Crystal structure of 17,18,19-trisnorstemodan-3,13-dione

1984 ◽  
Vol 62 (9) ◽  
pp. 1828-1830 ◽  
Author(s):  
Stephen V. Evans ◽  
James Trotter
Keyword(s):  
Crystal Structure ◽  
Least Squares ◽  
Title Compound ◽  
Direct Methods ◽  
Membered Ring ◽  
Full Matrix ◽  
Bond Lengths ◽  
Compound C ◽  
Tetracyclic System ◽  
Atom Bond

Crystals of the title compound, C17H24O2, are monoclinic, P21/c, a = 10.395(2), b = 10.980(1), c = 13.181(3) Å, β = 113.55(1)°, Z = 4. The structure was solved by direct methods and refined by full-matrix least-squares to R = 0.051 for 1622 reflections with I ≥ 3σ(I). The molecule contains a tetracyclic system of three six-membered rings and one five-membered ring; the structure exhibits disorder of one C atom. Bond lengths and angles are normal.

The crystal structure of 1-(Na-trifluoracetylalanyl)-indoline

1993 ◽  
Vol 208 (2) ◽  
Author(s):  
Raghuvir K. Arni ◽  
Virginia C. A. Martins ◽  
Yvonne P. Mascarenhas ◽  
Gilberto Goissis ◽  
C. A. Kavounis
Keyword(s):  
Crystal Structure ◽  
Least Squares ◽  
Title Compound ◽  
Direct Methods ◽  
Full Matrix ◽  
Compound C

AbstractThe crystal structure of the title compound, CThe structure was solved by direct methods and refined by full-matrix least-squares calculations to a final residual of 0.051 for 1030 observed reflections [

Structural studies of organoboron compounds XL. 4,7-Dicyclohexyl-2,2,5,6-tetraphenyl- 1,3-dioxa-4-aza-7-azonia-2-boratacycloheptane

1990 ◽  
Vol 68 (10) ◽  
pp. 1797-1802 ◽  
Author(s):  
Henning Amt ◽  
Wolfgang Kliegel ◽  
Steven J. Rettig ◽  
James Trotter
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bond ◽  
Least Squares ◽  
Direct Methods ◽  
Organoboron Compound ◽  
Chair Conformation ◽  
Membered Ring ◽  
Structural Studies ◽  
Full Matrix ◽  
Bond Lengths

The synthesis of 4,7-dicyclohexyl-2,2,5,6-tetraphenyl-1,3-dioxa-4-aza-7-azonia-2-boratacycloheptane is reported. Crystals of the compound are orthorhombic, a = 10.893(1), b = 28.072(1), c = 10.596(1) Å, Z = 4, space group P212121. The structure was solved by direct methods and was refined by full-matrix least-squares procedures to R = 0.036 and Rw = 0.043 for 2480 reflections with I ≥ 3σ(I). The molecule has a seven-membered chelate structure. The seven-membered ring, which has a twisted chair conformation, is stabilized by an intramolecular [Formula: see text] hydrogen bond. Bond lengths O—B = 1.468(4) and 1.554(4), C—B = 1.621(5) and 1.626(4) Å are consistent with moderately strong binding of the diphenylboron moiety by the O,O-chelating ligand. Keywords: crystal structure, organoboron compound, boron compound.

Structural studies of organoboron compounds. XXXIX.1 1,4-Bis(2,2-diethoxyethyl)-6,8-diphenyl-5,7,9-trioxa-4-aza-1-azonia-8- bora-6-boratabicyclo[4.3.0]nonane

1990 ◽  
Vol 68 (10) ◽  
pp. 1791-1796 ◽  
Author(s):  
Henning Amt ◽  
Wolfgang Kliegel ◽  
Steven J. Rettig ◽  
James Trotter
Keyword(s):  
Crystal Structure ◽  
Least Squares ◽  
Title Compound ◽  
Phenylboronic Acid ◽  
Direct Methods ◽  
Organoboron Compound ◽  
Structural Studies ◽  
Full Matrix ◽  
Space Group ◽  
Bond Lengths

