Optically Active Tetrapyrazinoporphyrazines and Their Circular Dichroism in Monomeric and Dimeric FormsOxford University Press (OUP) - Tập 27 Số 8 - Trang 851-852 - 1998
Nagao Kobayashi, W. A. Nevin
Abstract Metal-free and copper derivatives of tetrapyrazinoporphyrazines
containing four (1R)-(−)- or (1S)-(+)-camphor units have been synthesized and
their circular dichroism (CD) has been studied: in monomeric state, R and S
isomers showed mainly positive and negative CD signs, respectively, while CD
pattern in a cofacial dimeric state suggested that R and S isomers stack in
left- and right-hand... hiện toàn bộ
Fluoranthocyanine: A New Member of the Phthalocyanine FamilyOxford University Press (OUP) - Tập 27 Số 5 - Trang 423-424 - 1998
Nagao Kobayashi, Yuko Yoshikawa, Osamu Ito, H. Bruce Goodbrand, Jim Mayo
Abstract Fluoranthocyanine, a phthalocyanine analog fused by four five-membered
rings and four 1,8-naphthalene units, has been synthesized and characterized by
electronic absorption, magnetic circular dichroism, and fluorescence
spectroscopy.
Isolation and Structure of Magnoloside A, a New Phenylpropanoid Glycoside from Magnolia obovata Thunb.Oxford University Press (OUP) - Tập 17 Số 1 - Trang 163-166 - 1988
Takashi Hasegawa, Yoshiyasu Fukuyama, Toshihide Yamada, Kazuyuki Nakagawa
Abstract Magnoloside A, a novel phenylpropanoid glycoside has been isolated from
the MeOH extract of Magnolia obovata and its structure has been elucidated as
3,4-dihydroxy-β-phenyl-ethyl-O-α-l-rhamnopyranosyl-(1→2)-3-O-caffeoyl-β-d-allopyranoside
by means of spectroscopic and chemical evidences.
Enantioselective Syntheses of (+)- and (−)-FrontalinOxford University Press (OUP) - Tập 16 Số 1 - Trang 41-44 - 1987
Masaki Ohwa, Ernest L. Eliel
Abstract (+)- and (−)-Frontalin have been obtained from a chiral 1,3-oxathiane
precursor in a short (3-step) synthesis in moderate (70%) enantiomeric excess
(e.e.). A longer (6-step) modification gives the two enantiomers in 96% e.e.
Overall yields range from 28 to 43%.
1H NMR Study of Hydroxy Groups in Mesoporous Molecular Sieve SBA-15Oxford University Press (OUP) - Tập 30 Số 11 - Trang 1164-1165 - 2001
Lei Shi, Yan Zou, Heyong He
Abstract Three types of hydroxy groups, which are attributed to single,
hydrogen-bonded and geminal SiOHs in mesoporous molecular sieve SBA-15 are
directly and quantitatively observed by 1H ultrafast MAS NMR spectroscopy.
A New Ternary Compound in Rare Earth-Cobalt-Boron SystemOxford University Press (OUP) - Tập 1 Số 10 - Trang 875-876 - 1972
Koichi Niihara, Seishi Yajima
Abstract A new ternary boride RCo12B6 with a rhombohedral structure was
synthesized by arc-melting in R-Co-B system, where R is a rare earth ion. From
magnetic measurements, it was found that CeCo12B6 had a Curie temperature at
130°–140°K and exhibited a Curie–Weiss behavior in the paramagnetic region above
140°K.