Microwave-Assisted Synthesis of Spirofused Heterocycles Using Decatungstodivanadogermanic Heteropoly Acid as a Novel and Reusable Heterogeneous Catalyst under Solvent-Free Conditions

Table 2

H₆GeW₁₀V₂O₄₀·22H₂O catalyzed synthesis of spiroheterobicyclic rings 1(a-l).

Entry	X–Z–X	G	Product	Yield (%)	M.P. (°C)
1	O–C(Me)2–O	H	1a	80	223–225
2	O–C(Me)2–O	Me	1b	68	199-200
3	O–C(Me)2–O	Cl	1c	66	204–206
4	O–C(Me)2–O	F	1d	67	216–218
5	HN–CO–NH	H	1e	87	240–242
6	HN–CO–NH	Me	1f	84	246–248
7	HN–CO–NH	Cl	1g	82	291–293
8	HN–CO–NH	F	1h	77	213–215
9	MeN–CO–NMe	H	1i	83	232–234
10	MeN–CO–NMe	Me	1j	85	228–230
11	MeN–CO–NMe	Cl	1k	77	271–273
12	MeN–CO–NMe	F	1l	75	244–246