Synthesis and Evaluation of Substituted 4,4a-Dihydro-3H,10H-pyrano[4,3-b][1]benzopyran-10-one as Antimicrobial Agent

Table 1

Reaction time (h) and yield (%) of various purified products.

Sr. number	𝑅1	𝑅2	𝑅3	𝑋	Reaction time (h)	Products yield (%)
						endo	exo
1	H	H	H	O-^iBu	72	7a (77)	8a (traces)
2	H	H	CH3	O-^iBu	72	7b (70)	8b (traces)
3	Cl	H	Cl	O-^iBu	36	7c (74)	8c (traces)
4	H	H	Cl	O-^iBu	24	7d (72)	8d (traces)
5	H	Cl	F	O-^iBu	36	7e (78)	8e (traces)
6	H	H	Br	O-^iBu	24	7f (71)	8f (traces)
7	H	Br	H	O-^iBu	48	7g (73)	8g (traces)
8	H	F	H	O-^iBu	48	7h (70)	8h (traces)
9	H	H	F	O-^iBu	72	7i (72)	8i (traces)
10	H	Cl	H	O-^iBu	48	7j (73)	8j (traces)
11	H	H	H	OEt	168	7k (75)	8k (traces)
12	H	H	CH3	OEt	96	7l (72)	8l (traces)
13	Cl	H	Cl	OEt	216	7m (73)	8m (traces)
14	H	H	Cl	OEt	192	7n (76)	8n (traces)
15	H	H	F	OEt	72	7o (72)	8o (traces)
16	H	H	Br	OEt	48	7p (74)	8p (traces)
17	H	Br	H	OEt	96	7q (75)	8q (traces)
18	H	F	H	OEt	120	7r (76)	8r (traces)
19	H	Cl	F	OEt	96	7s (74)	8s (traces)
20	H	Cl	H	OEt	72	7t (72)	8t (traces)