Reaction of N,N′-1,2-ethanediylidenebis(2,2-diethoxyethanamine)- N,N′-dioxide and phenylboronic acid yields the title compound. Crystals of 1,4-bis(2,2-diethoxyethyl)-6,8-diphenyl-5,7,9-trioxa-4-aza-1-azonia-8-bora-6-boratabicyclo[4.3.0]-nonane are triclinic, a = 12.625(2), b = 13.962(2), c = 9.273(1) Å, α = 104.81(1), β = 98.61(1), γ = 106.52(1)°, Z = 2, space group [Formula: see text]. The structure was solved by direct methods and was refined by full-matrix least-squares procedures to R = 0.058 and Rw = 0.081 for 3677 reflections with I ≥ 3σ(I). The molecule has a bicyclo[4.3.0]nonane structure containing one transannular N—B bond. Important bond lengths are sp3-bomn, N—B = 1.759(3), O—B = 1.435(3) and 1.454(3), C—B = 1.579(4); sp2-boron, O—B = 1.335(3) and 1.404(3), C—B = 1.557(4) Å. The (sp3)B—C(phenyl) bond is the shortest yet reported for this type of compound.Keywords: crystal structure, boron compound, organoboron compound.

Structural studies of organoboron compounds. XXXVII. 8,8-Pentamethylene-6-phenyl-6,9-epoxy-5,7-dioxa-8-azonia-6-borata-6,7,8,9-tetrahydro-5H-benzocycloheptene

1990 ◽  
Vol 68 (1) ◽  
pp. 64-68 ◽  
Author(s):  
Wolfgang Kliegel ◽  
Hans-Walter Motzkus ◽  
Klaus Drückler ◽  
Steven J. Rettig ◽  
James Trotter
Keyword(s):  
Crystal Structure ◽  
Least Squares ◽  
Title Compound ◽  
Phenylboronic Acid ◽  
Direct Methods ◽  
Structural Studies ◽  
Boron Compounds ◽  
Full Matrix ◽  
Space Group ◽  
Bond Lengths

Condensation of equimolar amounts of salicylaldehyde, N-hydroxypiperidine, and phenylboronic acid yields the title compound. Crystals of 8,8-pentamethylene-6-phenyl-6,9-epoxy-5,7-dioxa-8-azonia-6-borata-6,7,8,9-tetrahydro-5H-benzocycloheptene are monoclinic, a = 12.773(1), b = 11.9600(7), c = 10.6411(6) Å, β = 103.786(7)°, Z = 4, space group P21/c. The structure was solved by direct methods and was refined by full-matrix least-squares procedures to R = 0.039 and Rw = 0.047 for 2420 reflections with I ≥ 3σ(I). The compound has a bridged heterocyclic B,N-betaine structure with a PhB(OR)3 anionic centre. Bond lengths (corrected for libration) include: B—O(aryl C) = 1.481(2), B—O(alkyl C) = 1.488(2), B—O(N) = 1.539(2), and B—C = 1.591(2) Å. Keywords: organoboron, boron compounds, crystal structure.

Structural studies of organoboron compounds. XLIII. 4-[(1-Hydroxycyclohexyl)methyl]-2,2,5-triphenyl-1,3-dioxa-4-azonia-2-borata-4-cyclopentene

1991 ◽  
Vol 69 (3) ◽  
pp. 545-549 ◽  
Author(s):  
Wolfgang Kliegel ◽  
Ute Schumacher ◽  
Mahmood Tajerbashi ◽  
Steven J. Rettig ◽  
James Trotter
Keyword(s):  
Crystal Structure ◽  
Least Squares ◽  
Key Words ◽  
Hydroxamic Acid ◽  
Direct Methods ◽  
Organoboron Compound ◽  
Structural Studies ◽  
Full Matrix ◽  
Bond Lengths ◽  
Acid Chelate

The reaction of N′-hydroxy-N-[(1-hydroxycyclohexyl)methyl]benzamide and diphenylborinic anhydride gives 4-[(1-hydroxycyclohexyl)methyl]-2,2,5-triphenyl-1,3-dioxa-4-azonia-2-borata-4-cyclopentene in nearly quantitative yield. Crystals of the product are monoclinic, a = 9.9117(6), b = 13.308(1), c = 17.339(2) Ǻ, β = 99.420(7)°, Z = 4, space group P21/c. The structure was solved by direct methods and was refined by full-matrix least-squares procedures to R = 0.040 and Rw = 0.047 for 2423 reflections with I > 3σ(I). The molecule has a normal five-membered hydroxamic acid chelate structure, the BONCO ring having a B-envelope conformation. Bond lengths (corrected for libration) (N)O—B = 1.535(3), (C)O—B = 1.569(3), C—B = 1.603(3) and 1.601(3) Ǻ are normal for this type of complex. Key words: organoboron compound, boron compound, crystal structure.

