction conditions to afford six new nickel(II) compounds ([NiCl₂( L1)] ( 1 ), [NiCl₂( L2 )] ( 2 ), [NiCl₂( L3 )] ( 3 ), [NiBr₂( L1 )] ( 4 ), [NiBr₂( L2 )] ( 5 ) and [NiBr₂( L3 )] ( 6 )). The new nickel(II) pre‐catalysts catalyze the oligomerization of ethylene, in the presence of ethylaluminium dichloride as co‐catalyst, to produce butenes, hexenes, octenes and higher carbon chain ethylene oligomers with very little Friedel‐Crafts alkylation products when the reactions were run in toluene.     

Planarity of benzoyldithiocarbazate tuberculostatics. II. Diesters of benzoyldithiocarbazic acid

The emergence of drug‐resistant strains of Mycobacterium tuberculosis has intensified efforts to identify new lead tuberculostatics. Our earlier studies concluded that the planarity of a molecule correlates well with its tuberculostatic activity. According to our hypothesis, only derivatives whose molecules are capable of adopting a planar conformation may show tuberculostatic activity. The structures of three new potentially tuberculostatic compounds, namely N′‐[bis(methylsulfanyl)methylidene]‐N‐methyl‐4‐nitrobenzohydrazide (denoted G1), C₁₁H₁₃N₃O₃S₂, N′‐[bis(benzylsulfanyl)methylidene]‐N‐methyl‐4‐nitrobenzohydrazide (denoted G2), C₂₃H₂₁N₃O₃S₂, and N′‐[(benzylsulfanyl)(methylsulfanyl)methylidene]‐4‐nitrobenzohydrazide (denoted G3), C₁₆H₁₅N₃O₃S₂, were determined by X‐ray diffraction. The significant distortion from planarity caused by the methyl substituent at the N atom of the hydrazide group or the NO₂ substituent in the aromatic ring leads to the loss of tuberculostatic activity for G1, G2 and G4 {systematic name: N′‐[bis(methylsulfanyl)methylidene]‐2‐nitrobenzohydrazide}. A similar effect is observed when there are large substituents at the S atoms (G2 and G3).     

Water‐Free Rare‐Earth‐Metal Ionic Liquids/Ionic Liquid Crystals Based on Hexanitratolanthanate(III) Anion

The hexanitratolanthanate anion (La(NO₃)₆^3?) is an interesting symmetric anion suitable to construct the component of water‐free rare‐earth‐metal ionic liquids. The syntheses and structural characterization of eleven lanthanum nitrate complexes, [C_nmim]₃[La(NO₃)₆] (n=1, 2, 4, 6, 8, 12, 14, 16, 18), including 1,3‐dimethylimidazolium hexanitratolanthanate ([C₁mim]₃[La(NO₃)₆], 1 ), 1‐ethyl‐3‐methylimidazolium hexanitratolanthanate ([C₂mim]₃[La(NO₃)₆], 2 ), 1‐butyl‐3‐methylimidazolium hexanitratolanthanate ([C₄mim]₃[La(NO₃)₆], 3 ), 1‐isobutyl‐3‐methylimidazolium hexanetratolanthanate ([isoC₄mim]₃[La(NO₃)₆], 4 ), 1‐methyl‐3‐(3′‐methylbutyl)imidazolium hexanitratolanthanate ([MC₄mim]₃[La(NO₃)₆], 5 ), 1‐hexyl‐3‐methylimidazolium hexanitratolanthanate ([C₆mim]₃[La(NO₃)₆], 6 ), 1‐methyl‐3‐octylimidazolium hexanitratolanthanate ([C₈mim]₃[La(NO₃)₆], 7 ), 1‐dodecyl‐3‐methylimidazolium hexanitratolanthanate ([C₁₂mim]₃[La(NO₃)₆], 8 ), 1‐methyl‐3‐tetradecylimidazolium hexanitratolanthanate ([C₁₄mim]₃[La‐(NO₃)₆], 9 ), 1‐hexadecyl‐3‐methylimid‐azolium hexanitratolanthanum ([C₁₆dmim]₃[La(NO₃)₆], 10 ), and 1‐methyl‐3‐octadecylimidazolium hexanitratolanthanate ([C₁₈mim]₃[La(NO₃)₆], 11 ) are reported. All new compounds were characterized by ¹H and ¹³C NMR, and IR spectroscopy as well as elemental analysis. The crystal structure of compound 1 was determined by using single‐crystal X‐ray diffraction, giving the following crystallographic information: monoclinic; P2₁/c; a=15.3170 (3), b=14.2340 (2), c=13.8954(2) Å; β=94.3453(15)°, V=3020.80(9) ų, Z=4, ρ=1.764 g cm^?3. The coordination polyhedron around the lanthanum ion is rationalized by six nitrate anions with twelve oxygen atoms. No hydrogen‐bonding network or water molecule was found in 1 . The thermodynamic stability of the new complexes was investigated by using thermogravimetric analysis (TGA). The water‐free hexanitratolanthanate ionic liquids are thermal and moisture stable. Four complexes, namely complexes 8 – 11 , were found to be ionic liquid crystals by differential scanning calorimetry (DSC) and polarizing optical microscopy (POM). They all present smectic A liquid‐crystalline phase.     

