Ethyl 27-oxo-15-oxa-2,20-diaza­hexa­cyclo­[18.6.1.0^1,8.0^2,6.0^9,14.0^21,26]hepta­cosa-9,11,13,21,23,25-hexa­ene-7-carboxyl­ate

In the title compound, C₂₇H₃₀N₂O₄, the pyrrolidine ring adopts a twisted conformation. The indoline ring system is almost perpendicular to the mean plane of the pyrrolidine ring, making a dihedral angle of 81.7 (8)°. In the crystal, mol­ecules are linked into centrosymmetric dimers with graph-set motif R₂²(16) via pairs of C—H...O hydrogen bonds. The terminal ethyl group of the ester group is disordered over two sets of sites, with a site-occupancy ratio of 0.587 (11):0.413 (11).

Ethyl 8,13-dioxa-21-aza­penta­cyclo­[18.5.1.0^2,7.0^14,19.0^21,25]hexa­cosa-2(7),3,5,14,16,18-hexa­ene-26-carboxyl­ate

In the title compound, C₂₆H₃₁NO₄, the five-membered rings of the central pyrrolizine system adopt N-envelope conformations. The ethyl acetate group adopts an extended conformation. The dihedral angle between the benzene rings is 36.6 (1)°. In the crystal, C—H...O hydrogen bonds form a zigzag chain running along the b-axis directions. The crystal structure is futher consolidated by C—H...π inter­actions.

6-Phenyl­benzo[d]naphtho­[2,3-b]thio­phene

In the title compound, C₂₂H₁₄S, the r.m.s. deviation from the mean plane of the four-fused-ring naphtho­thio­phene unit is 0.056 Å. The dihedral angle between the naphtho­thio­phene plane and the pendant phenyl ring is 67.24 (6)°. In the crystal, weak C—H...π and π–π stacking [minimum centroid–centroid separation = 3.7466 (10) Å] inter­actions are observed, which together lead to (010) sheets.

2-Hy­droxy-4-(prop-2-yn­yloxy)benz­alde­hyde

The asymmetric unit of the title compound, C₁₀H₈O₃, contains two independent mol­ecules, both of which are almost planar (r.m.s deviations for all non-H atoms of 0.044 and 0.053 Å). The dihedral angles between the benzene ring and the prop-1-yne group are 3.47 (1) and 3.07 (1)° in the two mol­ecules, and the prop-1-yne groups adopt extended conformations. In each mol­ecule, an intra­molecular O—H...O hydrogen bond involving the OH and aldehyde substituents forms an S(6) ring. In the crystal, mol­ecules are linked into cyclic centrosymmetric dimers via C—H...O hydrogen bonds, generating R₂²(14) ring motifs. The crystal structure is further stabilized by aromatic π–π stacking inter­actions between the benzene rings [centroid–centroid distances = 3.813 (2) and 3.843 (2) Å]

1-Cyclo­propyl-2-(2-fluoro­phen­yl)-5-(4-fluoro­phen­yl)-3-phenyl­pentane-1,5-dione

In the title compound, C₂₆H₂₂F₂O₂, the cyclo­propane ring makes dihedral angles of 47.6 (2), 51.3 (2) and 63.9 (2)° with the 2-fluoro-substituted phenyl ring, the unsubstituted phenyl ring and the 4-fluoro-substituted phenyl ring, respectively. There is a short C—H...F contact in the molecule. In the crystal, weak C—H...F hydrogen bonds lead to chains of mol­ecules extending along the b-axis direction.

5-(4-Chloro­phen­yl)-1-cyclo­propyl-2-(2-fluoro­phen­yl)-3-phenyl­pentane-1,5-dione

In the title compound, C₂₆H₂₂ClFO₂, the cyclo­propane ring makes dihedral angles of 45.7 (2), 49.0 (2) and 65.2 (2)° with the fluoro-substituted phenyl ring, the benzene ring and the chloro-substituted phenyl ring, respectively. The F and Cl atoms deviate by 0.0307 (11) and 0.0652 (6) Å, respectively, from the planes of the phenyl rings to which they are attached. In the crystal, mol­ecules are linked by C—H...F hydrogen bonds, forming chains along the b axis.

