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1.  4-Phenyl-1,2,4-tri­aza­spiro­[4.6]undec-1-ene-3-thione 
In the title compound, C14H17N3S, the plane of the phenyl ring makes a dihedral angle of 74.90 (4)° with that of the tri­aza­thione ring (r.m.s. deviation = 0.001 Å), while the seven-membered ring adopts a twist-chair conformation. No specific intermolecular interactions are discerned in the crystal packing.
doi:10.1107/S1600536814009817
PMCID: PMC4051002  PMID: 24940227
2.  4-Phenyl-1,2,4-tri­aza­spiro­[4.5]dec-1-ene-3-thione 
In the title compound, C13H15N3S, the 4,5-di­hydro-3H-1,2,4-triazole ring is nearly planar [maximum deviation = 0.020 (1) Å], while the cyclo­hexane ring adopts a chair conformation. The dihedral angle between the 4,5-di­hydro-3H-1,2,4-triazole ring and the phenyl ring is 74.68 (7)°. No specific inter­molecular inter­actions are discerned in the crystal packing.
doi:10.1107/S1600536813019120
PMCID: PMC3793756  PMID: 24109343
3.  4-Phenyl-1,2,4-tri­aza­spiro­[4.4]non-1-ene-3-thione 
In the title compound, C12H13N3S, the 4,5-di­hydro-3H-1,2,4-triazole system is nearly planar [maximum deviation = 0.014 (2) Å], while the cyclo­pentane ring adopts a half-chair conformation. The dihedral angle between the mean plane of the 4,5-di­hydro-3H-1,2,4-triazole-3-thione ring and the phenyl ring is 85.49 (14)°, with the S atom 0.046 (1) Å out of the former plane. The crystal structure is stabilized only by van der Waals inter­actions. The investigated crystal was found to be a non-merohedral two-component twin by a 180° rotation about c*, with a refined value of the minor twin fraction of 0.12203 (18).
doi:10.1107/S1600536814005418
PMCID: PMC3998538  PMID: 24826140
4.  5,6-Dimeth­oxy-4′,5′-diphenyl­indane-2-spiro-3′-pyrrolidine-2′-spiro-3′′-indoline-1,2′′-dione 
In the title compound, C33H28N2O4, the central pyrrolidine ring adopts a half-chair conformation. Both the indolinone and indanone groups are twisted, with their five-membered rings adopting a half-chair and an envelope conformation, respectively. The two benzene rings and the mean plane of the indolinone and indanone groups make dihedral angles of 71.98 (10), 84.32 (10), 86.26 (9) and 78.50 (9)°, respectively, with the central pyrrolidine ring. Intra­molecular C—H⋯O hydrogen bonds stabilize the mol­ecular conformation. In the crystal, pairs of inter­molecular N—H⋯O hydrogen bonds link the mol­ecules into centrosymmetric dimers. The dimers are inter­connected into ribbons propagating along [110] via weak inter­molecular C—H⋯O hydrogen bonds. Weak inter­molecular C—H⋯π and π–π [centroid–centroid distance = 3.6509 (11) Å] inter­actions are also observed.
doi:10.1107/S1600536810035865
PMCID: PMC2983396  PMID: 21587525
5.  2-(4-Methyl­pyridin-2-yl)-4′,4′,6′,6′-tetra­kis­(pyrrolidin-1-yl)-1H,2H-spiro­[naphtho­[1,2-e][1,3,2]oxaza­phosphinine-3,2′-[1,3,5,2,4,6]tri­aza­triphosphinine] 
In the title spiro-phosphazene derivative, C33H46N9OP3, the phosphazene and six-membered N/O rings are in flattened chair and twisted-boat conformations, respectively. The naphthalene ring system and the pyridine ring are oriented at a dihedral angle of 41.82 (4)°. In the crystal, weak C—H⋯O hydrogen bonds link the mol­ecules related by translation along the a axis into chains. C—H⋯π inter­actions aggregate these chains into layers parallel to the ab plane.
