Liangshanin A

31391955

The crystal structures of an inter­mediate, C10H9ClN4O, 3-[(6-chloro-7H-purin-7-yl)meth­yl]cyclo­butan-1-one (I), and two N-7 and N-9 regioisomeric oxetanocin nucleoside analogs, C10H13ClN4O, 3-[(6-chloro-8,9-di­hydro-7H-purin-7-yl)meth­yl]cyclo­butan-1-ol (II) and C10H11ClN4O, 3-[(6-chloro-9H-purin-9-yl)meth­yl]cyclo­butan-1-ol (IV), are reported. The crystal structures of the nucleoside analogs confirmed the reduction of the N-7- and N-9-substituted cyclo­butano­nes with LiAl(OtBu)3 to occur with facial selectivity, yielding cis-nucleosides analogs similar to those found in nature. Reduction of the purine ring of the N-7 cyclo­butanone to a di­hydro­purine was observed for compound (II) but not for the purine ring of the N-9 cyclo­butanone on formation of compound (IV). In the crystal of (I), mol­ecules are linked by a weak Cl⋯O inter­action, forming a 21 helix along [010]. The helices are linked by offset π-π inter­actions [inter­centroid distance = 3.498 (1) a], forming layers parallel to (101). In the crystal of (II), mol­ecules are linked by pairs of O—H⋯N hydrogen bonds, forming inversion dimers with an R 2 2(8) ring motif. The dimers are linked by O—H⋯N hydrogen bonds, forming chains along [001], which in turn are linked by C—H⋯π and offset π-π inter­actions [inter­centroid distance = 3.509 (1) a], forming slabs parallel to the ac plane. In the crystal of (IV), mol­ecules are linked by O—H⋯N hydrogen bonds, forming chains along [101]. The chains are linked by C—H⋯N and C—H⋯O hydrogen bonds and C—H⋯π and offset π-π inter­actions [inter­centroid distance = 3.364 (1) a], forming a supra­molecular framework.

crystal structure, oxetonacin, cyclo­butanone, cyclo­butanol, HIV, hydrogen bonding, offset π-π inter­actions, supra­molecular framework

Crystal structures of the synthetic inter­mediate 3-[(6-chloro-7H-purin-7-yl)meth­yl]cyclo­butan-1-one, and of two oxetanocin derivatives: 3-[(6-chloro-8,9-di­hydro-7H-purin-7-yl)meth­yl]cyclo­butan-1-ol and 3-[(6-chloro-9H-purin-9-yl)meth­yl]cyclo­butan-1-ol

Ayat Yaseen,a,‡ Muhammad Murtaza Hassan,a,‡ Edward Lee-Ruff,a and Gerald F. Audettea,*

2019 Jun 1

32196246

The I ii spectrum has been excited in electrodeless lamps and photographed from 655 A to 11084 A. Wavelengths and estimated intensities are given for almost 2,400 lines. A revision and extension of the earlier analyses of this spectrum has increased the number of known even levels from 43 to 124, and the number of odd levels from 55 to 190. New gJ-factors are given for 46 levels, and the previous designations of 40 levels are changed. Improved measurements in the vacuum ultraviolet region give a correction of 7.4 cm−1 to be subtracted from the values listed in Atomic Energy Levels, Vol. 3 (1958), for all levels above the ground configuration. The approximately 1,800 classified lines now include all of the strongest lines. The 1S0 of the ground configuration 5s25p4 has been found, and this configuration has been fitted to intermediate coupling theory. Magnetic dipole transitions between levels of the ground configuration, 3P2-1D2 (7282 A) and 3P1-1S0 (4460 A), have been observed and their nature confirmed by the Zeeman effect. The line 5p4 3P2-1D2 shows hyperfine structure which is in approximate agreement with a theoretical calculation of the expected structure. New levels have been found for almost all higher configurations. All previously known series have been extended and new ones found. From one of the new series, 5p3(4S°)5−12g5G6°, the principal ionization energy for I ii (154304 ±1 cm−1) has been derived. The results of the analysis are compared with theoretical expectations in a number of cases.

The Spectrum of Singly Ionized Atomic Iodine (I ii)

William C. Martin and Charles H. Corliss

1960 Nov-Dec;