**5. Miscellaneous**

Substituted 2-aminothiazoles were prepared in water through a highly efficient and facile synthesis, without the use of a catalyst or co-organic solvent. The reaction was carried out at ambient temperature and the products were obtained in excellent yields. The developed protocol is successfully utilised for the preparation of an antiinflammatory drug, fanetizole (**Figure 15**) [23].

A new and facile protocol for the synthesis of 2-amino-1,3,4-thiadiazoles in water by the reaction of acid hydrazides with dithiocarbamates in moderate to excellent yields (**Figure 16**) [24].

The reaction between TosMIC **63** and benzaldehyde **64** was carried out in the presence of various amounts of Et3N and β-CD (β-Cyclodextrin) at 50°C in water (**Figure 17**). The simple procedure, relatively short reaction times, easy workup and high yields are

*Synthesis of Five-Membered Heterocycles Using Water as a Solvent DOI: http://dx.doi.org/10.5772/intechopen.108929*

**Figure 15.**

*Synthesis of substituted 2-aminothiazoles in water.*

**Figure 16.** *Synthesis of 2-amino-1, 3, 4-thiadiazoles.*

**Figure 17.**

*Green method for the Van Leusen synthesis of oxazoles.*

the reasons that promote the use of β-CD/water as an inexpensive and environmentally benign catalyst for the synthesis of differently substituted oxazoles [25, 26].
