Akira Ujiie

[18F]fluoride production with a circulating [18O]water target

Abstract [ 18 F]fluoride was produced via the 18 O(p,n) 18 F reaction with a circulating 20% enriched [ 18 O]water target. Parameters affecting the production yield of [ 18 F]fluoride such as beam current, beam profile, irradiation time, target thickness, circulation rate, and window material were investigated and optimized. With a 20 μA irradiation of 2.5 mL [ 18 O]water circulated at a flow rate of over 35 mL/min, a [ 18 F]fluoride yield of more than 70% was obtained when the beam was defocussed and wobbled to get a uniform beam profile. In addition, radiolytically produced gases were recombined using a Pd catalyst into the target.

Comparative study of specific activity of [11C]methyl iodide: A search for the source of carrier carbon

Abstract Any no-carrier-added 11 C-compounds prepared from [ 11 C]CH 3 I seem to coexist with at least about 0.2 μmol of its non-radioactive form (carrier). In order to elucidate the source of the carrier, 11 C]CH 3 I prepared under various conditions was converted into several 11 C-compounds and their specific activities were measured by high performance liquid chromatography. Carbon contamination of LiAlH 4 was also examined by gas chromatography. It was shown that only a negligible amount of CO 2 was brought with the irradiated target N 2 gas and that the carrier amount decreased remarkably with the reduction of the amount and concentration of the LiAlH 4 THF solution but not to less than 0.2 μmol. The use of Et 2 O or Pr 2 O instead of THF was found to give EtOH or PrOH, respectively, together with MeOH, all in small amounts. Hence, the 0.2 μmol carrier can be regarded as being originated in MeOH formed from a trace of THF remaining in the LiALH 4 after its drying step.

Characteristics of specific in vivo labeling of neuroleptic binding sites with 3-N-[11C] methylspiperone

In vivo binding of 3-N-[11C]methylspiperone ([11C]NMSP) was saturable in the rat forebrain, but not in the cerebellum. Nonspecific binding was almost equivalent in all brain regions except for the white matter. [11C]NMSP binding was localized to receptor-rich fractions when low doses were administered (less than 20 nmol/kg body weight). The striatum-to-cerebellum ratio was a function of time after injection and administered dose. This radio remained constant in low doses of under 30 nmol/kg. The radioactivity curve of the cerebellum in a control positron-emission tomographic study almost equaled that of the striatum in the dog pretreated with spiperone (2 mg). This indicates that the amount of binding in the cerebellum might be considered a nonspecific binding and unbound pool. The data obtained by the pretreatment study was different from that of displacement, which suggested that displaceable [11C]NMSP in the specific binding sites of the striatum was not completely cleared from the brain tissue by a large amount of unlabeled spiperone.

Total synthesis of (±)-mecambridine (1,10,11-trimethoxy-2,3-methylenedioxyberbin-12-ylmethanol)

Hydroxymethylation of 1,10-dimethoxy-2,3-methylenedioxyberbin-11-ol (5), followed by O-methylation, gave (±)-mecambridine (2), thus confirming the suggested structure of the latter.

Studies on the syntheses of heterocyclic compounds. Part DCXX. Total synthesis of (±)-orientalidine and a positional isomer

The total synthesis of (±)-orientalidine (2) was accomplished by treatment of (±)-demethylmecambridine (3) with methylene chloride and sodium hydride in dimethylformamide. 11-Hydroxy-12-hydroxymethyl-3,10-dimethoxy-1,2-methylenedioxyberbine (16) was synthesised from 1-(3-benzyloxy-4-methoxybenzyl)-1,2,3,4-tetrahydro-6-methoxy-7,8-methylenedioxyisoquinoline (11) by way of 11-benzyloxy-3,10-dimethoxy-1,2-methylenedioxyberberine (12) and the corresponding phenolic base (15). Treatment of the hydroxymethylated berbines (5) and (16) under the same conditions as for the synthesis of orientalidine gave the corresponding berbines (6) and (18) containing a fused m-dioxin system.

Studies on the syntheses of heterocyclic compounds. Part 683. Stevens rearrangement of berbine methiodides by sodium bis-(2-methoxyethoxy)aluminium hydride

Refluxing berbine methiodides with sodium bis-(2-methoxyethoxy)aluminium hydride in dioxan resulted in Stevens rearrangements to afford spirobenzylisoquinolines and 8-methylberbines. The stereochemistry at the migrating carbon atom and the relationship between the configuration of the starting quinolizidinium salts and the products have been studied.

Studies on the alkaloids of formosan Corydalis species. Part VI. Elucidation of the structures of two spirobenzylisoquinoline alkaloids, yenhusomine and yenhusomidine, and two berbine alkaloids, corytenchine and corytenchirine, from Corydalis ochotensis(turcz.)

Separation of the basic fraction from Corydalis ochotensis(Turcz.) afforded four new alkaloids [yenhusomine (5), yenhusomidine (9), corytenchine (12), and corytenchirine (21)] together with the known alkaloids, protopine, ochotensimine, and adlumidine. The identification of the new alkaloids is described. Didehydrocheilantifoline was also isolated, from a quaternary base fraction.