2-Chloro-8,8-dimethyl-8,9-dihydro-7H-chromeno[2,3-b]quinoline-10,12-dione

The asymmetric unit of the title compound, C₁₈H₁₄ClNO₃, contains two independent mol­ecules (A and B). In both mol­ecules, the cyclo­hexa­none ring has a chair conformation. The dihedral angles between the pyran ring and the pyridine and chloro­phenyl rings are 2.13 (9) and 2.19 (9)°, respectively, in A, and 0.82 (9) and 1.93 (9)°, respectively, in B. The carbonyl O atoms deviate from the pyran and benzene rings to which they are attached by −0.092 (2) and 0.064 (2) Å, respectively, in A, and by −0.080 (2) and −0.063 (2) Å, respectively, in B. In the crystal, the A mol­ecules are linked via C—H...O hydrogen bonds, forming double-stranded chains along [100]. They lie parallel to the double-stranded chains formed by the B mol­ecules, which are also linked via C—H...O hydrogen bonds. The chains stack up the c axis in an –A–A–B–B–A–A– manner, with a number of π–π inter­actions involving A and B mol­ecules; the centroid–centroid distances vary from 3.4862 (11) to 3.6848 (11) Å

8,8-Dimethyl-8,9-dihydro-7H-chromeno[2,3-b]quinoline-10,12-dione

In the title compound, C₁₈H₁₅NO₃, the fused benzopyran and pyridine rings are essentially coplanar [r.m.s. deviation = 0.0533 Å with a maximum deviation of 0.080 (1) Å for a benzene C atom]. The cyclo­hexa­none ring adopts an envelope conformation with the dimethyl-substituted C atom 0.660 (2) Å out of the plane formed by the remaining ring atoms (r.m.s. deviation = 0.0305 Å). The dihedral angle between the mean planes of the pyran and cyclo­hexa­none rings is 12.95 (6)°. In the crystal, mol­ecules are linked via C—H...O hydrogen bonds, leading to chains running along [011].

Methyl 11-hy­droxy-9-[1-(4-meth­oxy­phen­yl)-4-oxo-3-phenyl­azetidin-2-yl]-18-oxo-10-oxa-2-aza­penta­cyclo­[9.7.0.0^1,8.0^2,6.0^12,17]octa­deca-12(17),13,15-triene-8-carboxyl­ate

In the title compound, C₃₄H₃₂N₂O₇, the furan ring adopts a twist conformation and both the pyrrolidine rings adopt envelope conformations with O and C as flap atoms. The β-lactam ring makes a dihedral angles of 80.20 (10)° with the furan ring, of 75.55 (10)° with the pyrrolidine ring, of 12.26 (10)° with the meth­oxy­phenyl ring and of 73.77 (13)° with the phenyl ring. The O atom attached to the β-lactam ring deviates by 0.0385 (13) Å from the ring plane. The mol­ecular conformation is stabilized by intra­molecular O—H...N and C—H...O hydrogen bonds. The packing of the crystal is stabilized by inter­molecular C—H...O hydrogen bonds, which form a chain running along the b axis.

6-Ferrocenoyl-7-phenyl­spiro­[hexa­hydro­pyrrolo­[1,2-c][1,3]thia­zole-5,11′-indeno­[1,2-b]quinoxaline]

In the title compound, [Fe(C₅H₅)(C₃₂H₂₄N₃OS)], both the thia­zolidine ring and the pyrrolidine ring adopt an envelope conformation, with the S atom and the phenyl-bearing C atom, respectively, as the flaps. The thia­zolidine ring mean plane makes a dihedral angle of 59.08 (11)° with the pyrrolidine ring mean plane, which in turn makes a dihedral angle of 83.40 (10)° with the cyclo­pentane ring, indicating that the latter two rings are almost orthogonal to one another. In the crystal, a pair of C—H...O hydrogen bonds link the mol­ecules forming inversion dimers. The dimers are linked via π–π inter­actions [centroid–centroid distance = 3.7764 (10) Å] involving the quinoxaline moieties forming chains propagating along [1-10].