Synthesis of Binam‐P Derived C2‐Symmetric bis‐Iminophosphonamide Ligands. Molecular Structure of [(R)‐Binam(Ph2PN(H)tBu)2]

The Staudinger reaction of organic azides tBuN₃, 1‐Ad‐N₃, and DippN₃ (Dipp = 2,6‐diisopropylphenyl) with (R)‐N,N′‐bis(diphenylphosphanyl)‐2,2′‐diamino‐1,1′‐binaphthyl [(R)‐Binam‐P], obtained by an optimized procedure from (R)‐(+)‐Binam, Ph₂PCl, and Et₃N in DCM, leads to preparation of a series of new C₂‐symmetric bis‐iminophosphonamide ligands [(R)‐Binam(Ph₂PN(H)R)₂] [R = tBu ( 1 ), Ad ( 2 ), and Dipp ( 3 )]. The molecular structure of 1· 2DMSO was confirmed by X‐ray structure analysis.     

Novel hydrazone derivatives of 7‐hydroxy‐3′,3′‐dimethyl‐3′H‐spiro[chromene‐2,1′‐isobenzofuran]‐8‐carbaldehyde

The structures of new oxaindane spiropyrans derived from 7‐hydroxy‐3′,3′‐dimethyl‐3′H‐spiro[chromene‐2,1′‐isobenzofuran]‐8‐carbaldehyde (SP1), namely N‐benzyl‐2‐[(7‐hydroxy‐3′,3′‐dimethyl‐3′H‐spiro[chromene‐2,1′‐isobenzofuran]‐8‐yl)methylidene]hydrazinecarbothioamide, C₂₇H₂₅N₃O₃S, (I), at 120 (2) K, and N′‐[(7‐hydroxy‐3′,3′‐dimethyl‐3′H‐spiro[chromene‐2,1′‐isobenzofuran]‐8‐yl)methylidene]‐4‐methylbenzohydrazide acetone monosolvate, C₂₇H₂₄N₂O₄·C₃H₆O, (II), at 100 (2) K, are reported. The photochromically active C_spiro—O bond length in (I) is close to that in the parent compound (SP1), and in (II) it is shorter. In (I), centrosymmetric pairs of molecules are bound by two equivalent N—H...S hydrogen bonds, forming an eight‐membered ring with two donors and two acceptors.     

New Dammarane Monodesmosides from the Acidic Deglycosylation of Notoginseng‐Leaf Saponins

Three new dammarane monodesmosides, named notoginsenosides Ft₁ ( 1 ), Ft₂ ( 2 ), and Ft₃ ( 3 ), together with three known ginsenosides, were obtained from a mild acidic hydrolysis of the saponins from notoginseng (Panax notoginseng (Burk .) F. H. Chen ) leaves. Their structures were elucidated to be (3β,12β,20R)‐12,20‐dihydroxydammar‐24‐en‐3‐yl O‐β‐D ‐xylopyranosyl‐(1 → 2)‐O‐β‐D ‐glucopyranosyl‐(1 → 2)‐β‐D ‐glucopyranoside ( 1 ), (3β,12β)‐12,20,25‐trihydroxydammaran‐3‐yl O‐β‐D ‐xylopyranosyl‐(1 → 2)‐O‐β‐D ‐glucopyranosyl‐(1 → 2)‐β‐D ‐glucopyranoside ( 2 ), and (3β,12β,24ξ)‐12,20,24‐trihydroxydammar‐25‐en‐3‐yl O‐β‐D ‐xylopyranosyl‐(1 → 2)‐O‐β‐D ‐glucopyranosyl‐(1 → 2)‐β‐D ‐glucopyranoside ( 3 ), by means of spectroscopic evidences. The known ginsenosides Rh₂ and Rg₃ 4 – 6 were obtained as the major products from this acidic deglycosylation.     

