# Comparing basic strengths between pyridine and 1,2-dihydropyrazine

Compare the basic strengths of above two compounds.

In the first compound (1,2-dihydropyrazine), the lone pair of one N will participate in resonance but the lone pair of other N will not, similarly in pyridine, lone pair will not participate in resonance. I think that since the first compound atleast has $$2$$ nitrogens (and only one in pyridine), it should be slightly more basic than pyridine, but I came to know that it's the other way round. So how do we compare their basic strengths and what are their $$\mathrm{p}K_\mathrm{b}$$ values?

• The additional nitrogen in 1,2-dihydropyrazine rather pulls the electrons towards itself since it is a electronegative atom causing decrease in basic nature. – Desai Jan 6 at 21:31
• pKb(pyridine) = 8.77 at 25°C [CRC HANDBOOK for Physics & Chemistry; 2004 - Edition 8] – Desai Jan 6 at 21:36
• Related : alfa.com/en/pyrazines/?page=2 – Desai Jan 6 at 21:43