6-Ferrocenoyl-7-(4-fluoro­phen­yl)spiro­[hexa­hydro­pyrrolo­[1,2-c][1,3]thia­zole-5,11′-indeno­[1,2-b]quinoxaline]

In the title compound, [Fe(C₅H₅)(C₃₂H₂₃FN₃OS)], both the thia­zolidine ring and the pyrrolidine ring adopt a twist conformation on the N—C(H) bridging bond. Their mean planes are inclined to one another by 10.05 (10)°, and they make dihedral angles of 82.09 (10) and 89.67 (11)°, respectively, with the cyclo­pentane ring. The F atom deviates by −0.0238 (2) Å from the benzene ring to which it is attached. In the crystal, mol­ecules are linked by a pair of C—H...O hydrogen bonds, forming inversion dimers.

2-(4-Bromo­benzo­yl)-1-ferrocenyl­spiro­[11H-pyrrolidizine-3,11′-indeno­[1,2-b]quinoxaline]

In the title compound, [Fe(C₅H₅)(C₃₃H₂₅BrN₃O)], the fused four-ring system, 11H-indeno­[1,2-b]quinoxaline is essentially planar, with a maximum deviation of 0.087 (3) Å from the least-squares plane of the attached benzene ring. The pyrrolidine rings adopt envelope conformation and make a dihedral angle of 51.76 (19)° with each other. The cyclopentadiene rings of the ferrocenyl moiety have an eclipsed conformation. The Br atom deviates by 0.0190 (9) Å from the attached benzene ring. The mol­ecular structure features an intra­molecular C—H...N inter­action, which generates an S(8) ring motif. The crystal packing features C—H...O inter­actions, which generate R₂²(18) centrosymmetric dimers, as well as C—H...π inter­actions.

1,4-Bis(3-chloro­pyrazin-2-yl­oxy)benzene

In the title compound, C₁₄H₈Cl₂N₄O₂, the pyrazine rings are orthogonal to the benzene ring, making dihedral angles of 88.42 (8) and 89.22 (8)°. The Cl atoms attached to the pyrazine rings deviate by −0.0597 (5) and 0.0009 (5) Å from the ring plane. The crystal structure features C—H...N hydrogen bonds.

N-tert-Butyl-2-[4-(dimethyl­amino)­phen­yl]imidazo[1,2-a]pyrazin-3-amine

In the title compound, C₁₈H₂₃N₅, the imidazole ring makes a dihedral angles of 3.96 (8) and 19.02 (8)°, respectively, with the pyrazine and benzene rings while the dihedral angle between the pyrazine and benzene rings is 16.96 (7)°. In the crystal, mol­ecules are linked via N—H...N hydrogen bonds, forming chains along [010]. These chains are linked by C—H...N hydrogen bonds, forming two-dimensional networks lying parallel to (001).

4-[2-(4-But­oxy­phen­yl)ethen­yl]-1-methyl­pyridinium tosylate

In the title mol­ecular salt, C₁₈H₂₂NO⁺·C₇H₇O₃S⁻, the dihedral angle between the aromatic rings in the cation is 10.00 (9)°; its alkyl side chain adopts an extended conformation. In the crystal, weak C—H...O and π–π [centroid–centroid distance = 3.7658 (17) Å] inter­actions link the components, generating a three-dimensional network.

