Halogenation of 5-substituted-6,2'-O-cyclouridines afforded 6,2':6,5'-dianhydro-5,6-dihydro-6, 6-dihydroxy-5-halo-5-substituted-uracil arabinosides. Their steric configurations and mass spectra were also discussed.
The reaction of the lithiated species of 2', 3', 5'-tri-O-protected uridines and 6-chloropurine ribonucleoside with diethyl chlorophosphate provided the corresponding diethyl phosphonate derivatives (III, IV and VIII). The Arbuzov-reaction of 2', 3', 5'-tri-O-protected 4-chloro-2(1H)-pyrimidinone ribonucleoside with triethyl phosphite afforded the diethyl phosphonate derivative (VI).
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
Photochemical reaction of 2',3',5'-tri-O-acetyl-8-bromoadenosine (2) with triethyl phosphite, followed by deacetylation, gave diethyl adenosine-8-phosphonate (1). Intramolecular cyclization of diethyl 8-bromo-2',3'-O-isopropylideneadenosine-5'-phosphite (6) was accomplished with photo-irradiation to yield ethyl 2',3'-O-isopropylidene-adenosine-8,5'-phosphonate (4).
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
Coronary artery fistulae that communicate with the left ventricle are quite rare; those accompanied by sinus-node dysfunction are even more unusual. We report 2 cases of congenital coronary-artery-to-left-ventricle fistula with sinus-node dysfunction. In each of these patients, fistulae arose from both left and right coronary arteries. One patient had, in addition, a right coronary artery fistula that communicated with his right ventricle. Sinusnode dysfunction encountered in these 2 patients was likely caused by chronic general ischemia arising from a steal syndrome associated with the fistulae.
These abstracts are prepared for fhe benefit of our readers abroad to assist them to form a general idea of the contents of the present issue, written in Japanese by the respective authors. Readers are recommended to refer to the tables, the figures, the formulae etc. in the original papers. Editor
Summary form only given, as follows. The shunting arc discharge is an alternating capacitor discharge through a rod of metal or semi-metal. An optimization of the discharge condition has realized the self-ignition of the arc discharge at a low input power to the rod, leading to a much longer lifetime of the rod compared with the conventional shunting arc and the peripheral arc. The shunting-arc-produced plasma mainly consists of metal or semi-metal ions, and it has also been demonstrated that the ions can be extracted from the plasma. Thus, the shunting arc can be used as pulsed ion sources of metal and semi-metal for plasma-based ion implantation and deposition (PBII-D). In this study, an amorphous diamond-like carbon film was prepared by PBII-D using a pulsed carbon shunting arc at pressure of 10/sup -3/ Pa. The morphology and characteristics of the film were measured by using XPS, XRD, and Raman spectroscopy. The plasma was generated by the release of the capacitor energy (20 /spl mu/F at a charging voltage of 1.2 kV) to serve into a carbon rod of 2 mm in diameter and 40 mm long. The carbon rod was held at each end by a pair of 10 /spl times/ 10 mm square tungsten plates. The shunting arc current showed a damping oscillation with a peak current of 1.2 kA at 20 /spl mu/s. A negative high voltage pulse of -0.3 to 3 kV with a pulse width of 10 /spl mu/s and 20 kHz was repeatedly applied to the target of 80 mm in diameter, which was located at 40 mm away from the plasma source. The maximum film thickness was obtained at an applied voltage of around 1 kV. The XRD pattern indicated that the prepared film was amorphous. The XPS measurements showed that the film included tungsten. This means that the film of carbon-tungsten alloy can be prepared by the shunting arc system.
Abstract 6,2′‐O‐Cyclouridin (I) ergibt mit Halogenen oder mit N‐Halogensuccinimiden die Halogenverbindungen (II) und bei weiterer Reaktion die Bis‐Cyclo‐Derivate (III), die auch aus (IV) erhalten werden können.
Coronary ostial stenosis with otherwise normal coronary vessels occurs in patients with syphilis or Takayasu's aortitis. Iatrogenic ostial stenosis may develop as a complication of coronary angiography or after coronary perfusion at the time of cardiac surgery. Isolated ostial stenosis in the absence of these factors has been reported infrequently and its unique clinical and angiographic profile has been noted recently. Hence, it is proposed that this type of isolated ostial stenosis may represent a clinical entity distinct from the usual atherosclerotic coronary disease. We report the case of a middle-aged woman with this type of isolated coronary ostial stenosis. A 55-year-old female was admitted with the complaint of exertional chest pain, which had appeared 2 months admission and which had gradually become more frequent. The ECG on admission was normal. She had no coronary risk factor. Treadmill exercise test was stopped at stage 2 of Bruce protocol because ischemic S-T segment depression appeared in II, III, aVF, V4-V6 and she complained of a chest pain. Coronary angiography showed a 90% stenosis of the left coronary ostium with normal distal vessels. The right coronary artery was normal. A coronary artery bypass graft to the left anterior descending branch was performed uneventfully and the patient remains asymptomatic.
