Facile synthesis of a cis-syn thymine dimer building block and its incorporation into oligodeoxynucleotides

The synthesis of a building block containing the photobiologically relevant cis-syn thymine cyclobutane photoproduct and its incorporation into oligonucleotides by the phosphoramidite-based solid-phase synthesis is reported. Compared to previous syntheses, this route is extremely short and allows such modified oligonucleotides to be easily available for biological studies.     

Carbon-13 nuclear magnetic resonance spectra of some heterocyclic D-homoandrostanes

The ¹³C chemical shift data of several D-homoandrostanes with heteroatoms (N,O) in the 17a-position are reported. Heteroatom effects on the shieldings of the carbons of rings C and D are discussed.     

A novel synthesis of 2,3-dihydrooxazoles from dimethyl n-ethoxycarbonylmethyliminodithiocarbonate and aromatic aldehydes

We report the synthesis of 5-aryl-2-ethoxycarbonyl-4-methylthio-2,3-dihydrooxazoles from a cyclocondensation reaction betweeen dimethyl N-ethoxycarbonylmethyliminodithiocarbonate and aromatic aldehydes.     

Thermal expansion of cadmium fluoride crystals at high temperatures

The thermal expansion coefficient of cadmium fluoride crystals has been measured over the temperature range of 300 to 1070 K. The data fit well to measurements done by other authors in the range 80–300 K. At temperatures above 1070 K the thermal expansion coefficient shows an anomalous behaviour which has been attributed to the formation of cadmium oxide on the surface of the sample.     

Hydrogen complexes and their vibrations in undoped crystalline silicon

Geometry, relative stability, and vibration frequencies of hydrogen complexes — with and without the presence of vacancies and self-interstitials — are calculated. Assignments proposed by various experimental investigators for hydrogen related vibrational bands are discussed based on the relation between Si-H bond-character and stretching mode frequency.     

Quenching cross sections of the B3Π+(Ou+) v′ = 14 level of I2 by H2, CO,and CH4

In this work the deexcitation of the B³Π⁺(O_u⁺), v′ = 14 level of I₂ after pulsed laser excitation has been studied. The quenching cross sections by collisions with I₂, H₂, CO, and CH₄ have been measured. The experimental results are 190 ± 14, 2.5 ± 0.3, 15.1 ± 0.4, and 18.0 ± 0.6 Ų, respectively. These values are compatible (within 30%) with the semiempirical scaling law of proportionality with the product of polarizability and the square root of reduced mass.     

Synthesis of perhydropyrazino[1,2-d][1,4]diazepine,a new heterocyclic compound

A novel heterocycle, perhydropyrazino[1,2-d][1,4]diazepine, is prepared in good yield by an efficient method starting from facile available compounds.