THE SYNTHESIS OF 5-[1-C-11]ETHYL BARBITURATES FROM LABELED MALONIC ESTERS

TY - JOUR

T1 - THE SYNTHESIS OF 5-[1-C-11]ETHYL BARBITURATES FROM LABELED MALONIC ESTERS

AU - GEE, A

AU - LANGSTROM, B

PY - 1991

Y1 - 1991

N2 - The synthesis of [C-11]phenobarbital (3a), [C-11]pentobarbital (3b) and [C-11]amobarbital (3c) labelled in the 5-[1-C-11]ethyl position is reported. The malonic esters R-CH(CO2Et)2 [R = phenyl- (1a), 1-methylbutyl- (1b), and 3-methylbutyl- (1c)] were alkylated with [1-C-11]ethyl iodide prepared from [C-11]carbon dioxide. Ring closure of the 2-[1-C-11]ethyl-labelled malonic esters (2a-c) with urea afforded 5-[1-C-11]ethyl-3a-c in synthesis times of 42-47 min, counted from [C-11]carbon dioxide. In typical syntheses starting with 3 GBq (81 mCi) [C-11]carbon dioxide, 150-215 MBq (4-6 mCi 3a-c were produced in 25-30% decay corrected radiochemical yields with radiochemical purities greater than 98%.

AB - The synthesis of [C-11]phenobarbital (3a), [C-11]pentobarbital (3b) and [C-11]amobarbital (3c) labelled in the 5-[1-C-11]ethyl position is reported. The malonic esters R-CH(CO2Et)2 [R = phenyl- (1a), 1-methylbutyl- (1b), and 3-methylbutyl- (1c)] were alkylated with [1-C-11]ethyl iodide prepared from [C-11]carbon dioxide. Ring closure of the 2-[1-C-11]ethyl-labelled malonic esters (2a-c) with urea afforded 5-[1-C-11]ethyl-3a-c in synthesis times of 42-47 min, counted from [C-11]carbon dioxide. In typical syntheses starting with 3 GBq (81 mCi) [C-11]carbon dioxide, 150-215 MBq (4-6 mCi 3a-c were produced in 25-30% decay corrected radiochemical yields with radiochemical purities greater than 98%.

U2 - 10.1016/0883-2889(91)90196-8

DO - 10.1016/0883-2889(91)90196-8

M3 - Article

SN - 0969-8043

VL - 42

SP - 1195

EP - 1198

JO - Applied Radiation and Isotopes

JF - Applied Radiation and Isotopes

IS - 12

ER -