Synthesis of a family of 3-alkyl- or 3-aryl-substituted 1,2-dihydroquinazolinium salts and their isomerization to 4-iminium-1,2,3,4-tetrahydroquinolines.

A straightforward synthesis of substituted 1,2-dihydroquinazolinium triflates (3) is reported by reaction of 2-imino-substituted anilines with a range of carbonyl compounds in the presence of triflic acid via intermediate iminium salts. Similar reactions with di- or trialdehydes and triflic acid give bis- or tris-(1,2-dihydroquinazolinium) salts. Some 4-methyl substituted 1,2-dihydroquinazolinium salts rearrange, under various conditions, to their corresponding 4-iminium-1,2,3,4-tetrahydroquinolinium isomers (7). Most of salts 3 derived from ketones are rather unstable, which prevents their isolation or full characterization. The crystal structures of various 3 and 7 salts have been determined.

2-(Aminomethyl)phenyl complexes of Au(III), mixed Au(III)/Ag(I), and Pd(II) with the 2,2-diacetyl-1,1-ethylenedithiolato ligand: dancing of palladacycles around a juggler ligand.

The reaction of [Tl(2){mu-S,S-S(2)C=C{C(O)Me}(2)}] with [Au(C,N-C(6)H(4)CH(2)NMe(2)-2)Cl(2)] (1:1) gives [{Au(C,N-C(6)H(4)CH(2)NMe(2)-2)}{S,S-S(2)C=C{C(O)Me}(2)}] (1) which, in turn, reacts with AgClO(4) (1:1) to give [{Au(C,N-C(6)H(4)CH(2)NMe(2)-2)}{Ag(OClO(3))}{S(2)C=C{C(O)Me}(2)}] (2). Complexes [{Au(C,N-C(6)H(4)CH(2)NMe(2)-2)}{Ag(X)(PPh(3))}{S(2)C=C{C(O)Me}(2)}] [X = OClO(3) (3), ONO(2) (4)] have been obtained by reaction of 1 with PPh(3) and AgClO(4) or AgNO(3), respectively (1:1:1). Complex 3 can also be obtained by reacting 2 with PPh(3) (1:1). Complexes [Pd(C,N-C(6)H(4)CH(2)NR(2)-2)(mu-Cl)](2) (R = Me, H) react (i) with [Tl(2){S(2)C=C{C(O)Me}(2)}] and [PPN]Cl (0.5:1:1, PPN = Ph(3)P=N=PPh(3)) to form PPN[Pd(C,N-C(6)H(4)CH(2)NR(2)-2){S,S-S(2)C=C{C(O)Me}(2)}] [R = H (5a), Me (5b)], or (ii) with [Tl(2){S(2)C=C{C(O)Me}(2)}] (1:1) to form [{Pd(C,N-C(6)H(4)CH(2)NR(2)-2)}(2){mu-S,S,O-S(2)C=C{C(O)Me}(2)}] [R = H (6a), Me (6b)]. The trinuclear complexes [{Pd(C,N-C(6)H(4)CH(2)NR(2)-2)}(3){mu(3)-O,S,S,O-S(2)C=C{C(O)Me}(2)}]ClO(4) [R = H (7a), Me (7b)] can be prepared by reacting the corresponding dinuclear complex 6a or 6b with [Pd(C,N-C(6)H(4)CH(2)NR(2)-2)(NCMe)(2)]ClO(4) (1:1). The crystal structures of 1, 6b x CH(2)Cl(2), and 7b x CH(2)Cl(2) have been determined. NMR studies have been carried out to explain the solution behavior of these complexes. VT-NMR and line shape analysis for the species where R = Me (5b, 6b, 7b) have allowed the estimation of the activation parameters for these exchange processes.