doi:10.1107/S1600536813014220
PMCID: PMC3685126  PMID: 23795145
6.  (1′S,12′R,13′S,17′S)-15′,15′-Dimethyl-1,2-dihydro-11′,14′,16′,18′-tetra­oxa-7′-aza­spiro­[indole-3,8′-penta­cyclo­[10.6.0.02,9.03,7.013,17]octa­deca­ne]-2,10′-dione 
In the title compound, C22H24N2O6, the indole ring has a twist conformation and the tetra­hydro-2H-pyran-2-one ring a half-chair conformation. One of the pyrrolidine rings adopts an envelope conformation on the N atom, while the other has a twist conformation; the ‘butterfly’ angle between their mean planes is 62.98 (11)°. The dioxolane ring adopts a twist conformation and the tetra­hydro­furan ring has an envelope conformation on the C atom in the fused tetra­hydro-2H-pyran-2-one ring adjacent to the O atom of the tetra­hydro­furan ring. The ‘butterfly’ angle between the mean planes of these two five-membered rings is 69.14 (10)°. In the crystal, mol­ecules are linked by N—H⋯O hydrogen bonds, forming chains along the a axis.
doi:10.1107/S1600536813005436
PMCID: PMC3629507  PMID: 23634025
7.  1-Benzyl-4′,5′-diphenyl­piperidine-3-spiro-3′-pyrrolidine-2′-spiro-3′′-indoline-4,2′′-dione 
The asymmetric unit of the title compound, C34H31N3O2, consists of two independent mol­ecules which differ slightly in the orientations of the phenyl rings with respect to the pyrrolidine ring. In both mol­ecules, the piperidin-4-one ring adopts a chair conformation, whereas the pyrrolidine ring adopts an envelope conformation in one of the mol­ecules and a twisted conformation in the other. An intra­molecular C—H⋯O hydrogen bond is observed. The crystal packing is stabilized by inter­molecular N—H⋯O hydrogen bonds and C—H⋯π inter­actions.
doi:10.1107/S160053680804141X
PMCID: PMC2968062  PMID: 21581605
8.  3-Methyl-1,2,3,4,5,6,1′,2′,3′,4′-deca­hydro­spiro­[benz[f]isoquinoline-1,2′-naphthalen]-1′-one 
The title compound, C23H23NO, is the product of a tandem transformation of the double Mannich base bis­(1-oxo-1,2,3,4-tertrahydro-2-naphtho­ylmeth­yl)amine hydro­chloride in HBr solution upon heating. The tetra­hydro­pyridine ring has a non-symmetrical half-chair conformation, whereas the cyclo­hexa­diene and cyclo­hexene rings adopt non-symmetrical half-boat conformations. The dihedral angle between the planes of the terminal benzene rings is 62.85 (6)°. The N atom has a trigonal–pyramidal geometry [sum of the bond angles = 332.4 (3)°]. In the crystal, mol­ecules form [001] chains via weak non-classical C—H⋯N hydrogen bonds. The chains are stacked along the b axis.
doi:10.1107/S1600536812043309
PMCID: PMC3515312  PMID: 23284532
9.  1′-Phenyl-6′-thia­cyclo­heptane-1-spiro-2′-perhydro­pyrrolizine-3′-spiro-3′′-indoline-2,2′′-dione 
The thia­zolidine ring and the pyrrolidine ring in the title compound, C25H26N2O2S, both adopt an envelope conformation. The seven-membered ring has a twist-chair conformation. The crystal packing is stabilized by inter­molecular N—H⋯O hydrogen bonds.
doi:10.1107/S1600536807068705
PMCID: PMC2960420  PMID: 21201511
10.  Methyl (3S,10b’S)-5-chloro-9′-fluoro-1-methyl-2-oxo-5′-phenyl-10b’H-spiro­[indoline-3,1′-pyrazolo­[3,2-a]iso­quinoline]-2′-carboxyl­ate 
In the title compound, C27H19ClFN3O3, the pyrazole ring has a twist conformation and the six-membered ring to which it is fused has a screw-boat conformation. The mean plane of the pyrazole ring is inclined to the 2-methyl­indoline ring by 85.03 (9) and by 28.17 (8)° to the mean plane of the iso­quinoline ring system. In the crystal, mol­ecules are linked by pairs of C—H⋯F hydrogen bonds, forming inversion dimers. These dimers are linked via C—H⋯O hydrogen bonds, forming a two-dimensional network lying parallel to (10-1).
doi:10.1107/S1600536813011549
PMCID: PMC3684913  PMID: 23795015
11.  1′-Benzyl-4,4′′-bis­(4-chloro­phen­yl)-3-(2,6-dichloro­phen­yl)-1′′-methyl-4,5-dihydro­isoxazole-5-spiro-3′-piperidine-5′-spiro-3′′-pyrrolidine-2′′-spiro-3′′′-indoline-2′′′,4′-dione 
The asymmetric unit of the title compound, C43H34Cl4N4O3, contains two crystallographically independent mol­ecules. In both mol­ecules, the pyrrolidine ring adopts a twist conformation, the oxindole units are slightly distorted from planarity and the isoxazoline ring adopts an envelope conformation. The crystal structure is stabilized by N—H⋯O hydrogen-bonding inter­actions giving one-dimensional chain structures.
