Cyanoethylation, Decyanoethylation, and Transcyanoethylation

Abstract

In the long gap between the boiling point of sulphur (444O.60 c.) and the freezing point of gold (1063" c.) there is no fixed point which can conveniently be used for the routine calibration of thermocouples in terms of the International Temperature Scale. The boiling point of selenium (about 690" c.) is suggested as a possible fixed point in this region, and as a first step towards enabling it to be used for this purpose the precise determination of its value has been undertaken.The determination was carried out in a silica boiling tube similar to that normally used at the sulphur point, having a re-entrant tube fitted with a radiation shield. By connecting the apparatus to a reservoir the variation of the boiling point with pressure over the range 700 to 800 mm. of mercury was also determined. The measurements were made by means of three standard platinum vs. platinum-rhodium thermocouples calibrated at the freezing points of gold, silver and antimony. Samples of selenium from two sources, and two types of radiation shield, were employed and gave the same result.The value found for the boiling point in terms of the International Temperature Scale was 6848&0°*1 C. at normal atmospheric pressure, with a variation of 1O.08 c. per cm. of mercury.

Propylenamines by cobalt-catalyzed nitrile hydrogenations

“…Again, as in reaction 1-6, the rate of reaction with primary amines (specifically EDA) is faster than with NH3. Such transcyanoethylations have been observed in aromatic nitrile reduction (Butskus, 1961), and by Whitmore et al (1944), who observed that VCN reacts with aminopropionitrile approximately 20X faster than with NH3.…”

Streamlined Process for the Chemical Synthesis of RNA Using 2′-O-Thionocarbamate-Protected Nucleoside Phosphoramidites in the Solid Phase

“…For large-scale synthesis or to obtain higher integrity DNA products, the phosphorus protective group is removed first with a hindered primary or secondary amine such as tert -butylamine or diethylamine . The amine traps the acrylonitrile byproduct of the β-cyanoethyl protective group and prevents modification to the heterobases. The solid-support linkage is then cleaved along with the heterobase amide protective groups using a more nucleophilic amine, typically ammonia or methylamine under aqueous conditions.…”

Cyanoethylation of 2-cyanomethylbenzimidazole

“…Apparently, the role of the catalyst consists in ionization of the benzimidazole NH group of molecule II, which leads to the formation of N-anions subjected to the electrophylic attack of AN molecules. However, the process of N-cyanoethylation, in contrast to the C-cyanoethylation, is reversible [6]. Therefore, the thermodynamically controlled interaction of 2-cyanomethylbenzimidazole (II) with AN involves the following sequence of proc- II 98 60 4t 33 II1 0 19 34 39 VI 0 6 II 15 VII 0 5 5 5 Notes.…”