15851-81-7Relevant articles and documents
Design and synthesis of novel pyridopyrimidine derivatives with anchoring non-coplanar aromatic extensions of EGFR inhibitory activity
Eissa, Amal A.M.,Aljamal, Kholoud F.M.,Ibrahim, Hany S.,Abdelrasheed Allam, Heba
, (2021/09/06)
The present study describes the synthesis of three series of 4-substituted pyridopyrimidin derivatives 4a-h, 5a-d. 6a-d, starting from 2-amino-6-(4-methoxyphenyl)-4-(4-(substituted) phenyl)nicotinonitrile 2a-d via the reaction with N,N-dimethyl-N-' substi
Change of the favored routes of EI MS fragmentation when proceeding from N1, N1-dimethyl-N2-arylformamidines to 1,1,3,3-tetraalkyl-2-arylguanidines: Substituent effects
Raczynska, Ewa D.,Makowski, Mariusz,Gal, Jean-Francois,Maria, Pierre-Charles
body text, p. 762 - 771 (2011/09/12)
Although series of N1, N1-dimethyl-N 2-arylformamidines and of 1,1,3,3-tetraalkyl-2-arylguanidines are structurally analogous and similar electron-ionization mass spectral fragmentationmay be expected, they display important differences in the favored routes of fragmentation andconsequently in substituent effectsonion abundances. In the caseof formamidines, the cyclizationelimination process (initiated by nucleophilic attack of the N-amino atom on the 2-position of the phenyl ring) and formation of the cyclic benzimidazolium [M-H]+ ions dominates, whereas the loss of the NR2 group ismore favored for guanidines. In order to gain information on the most probable structures of the principal fragments, quantum-chemical calculations were performed on a selected set. A good linear relation between log{I[M-H]+I [M]+?} and σR+ constants of substituent at para position in the phenyl ring occurs solely for formamidines (r = 0.989). In the case of guanidines, this relation is not significant (r = 0.659). A good linear relation is found between log{I[M-NMe2]+/I [M]+?} and σp+ constants (r = 0.993). Copyright
