M. R. Grimmett 
Imidazole and Benzimidazole Synthesis [PDF ebook] 

Imidazole and Benzimidazole Synthesis is a comprehensive survey of the known methods of syntheses and ring modification. It brings together the multitude of synthesis of the imidazole ring in a systemic way interms of specific bond formation, and recommends the most attractive synthetic approaches. It also collects non-ring-synthetic approaches to classes of compounds such as nitro-, halogeno-, and amino-imidazoles, and covers the synthesis of N-substituted compounds and preparations of specific isomers. — The only book in print dealing specifically with this topic- Comprehensive survey of the known methods of synthesis and ring modification- Recommends the most attractive synthetic approaches