Structural studies of organoboron compounds. XLII. 4,6-Bis(1-cyano-1-methylethyl)-2-mesityl-1,3-dioxa-4,6-diaza-2-boracyclohexane

1991 ◽  
Vol 69 (2) ◽  
pp. 234-238 ◽  
Author(s):  
Wolfgang Kliegel ◽  
Gottfried Lubkowitz ◽  
Steven J. Rettig ◽  
James Trotter
Keyword(s):  
Crystal Structure ◽  
Solid State ◽  
Least Squares ◽  
Key Words ◽  
Good Yield ◽  
Direct Methods ◽  
Organoboron Compound ◽  
Structural Studies ◽  
Full Matrix ◽  
Bond Lengths

The condensation of N,N′-bis(1-cyano-1-methylethyl)-N,N′-dihydroxymethanediamine and mesitylboronic acid gives 4,6-bis(1-cyano-1-methylethyl)-2-mesityl-1,3-dioxa-4,6-diaza-2-boracyclohexane in good yield. Crystals of the latter compound are orthorhombic, a = 15.825(1), b = 17.958(1), c = 14.014(1) Ǻ, Z = 8, space group Pbca. The structure was solved by direct methods and was refined by full-matrix least-squares procedures to R = 0.037 and Rw = 0.051 for 2844 reflections with 1 ≥ 3σ(I). The molecule has a six-membered cycloboronate structure featuring the first structurally characterized BONCNO ring. The ring was found to have a C-envelope conformation in the solid state. Bond lengths include: O—B(sp2) = 1.356(2) and 1.370(2), and C(aryl)—B = 1.560(2) Ǻ. Key words: organoboron compound, boron compound, crystal structure.

Structural studies of organoboron compounds. LIII. N,N-Diethylhydroxylamine-(O-B)1,7-dimethyl-3,5-diphenyl-2,4,6-trioxa-7-aza-1-azonia-3-bora-5- boratabicyclo[3.3.0]octane

1992 ◽  
Vol 70 (7) ◽  
pp. 2022-2026 ◽  
Author(s):  
Wolfgang Kliegel ◽  
Gottfried Lubkowitz ◽  
Steven J. Rettig ◽  
James Trotter
Keyword(s):  
Hydrogen Bond ◽  
Least Squares ◽  
Title Compound ◽  
Condensation Product ◽  
Phenylboronic Acid ◽  
Direct Methods ◽  
High Yield ◽  
Structural Studies ◽  
Full Matrix ◽  
Bond Lengths

Reaction of the condensation product of N,N′-dimethyl-N,N′-dihydroxymethanediamine and phenylboronic acid with N,N-diethylhydroxylamine gives N,N-diethylhydroxylamine(O-B)1,7-dimethyl-3,5-diphenyl-2,4,6-trioxa-7-aza-1-azonia-3-bora-5-boratabicyclo[3.3.0]octane [3-(2-ethyl-1-oxa-2-azoniabutyl)-1,7-dimethyl-3,5-diphenyl-2,4,6-trioxa-7-aza-1-azonia-3,5-diboratabicyclo[3.3.0]octane, 3] in high yield. Crystals of 3 are orthorhombic, a = 11.8132(11), b = 15.4768(11), c = 11.7325(16) Å, Z = 4, space group P212121. The structure was solved by direct methods and was refined by full-matrix least-squares procedures to R = 0.039 and Rw = 0.044 for 1729 reflections with I ≥ 2σ(I). The title compound is the second example of this recently characterized class of O-B coordinated hydroxylamine complexes, stabilized by an intramolecular [Formula: see text] hydrogen bond [Formula: see text]. Bond lengths about boron are: B—O(N) = 1.482(4)–1.526(4), B—O(B) = 1.412(4) and 1.420(4), B—N = 1.712(4), B—C = 1.591(5) and 1.602(5) Å.

