Synthesis and conformations of α-aminoadipyl- and glycyl-α-aminoadipylthiazepine sulfoxides

1981 ◽  
Vol 59 (2) ◽  
pp. 406-421 ◽  
Author(s):  
Saul Wolfe ◽  
Raymond John Bowers ◽  
Syed Khaqan Hasan ◽  
Peter Michael Kazmaier
Keyword(s):  
Hydrogen Bond ◽  
Carbon Atom ◽  
Formic Acid ◽  
Chair Conformation ◽  
Membered Ring ◽  
Amide Proton ◽  
Penicillin Biosynthesis ◽  
Boat Conformation ◽  
Internal Hydrogen Bond ◽  
Twist Boat

The title compounds, having the R-absolute configurations at sulfur, and labelled with 14C at carbons 5, 6, and 7 of the seven-membered ring, have been synthesized by condensation of isotopically labelled 3D-benzhydryloxycarbonyl-6L-amino-2,2-dimethyl-5-oxoperhydro-1,4-thiazepine with N-Boc- and α-benzhydryl-protected L-α-aminoadipic acid and glycyl-L-α-aminoadipic acid, followed by oxidation with m-chloroperoxybenzoic acid and complete deprotection with formic acid. The conformations of the sulfoxides, and related thiazepines and thiazepine sulfoxides, have been examined by 1Hmr spectroscopy. All thiazepines, and the two title sulfoxides, appear to exist in a twist boat conformation. Most other sulfoxides exist in a chair conformation, which is stabilized by an internal hydrogen bond between the sulfinyl oxygen and the amide proton at C6; when this hydrogen bond is not present, both chair and twist boat conformations may be observable. The title compounds are of interest as possible intermediates in penicillin biosynthesis from glycyl-δ-(L-α-aminoadipyl)-L-cysteinyl-D-valine (GACV) or ACV, according to a new theory, which deals, in particular, with the stereochemical course of the biosynthesis at the beta (β) carbon atom of valine.

scholarly journals (1′S,6′S,8′S,9′R)-9′-Bromo-12′-oxaspiro[1,3-dioxolane-2,4′-tricyclo[6.3.1.01,6]dodecane]

2012 ◽  
Vol 68 (8) ◽  
pp. o2411-o2412
Author(s):  
Goverdhan Mehta ◽  
Tabrez Babu Khan
Keyword(s):  
Hydrogen Bond ◽  
Natural Products ◽  
Title Compound ◽  
Crystal Packing ◽  
Chair Conformation ◽  
Membered Ring ◽  
Boat Conformation ◽  
Bioactive Natural Products ◽  
Compound C ◽  
Twist Boat

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-olviaa 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 thebaxis.

scholarly journals Crystal structure of 16-hydroxy-4,4,10,13,14-pentamethyl-17-(6-methylhept-5-en-2-yl)-4,5,6,9,10,11,12,13,14,15,16,17-dodecahydro-1H-cyclopenta[a]phenanthren-3(2H)-one

2015 ◽  
Vol 71 (7) ◽  
pp. o464-o465 ◽  
Author(s):  
Jun-Jun Ge ◽  
Pian Chen ◽  
Xiao-Xia Ye
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Chair Conformation ◽  
Membered Ring ◽  
Boat Conformation ◽  
Carbonyl Groups ◽  
Compound C ◽  
Cyclohexene Ring ◽  
Supramolecular Chains ◽  
Twist Boat

The title compound, C30H48O2, contains a fused four-ring triterpenoid system. In the molecule, the two cyclohexane rings adopt a chair conformation and a twist boat conformation, respectively, the central cyclohexene ring adopts a half-chair conformation whereas the five membered ring adopts an envelope conformation. In the crystal, O—H...O hydrogen bonds between the hydroxy and carbonyl groups of adjacent molecules link the molecules into supramolecular chains propagating along theb-axis direction.

Crystal Structure and Conformation of Ring A of 2β-Bromo-19β,28-epoxy-18α-oleanan-3-one

1993 ◽  
Vol 58 (11) ◽  
pp. 2737-2744 ◽  
Author(s):  
Jiří Novotný ◽  
Jaroslav Podlaha ◽  
Jiří Klinot
Keyword(s):  
Crystal Structure ◽  
Opposite Direction ◽  
Chair Conformation ◽  
Boat Conformation ◽  
Form Ring ◽  
Twist Boat

The crystal structure of β-bromo-19β,28-epoxy-18α-oleanan-3-one was elucidated. The crystal is orthorhombic, P212121, a = 9.686(1), b = 14.355(2), c = 19.687(4) Å, Z = 4, R = 0.042 for 2 410 observed reflections. Rings B, C, D and E adopt the chair conformation, the five membered ether cycle in ring E occurs in the envelope form. Ring A takes the twist-boat conformation turned towards the classical boat with C2 and C5 in the stem-stern position, in contrast to the conformation in solution, which is turned in the opposite direction towards the classical boat with C3 and C10 in the stem-stern positions.

