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A procedure is described that permits the preparation of [18F]haloperidol in 140 min at specific activities ranging from 4-5 muCi mg-1. A key step in the synthetic route involves the incorporation of 18F into the molecule through a Schiemann-type reaction, which involves the pyrolysis of the diazonium tetrafluoroborate salt of 4-[4-(p-chlorophenyl)-4-hydroxypiperidino]-4'-aminobutyrophenone.

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l-Phenyl-2-arylcyclopropanols. These compounds were prepared from the corresponding acetates by reaction with methyllithium and work-up in boric acid solution as previously described.16 The alcohols are air and base sensitive, and must be stored in polyethylene bottles in the freezer. Their melting points tended to vary depending upon their method of recrystallization, and were broad in range.cis-l,2-Diphenycyclopropanol had mp 79-82.5°( hexaneether), nmr (CDCI3) 1.65 (m, 2 ), 2.21 (s, 1 H, OH), 2.49 (dd, 1 H), 7.33 (d, 10 H). trans-l-2-Diphenylcyclopropanol had mp 96.5-99°(hexaneether), nmr (CDCI3) 1.65 (m, 2 H), 2.53 (s, 1 H), 2.77 (dd, 1 H), 7.03, 7.18 (m, 10H).trans-l-Phenyl-2-(4-methylphenyl)cyclopropanol had mp 75-77°.Kinetic Procedures. Kinetics were run in 60:40 v/v dioxanewater with either perchloric acid or sulfuric acid as catalyst, or in 95% ethanol with NaOH as catalyst. For the acid-catalyzed reactions an appropriate amount of the alcohol or acetate (0.01-0.03 g) was accurately weighted into a 100-ml volumetric flask and the flask was allowed to equilibrate with the constant-temperature bath for 2 min. The flask was then filled to the mark with the acid solution, which was already at thermal equilibrium with the bath.

Maleic hydrazide (MH) has been pyrolysed at 600°C in our controlled pyrolysis apparatus. During pyrolysis volatile compounds distil out ahead of the moving heated zone and are not extensively repyrolysed, while those substances which are absorbed by pyrolysand or are relatively nonvolatile are repyrolysed. Also, reactive intermediates can react with one another or with unpyrolysed material. Pyrolysis products determined include CO2 (24 wt%), CO (2 wt%), HCN (3 wt%), NH3 (9 wt%) and N2 (3 wt%). The gases identified account for 41 % of the maleic hydrazide pyrolysed. An additional 50% of the material pyrolysed remains as a black solid having the approximate composition C15H15N5O2. Approximately 1 % of the maleic hydrazide is unchanged. Thus, the fate of 92% of the maleic hydrazide can be accounted for. A trace amount of hydrazine could be detected. The results obtained using controlled pyrolysis are compared with results obtained by us and others using different pyrolytic conditions.