Supersonic jet studies of alkyl-substituted pyrazines and pyridines. Minimum energy conformations and torsional motion
Conformational reference for methyl-, ethyl-, propyl-, and isoproply-substituted pyrazines and pyridines are determined by mass resolved excitation spectroscopy (MRES) and MOPAC 5/PM3 semiempirical calculations. The results of these studies suggest that the conformational behavior of alkyl-substituted pyrazines and pyridines is different from that of alkyl-subtituted benzenes. Based on the experimental and semiempirical theoretical results reported herein and published ab initio calculations, this difference can be attributed to a stabilizing interaction between an α-hydrogen atom of alkyl subsituted and the adjacent lone pair nonbonding electrons on the ring nitrogen atom.
Seeman, Jeffey I.,Paine III, John B.,Secor, Henry V.,Im, Hoong-Sun,Bernstein
p. 5269 - 5280
(2007/10/02)
SYNTHESIS OF ARGVALIN AND ITS RELATED COMPOUND
Argvalin (3) and 6-(4-guanidinobutyl)-3-isobutyl-2(1H)-pyrazinone (4) were synthesized from DL-alanyl-valyl anhydride (6) and DL-alanyl-leucyl anhydride (5) respectively.