(1S,3′S,3a′R,6′S)-6′-(2-Chloro­phen­yl)-3′-[(2R,3S)-1-(4-meth­oxy­phen­yl)-4-oxo-3-phenyl­azetidin-2-yl]-2-oxo-3′,3′a,4′,6′-tetra­hydro-2H,2′H-spiro­[ace­naphthyl­ene-1,1′-pyrrolo­[1,2-c][1,3]thia­zole]-2′,2′-dicarbo­nitrile

The mol­ecular conformation of the title compound, C₄₁H₂₉ClN₄O₃S, is stabilized by intra­molecular C—H...O and C—H...Cl hydrogen bonds. The thia­zole ring adopts an envelope conformation with the N atom as the flap, while the pyrrolidine ring has a twisted conformation on the N—C bond involving the spiro C atom. The β la­ctam ring makes dihedral angles of 39.74 (15) and 16.21 (16)° with the mean planes of the thia­zole and pyrrolidine rings, respectively. The thia­zole ring mean plane makes dihedral angles of 23.79 (13) and 70.88 (13) ° with the pyrrolidine and cyclo­pentane rings, respectively, while the pyrrolidine ring makes a dihedral angle of 85.63 (13)° with the cyclo­pentane ring. The O atom attached to the β la­ctam ring deviates from its mean plane by 0.040 (2) Å, while the O atom attached to the cyclo­pentane ring deviates from its mean plane by 0.132 (2) Å. In the crystal, mol­ecules are linked by C—H...O hydrogen bonds, forming chains along [010], and C—H...π and π-π inter­actions [centroid-centroid distance = 3.6928 (17) Å].

Methyl 3,5-bis­[(3-chloro­pyrazin-2-yl)­oxy]benzoate

In the title compound, C₁₆H₁₀Cl₂N₄O₄, the pyrazine rings make dihedral angles of 67.82 (9) and 75.91 (9)° with the benzene ring, while the dihedral angle between the pyrazine rings is 44.69 (10)°. The meth­oxy­carbonyl group makes a dihedral angle of 16.82 (8)° with the benzene ring to which it is attached. In the crystal, C—H...O hydrogen bonds link the mol­ecules, forming chains running along the ab plane.

3-Hy­droxy-1-[(morpholin-4-yl)meth­yl]pyridazin-6(1H)-one

In the title compound, C₉H₁₃N₃O₃, the morpholine ring adopts a chair conformation and its mean plane makes a dihedral angle of 68.00 (11)° with the pyridazine ring. The carbonyl O atom deviates from the plane of the pyridazine ring by 0.0482 (12) Å. An intra­molecular C—H...O hydrogen bond occurs. In the crystal, mol­ecules are linked by O—H...O and C—H...O hydrogen bonds, forming chains along [1-10].

(Z)-3-(2-Amino­anilino)-1-phenyl­but-2-en-1-one

In the title compound, C₁₆H₁₆N₂O, the phenyl and 2-amino­phenyl rings are almost perpendicular to one another, with a dihedral angle of 82.77 (8)°. There is an intra­molecular N—H...O hydrogen bond in the mol­ecule. In the crystal, mol­ecules are linked via N—H...O hydrogen bonds forming chains along [001]. There are also C—H...π inter­actions present, linking the chains to form a three-dimensional structure.

L-Histidinium p-toluene­sulfonate

In the title salt, C₆H₁₀N₃O₂⁺·C₇H₇O₃S⁻, the imidazole ring makes a dihedral angle of 70.93 (12)° with the plane of the toluene ring. In the crystal, the ions are linked via N—H...O and weak C—H...O hydrogen bonds forming two-dimensional networks lying parallel to (001). These networks are linked via C—H...π inter­actions, forming a three-dimensional structure.

(E)-3-[4-(Di­fluoro­meth­oxy)-3-hy­droxy­phen­yl]-1-phenyl­prop-2-en-1-one

In the title compound, C₁₆H₁₂F₂O₃, the plane of the phenyl ring makes a dihedral angle of 3.22 (8)° with that of the benzene ring. The mol­ecule has an E conformation about the C=C bond. In the crystal, mol­ecules are linked via pairs of O—H...O hydrogen bonds, forming inversion dimers which are further consolidated by a pair of C—H...O hydrogen bonds. The dimers are linked via C—H...O hydrogen bonds, forming columns along the b-axis direction.

