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. Author manuscript; available in PMC: 2011 Nov 14.
Published in final edited form as: Tetrahedron Lett. 2009 Jan 14;50(2):212–215. doi: 10.1016/j.tetlet.2008.10.127

Table 1.

Optimization of MAOS conditions to produce 15

graphic file with name nihms-94278-f0004.jpg
Entry T (°C) Solvent Time (min) 15:16a
1 140 HOAc 10 42:58
2 160 HOAc 10 28:72
3 180 HOAc 10 24:76
4 200 HOAc 10 13:87
5 150 50% HOAc/EtOH 10 78:22
6 170 50% HOAc/EtOH 10 64:36
7 150 10% HOAc/EtOH 10 79:21
8 170 10% HOAc/EtOH 10 74:26
9 150 5% HOAc/EtOH 10 85:15
10 170 5% HOAc/EtOH 10 77:23
11 135 5% HOAc/EtOH 20 80:20
12 135 EtOHb 10 –
13 150 5% HCI/EtOHc 10 100:0
a

Ratio determined by analytical LC-MS and 1H NMR; conversion >95%.

b

No product formed without acid catalysis.

c

5% 4 N HCl/dioxane.