doi:10.1107/S1600536809053276
PMCID: PMC2980235  PMID: 21580030
12.  1-Ethyl-4′-(1H-indol-3-ylcarbon­yl)-1′-methyl-2,2′′-dioxodi­spiro­[indoline-3,2′-pyrrolidine-3′,3′′-indoline]-4′-carbo­nitrile dimethyl sulfoxide monosolvate 
In the title compound, C31H25N5O3·C2H6OS, the three indole/indoline units are all essentially planar with maximum deviations of 0.0172 (3), 0.053 (2) and 0.07 (2) Å. The pyrrolidine ring adopts an envelope conformation with the C atoms bearing the 1-ethyl-2-oxo­indole substituent (in which the five-membered ring adopts a twisted conformation) as the flap. The dimethyl sulfoxide solvent mol­ecule is disordered over two positions, with an occupancy factor ratio of 0.871 (4):0.129 (4). The solvent components are linked to the heterocyclic mol­ecule via C—H⋯O and C—H⋯S hydrogen bonds. In the crystal, the solvent components are linked to the heterocyclic molecule via C—H⋯O and C—H⋯S inter­actions, forming R 2 2(10) ring motifs. The mol­ecules are further connected into a chain along the a-axis direction via N—H⋯O hydrogen bonds.
doi:10.1107/S1600536813020485
PMCID: PMC3793813  PMID: 24109400
13.  (1R,6R)-1-Methyl-8-aza­spiro­[5.6]dodecan-7-one 
The crystal structure of the title compound, C12H21NO, has been investigated to establish the absolute stereochemistry at position 1. The absolute stereochemistry at the quaternary centre at position 6 is established to be R using an asymmetric Birch reductive alkyl­ation reaction for which the stereochemical outcome is known. The crystal structure indicates the presence of two conformers of the bicyclic (1R,6R)-spiro­lactam ring system that differ in the conformation adopted by the six-membered ring. In one conformer, the meth­yl group adopts an axial position whereas in the other conformer, the same methyl group adopts an equatorial position. In both conformers, the seven-membered ring adopts a chair conformation. The two conformers of the bicyclic spiro­lactam are connected to each other via inter­molecular N—H⋯O hydrogen bonds forming a heterodimer. The asymmetric unit contains two such dimers.
doi:10.1107/S1600536808015158
PMCID: PMC2961468  PMID: 21202659
14.  8-Methyl-4-morpholinoethyl-1-thia-4-aza­spiro­[4.5]decan-3-one 
In the title compound, C15H26N2O2S, the cyclo­hexane and morpholine rings adopt chair conformations, while the thia­zole ring has a twist conformation. An intra­molecular C—H⋯S hydrogen-bond inter­action forms a five-membered ring. The crystal packing involves C—H⋯O=C inter­molecular inter­actions where carbonyl O atoms act as double acceptors to two symmetrically related H atoms.
doi:10.1107/S1600536808022459
PMCID: PMC2962192  PMID: 21203273
15.  Ethyl 2-(1,2,3,4-tetrahydro­spiro­[carba­zole-3,2′-[1,3]dioxolan]-9-yl)acetate 
In the title compound, C18H21NO4, the hydrogenated six-membered ring of the carbazole unit adopts a half-chair conformation. The dioxolane ring and ethyl­acetate substituent point to opposite sides of the carbazole plane. The ethyl­acetate substituent adopts an essentially fully extended conformation, and its mean plane forms a dihedral angle of 83.8 (1)° with respect to the carbazole mean plane. The mol­ecules are arranged into stacks in which the carbazole planes form a dihedral angle of 4.4 (1)° and have an approximate inter­planar separation of 3.6 Å.