8,15-Dioxa-10,13-di­aza­tetra­cyclo­[14.4.0.0^2,7.0^9,14]icosa-1(16),2,4,6,9(14),10,12,17,19-nona­ene

The asymmetric unit of the title compound, C₁₆H₁₀N₂O₂, contains one half-mol­ecule, the complete mol­ecule being generated by twofold rotation symmetry. The plane of the pyrazine ring forms a dihedral angle of 64.87 (6)° with that of the benzene ring, and the planes of the two benzene rings are inclined to one another by 54.20 (6)°. The O atom deviates from the plane of the benzene ring by 0.1549 (8) Å. There are no significant inter­molecular inter­actions in the crystal.

1,3-Bis[(3-chloro­pyrazin-2-yl)­oxy]benzene

The asymmetric unit of the title compound, C₁₄H₈Cl₂N₄O₂, contains one half-mol­ecule, the complete mol­ecule being generated by the operation of a twofold rotation axis. The Cl atom deviates significantly from the plane of the pyrazine ring [0.0215 (4) Å]. The central benzene ring makes a dihedral angle of 72.82 (7)° with the plane of the pyrazine ring.

3-(4-Chloro­phen­yl)-1-cyclo­propyl-2-(2-fluoro­phen­yl)-5-phenyl­pentane-1,5-dione

In the title compound, C₂₆H₂₂ClFO₂, the cyclo­propane ring is disordered over two orientations, with site-occupancy factors of 0.64 (2) and 0.36 (2). The major occupancy component of the cyclo­propane ring makes dihedral angles of 47.6 (7), 50.4 (7) and 65.4 (7)° with the fluoro-, chloro- and unsubstituted benzene rings, respectively [the corresponding values for the minor occupancy component are 47.6 (12), 51.0 (12) and 60.9 (12)°]. An intra­molecular C—H...O hydrogen bond occurs. The F and Cl atoms deviate by 0.0508 (12) and 0.0592 (7) Å from the planes of their attached benzene rings. In the crystal, C—H...F hydrogen bonds link the mol­ecules into chains along the b-axis direction.

8,13,26-Trioxa-23-thia-21-aza­penta­cyclo­[18.6.0.0^2,7.0^14,19.0^21,25]hexa­cosa-2(7),3,5,14,16,18-hexa­ene

In the title compound, C₂₁H₂₃NO₃S, both the thia­zole and oxazolidine rings adopt twist conformations. The mean plane of the thia­zole ring makes a dihedral angle of 61.02 (7)° with the oxazolidine ring mean plane, and dihedral angles of 22.72 (6) and 75.07 (6)° with the benzene rings. The benzene rings are almost perpendicular to one another, making a dihedral angle of 89.14 (6)°. There are bifurcated intra­molecular C—H...O hydrogen bonds in the mol­ecular structure. In the crystal, mol­ecules are linked via C—H...π inter­actions, forming chains propagating along [100].

8,11,24-Trioxa-21-thia-19-aza­penta­cyclo­[16.6.0.0^2,7.0^12,17.0^19,23]tetra­cosa-2(7),3,5,12,14,16-hexa­ene

In the title compound, C₁₉H₁₉NO₃S, the thia­zole and oxazolidine rings each adopt an envelope conformation, with the S and O atoms as the respective flap atoms. The thia­zole and oxazolidine rings (all atoms) make a dihedral angle of 66.39 (11)° while the phenyl rings subtend a dihedral angle of 22.71 (10)°.

2-Amino-4-methyl­pyridinium 2-nitro­benzoate

In the title mol­ecular salt, C₆H₉N₂⁺·C₇H₄NO₄⁻, the original pyridine N atom of 2-amino-4-methyl­pyridine is protonated and the carb­oxylic acid group of nitro­benzoic acid is deprotonated. In the crystal, the ions are linked by N—H...O hydrogen bonds, forming chains propagating along [001]. The chains are linked via C—H...O hydrogen bonds, forming two-dimensional networks lying parallel to the bc plane.

