for 1 h, the temperature is allowed to rise to 20°C, and the product is worked up with CH2C12, dried over Na2S04, and concentrated in a rotary evaporator. The crude product is treated with methyl iodide (1.9m1, 30mmol) and refluxed (60°C) for 16h. Excess methyl iodide is removed in a rotary evaporator and the residual oil stirred vigorously with 3 N HCl(40 ml)/n-pentane (200ml) for 30 min. The organic phase is separated off, dried over Na2S04, and carefully evaporated down. Molecular distillation over quartz wool [130-140°C (oil-

The search for new organic conductors has led to a broadly variable class consisting of the radical anion salts of naphthalenetetracarboxylic dianhydride and diimide. The X‐ray structure analysis of the complex 1 (single crystal conductivity σ20°C = 10 S cm−1) revealed a stacking of anionic units characteristic of one‐dimensional conductors.

No abstract

SummaryUreas of type 3 with sterically protected carbonyl groups such as 4a-7a are prepared by successively adding 2 equivalents of a highly substituted sec. amine and an excess of dimethylamine to benzene or toluene solutions of phosgene. The piperidine derivatives 6a and 7a are metalated in high yields to 6b and 7b, respectively, with sec.-butyllithium/TMEDA in THF at 0" [see derivatives 6, 7 (c-i) in Table 11. Methods of cleaving urethanes 2 (see 8 4 9 ) and ureas 3 are described, among which the retro-Mannich reaction, removing the piperidine ring from 7 under acidic hydrolysis conditions, appears to be promising also for other applications of sterically blocked carbonyl compounds in organic synthesis.In previous papers we have shown that imides [ l ] and amides with sterically protected but electronically effective carbonyl groups such as triphenyl-acetamides Part of the planned dissertation of T.H., Universitat Giessen.

5] The cubic unit cell of these crystals contains eight heterocubane and six cyclohexane molecules: P?3n, a = 1873(1) pm; 717 independent reflections, solution of structure with MULTAN program, R=0.051. Given adequate steric protection['] of the carbonyl group of amides such as ( I ) , it proves possible to accomplish their deprotonation at the a-N-CH3 and --CH2 groups with 234"CI.( 4 ) --t ( 5 ) .