SYNTHESIS AND PROPERTIES OF 2,3,9,10,16,17,23,24-OCTAALKYLTETRAPYRAZINOPORPHYRAZINES

In order to obtain novel derivatives of tetrapyrazinoporphyrazine [2] in a pure state, symmetrically alkyl-substituted compound [2] were synthesized. Diaminomaleonitrile (DAMN) was refluxed in ethanol with 3,4-hexanedione to give 2, 3-dicyano-5,6-diethylpyra-zine [5 b]. 2, 3-Diethyl-6 H-pyrrolo[3, 4-b] pyrazine-5,7-diimine [3 b] was prepared by passing a stream of gaseous ammonia through the methanolic solutions of [5 b] in the presence of sodium methoxide. Compound [3 b] was then refluxed in 2-(dimethylamino)- ethanol to give 2, 3, 9,10,16,17, 23, 24-octaethyltetrapyrazinoporphyrazine [2 b]. The structure of [2 b] is confirmed by IR, 1H-NMR, MS, electronic spectrum, and elemental analysis. DAMN was refluxed in ethanol with various a-diketones to give 2, 3-dicyano-5, 6-dialkylpy-razines [5 c]~[5 g]: alkyl = n-C8H7, n-C5Hn, n-C7H15, n-C,H19, w-C11H23. Compound [5 c] was heated to reflux in methanol in the presence of 1,8-diazabicyclo[5.4.0]undee-7-ene (DBU) to give [2 c], Compound [5d]~[5 g] were similarly treated with DBU to give [2d]~[2g] respectively Octaalkyltetrapyrazihoporphyrazines [2 b]~[2 g] thus obtained showed high solubilities to organic solvents such as chloroform. They could be purified either by column chromatography or by recrystallization. Different from corresponding alkyl-substituted phthalocyanines, they showed no tendency to aggregate in chloroform. © 1990, The Chemical Society of Japan. All rights reserved.