Abstract:4‐α‐(or β)‐p‐Chlorobenzoyloxy‐1‐azaadamantane hydrochloride have been synthesized and studied by 1H and 13C nmr spectroscopy, and the crystal structure of the α‐epimer has been determined by X‐ray diffraction. Each ring of the adamantane cage system is a nearly perfect chair, the substituted cyclohexane and piperidine rings, in endo and exo position respectively, having the biggest deviation. From the 1H and 13C nmr data, several stereoelectronic effects have been deduced.
“…The carbonyl group is pyramidalized and is bent away from the nitrogen-containing ring. During a search for experimental parameters for comparison to our calculation, the crystal structure for 4-α- p -chlorobenzoyloxy-1-azaadamantane hydrochloride was found to be distorted . The distortion observed in the crystal of this compound is in the same direction as in the calculated structure of 17 , i.e., the piperidine ring is flatter than the cyclohexane ring.…”
Section: B Distortion Of 5-azaadamantanone and Its
N-oxidementioning
“…The carbonyl group is pyramidalized and is bent away from the nitrogen-containing ring. During a search for experimental parameters for comparison to our calculation, the crystal structure for 4-α- p -chlorobenzoyloxy-1-azaadamantane hydrochloride was found to be distorted . The distortion observed in the crystal of this compound is in the same direction as in the calculated structure of 17 , i.e., the piperidine ring is flatter than the cyclohexane ring.…”
Section: B Distortion Of 5-azaadamantanone and Its
N-oxidementioning
“…To the best of our knowledge, there are no experimental parameters on the structures of 5-azaadamantanone ( 2 ) and its N -oxide ( 3 ) . To search for experimental parameters for comparison to our calculation, we have carefully reviewed the three articles previously referred to by le Noble. − The first was a report on the crystal structure of 4-α-( p -chlorobenzoyloxy)-1-azaadamantane hydrochloride ( 4 , Chart ) by Galvez . The sentence “each ring is a nearly perfect chair” was used, and quoted by le Noble .…”
Section: Resultsmentioning
confidence: 99%
“…The result of the observed high diastereofacial selectivity has been described as an excellent example of Cieplak model in operation . To support the argument that 2 and 3 are free from distortion, three references of crystal structures of related compounds have been provided. ,− …”
Ab initio molecular orbital studies of adamantanone (1), 5-azaadamantanone (2), and 5-azaadamantanone N-oxide (3) show that 2 and 3 have distorted structures. The torsional angle τ OCCRC in the C 2v symmetric adamantanone 1 is 120.6°. τ OCCRC is 124.0°in the piperidinedione ring of 3 and 117.8°in the cyclohexanone ring of 3, indicating a significant distortion. The corresponding values for 2 are 122.5°and 120.3°indicating a slightly distorted structure. These structural results are consistent with the previously observed π-facial selectivity in NaBH 4 reduction of 2 and 3, but contradict with the suggestion that they are symmetrical.
hA. N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, 28ul. l/avilova, 117813 Moscow. Russian Federation. Fax: + 7 (095) 135 5085The reactions of I-boraadamantane and 2-methyl-, 2-ethyl-, 2,2-dimethyl-, and 3,5-dimethyl-substituted l-boraadamantan~s with their I-azaadamantane analogs afforded a series of 1 : 1 adducts, which are stable to atmospheric air and moisture. Ill, 13C, and 3LB NMR spectra as well as mass spectra of the compounds synthesized were investigated. Only the adduct of 2,2-dimethyl-l-boraadamantane with 2,2-dimethyl-l-azaadamanlane readily dissociates into the initial components due to steric hindrances that prevent strong BuN coordination. The structure and geometric parameters of the l-boraadamantane complex with 3,5-dimethyl-l-azaadamantane were established by X-ray diffraction analysis.
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