scholarly journals Synthesis of Trithia-Borinane Complexes Stabilized in Diruthenium Core: [(Cp*Ru)2(η1-S)(η1-CS){(CH2)2S3BR}] (R = H or SMe)

Inorganics ◽  
2019 ◽  
Vol 7 (2) ◽  
pp. 21 ◽  
Author(s):  
Koushik Saha ◽  
Urminder Kaur ◽  
Rosmita Borthakur ◽  
Sundargopal Ghosh
Keyword(s):  
Mass Spectrometry ◽  
1H Nmr Spectroscopy ◽  
Chair Conformation ◽  
Membered Ring ◽  
Molecular Structures ◽  
Boat Conformation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Butterfly Cluster ◽  
Tellurium Powder

The thermolysis of arachno-1 [(Cp*Ru)2(B3H8)(CS2H)] in the presence of tellurium powder yielded a series of ruthenium trithia-borinane complexes: [(Cp*Ru)2(η1-S)(η1-CS){(CH2)2S3BH}] 2, [(Cp*Ru)2(η1-S)(η1-CS){(CH2)2S3B(SMe)}] 3, and [(Cp*Ru)2(η1-S)(η1-CS){(CH2)2S3BH}] 4. Compounds 2–4 were considered as ruthenium trithia-borinane complexes, where the central six-membered ring {C2BS3} adopted a boat conformation. Compounds 2–4 were similar to our recently reported ruthenium diborinane complex [(Cp*Ru){(η2-SCHS)CH2S2(BH2)2}]. Unlike diborinane, where the central six-membered ring {CB2S3} adopted a chair conformation, compounds 2–4 adopted a boat conformation. In an attempt to convert arachno-1 into a closo or nido cluster, we pyrolyzed it in toluene. Interestingly, the reaction led to the isolation of a capped butterfly cluster, [(Cp*Ru)2(B3H5)(CS2H2)] 5. All the compounds were characterized by 1H, 11B{1H}, and 13C{1H} NMR spectroscopy and mass spectrometry. The molecular structures of complexes 2, 3, and 5 were also determined by single-crystal X-ray diffraction analysis.

scholarly journals (1R,4R,6S,7R)-5,5-Dibromo-1,4,8,8-tetramethyltricyclo[5.4.1.04,6]dodecan-12-one

2014 ◽  
Vol 70 (5) ◽  
pp. o526-o526 ◽  
Author(s):  
Mohamed Zaki ◽  
Ahmed Benharref ◽  
Jean-Claude Daran ◽  
Moha Berraho
Keyword(s):  
Title Compound ◽  
Chair Conformation ◽  
Membered Ring ◽  
The Other ◽  
Boat Conformation ◽  
Asymmetric Unit ◽  
Cedrus Atlantica ◽  
Compound C ◽  
Independent Molecules

The title compound, C16H24Br2O, was synthesized from the reaction of β-himachalene (3,5,5,9-tetramethyl-2,4a,5,6,7,8-hexahydro-1H-benzocycloheptene), which was isolated from Atlas cedar (Cedrus atlantica). The asymmetric unit contains two independent molecules with similar conformations. Each molecule is built up from two fused seven-membered rings and an additional three-membered ring. In both molecules, one of the seven-membered rings has a chair conformation, whereas the other displays a screw-boat conformation.

scholarly journals Crystal structure of 3-(3-oxo-2,3,4,4a,5,6-hexahydrobenzo[h]cinnolin-2-yl)propionic acid

2014 ◽  
Vol 70 (10) ◽  
pp. o1088-o1089
Author(s):  
Fiorella Meneghetti ◽  
Daniela Masciocchi ◽  
Arianna Gelain ◽  
Stefania Villa
Keyword(s):  
Chair Conformation ◽  
Membered Ring ◽  
Side Chain ◽  
Boat Conformation ◽  
Asymmetric Unit ◽  
Torsion Angles ◽  
Compound C ◽  
Centroid Distance ◽  
Independent Molecules ◽  
Twisted Boat

The asymmetric unit of the title compound, C15H16N2O3, contains two independent molecules, which present a different conformation of the carboxylic acid side chain [C—C—C—OH torsion angles = 65.3 (7) and −170.1 (5)°]. In both molecules, the dihydropyridazinone ring adopts a geometry intermediate between a twisted-boat and a half-chair conformation, while the central six-membered ring is almost in a half-boat conformation. In the crystal, molecules are linked by O—H...Ok(k = ketone) hydrogen bonds, generating [01-1] chains. Aromatic π–π stacking contacts between the benzene and the dihydropyridazinone rings [centroid–centroid distance [3.879 (9) Å] are also observed.

scholarly journals (1S,2R,3S,6S,7R)-3,7,11,11-Tetramethyl-6,7-epoxybicyclo[5.4.0]undecane-2-ol