Sesquiterpenoids‐Related Metabolites from the Soft Coral Sinularia sp.

Two new sesquiterpenoids, sinularioperoxide E ( 1 ), ethyl 5‐[(2′S,5′E)‐2′, 6′‐dimethylocta‐5′,7′‐dienyl]furan‐3‐carboxylate ( 3 ), and a new C₁₁ terpenoid‐related carboxylic acid, (3S,6E)‐3,7‐dimethyl‐nona‐6,8‐dienoic acid ( 2 ) were isolated from a Formosan soft coral Sinularia sp. The structures of 1‐3 were elucidated on the basis of extensive spectroscopic analyses and by comparison of the spectral data with those of the related metabolites.     

Stereochemistry of two new polyfunctionalized gem‐dihalo­cyclo­propanes

The two new gem‐dihalogeno­cyclo­propanes (1′S,3R)‐3‐(2′,2′‐di­chloro‐1′‐methyl­cyclo­propyl)‐6‐oxoheptanoic acid, C₁₁H₁₆­Cl₂O₃, (2), and (1′S,3R)‐3‐(2′,2′‐di­bromo‐1′‐methyl­cyclo­propyl)‐6‐oxoheptanoic acid, C₁₁H₁₆Br₂O₃, (3), are isostructural. Both present two stereogenic centers at C1′ and C3. The absolute configuration was determined by X‐ray methods. The cyclo­propyl rings are unsymmetrical, the shortest bond being distal with respect to the alkyl‐substituted C atom.     

Tunable Fluorophores Based on 2‐(N‐Arylimino)pyrrolyl Chelates of Diphenylboron: Synthesis,Structure, Photophysical Characterization,and Application in OLEDs

Reactions of 2‐(N‐arylimino)pyrroles (HNC₄H₃C(H)?N‐Ar) with triphenylboron (BPh₃) in boiling toluene afford the respective highly emissive N,N′‐boron chelate complexes, [BPh₂{κ²N,N′‐NC₄H₃C(H)?N‐Ar}] (Ar=C₆H₅ ( 12 ), 2,6‐Me₂‐C₆H₃ ( 13 ), 2,6‐iPr₂‐C₆H₃ ( 14 ), 4‐OMe‐C₆H₄ ( 15 ), 3,4‐Me₂‐C₆H₃ ( 16 ), 4‐F‐C₆H₄ ( 17 ), 4‐NO₂‐C₆H₄ ( 18 ), 4‐CN‐C₆H₄ ( 19 ), 3,4,5‐F₃‐C₆H₂ ( 20 ), and C₆F₅ ( 21 )) in moderate to high yields. The photophysical properties of these new boron complexes largely depend on the substituents present on the aryl rings of their N‐arylimino moieties. The complexes bearing electron‐withdrawing aniline substituents 17 – 20 show more intense (e.g., ?_f=0.71 for Ar=4‐CN‐C₆H₄ ( 19 ) in THF), higher‐energy (blue) fluorescent emission compared to those bearing electron‐donating substituents, for which the emission is redshifted at the expense of lower quantum yields (?_f=0.13 and 0.14 for Ar=4‐OMe‐C₆H₄ ( 15 ) and 3,4‐Me₂‐C₆H₃ ( 16 ), respectively, in THF). The presence of substituents bulkier than a hydrogen atom at the 2,6‐positions of the aryl groups strongly restricts rotation of this moiety towards coplanarity with the iminopyrrolyl ligand framework, inducing a shift in the emission to the violet region (λ_max=410–465 nm) and a significant decrease in quantum yield (?_f=0.005, 0.023, and 0.20 for Ar=2,6‐Me₂‐C₆H₃ ( 13 ), 2,6‐iPr₂‐C₆H₃ ( 14 ), and C₆F₅ ( 21 ), respectively, in THF), even when electron‐withdrawing groups are also present. Density functional theory (DFT) and time‐dependent DFT (TD‐DFT) calculations have indicated that the excited singlet state has a planar aryliminopyrrolyl ligand, except when prevented by steric hindrance (ortho substituents). Calculated absorption maxima reproduce the experimental values, but the error is higher for the emission wavelengths. Organic light‐emitting diodes (OLEDs) have been fabricated with the new boron complexes, with luminances of the order of 3000 cd m^?2 being achieved for a green‐emitting device.     