N-tert-Butyl-2-(2,6-di­chloro­phen­yl)imidazo[1,2-a]pyrazin-3-amine

In the title compound, C₁₆H₁₆Cl₂N₄, the imidazole ring mean plane makes a dihedral angle of 70.01 (1)° with the phenyl ring. The Cl atoms deviate by −0.0472 (6) and 0.0245 (8) Å from the plane of their attached benzene ring. In the crystal, mol­ecules are linked via pairs of C—H...N hydrogen bonds, forming inversion dimers.

6a-Nitro-6-phenyl-6,6a,6b,7,8,9,10,12a-octa­hydro­spiro­[chromeno[3,4-a]indol­izine-12,3′-indolin]-2′-one

In the title compound, C₂₈H₂₅N₃O₄, the central pyrrolidine ring adopts adopts an envelope conformation with the N atom as the flap and the piperidine ring adopts a chair conformation. The pendant pyrrolidine ring is almost planar (r.m.s. deviation = 0.008 Å). An intra­molecular C—H...O inter­action closes an S(6) ring. In the crystal, inversion dimers linked by pairs of N—H...O hydrogen bonds generate R₂²(8) loops.

4-Nitro­phenol–piperazine (2/1)

In the title adduct, C₆H₅NO₃·0.5C₄H₁₀N₂, the piperazine ring possesses inversion symmetry and has a chair conformation. Its mean plane makes a dihedral angle of 65.45 (7)° with the 4-nitro­phenol ring. In the crystal, the piperazine ring is linked to two 4-nitro­phenol mol­ecules via O—H...N hydrogen bonds. The mol­ecules are also linked via bifurcated N—H...(O,O) hydrogen bonds involving the NO₂ O atoms, forming a two-dimensional network lying parallel to (102). The networks are linked via C—H...O hydrogen bonds, forming a three-dimensional structure.

2-Methyl-4-(naphthalen-2-yl)-3a-nitro-3,3a,4,9b-tetra­hydro-2H-spiro­[chromeno[3,4-c]pyrrole-1,3′-indolin]-2′-one

In the title compound, C₂₉H₂₃N₃O₄, the 2-methylpyrrolidine ring adopts a twist conformation on the N—C bond involving the spiro C atom, while the hydropyran ring adopts an envelope conformation with the methine C atom bonded to the O atom as the flap. The mean plane of the indoline-2-one ring system is almost perpendicular to the mean plane of the pyrrolidine ring, making a dihedral angle of 89.73 (8)°. The latter ring makes dihedral angles of 47.80 (8) with the naphthalene ring system and 32.38 (8)° with the hydropyran ring mean plane. There is an intra­molecular C-H...O hydrogen bond involving the indoline-2-one O atom. In the crystal, adjacent mol­ecules are linked via N—H...O hydrogen bonds, forming chains propagating along [100]. The chains are linked via weak C—H...O hydrogen bonds, forming two-dimensional networks, lying parallel to (101), and consolidated by C—H...π inter­actions.

6-(4-Meth­oxy­phen­yl)-6a-nitro-6,6a,6b,7,8,9,10,12a-octa­hydro­spiro­[chromeno[3,4-a]indolizine-12,3′-indolin]-2′-one

In the title compound, C₂₉H₂₇N₃O₅, the hydropyran ring adopts an envelope conformation with the methine C atom bearing the para-meth­oxy­benzene ring as the flap. The central pyrrolidine ring has a twist conformation on the N—C bond involving the spiro C atom. The piperidine ring adopts a chair conformation. An intra­molecular C—H...O contact closes an S(7) ring. In the crystal, inversion dimers linked by C—H...O inter­actions generate R₂²(18) loops and N—H...O hydrogen bonds connect the dimers into [100] chains.

3-[(E)-2-(4-Chloro­phen­yl)ethen­yl]-5,5-di­methyl­cyclo­hex-2-en-1-one

In the title compound, C₁₆H₁₇ClO, the cyclo­hexene ring adopts a half-chair conformation and the best plane through the six ring atoms makes a dihedral angle of 6.69 (7)° with the chlorophenyl ring. In the crystal, pairs of C—H...O hydrogen bonds link the mol­ecules into centrosymmetric R₂²(20) dimers. The dimers are linked into an infinite chains along the b-axis direction by further C—H...O hydrogen bonds.

