6-[(4-Hy­droxy­phen­yl)diazenyl]-1,10-phenanthrolin-1-ium chloride monohydrate

In the cation of the title mol­ecular salt, C18H13N4O+·Cl−·H2O, the dihedral angle between the mean planes of the 1,10-phenanthroline system and the phenol ring is 14.40 (19)°. The crystal packing is stabilized by O—H⋯O hydrogen bonds, weak N—H⋯Cl and O—H⋯Cl inter­molecular inter­actions and π—π stacking inter­actions [centroid–centroid distance = 3.6944 (13) and 3.9702 (12) Å

Nucleophilic substitutions on 2‐Chloro‐3‐Nitroquinoxaline

Piperidine, cyclohexylamine, methoxide ion and para‐thiocresolate ion react with 2‐chloro‐3‐nitroquinoxaline 1 by selectively substituting the nitro group, in contrast to the behavior of most ortho‐chloronitroaromatics which loose halide when subjected to nucleophilic substitution reactions. This inversion is interpreted as being due to the lack of activation of the 2‐position by the nitro group in the 3‐position because of the low value of the π‐bond index between these two vertices. It is also suggested that the substitution by neutral reagents such as amines is strongly influenced by stabilizing interactions between the negatively charged nitro group and the ammonium moiety in the σ complex; this built‐in solvation may be responsible for inversions in the chemoselectivity between chloro and nitro nucleofugicities. Copyright © 1988 Wiley‐VCH Verlag GmbH & Co. KGaA, WeinheimSCOPUS: ar.jinfo:eu-repo/semantics/publishe

Fragmentation of 1,4,5,8‐tetraazaphenanthrenes upon electron impact: A new example of structural integrity of gas phase heteroaromatic cations

1,4,5,8‐Tetraazaphenanthrene and some derivatives have been studied by mass and ion kinetic energy spectrometries. Deuterium labelling experiments show an unexpected structural integrity of the gas phase molecular ions which eliminate H(D)CN, even near threshold energies (field‐free region reactions). The loss of N(1(8)) predominates largely over the loss of N(4(5)); the consecutive losses of H(D)CN are also highly specific. A similar specificty is observed for the chlorinated and methylated isomers. The atoms of the homocycle are not involved in the first steps of the fragmentation as indicated by the behaviour of 9‐chloro‐and 9‐methyl‐tetraazaphenanthrenes. Copyright © 1985 Wiley Heyden LtdSCOPUS: ar.jinfo:eu-repo/semantics/publishe

Chemoselectivity Reversals in Quinoxalines: The Reaction of 5‐Chloro‐6‐Nitroquinoxaline with Nucleophiles

5‐Chloro‐6‐nitroquinoxaline 2, made in six steps from 2,3‐dichloronitro‐benzene, reacts 1) with piperidine to give 6‐nitro‐5‐piperidinoquinoxaline as the only product; 2) with methoxide to give a 95:5 ratio of 5‐methoxy‐6‐nitro‐ and 5‐chloro‐6‐methoxy‐quinoxaline; 3) with p‐thiocresolate to give the disubstitution product without showing any monosubstitution product. Copyright © 1992 Wiley‐VCH Verlag GmbH & Co. KGaA, WeinheimSCOPUS: ar.jinfo:eu-repo/semantics/publishe