Structural studies of organoboron compounds. XXXV. 4,8-Diethyl-2,2,6,6-tetraphenyl-1,3,5,7-tetraoxa-4,8-diazonia- 2,6-diborata-1,2,3,5,6,7-hexahydronaphthalene

1989 ◽  
Vol 67 (10) ◽  
pp. 1644-1649 ◽  
Author(s):  
Wolfgang Kliegel ◽  
Mahmood Tajerbashi ◽  
Steven J. Rettig ◽  
James Trotter
Keyword(s):  
Crystal Structure ◽  
Least Squares ◽  
Title Compound ◽  
Direct Methods ◽  
Organoboron Compound ◽  
Boron Compound ◽  
Structural Studies ◽  
Full Matrix ◽  
Binding Strength ◽  
The Mean

The reaction of Ν,Ν′-diethyloxalohydroxamic acid with oxybis(diphenylborane) yields the title compound. Crystals of 4,8-diethyl-2,2,6,6-tetraphenyl-1,3,5,7-tetraoxa-4,8-diazonia-2,6-diborata-1,2,3,5,6,7-hexahydronaphthalene are monoclinic, a = 14.3405(9), b = 14.3053(5), c = 14.9301(8) Å, β = 116.136(4)°, Z = 4, space groupP21/n. The structure was solved by direct methods and was refined by full-matrix least-squares procedures to R = 0.038 and Rw = 0.038 for 3501 reflections with I ≥ 3σ(I). The molecule has a novel bis-six-membered binuclear chelate structure, the Ph2B moieties each being coordinated by (N)O and (C=)O oxygen atoms from different hydroxamate groups. The mean libration-corrected bond distances (C=)O—B, 1.587 Å, (N)O—B, 1.511 Å, and B—C, 1.602 Å, represent the weakest overall binding strength of an O,O-chelating ligand with respect to the Ph2B moiety yet observed for a six-membered O—B—O chelate. Keywords: crystal structure, boron compound, organoboron compound.

Crystal and molecular structure of L-prolinatodiphenylboron

1977 ◽  
Vol 55 (6) ◽  
pp. 958-965 ◽  
Author(s):  
Steven J. Rettig ◽  
James Trotter
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Least Squares ◽  
Crystal And Molecular Structure ◽  
Direct Methods ◽  
Conformational Disorder ◽  
Full Matrix ◽  
Space Group ◽  
Bond Lengths

Crystals of L-prolinatodiphenylboron are monoclinic, a = 5.9427(5), b = 14.4633(7), c = 8.9654(4) Å, β = 98.423(8)°, Z = 2, space group P21. The structure was solved by direct methods and was refined by full-matrix least-squares procedures to a final R of 0.037 and Rw of 0.053 for 1477 reflections with I ≥ 3σ(I). The proline ring exhibits conformational disorder. The crystal structure consists of discrete molecules linked by N—H … O hydrogen bonds (N … O = 2.893(3) Å) along the short a axis. Intramolecular N—B coordination occurs to form a system of two fused five-membered rings. Bond lengths (corrected for libration) are: N—B, 1.630(3), O—B, 1.529(3), O—C, 1.219(3) and 1.300(3), N—C, 1.506(3) and 1.507(3), C(sp3)–C(sp3), 1.525(4), C(sp2)—C(sp3), 1.517(3), and mean C—C(phenyl), 1.394 Å.

Structural studies of organoboron compounds. XXIX. 6,6-Diethyl-2,2-diphenyl-1,3-dioxa-6-azonia-2-boratacyclooctane monohydrate

1988 ◽  
Vol 66 (5) ◽  
pp. 1091-1096 ◽  
Author(s):  
Wolfgang Kliegel ◽  
Steven J. Rettig ◽  
James Trotter
Keyword(s):  
Least Squares ◽  
Title Compound ◽  
Chelate Ring ◽  
Direct Methods ◽  
Structural Studies ◽  
Organoboron Compounds ◽  
Full Matrix ◽  
Space Group ◽  
Bond Lengths ◽  
Conformation Intermediate

Details of the preparation and structure of the title compound are given. Crystals of 6,6-diethyl-2,2-diphenvl-1,3-dioxa-6-azonia-2-boratacyclooctane monohydrate are orthorhombic, a = 7.0322(2), b = 16.3505(7), c = 16.8164(4) Å, Z = 4, space group P212121. The structure was solved by direct methods and was refined by full-matrix least-squares procedures to R = 0.045 and Rw = 0.050 for 2013 reflections with I ≥ 3σ(I). The monocyclic eight-membered B, N-betaine is the first to be structurally characterized. The eight-membered chelate ring has a conformation intermediate between the S4 and boat-boat forms which is probably stabilized by transannular [Formula: see text] interactions. The average libration-corrected O—B and B—C bond lengths of 1.500 and 1.639 Å are, respectively, the shortest and longest yet observed for an O,O-chelate of diphenylboron.

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