Three components coupling catalysed by NaHSO₄.Sio₂ – A convenient synthesis, antibacterial and antifungal activities of novel 6-Aryl-1,2,4,5-tetrazinan-3-ones

Figures & data

Scheme 1 Three components novel ’one-pot’ synthesis of some 6-aryl-1,2,4,5-tetrazinan-3-ones catalyzed by NaHSO₄.SiO₂ in dry ’media’.

Table I.  Physical and analytical properties of 6-aryl-1,2,4,5-tetrazinan-3-ones (1–6).

		Reaction conditions				Elemental analysis (%)
Entry	R	MW (W)/T (°C) Δ	Time MW (s)/Δ (min)	Yield (%) MW/Δ	m.p °C	C Found (calculated)	H Found (calculated)	N Found (calculated)	m/z (M^+.) Molecular formula
1	C6H5	320/75	130/35	75/38	192–194	53.95 (53.93)	5.60 (5.61)	31.50 (31.46)	(179) C8H10N4O
2	p-Cl	320/75	150/38	70/33	180–181	45.16 (45.19)	4.24 (4.27)	16.65 (16.67)	(213) C8H9N4ClO
3	p-F	320/75	165/43	68/30	150–152	48.95 (48.98)	4.65 (4.62)	28.55 (28.56)	(197) C8H9N4FO
4	p-CH3	320/75	140/40	70/35	176–178	58.28 (56.25)	6.22 (6.25)	29.19 (29.16)	(193) C8H12N4O
5	p-OCH3	320/75	155/41	73/37	160–162	51.95 (51.92)	5.26 (5.28)	26.95 (26.92)	(209) C9H12N4O2
6	m-NO2	320/75	180/43	70/30	188–190	43.01 (43.05)	4.04 (4.06)	31.35 (31.38)	(224) C8H9N5O3

Scheme 2 Probable mechanistic pathway for the synthesis of 6-phenyl-2,4,5-tetrazinan-3-one

Figure 1 Numbering of the tetrazinan-3-one ring.

Figure 2 Major isomer.

Figure 3 Minor isomer.

Table II.  In vitro screening of compounds 1–3 against test bacteria and fungi.

	Compound 1			Compound 2			Compound 3
Microorganisms	100 ppm	200 ppm	500 ppm	100 ppm	200 ppm	500 ppm	100 ppm	200 ppm	500 ppm
Staphylococcus aureus	−	++	+++	+	++	+++	−	++	++
β-Haemolytic streptococcus	+	++	++++	+	++	+++	−	++	+++
Vibreo cholerae	+	+	+++	+	++	+++	−	++	+++
Salmonella typhii	+	++	+++	+	++	+++	−	++	+++
Shigella felxneri	+	++	+++	+	++	+++	+	++	+++
Escherichia coli	+	++	+++	+	++	+++	+	++	+++
Klebsiella pneumonia	−	+	+++	+	++	+++	+	++	+++
Pseudomonas	+	++	+++	+	++	+++	−	+	+++
Aspergillus flavus	++	++	+++	+	++	+++	−	++	+++
Mucor	++	++	+++	+	++	+++	−	++	+++
Rhizopus	+	++	+++	+	++	+++	−	++	+++
Microsporum gypsuem	+	++	+++	+	++	+++	−	++	+++

( − ) = inactive, (+) = weakly active (12–16 mm), (+)(+) = moderately active (17–21 mm), (+)(+)(+) = strong active (22–29), (+)(+)(+)(+) = highly active (30–33).

Table III.  In vitro screening of compounds 4–6 against test bacteria and fungi.

	Compound 4			Compound 5			Compound 6
Microorganisms	100 ppm	200 ppm	500 ppm	100 ppm	200 ppm	500 ppm	100 ppm	200 ppm	500 ppm
Staphylococcus aureus	++	++	+++	+	+++	+++	−	++	+++
β-Heamolytic streptococcus	++	++	+++	−	+++	+++	+	++	+++
Vibreo cholerae	−	+	+++	−	+++	+++	−	+	+++
Salmonella typhii	−	+	+++	−	+++	+++	−	++	+++
Shigella felxneri	−	++	+++	+	+++	+++	+	++	+++
Escherichia coli	−	++	+++	−	+++	+++	−	+	+++
Klebsiella pneumonia	+	+++	+++	−	+++	+++	+	++	+++
Pseudomonas	+	+	+++	+	++++	++++	+	++	+++
Aspergillus flavus	++	++	+++	+	++++	++++	+	++	+++
Mucor	++	++	+++	+	+++	+++	−	++	+++
Rhizopus	+	++	+++	+	+++	+++	+	++	+++
Microsporum gypsuem	++	++	+++	+	+++	+++	+	++	+++