2014 ◽  
Vol 70 (5) ◽  
pp. o595-o595
Author(s):  
Mohamed Loubidi ◽  
Ahmed Benharref ◽  
Lahcen El Ammari ◽  
Mohamed Saadi ◽  
Moha Berraho
Keyword(s):  
Hydrogen Bonds ◽  
Title Compound ◽  
Membered Ring ◽  
Boat Conformation ◽  
Axis Direction ◽  
Cedrus Atlantica ◽  
Compound C ◽  
Twist Boat

The title compound, C15H26O2, was synthesized from β-himachalene (3,5,5,9-tetramethyl-2,4a,5,6,7,8-hexahydro-1H-benzocycloheptene), which was isolated from the Atlas cedar (cedrus atlantica). The molecule is built up from a seven-membered ring to which a six- and a three-membered ring are fused. The seven- and six-membered rings each have a twist-boat conformation. In the crystal, O—H...O hydrogen bonds link the molecules into zigzag chains running along theb-axis direction.

scholarly journals The crystal structures and Hirshfeld surface analysis of 6-(naphthalen-1-yl)-6a-nitro-6,6a,6b,7,9,11a-hexahydrospiro[chromeno[3′,4′:3,4]pyrrolo[1,2-c]thiazole-11,11′-indeno[1,2-b]quinoxaline] and 6′-(naphthalen-1-yl)-6a′-nitro-6′,6a′,6b′,7′,8′,9′,10′,12a′-octahydro-2H-spiro[acenaphthylene-1,12′-chromeno[3,4-a]indolizin]-2-one

2019 ◽  
Vol 75 (10) ◽  
pp. 1519-1524
Author(s):  
G. Foize Ahmad ◽  
A. Syed Mohammed Mujaheer ◽  
M. NizamMohideen ◽  
M. Gulam Mohamed ◽  
V. Viswanathan
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Chair Conformation ◽  
Piperidine Ring ◽  
Thiazole Ring ◽  
Boat Conformation ◽  
Pyran Ring ◽  
Axis Direction ◽  
Π Interactions ◽  
Spiro Derivatives

The title compounds, 6-(naphthalen-1-yl)-6a-nitro-6,6a,6 b,7,9,11a-hexahydrospiro[chromeno[3′,4′:3,4]pyrrolo[1,2-c]thiazole-11,11′-indeno[1,2-b]quinoxaline], C37H26N4O3S, (I), and 6′-(naphthalen-1-yl)-6a′-nitro-6′,6a′,6b′,7′,8′,9′,10′,12a′-octahydro-2H-spiro[acenaphthylene-1,12′-chromeno[3,4-a]indolizin]-2-one, C36H28N2O4, (II), are new spiro derivatives, in which both the pyrrolidine rings adopt twisted conformations. In (I), the five-membered thiazole ring adopts an envelope conformation, while the eight-membered pyrrolidine-thiazole ring adopts a boat conformation. An intramolecular C—H...N hydrogen bond occurs, involving a C atom of the pyran ring and an N atom of the pyrazine ring. In (II), the six-membered piperidine ring adopts a chair conformation. An intramolecular C—H...O hydrogen bond occurs, involving a C atom of the pyrrolidine ring and the keto O atom. For both compounds, the crystal structure is stabilized by intermolecular C—H...O hydrogen bonds. In (I), the C—H...O hydrogen bonds link adjacent molecules, forming R 2 2(16) loops propagating along the b-axis direction, while in (II) they form zigzag chains along the b-axis direction. In both compounds, C—H...π interactions help to consolidate the structure, but no significant π–π interactions with centroid–centroid distances of less than 4 Å are observed.

Synthesis and Structure of the Helicate (M)-(–)-[Pt2 {(R,R)-tetraphos}2](CF3SO3)4 · 4.5 H2O

2004 ◽  
Vol 59 (11-12) ◽  
pp. 1458-1461
Author(s):  
Heather J. Kitto ◽  
A. David Rae ◽  
Anthony C. Willis ◽  
Johann Zank ◽  
S. Bruce Wild
Keyword(s):  
Membered Ring ◽  
Boat Conformation ◽  
Fold Axis ◽  
Space Group ◽  
Independent Molecules ◽  
Α Helix ◽  
Twist Boat

The complex (M)-(-)-[Pt2{(R,R)-tetraphos}2](CF3SO3)4 · 4.5 H2O, where tetraphos = 1,1,4,7, 10,10-hexaphenyl-1,4,7,10-tetraphosphadecane, has been isolated and structurally characterized. The compound crystallizes in the space group C2 with two crystallographically different, but very similar, cations in the structure, each of which contains a 2-fold axis coincident with the crystallographic 2-fold axis. Each independent cation of the salt consists of a double-stranded, diplatinum(II) helicate that completes a ca. one-eighth turn of a double α-helix in the M direction, as evidenced by the angle between the two, non-orthogonal PtP4 square planes in each of the independent molecules. A feature of the structures is the 10-membered ring containing the two platinum atoms and the four chiral phosphorus stereocentres of R configuration; this ring has a distorted twist-boat-chair-boat conformation of λ helicity, which is responsible for the M twist of the helicate.

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