N-Phenyl substitution of amino-and imino-groups in benzamidines is shown to reduce basic strength by factors of ca. 10 and 1000, respectively. The configuration of the imino-N-phenyl ring is discussed. The structure of the predominant tautomer of N -( 3-diethylaminopropyl)-N'-phenylbenzamidine is indicated.

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Ausgehend vom 6‐lithiierten 2‐Brompyridin wird durch Cu‐induzierte Dimerisierung bei ‐100°C das Bipyridyl (I) erhalten (Ausb. 60%), das mit den Di‐Na‐Derivaten der Glykole (II) in siedendem Xylol die Kronenether (III) und (IV) liefert, wobei die Ausb. mit steigender Ringgröße zunehmen.

with chloroform and the combined organic layers were washed with water, saturated brine, and dried (MgS04). The solvent was removed under reduced pressure. The residue and DBU (2 equiv) were refluxed together in benzene under nitrogen for 3 h. The mixture became black and formed a thick precipitate. The reaction mixture was cooled to 20 °C and poured onto excess dilute HC1 and the layers separated. The aqueous layer was extracted with ether and the combined organic layers were washed with water and saturated brine and dried (MgS04). Solvent was removed under reduced pressure, and the residual oils were purified by preparative TLC to give, as the major or only product, the para-substituted product, as shown by NMR comparison with known compounds. Compound 9a gave 12a in 68% yield. Compounds 13a and 13b both gave 14a in 58% yield. Compound 9c gave 12c in 53% yield.General Procedure for Aromatiration of Trisubstituted Diene Diels-Alder Adducts. The dienone 15 (1 equiv) and DBU(1 equiv) were refluxed together in benzene under nitrogen for 3 h. The reaction became black and formed a thick precipitate. The mixture was cooled to 20 °C and poured onto excess dilute HC1. The layers were separated and the aqueous layer was extracted with ether. The combined organic layers were washed with water and saturated brine and dried (MgS04). The solvent was removed under reduced pressure, and the residual oil was purified by preparative TLC to give as the major, or only aromatic product, the para-substituted aromatic as shown by NMR comparison with known compounds. Compounds 15a and 15b both gave 12a in 100% yields. Compounds 15 g and 15 h gave 14 in 70% and 100% yields, respectively. Compounds 15c and 15d gave 12c in 40% and 100% yields, respectively. Compound 15e gave 12e in 88% yield. Compound 15f gave 12f in undetermined yield (due to the presence of MVK dimer).p-(Phenylseleno)acetophenone (12c). Acetyl chloride (0.13 mL, 1.8 mmol) was added dropwise to a stirring solution of diphenyl selenide (0.41 g, 1.8 mmol) and anhydrous aluminum chloride (0.29 g, 2.2 mmol) in carbon disulfide (5 mL) at 20 °C under nitrogen. There was a violent exothermic reaction, and the mixture was stirred for 1.5 h after the addition was completed. The reaction was quenched by pouring onto water (10 mL) and the layers were separated. The aqueous layer was extracted with ether (2 X 10 mL). The combined organic layers were washed with water (10 mL) and saturated brine (10 mL) and dried (MgS04). The solvent was removed under reduced pressure to yield a yellow oil which was purified by preparative TLC eluting with 10% ethyl acetate/hexane to give 13c (0.14 g, 28%). Recrystallization from 95% EtOH gave yellow crystals: mp 47.5-49 °C.

Strong intermolecular interactions between selenium atoms of adjacent P4Se3 molecules are implied by the results of a recent redetermination of the X-ray structure of P4Se3. The seleniumselenium interactions produce helical chains of P4Se3 molecules directed along the unit cell a and b axes. There are four layers containing a-and ¿-directed helical chains per unit cell. This