N‐(l‐2‐Aminobutyryl)‐l‐alanine and 2‐(l‐alanylamino)‐l‐butyric acid 0.33‐hydrate

The crystal structure of N‐(l ‐2‐amino­butyryl)‐l ‐alanine, C₇H₁₄N₂O₃, is closely related to the structure of l ‐alanyl‐l ‐alanine, both being tetragonal, while the retro‐analogue 2‐(l ‐alanyl­amino)‐l ‐butyric acid 0.33‐hydrate, C₇H₁₄N₂O₃·­0.33H₂O, forms a new type of molecular columnar structure with three peptide mol­ecules in the asymmetric unit.     

N‐Acetyl‐l‐tyrosine methyl ester monohydrate at 293 and 123 K

The crystal structure of a protected l ‐tyrosine, namely N‐acetyl‐l ‐tyrosine methyl ester monohydrate, C₁₂H₁₅NO₄·H₂O, was determined at both 293 (2) and 123 (2) K. The structure exhibits a network of O—H...O and N—H...O hydrogen bonds, in which the water molecule plays a crucial role as an acceptor of one and a donor of two hydrogen bonds. Molecules of water and of the protected l ‐tyrosine form hydrogen‐bonded layers perpendicular to [001]. C—H...π interactions are observed in the hydrophobic regions of the structure. The structure is similar to that of N‐acetyl‐l ‐tyrosine ethyl ester monohydrate [Soriano‐García (1993). Acta Cryst. C 49 , 96–97].     

N‐(tert‐Butoxycarbonyl)‐O‐allyl‐l‐seryl‐α‐aminoisobutyryl‐l‐valine methyl ester: a protected tripeptide with an allylated serine residue

The title compound [systematic name (6S,12S)‐methyl 6‐(allyloxymethyl)‐12‐isopropyl‐2,2,9,9‐tetramethyl‐4,7,10‐trioxo‐3‐oxa‐5,8,11‐triazatridecan‐13‐oate], C₂₁H₃₇N₃O₇, containing the little studied O‐allyl‐l ‐serine residue [Ser(All)], crystallizes in the monoclinic space group C2 with one molecule in the asymmetric unit. The compound is an analogue of the Ser140‐Val142 segment of the water channel aquaporin‐4 (AQP4). It forms a distorted type‐II β‐turn with a P_II–3_10L–P_II backbone conformation (P_II is polyproline II). The overall backbone conformation is markedly different from that of the CO(Pro139)–Val142 stretch of rat AQP4, but is quite similar to the corresponding segment of human AQP4, despite significant differences at the level of the individual residues. The side chain of the Ser(All) residue adopts a gauche conformation relative to the backbone CO—C^α and C^α—N bonds. The H atoms of the two CH₂ groups in the Ser(All) side chain are almost eclipsed. The crystal packing of the title compound is divided into one‐molecule‐thick layers, each layer having a hydrophilic core and distinct hydrophobic interfaces on either side.     

1‐[(4‐Chloro­benzoyl)­methyl]‐4‐(N,N‐di­methyl­amino)­pyridinium bromide sesquihydrate and 1‐[(4‐bromo­benzoyl)­methyl]‐4‐(N,N‐di­methyl­amino)­pyridinium bromide sesquihydrate

The title compounds, C₁₅H₁₆ClN₂O⁺·Br⁻·1.5H₂O and C₁₅H₁₆BrN₂O⁺·Br⁻·1.5H₂O, are isomorphous. The benzene ring is oriented nearly normal to the pyridine ring in both compounds. The molecular packing is mainly influenced by intermolecular O—H⋯O and O—H⋯Br interactions, as well as weak intramolecular C—H⋯O interactions. The H₂OBr⁻ units form an extended water–bromide chain, with a bridging water mol­ecule on a twofold axis.     

N‐(4‐Methoxy­benzyl­idene)‐N′‐(2‐pyridyl)­hydrazine

Molecules of the title compound (alternative name p‐methoxybenzaldehyde 2‐pyridyl­hydrazone), C₁₃H₁₃N₃O, adopt an E configuration about the azomethine C=N double bond. Molecules are almost planar, the dihedral angle between the pyridine and methoxy­phenyl rings being only 6.19 (12)°. Pairwise N—H⃛N hydrogen bonds [R(8) in graph‐set notation] link centrosymmetrically related mol­ecules into discrete pairs.     

3‐(4‐Chloro­benzoyl)‐7‐(N,N‐di­methyl­amino)‐1‐phenyl­indolizine and 3‐(2,4‐di­chloro­benzoyl)‐7‐(N,N‐di­methyl­amino)‐1‐phenyl­indolizine

In both of the title compounds, C₂₃H₁₉ClN₂O, (I), and C₂₃H₁₈Cl₂N₂O, (II), the molecular packing is influenced by weak intermolecular C—H⋯O and C—H⋯π interactions, but despite the chemical similarity of the compounds, the packing in (II) is entirely different from that observed in (I).     