Allyl 2-(2,2-dimethyl-3a,6a-di­hydro­furo[3,2-d][1,3]dioxol-5-yl)-4-oxo-4H-chromene-3-carboxyl­ate

In the title compound, C₂₀H₁₈O₇, the dioxolane ring adopts an envelope conformation with the dimethyl-substituted C atom as the flap, and its mean plane makes a dihedral angle of 73.25 (2)° with the pyran ring mean plane. The furan ring makes dihedral angles of 67.43 (12) and 6.20 (11)° with the mean plane of the dioxolane and pyran rings, respectively. The O atom attached to the pyran ring deviates by 0.0219 (2) Å from its mean plane. In the crystal, mol­ecules are linked via C—H...O hydrogen bonds, forming chains along [010] and enclosing R₂²(9) loops. They stack along the a axis with π–π inter­actions involving the 4H-chromene units [centroid–centroid distances of 3.6389 (13) and 3.6555 (13) Å]. The terminal CH₂=CH- atoms of the allyl acetate group are disordered over two sets of sites with a refined occupancy ratio of 0.717 (6):0.283 (6).

[(4E)-1-Methyl-2,6-diphenyl-3-(propan-2-yl)piperidin-4-yl­idene]amino 3-methyl­benzoate

In the title compound, C₂₉H₃₂N₂O₂, the piperidine ring exists in a chair conformation (the bond-angle sum at the sp²-hybridized C atom is 359.79°). The phenyl rings and the methyl group substituted on the heterocyclic ring are in equatorial orientations. In the crystal, pairs of C—H...π inter­actions result in the formation of inversion dimers.

Methyl 2-(2,2-dimethyl-3a,6a-di­hydro­furo[3,2-d][1,3]dioxol-5-yl)-4-oxo-4H-chromene-3-carboxyl­ate

In the title mol­ecule, C₁₈H₁₆O₇, the dioxolane ring adopts an envelope conformation with the dimethyl-substituted C atom as the flap. The furan ring is almost coplanar with the pyran ring, with a dihedral angle of 1.04 (10)° between the planes, and it makes a dihedral angle of 67.97 (11)° with the mean plane of the dioxolane ring. The latter makes a dihedral angle of 67.15 (10)° with the pyran ring. The O atom attached to the pyran ring deviates by −0.009 (1) Å. The crystal packing features C—H...O hydrogen bonds, forming a three-dimensional structure. The meth­oxy­carbonyl atoms are disordered over two positions, with a refined occupancy ratio of 0.508 (18):0.492 (18).

1-[2-(3-Meth­oxy­phen­yl)eth­yl]pyrroli­dine-2,5-dione

In the title compound, C₁₃H₁₅NO₃, the pyrrolidine ring makes a dihedral angle of 4.69 (9)° with the 3-meth­oxy-phenyl ring. In the crystal, hydrogen-bonded chains running along [101] are generated by connecting neighbouring mol­ecules via C—H...O hydrogen bonds. Parallel chains are linked by further C—H...O hydrogen bonds, forming a three-dimensional structure.

N-(4-Meth­oxy­phen­yl)-2,6-dimethyl-1,3-dioxan-4-amine

In the title compound, C₁₃H₁₉NO₃, the dioxane ring adopts a chair conformation. Its mean plane is inclined to the 4-meth­oxy­phenyl ring by 70.34 (9)°. In the crystal, mol­ecules are linked by pairs of C—H...O hydrogen bonds, forming inversion dimers with an R²₂(16) ring motif. The dimers are linked via C—H...π inter­actions, forming two-dimensional networks lying parallel to the ac plane.

N-(2-Fluoro­phen­yl)-2,6-dimethyl-1,3-dioxan-4-amine

In the title compound, C₁₂H₁₆FNO₃, the dioxane ring adopts a chair conformation with the methyl groups and amine N atom in equatorial positions. The best plane through the dioxane ring makes a dihedral angle of 43.16 (8)° with the phenyl ring. In the crystal, pairs of C—H...O hydrogen bonds link the mol­ecules into centrosymmetric R₂²(8) dimers, which are linked into [100] chains by further C—H...O hydrogen bonds. The N—H group does not participate in hydrogen bonding.