Synthesis of Some New 2‐Oxo‐N‐[(10H‐phenothiazin‐10‐yl)alkyl] Derivatives of Azetidine‐1‐carboxamides

The synthesis of a new series of 4‐aryl‐3‐chloro‐2‐oxo‐N‐[3‐(10H‐phenothiazin‐10‐yl)propyl]azetidine‐1‐carboxamides, 4a – 4m , is described. Phenothiazine on reaction with Cl(CH₂)₃Br at room temperature gave 10‐(3‐chloropropyl)‐10H‐phenothiazine ( 1 ), and the latter reacted with urea to yield 1‐[3‐(10H‐phenothiazin‐10‐yl)propyl]urea ( 2 ). Further reaction of 2 with several substituted aromatic aldehydes led to N‐(arylmethylidene)‐N′‐[3‐(phenothiazin‐10‐yl)propyl]ureas 3a – 3m , which, on treatment with ClCH₂COCl in the presence of Et₃N, furnished the desired racemic trans‐2‐oxoazetidin‐1‐carboxamide derivatives 4a – 4m . The structures of all new compounds were confirmed by IR, and ¹H‐ and ¹³C‐NMR spectroscopy, FAB mass spectrometry, and chemical methods.     

Synthesis and Structures of Metallated N‐Heterocyclic Derivatives

The synthesis and structures of five new compounds are reported. [Mg(6‐Oq)₂(phen)₂] ( 1 ), [Na(phen)₃][(6‐HOq)(6‐Oq)] ( 2 ), 1/∞[Cu(3‐Opy)(3‐HOpy)₂(PPh₃)]_∞ ( 3 ), 1/∞[Cu₂{μ‐(6‐Oq)}(PPh₃)₂]_∞ ( 4 ) and [Cu₂(pht)₂(μ‐dppm)₂] ( 5 ) (6‐HOq = 6‐hydroxyquinoline; phen = 1,10‐phenanthroline, 3‐HOpy = 3‐hydroxypyridine; Hpht = phthalimide; dppm = bis‐(diphenylphosphino)methane) were prepared by deprotonation of N‐heterocyclic aromatic compounds with metal alkoxides. 1 – 5 represent useful starting materials for investigating the supramolecular cordination chemistry of organic anhydrides.     

Terpenoids from Eupatorium fortunei Turcz

Four new terpenoids, namely, rel‐(1R,2S,3R,4R,6S)‐p‐menthane‐1,2,3,6‐tetrol ( 1 ), rel‐(1R,2R,3R,4S,6S)‐p‐menthane‐1,2,3,6‐tetrol ( 2 ), 9‐hydroxythymol 3‐O‐angelate ( 3 ), and (3β,20R)‐20‐hydroxylanost‐25‐en‐3‐yl palmitate ( 4 ), together with fourteen known compounds, were isolated from the AcOEt part of the MeOH extracts of Eupatorium fortunei. In addition, two other monoterpenoids, ‘acetone thymol‐8,9‐diyl ketal’ ( 19 ) and 8‐methoxy‐9‐hydroxythymol 3‐O‐angelate ( 20 ) were also obtained which were probably artifacts but have never been reported in the literature. The structures of the new compounds, including their relative configurations, were established by an extensive study of their spectral data, especially 1D‐ and 2D‐NMR. The cytotoxic activity of the new compounds against human hepatoma (SMMC‐7721), human leukemia (HL‐60), and human hepatocyte (LO₂) cells was investigated.     

Planarity of benzoylthiocarbazate tuberculostatics. IV. Polymorphs of N′‐(1,3‐dithiolan‐2‐ylidene)‐4‐nitrobenzohydrazide

The search for new tuberculostatics is important considering the occurrence of drug‐resistant strains of Mycobacterium tuberculosis . Three polymorphs of N ′‐(1,3‐dithiolan‐2‐ylidene)‐4‐nitrobenzohydrazide (a potentially tuberculostatic agent), C₁₀H₉N₃O₃S₂, denoted (I1), (I2) and (I3), and the monohydrate of this compound, C₁₀H₉N₃O₃S₂·H₂O, (I4), have been characterized by single‐crystal X‐ray diffraction. The conformations of the molecules in all these structures are very similar. Structures (I1), (I2) and (I3) provide an example of packing polymorphism resulting from different intermolecular interactions.