Synthesis of [Carbonyl‐¹⁴c] labeled carbonate and carbamate esters

Abstract

A two-step s y n t h e s i s of t h r e e carbonate and f o u r carbamate esters l a b e l e d a t t h e carbonyl with c a r n-14 i s described. The method u t i l i z e s t h e r e a d i l y a v a i l a b l e [' %I -phosgene which i s f i r s t converted t o an i s o l a b l e [14C] -labeled a l k y l o r a r y l chloroformate and subsequently r e a c t e d with t h e a p p r o p r i a t e a l c o h o l o r amine t o give t h e corresponding ester.Synthesis of [Carbonyl-"C] Labeled Carbonate and Carbamate 675 with carbon-14. procedures (9) is not limited by the availability of the [l4C1labeled isocyanates. formate intermediate is isolable, asymmetric carbonates can be easily prepared. This method unlike previously reported Furthermore since the [ l4C1 -labeled chloro-

Synthesis of 2‐Arylquinazolin‐4(3H)‐ones by N‐Aryl Benzamidines with Aromatic Carbonates

“…Ethyl phenyl carbonate was prepared by modifying the literature procedure [8]. Toluene solution containing phenol (0.39 mol) and pyridine (0.26 mol) was added into ethyl chloroformate (0.26 mol) and dissolved with toluene at room temperature.…”

“…2-(4-Methoxyphenyl)quinazolin-4(3H)-one (3g) [8,9]. The product was obtained as colorless powder, synthesized by the reaction of N-phenyl-4-methoxybenzamidine 1g (10 mmol) and diphenyl carbonate 2a (10 mmol) in triglyme (20 mL); 83.7% yield; mp 240-242 C; 1 H NMR: ,4.79;N,11.10.…”