Table 1.

Synthesis of the macrocyclic tetrazoles^[a].

entry	base	product	yield (%)[b]
1	LiOH•H2O		trace
2	Na2CO3		<5[c]
3	K2CO3		<30[c]
4	Cs2CO3		38
5	LiOH•H2O		trace
6	Na2CO3		trace
7	K2CO3		51
8	Cs2CO3		78
9	LiOH•H2O		trace
10	Na2CO3		trace
11	K2CO3		<35[c]
12	Cs2CO3		45
13	LiOH•H2O		trace
14	Na2CO3		trace
15	K2CO3		<60[c]
16	Cs2CO3		67
17	LiOH•H2O		trace
18	Na2CO3		trace
19	K2CO3		<50[c]
20	Cs2CO3		61
21	LiOH•H2O		trace
22	Na2CO3		70
23	K2CO3		<20[c]
24	Cs2CO3		trace

^[a]For bis-O-alkylation, reactions were carried out by refluxing tetrazole 1 with 1.1 equiv of dibromide and 3 equiv of base in acetone overnight. For intramolecular O-alkylation, tetrazole 8 was refluxed in acetonitrile with 3 equiv of base.

^[b]Isolated yields were reported unless noted otherwise.

^[c]Estimated yields based on TLC.