RadiosynthesisRadiosynthesis and and Bioconjugation of [Bioconjugation of [1818F]FPy5yneF]FPy5yne

A prosthetic group for the A prosthetic group for the 1818F labeling of F labeling of bioactive peptidesbioactive peptides

James Inkster, James Inkster, MScMSc..TRIUMFTRIUMF

N 18F

O

The ‘Click’ Reactions: Efficient, The ‘Click’ Reactions: Efficient, Specific (and PETSpecific (and PET--friendly)friendly)

CycloadditionsCycloadditions of of unsaturated speciesunsaturated species

NucleophilicNucleophilicsubstitutionssubstitutions

NonNon--aldolaldol carbonyl carbonyl chemistrychemistry

Additions to CAdditions to C--C C multiple bondsmultiple bonds

1,31,3--dipolar dipolar cycloadditionscycloadditions, certain , certain DielsDiels--AlderAlderepoxideepoxide, , aziridineaziridineopening reactionsopening reactions

oximesoximes, hydrazones, , hydrazones, thioureasthioureas

EpoxidationsEpoxidations, , dihydroxylationsdihydroxylations, , certain certain MichealMicheal rxrx..

Kolb, HC; Finn, MG; Sharpless, KB. Angew. Chem. Int. Ed. (2001) 40, 2004.

1818FF--based based HuisgenHuisgen [3+2] [3+2] cycloadditioncycloaddition prosthetic groups prosthetic groups

18F

18FO

OO

N318F

18F

O

NH

(2)

(1)

(3)

(4)

(1) Marik and Sutcliffe, Tet. Lett. (2006) 47, 6681.(2) Li et al. Bioconjugate Chem. (2007) 18, 1987.(3) Glaser and Arstad, Bioconjugate Chem. (2007) 18, 989.(4) Ramenda et al. Lett. Drug Des. Discovery (2007) 4, 279.

NucleophilicNucleophilic HeteroaromaticHeteroaromatic[[1818F]FluorinationsF]Fluorinations

N

ONH

O

Br

18F N

O N

18F

O

O

[18F]FPyME2[18F]FPyBrA1

HN

N

18F

[18F]NFEP3

NH

O

N18F

2-[18F]-A-853804

1Kuhnast et al. Bioconjugate Chem. (2004) 15, 617.2de Bruin et al. Bioconjugate Chem. (2005) 16, 406.3Ding et al. Synapse (1996) 24, 403.4Ding et al. Nucl. Med. Biol. (2000) 27, 381.

Cold Chemistry 1Cold Chemistry 1

N

OH

NO2 N

O

NO2

N

O

F

NaH6-chloro-1-hexyne

DMF, 60oC, 75%

2

1M TBAF

THF:DMF, 80oC77%

1, FPy5yne

Cold Chemistry 2Cold Chemistry 2

N

OH

NH2N

OH

N

N

O

NN

O

N

37% CH2OaqNaCNBH3, AcOH

52%

NaH6-chloro-1-hexyne

DMF, 70oC, 73%

MeOTf

toluene, 0oC-RT95%

OTf

Preparation of [Preparation of [1818F]FPyr5yneF]FPyr5yne

N

O

X N

O

18FDMSO or MeCN110οC, 15 minX = NO2, [NMe3][OTf]

K[18F]F-K222

Efficient, OneEfficient, One--Step Step RadiosynthesesRadiosyntheses

N

O

NO2

N

O

N O

S

O

-O CF3

RCY: 89%±1.6%, RCY: 89%±1.6%, nn=3=3

In DMSO 110ºC, 15 min

RCY: 90,93% RCY: 90,93% nn=2=2

In MeCN, 110ºC, 15 min

[[1818F]FPy5yne Reaction MixturesF]FPy5yne Reaction Mixtures

From NO2From NMe3OTf UV

Rad

ProsProsExcellent Excellent 1818F F incorporationsincorporationsOneOne--step step preparationspreparationsArylAryl--[[1818F]fluorine F]fluorine imaging agentimaging agent

ConsConsVolatile product Volatile product (57(57--58ºC)58ºC)NMeNMe22 side product side product necessitates HPLCnecessitates HPLC

UV

Rad

[18/19F]FPy5yne Co-injection

1818FF--Peptide Preparation Peptide Preparation viaviaAzide/alkyneAzide/alkyne [3+2] [3+2] CycloadditionCycloaddition

N3

O

HN

O

OH

NH

NH2

O

HN

O

NH

NH

HN NH2

O

OH

BG142

[18F]FPy5yneCu(MeCN)4PF6TBTA, DIEA

2:1 PBS:DMF37οC, 10 min.

N

O

HN

O

OH

NH

NH2

O

HN

O

NH

NH

HN NH2

O

OH

NN

NF

18F-BG142

O

1818FF--BG142: 90BG142: 90--100% RCY by 100% RCY by radioHPLCradioHPLCBest collected Best collected yield: 5.8% yield: 5.8% (18.7% decay(18.7% decay--corrected) from corrected) from EOBEOB

[18/19F]F-BG142 Reaction Mixture

[18/19F]F-BG142 Co-injection

SM volatility + two SM volatility + two HPLCsHPLCs = Relatively = Relatively low collected yieldslow collected yields

long synthesis time long synthesis time (160 min.)(160 min.)

Optimization Optimization continuescontinues

Distillation?Distillation?

UV

Rad