[(4E)-3-Ethyl-1-methyl-2,6-di­phenyl­piperidin-4-yl­idene]amino 3-methyl­benzoate

In the title compound, C₂₈H₃₀N₂O₂, the piperidine ring exists in a chair conformation with an equatorial orientation of the phenyl rings and methyl group substituted on the heterocycle. In the crystal, C—H...π inter­actions result in chains of mol­ecules running parallel to the a-axis direction.

2,6-Dimethyl-N-(2-methyl­phen­yl)-1,3-dioxan-4-amine

In the title compound, C₁₃H₁₉NO₂, the dioxane ring adopts a chair conformation and its mean plane makes a dihedral angle of 45.36 (8)° with the phenyl ring. In the crystal, mol­ecules are linked by pairs of N—H...O hydrogen bonds, forming inversion dimers with R²₂(12) ring motifs. These dimers are consolidated by pairs of C—H...O hydrogen bonds with R²₂(8) ring motifs.

N-(4-Bromo­phen­yl)-2,6-dimethyl-1,3-dioxan-4-amine

In the title compound, C₁₂H₁₆BrNO₂, the dioxane ring adopts a chair conformation and its mean plane makes a dihedral angle of 60.63 (12)° with the 4-bromo­phenyl ring. In the crystal, mol­ecules are linked by pairs of N—H...O hydrogen bonds, forming inversion dimers with an R₂²(8) ring motif. These dimers are consolidated by pairs of C—H...O hydrogen bonds with an R₂²(16) ring motif. Adjacent dimers are connected via C—H...O hydrogen bonds, forming infinite chains propagating along the c-axis direction.

N-(4-Fluoro­phen­yl)-2,6-dimethyl-1,3-dioxan-4-amine

In the title compound, C₁₂H₁₆FNO₂, the dioxane ring adopts a chair conformation with the methyl substituents and the C—N bond in equatorial orientations. Its mean plane subtends a dihedral angle of 40.17 (6)° with the benzene ring. In the crystal, weak N—H...F hydrogen bonds link the mol­ecules into C(7) chains propagating in [100].

2,15-Dioxa-7,18,19,20,23-penta­aza­hepta­cyclo­[21.6.1.1^17,20.0^1,8.0^3,7.0^9,14.0^24,29]hentriaconta-9,11,13,17(31),18,24,26,28-octaen-30-one

In the title compound, C₂₄H₂₃N₅O₃, the oxindole ring system is nearly planar, with a dihedral angle between the two fused rings of 3.3 (1)°. In the fused pyrrolo–oxazole ring system, the oxazole and pyrrolidine rings adopt envelope conformations with the spiro C atom and one of the methyl­ene C atoms, respectively, as the flap atoms. In the crystal, mol­ecules are linked into a helical chain along the b axis via C—H...O inter­actions generating R₂¹(7) and R₂²(8) ring motifs.

Pyrrolidinium-2-carboxyl­ate–4-nitro­phenol (1/2)

In the title compound, C₅H₉NO₂·2C₆H₅NO₃, the pyrrolidine ring of the pyrrolidinium-2-carboxyl­ate zwitterion adopts a twisted conformation on the –CH₂—CH₂– bond adjacent to the N atom. The mean plane of this pyrrolidine ring forms dihedral angles of 25.3 (3) and 32.1 (3)° with the two nitro­phenol rings. An intra­molecular N—H...O hydrogen bond occurs in the pyrrolidinium-2-carboxyl­ate mol­ecule. In the crystal, mol­ecules are linked via O—H...O and N—H...O hydrogen bonds, enclosing R³₂(8) ring motifs, forming chains running parallel to the a axis. These chains are further cross-linked by O—H...O and C—H...O hydrogen bonds, forming undulating two-dimensional networks lying parallel to (001).