Ultrasound-assisted green synthesis and antimicrobial assessment of 1,3-thiazoles and 1,3,4-thiadiazines

Figures & data

Figure 1. The growth inhibition zones of the newly synthesized compounds against Escherichia coli, staphylococcus aureus, Candida albicans and Aspergillus niger.

Scheme 1. Mechanism of formation of thicarbohydrazones 3a,b.

Scheme 2. Synthesis of 1,3-thiazole 4 and 1,3-thiazolinone 5.

Scheme 3. Synthesis of 1,3,4-thiadiazine and phthalazine derivativies.

Scheme 4. Synthesis of 1,3,4-thiadiazines.

Table 1. In vitro antimicrobial activities of the newly synthesized compounds against pathogenic bacteria and fungi.

Sample name	Growth inhibition zone (ϕmm)
	S. aureus	E. coli	C. albicans	A. niger
3a	33	31	35	38
3b	29	27	32	36
4	15	32	14	35
5	22	14	24	25
6	0	0	0	28
7a	0	0	0	0
7b	16	0	18	16
8	32	23	31	30
10	23	22	21	35
11a	22	0	22	25
11b	18	0	13	21
11c	25	21	24	35
Neomycin	37	30	39	0
Cyclohexamide	0	0	0	39

Figure 2. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of promised compounds from the cup diffusion method 3a, 3b, 4, 5, 8, 10, 11a, and 11c against S. aureus (G+ve bacteria) and E. coli (G−ve bacteria).

Table 2. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of the promised compounds against S. aureus (G+ve bacteria) and E. coli (G−ve bacteria).

Sample	Staphylococcus aureus		Escherichia coli
	MIC (µg/ml)	MBC (µg/ml)	MIC (µg/ml)	MBC (µg/ml)
3a	39.06	78.13	156.25	156.25
3b	78.13	31.5	156.25	625.00
4	312.00	625	312.50	625.00
5	312.00	625	312.50	312.50
8	39.06	39.06	156.25	312.50
10	9.77	19.06	625.00	1250.00
11a	39.06	78.13	625.00	625.00
11c	19.06	39.06	312.50	625.00