Explain why oxazole is a weaker base than thiazole. ... The oxygen atom of oxazole decreases the electron density at the nitrogen atom by an inductive effect. Thus, the oxazole is a weaker base than thiazole. Sulfur is less electronegative than oxygen and inductively is a weaker electron withdrawing atom.

Why is imidazole the most basic?

Imidazole is an aromatic ring found in many biological molecules. One of its nitrogen atoms resembles that of pyrrole, and is not basic. ... However, imidazole is about 100 times more basic than pyridine. The increased basicity results from resonance stabilization of the positive charge of the conjugate acid.

Why is imidazole less basic than pyridine?

(ii) There are two nitrogen atoms in imidazole, one is pyrrole-like and the other is pyridine-like (see above). ... For this reason the sp2 lone pair of electrons on nitrogen in pyridine (~33% s- character) are less basic than the sp3 lone pair of electrons in triethylamine (~25% s-character, pKa 11).