Regioselective deuteration kinetics of 2,3,6-trimethyl-4-phenylpyrylium and 2,6-dimethyl-3,4-diphenylpyrylium salts (1)

✍ Scribed by Alexandru T. Balaban; Teodor Silviu Balaban; Cornelia Uncuta; Mircea D. Gheorghiu; Filip Chiraleu

• Publisher: John Wiley and Sons
• Year: 1983
• Tongue: French
• Weight: 400 KB
• Volume: 20
• Category: Article
• ISSN: 0022-2135
• DOI: 10.1002/jlcr.2580200908

✦ Synopsis

a b Alexandru T. Baaban,-Teodor S i l v i u Balaban,' Cornelia Uncuta,a b Mircea D. Gheorghiu,-and F i l i p Chiraleu -

a Polytechnic I n s t i t u t e , Organic Chemistry Department, S p l a i u l Independentei 31 3, 76206 Bucharest, Roumania a Center for Organic Chemistry -ICECHIM. Bucharest, Roumania SUMMARY The d e u t e r a t i o n o f 2,3,6-trimethyl-4-phenylpyrylium salts i n D20 D3CCN i n d i c a t e s t h a t t h e 2-methyl group i s deuterated 3.3 times f a s t e r than t h e 6-methyl group. The H-NMR assignment i s based on an unambiguous s y n t h e s i s o f t h e 2-CD congener : similar assignments were made for 2,3,6-trimethyl-4-phenylpyridine, and lanthanide-induced s h i f t s were determined. The d e u t e r a t i o n of 2,6-dimethyl-3,4-diphenylpyrylium p e r c h l o r a t e i n anhydrous HCOOD + NaOOCH ( t h e assignment i n 'H-NMR s p e c t r a is s t r a i g h t f o r w a r d owing t o t h e s h i e l d i n g o f 2-methyl protons by t h e neighbouring orthogonal phenyl group) i n d i c a t e s s i m i l a r l y t h a t t h e 2-methyl group i s deuterated 3.