Hexanuclear Wheel‐Shaped Lithium N‐(2,6‐Diisopropylphenyl)‐N′‐(2‐pyridylethyl)benzamidinate

Lithiation of N‐(2,6‐diisopropylphenyl)‐N′‐(2‐pyridylethyl)benzamidine ( 1 ) with LiN(SiMe₃)₂ in a solvent mixture of toluene and TMEDA yields hexameric lithium N‐(2,6‐diisopropylphenyl)‐N′‐(2‐pyridylethyl)benzamidinate ( 2 ), which can be purified by recrystallization from a solvent mixture of toluene and THF. The three‐coordinate lithium ions have T‐shaped coordination spheres. The negative charge is delocalized within the 1,3‐diazaallylic system, which adopts a (syn‐Z)‐arrangement.     

N‐(4‐Methyl­phenyl)‐N‐(5‐nitro­furfuryl)‐N‐prop‐2‐ynyl­amine

The title compound, C₁₅H₁₄N₂O₃, is the first example of a structurally determined tertiary amine with both N‐5‐nitro­furfuryl and N‐prop‐2‐ynyl moieties. The mol­ecule is not planar, i.e. the furan ring is inclined at an angle of 84.35 (4)° to the phenyl ring. The crystal structure is dominated by van der Waals forces. The terminal alkynyl group as the strongest C—H hydrogen‐bond donor is not involved in hydrogen‐bond formation.     

N‐(Ferrocenecarbonyl)‐N′‐(quinolin‐8‐yl)thio­urea

In the title compound, [Fe(C₅H₅)(C₁₆H₁₂N₃OS)], the 8‐am­inoquinoline and acyl­thio­urea moieties are almost planar. There are two perpendicular arrangements of the mol­ecules in the crystal with slightly different conformations. The two cyclo­penta­dienyl rings in each mol­ecule are parallel and eclipsed.     

2‐Benzoyl‐N‐phenyl‐2‐(1,2,4‐triazol‐1‐yl)­thio­acet­amide and 2‐(4‐methoxy­benzoyl)‐N‐phenyl‐2‐(1,2,4‐triazol‐1‐yl)­thio­acet­amide

In the two title compounds, C₁₇H₁₄N₄OS, (I), and C₁₈H₁₆N₄O₂S, (II), the dihedral angles between the planes of the triazole and N‐phenyl rings and the plane of five of the atoms that link these two rings are 63.5 (8) and 73.2 (6)° for (I), and 65.1 (1) and 72.1 (3)° for (II), respectively. There are some inter‐ and intramolecular interactions in the crystal structure.     

N‐(2‐Amino­benz­yl)‐N,N‐bis­(quinolin‐2‐ylmeth­yl)amine

The title new diquinaldine derivative, C₂₇H₂₄N₄, forms mol­ecular assemblies organized by inter­molecular quinoline π–π stacking [3.356 (3) and 3.440 (3) Å] and both inter‐ and intra­molecular N—H⋯N hydrogen bonds [3.039 (3)–3.104 (3) Å and 129 (2)–172 (2)°]. The combination of such inter­actions provides readily definable contacts that propagate along each crystallographic axis.     

6‐(2‐Hydro­xy­benzoyl)‐5‐(pyrrol‐2‐yl)‐3H‐pyrrolizine

The title compound, 2‐hydroxy­phenyl 5‐(pyrrol‐2‐yl)‐3H‐pyrrolizin‐6‐yl ketone, C₁₈H₁₄N₂O₂, was isolated from the base‐catalyzed 1:2 condensation of 2‐hydroxy­aceto­phenone with pyrrole‐2‐carbaldehyde. The pyrrole N—H and hydroxy­benzoyl O—H groups are hydrogen bonded to the benzoyl O atom. The allyl­ic C=C double bond of the 3H‐pyrrolizine system is located between ring positions 1 and 2, the C atom at position 3 (adjacent to the N atom) being single bonded.     

N‐(2‐Hydroxyethyl)ethylenediammonium hydrogenphosphate monohydrate

The title compound, C₄H₁₄N₂O²⁺·HPO₄^2?·H₂O, contains alternating interleaved layers of hydrogenphosphate and N‐(2‐hydroxyethyl)ethyl­enedi­ammonium moieties. The water mol­ecules are associated with channel‐like voids in the structure and a network of hydrogen bonds stabilizes the crystal packing.     