doi:10.1107/S160053680900748X
PMCID: PMC2969037  PMID: 21582427
16.  (1S*,4′S*,5R*)-1-Isopropyl-5-meth­oxy-2′,3-dimethyl-4,6-dioxa-2-aza­spiro­[bicyclo­[3.2.0]hept-2-ene-7,4′-isoquinoline]-1′,3′(2′H,4′H)-dione 
In the isoquinoline ring system of the title mol­ecule, C18H20N2O5, the N-heterocyclic ring is in a half-boat conformation. The dioxa-2-aza­spiro ring is essentially planar, with a maximum deviation of 0.029 (1) Å, and makes a dihedral angle of 30.63 (5)° with the benzene ring. The mol­ecular structure is stabilized by a weak intra­molecular C—H⋯O hydrogen bond, which generates a S(6) ring motif. In the crystal, mol­ecules are linked via weak inter­molecular C—H⋯O hydrogen bonds into a three-dimensional supra­molecular network. Additional stabilization is provided by π–π stacking inter­actions between symmetry-related benzene rings with a centroid–centroid distance of 3.6507 (5) Å.
doi:10.1107/S1600536811015315
PMCID: PMC3089152  PMID: 21754556
17.  1-Benzyl-5-meth­oxy-2′,3-dimethyl-4,6-dioxa-2-aza­spiro­[bicyclo­[3.2.0]hept-2-ene-7,4′-isoquinoline]-1′,3′(2′H,4′H)-dione 
In the isoquinoline ring system of the title mol­ecule, C22H20N2O5, the N-heterocyclic ring is in a half-boat conformation. The dioxa-2-aza­spiro ring is essentially planar [maximum deviation = 0.026 (1) Å] and forms dihedral angles of 22.53 (5) and 64.46 (5)° with the benzene and phenyl rings, respectively. The mol­ecular structure is stabilized by a weak intra­molecular C—H⋯O hydrogen bond, which generates an S(7) ring motif. In the crystal, mol­ecules are linked via weak inter­molecular C—H⋯O and C—H⋯N hydrogen bonds into layers parallel to (102).
doi:10.1107/S160053681101600X
PMCID: PMC3120373  PMID: 21754712
18.  1-[3-(Morpholin-4-yl)prop­yl]-4-(3-nitro­phen­yl)spiro­[azetidine-3,9′-xanthen]-2-one 
The β-lactam (azetidin-2-one) ring of the title compound, C28H27N3O5, is nearly planar [maximum deviation = 0.010 (1) Å] and makes dihedral angles of 75.77 (5), 52.78 (9) and 88.72 (5)°, respectively, with the benzene ring, the least-squares plane formed by the four C atoms of the morpholine ring, which adopts a chair conformation, and the xanthene ring system. In the crystal, C—H⋯O hydrogen-bond contacts connect neighbouring mol­ecules into infinite zigzag chains running parallel to the b axis.
doi:10.1107/S160053681400419X
PMCID: PMC3998443  PMID: 24765052
19.  Xyloccensin E 
The title compound (also known as phragmalin triacetate), C35H42O14, is a phragmalin-type limonoid extracted from X. rumphii. The mol­ecule consists of eight rings with the orthoacetate group bridged at positions 1, 8 and 9. The two five-carbocyclic rings (A 1 and A 2) and the dioxolane ring (G) adopt a distorted envelope conformation. The 1,3-dioxane ring (E) exists in a chair conformation. The six-carbocyclic rings (B and C) exhibit a twisted-boat conformation. The lactone ring has a half-chair conformation and the furan ring is planar (r.m.s. deviation = 0.002 Å). Rings A 1/B, A 2/B, B/C, C/D and C/G are all cis-fused. The two acet­oxy groups attached to ring B and the furan ring attached to the lactone ring are in equatorial positions. The porous crystal packing exhibits voids of 688 Å3 and weak inter­molecular C—H⋯O inter­actions. The absolute configuration was assigned on the basis of literature data.
doi:10.1107/S1600536810016582
PMCID: PMC2979606  PMID: 21579436
20.  Methyl 4′-benzyl-2,2′-dimethyl-1,3-dioxo-2,3-dihydro-1H,4′H-spiro­[iso­quinoline-4,5′-oxazole]-4′-carboxyl­ate 
In the isoquinoline ring system of the title mol­ecule, C22H20N2O5, the N-heterocyclic ring is in a half-boat conformation. The least-squares plane of the dioxa-2-aza­spiro ring [maximum deviation = 0.076 (1) Å] and forms a dihedral angle of 14.54 (4)° with the phenyl ring. In the crystal, mol­ecules are linked via inter­molecular C—H⋯O hydrogen bonds into layers parallel to (100).
