Table 2. Synthesis of dihydropyrano[2,3-c]pyrazole derivatives in the presence of Fe₃O₄@BTC NCs.

Entry	Aldehyde	Product	Time (min)	Yield (%)	MP (°C) found	MP (°C) reported
1	C6H5CHO	5a	7	92	240–242	241–243 (ref. 29)
2	2-NO2–C6H4CHO	5b	5	89	220–222	223–225 (ref. 28)
3	3-NO2–C6H4CHO	5c	5	89	237–239	239–242 (ref. 59)
4	4-NO2–C6H4CHO	5d	4	90	192–194	191–193 (ref. 29)
5	2-Cl–C6H4CHO	5e	6	85	260–262	267–268 (ref. 60)
6	4-Cl–C6H4CHO	5f	5	91	225–227	230–232 (ref. 28)
7	2-OH–C6H4CHO	5g	6	90	209–211	210–212 (ref. 61)
8	3-OH–C6H4CHO	5h	8	87	255–257	259–261 (ref. 61)
9	4-OH–C6H4CHO	5i	10	79	210–213	215 (ref. 28)
10	4-OCH3–C6H4CHO	5j	12	80	205–207	206–208 (ref. 29)
11	4-CH3–C6H4CHO	5k	7	85	170–174	174–176 (ref. 29)