2‐Benzothiazolyl‐N‐(arenesulfonyl)‐sulfinimidoyl fluorides

2‐Benzothiazolyl‐N‐(arenesulfonyl)‐sulfinimidoyl fluorides were synthesized by the treatment of benzothiazolyl‐2‐sulfur trifluoride with sulfonamides. The reaction of 2‐benzothiazolyl‐N‐ (p‐toluenesulfonyl)‐sulfinimidoyl fluoride with tert‐ butylamine and morpholine gave 2‐benzothiazolyl‐ N‐(arenesulfonyl)‐sulfinimidoyl amides. The reaction of 2‐benzothiazolyl‐N‐(p‐toluenesulfonyl)‐sulfinimi‐ doyl fluoride or 2‐benzothiazolyl‐¹⁵N‐(p‐tosyl)sul‐ finimidoyl fluoride with S‐trimethylsilylbenzenethiol gave di(benzothiazolyl‐2) disulfide, fluorotrimethylsi‐ lane and N,N′‐bis(p‐toluenesulfonyl)‐N,N′‐bis(phenyl‐ thio)‐hydrazine or ¹⁵N,¹⁵N′‐bis(p‐toluenesulfonyl)‐¹⁵N, ¹⁵N′‐bis(phenylthio)‐hydrazine, respectively. © 2005 Wiley Periodicals, Inc. Heteroatom Chem 16:352–356, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20102     

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.     

An interesting cyclization of N‐methyl‐3‐phenyl‐N‐(2‐(Z)‐phenylethenyl)‐cis‐oxiranecarboxamide

Under Lewis acid condition, N‐methyl‐3‐phenyl‐N‐(2‐(Z)‐phenylethenyl)‐cis‐oxiranecarboxamide undergoes elegant double cyclizations to give interesting products.     

Structural comparison of three N‐(4‐halogenophenyl)‐N′‐[1‐(2‐pyridyl)ethylidene]hydrazine hydrochlorides

2‐{1‐[(4‐Chloroanilino)methylidene]ethyl}pyridinium chloride methanol solvate, C₁₃H₁₃ClN₃⁺·Cl⁻·CH₃OH, (I), crystallizes as discrete cations and anions, with one molecule of methanol as solvent in the asymmetric unit. The N—C—C—N torsion angle in the cation indicates a cis conformation. The cations are located parallel to the (02) plane and are connected through hydrogen bonds by a methanol solvent molecule and a chloride anion, forming zigzag chains in the direction of the b axis. The crystal structure of 2‐{1‐[(4‐fluoroanilino)methylidene]ethyl}pyridinium chloride, C₁₃H₁₃FN₃⁺·Cl⁻, (II), contains just one anion and one cation in the asymmetric unit but no solvent. In contrast with (I), the N—C—C—N torsion angle in the cation corresponds with a trans conformation. The cations are located parallel to the (100) plane and are connected by hydrogen bonds to the chloride anions, forming zigzag chains in the direction of the b axis. In addition, the crystal packing is stabilized by weak π–π interactions between the pyridinium and benzene rings. The crystal of (II) is a nonmerohedral monoclinic twin which emulates an orthorhombic diffraction pattern. Twinning occurs via a twofold rotation about the c axis and the fractional contribution of the minor twin component refined to 0.324 (3). 2‐{1‐[(4‐Fluoroanilino)methylidene]ethyl}pyridinium chloride methanol disolvate, C₁₃H₁₃FN₃⁺·Cl⁻·2CH₃OH, (III), is a pseudopolymorph of (II). It crystallizes with two anions, two cations and four molecules of methanol in the asymmetric unit. Two symmetry‐equivalent cations are connected by hydrogen bonds to a chloride anion and a methanol solvent molecule, forming a centrosymmetric dimer. A further methanol molecule is hydrogen bonded to each chloride anion. These aggregates are connected by C—H...O contacts to form infinite chains. It is remarkable that the geometric structures of two compounds having two different formula units in their asymmetric units are essentially the same.     

Synthesis of 2‐(N‐arylimino)pyrrolide nickel complexes and polymerization of methyl methacrylate

The synthesis, characterization and methyl methacrylate polymerization behaviors of 2‐(N‐arylimino)pyrrolide nickel complexes are described. The nickel complex [NN]₂Ni ( 1 , [NN] = [2‐C(H)NAr‐5‐tBu‐C₄H₂N]^?, Ar = 2,6‐iPr₂C₆H₃) was prepared in good yield by the reaction of [NN]Li with trans‐[Ni(Cl)(Ph)(PPh₃)₂] in THF. Reaction of [NN]Li with NiBr₂(DME) yielded the nickel bromide [NN]Ni(Br)[NNH] ( 2 ). Complexes 1 and 2 were characterized by ¹H NMR and IR spectroscopy and elemental analysis, and by X‐ray single crystal analysis. Both complexes, upon activation with methylaluminoxane, are highly active for the polymerization of methyl methacrylate to give high molecular weight polymethylmethacrylate with narrow molecular distributions. Copyright © 2009 John Wiley & Sons, Ltd.