doi:10.1107/S160053681101899X
PMCID: PMC3120312  PMID: 21754882
21.  Methyl 4′-isobutyl-2,2′-dimethyl-1,3-dioxo-2,3-dihydro-1H,4′H-spiro­[iso­quinoline-4,5′-oxazole]-4′-carboxyl­ate 
In the isoquinoline ring system of the title mol­ecule, C19H22N2O5, the N-heterocyclic ring is in a half-boat conformation. The dioxa-2-aza­spiro ring is essentially planar [maximum deviation = 0.042 (1) Å] and forms a dihedral angle of 81.85 (4)° with the benzene ring. In the crystal, the mol­ecules are linked via inter­molecular C—H⋯O hydrogen bonds into chains along [010].
doi:10.1107/S1600536811019003
PMCID: PMC3120529  PMID: 21754883
22.  1′-(1,3-Diphenyl-1H-pyrazol-4-yl)-1′′-(prop-2-en-1-yl)-2′,3′,5′,6′,7′,7a’-hexa­hydro-1′H-di­spiro­[1-benzo­pyran-3,2′-pyrrolizine-3′,3′′-indoline]-2′′,4-dione 0.75-hydrate 
In the central aza-bi­cyclo­octane unit of the title compound, C40H34N4O3·0.75H2O, the peripheral pyrrolidine ring adopts an envelope conformation with the N atom deviating by 0.209 (2) Å, whereas the other pyrrolidine ring adopts a twisted conformation with the bridging N and C atoms deviating by −0.218 (2) and 0.236 (3) Å, respectively, from the rest of the ring. The pyrazole ring forms dihedral angles of 42.36 (7) and 24.07 (8)° with its C- and N-attached phenyl groups, respectively. The solvent water mol­ecule has a partial occupancy of 0.75. In the crystal, the water mol­ecules link the fused-ring mol­ecules into chains along the b axis via O—H⋯N and O—H⋯O hydrogen bonds. The crystal packing is further stabilized by C—H⋯π inter­actions involving a methyl­ene group of the pyran ring and the C-attached benzene ring on the pyrazole ring.
doi:10.1107/S160053681301773X
PMCID: PMC3793707  PMID: 24109294
23.  1-(4-Methoxy­phen­yl)-7-phenyl-3-(phenyl­selenylmeth­yl)perhydro­isoxazolo[2′,3′:1,2]pyrrolo[3,4-b]azetidine-6-spiro-2′-chroman-2,4′-dione 
In the title compound, C35H30N2O5Se, the pyrrolidine ring adopts an envelope conformation and the oxazolidine ring is in a twist conformation. The tetra­hydro­pyran ring adopts a half-chair conformation. The methoxy­phenyl ring is twisted away from the attached azetidinone ring by 15.7 (1)°. In the crystal structure, inter­molecular C—H⋯O inter­actions link the mol­ecules into a two-dimensional network.
doi:10.1107/S1600536808008829
PMCID: PMC2961224  PMID: 21202339
24.  (1′S,6′S,8′S,9′R)-9′-Bromo-12′-oxa­spiro­[1,3-dioxolane-2,4′-tricyclo­[6.3.1.01,6]dodeca­ne] 
In an endeavor directed towards the construction of the oxabicyclic[3.2.1]octane segment present in the bioactive natural products of cortistatins and icetexanes genre, the title compound, C13H19BrO3, was synthesized from (4aR,9aS)-1,3,4,4a,5,6,9,9a-octa­hydro­spiro­[benzo[7]annulene-2,2′-[1,3]dioxolane]-4a-ol via a transannular bromo-etherification protocol. The six-membered ring adopts a twist-boat conformation, while the fused cycloheptane ring adopts a chair conformation. The crystal packing is effected through two distinct inter­molecular C—H⋯O hydrogen-bond patterns and mol­ecules are arranged to define an inter­esting motif along the b axis.
doi:10.1107/S1600536812029777
PMCID: PMC3414332  PMID: 22904865
25.  5-Bromo­spiro­[1,2-dioxane-4,4′-tricyclo­[4.3.1.13,8]undeca­ne]-3′-ol 
The title compound, C14H21BrO3, comprises a seven- (C7) and three six-membered (1 × O2C4 and 2 × C6) rings, and each adopts a conformation based on a chair. Stability to the mol­ecular structure is afforded by an intra­molecular O—H⋯Br hydrogen bond. In the crystal structure, mol­ecules are arranged into a helical supra­molecular chain along the b axis, linked by C—H⋯O inter­actions, where the O-atom acceptor is one of the dioxane O atoms. The crystal studied was found to be a racemic twin. The major component was present 94% of the time.
doi:10.1107/S1600536809054762
PMCID: PMC2980170  PMID: 21580128

Results 1-25 (143346)