Phenazine Syntheses. I. Halogen-Substituted Phenazines

Synthesis and pesticidal evaluation of phenazines I.—Halophenazines

“…In the control of cucumber powdery mildew both 2-chloroand 2-bromophenazine (3,4) were more active than 2-fluorophenazine (2), but 1-chlorophenazine (1) was significantlymore effective. Dichloro substitution in one ring (6)(7)(8)13) conferred activity which closely paralleled the acaricidal activity. Dichlorophenazines having one substituent in the 1-position were at least as active as 1-chloro-phenazine (1) when the second substituent was in the 2-,4-,7-or 9-position, but were less active than 1-chlorophenazine when the second substituent was in the 3-,6-or 8-position.…”

“…Substitution into both rings conferred less activity than substitution in one ring so that the six examples of dichloro substitution in both rings (9-12, 14, 15) were generally less active than the four examples of dichloro substitution in one ring (6)(7)(8)13). Trichloro substitution, whether in one or both rings, resulted in such low levels of phytotoxicity that no obvious patterns emerged, while tetrachloro substitution rendered the compound inactive (21 and 22).…”

“…Fd Agric., 1969, Vol. 20, January phenazines (6)(7)(8)13) with halogen in only one ring varied considerably with positional isomers, in the order 1,4 > 1,2 > 1,3 > 2,3. Trichlorophenazines (16 and 17) were considerably less active, whilst the tetrachloro compound (21) was virtually inactive.…”

Efficient Methods for the Synthesis of 2‐Hydroxyphenazine Based on the Pd‐Catalyzed N‐Arylation of Aryl Bromides.

“…: 116 °C (Lit. 2 : 112-113 °C). 1 H NMR (500 MHz, CDCl 3 ): δ = 9.49 (s, br, 1H, NH); 8.23 (dd, J = 8.7, 1.5, 1H, 3-H); 7.52 (dd, J = 7.9, 1.2, 1H, 3'-H); 7.46 (dt, J = 7.8, 1.5, 1H, 5-H); 7.42 (dd, J = 7.9, 1.1, 1H, 6'-H); 7.31 (dd, J = 7.9, 1.2, 1H, 5'-H); 7.14-7.21 (m, 2H, 4'-H, 6-H); 6.86 (ddd, J = 8.8, 7.8, 1.0, 1H, 4-H).…”

Synthesis of I‐diazo‐2(IH)‐phenazinone

“…114-1 15'. The mother liquor from the recrystallization was combined with the material eluted from the red band and the mixture was subjected to ring closure (14). Purification by sublimation and recrystallization from methanol gave 5.1 g. of 2-ethoxyphenazine, m.p.…”