Table 5. One-Pot Synthesis of 4H-Pyran Derivatives in Refluxing Ethanol.

entry	aldehyde	1,3-dicarbonyl	product	time (min)	yield (%)	mp (°C)	lit. mp (°C)
1	4-chlrobenzaldehyde	3	10a	60	90	172–174	174–17527
2	4-nitrobenzaldehyde	3	10b	60	92	182–186	183–18527
3	4-methylbenzaldehyde	3	10c	95	82	175–177	177–17927
4	4-methoxybenzaldehyde	3	10d	110	78	135–137	136–13727
5	3-nitrobenzaldehyde	3	10e	15	95	199–202	198–20027
6	4-chlrobenzaldehyde	4	10f	15	92	214–216	215–21628
7	4-cyanobenzaldehyde	4	10g	20	90	229–231	228–22927
8	3-nitrobenzaldehyde	4	10h	20	90	216–218	214–21629
9	4-methoxybenzaldehyde	4	10i	50	85	200–203	201–20227
10	furfural	4	10j	90	80	221–224	221–22430
11	4-chlrobenzaldehyde	5	10k	20	91	222–225	223–22630
12	4-cyanobenzaldehyde	5	10l	30	90	237–238	235–23731
13	3-nitrobenzaldehyde	5	10m	35	89	197–200	200–20220
14	4-methoxybenzaldehyde	5	10n	90	83	206–209	207–20932
15	furfural	5	10o	85	81	236–239	237–23930
16	thiophene-2-carbaldehyde	5	10p	40	96	223–224	223–22542
17	4-chlrobenzaldehyde	8	10q	25	90	232–236	234–23629
18	2-nitrobenzaldehyde	8	10r	30	91	257–258	255–25729
19	benzaldehyde	8	10s	40	88	208–210	209–21034
20	4-methylbenzaldehyde	8	10t	50	85	228–230	226–22734
21	4-methoxybenzaldehyde	8	10u	65	89	282–283	280–28134