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. 2013 Sep 19;9:1899–1906. doi: 10.3762/bjoc.9.224

Table 1.

Calculated energy of the ground state of 3-acyltetramic acids 10a,b, 3-carboxamide tetramic acids 11a,b and 3-alkoxycarbonyl tetramic acids 12a,b.

graphic file with name Beilstein_J_Org_Chem-09-1899-i001.jpg
Entry Compound Calcd relative energy (kcal/mol)a,b
Form A Form B Form C Form D
1 10a +4.16 +1.61 +4.30 0
2 10bc +1.59 +0.17 +5.62 0
3 11a −0.51 +0.42 +1.74 0
4 11b −0.91 −0.15 +3.82 0
5 12a −3.58 +1.75 −1.41 0
6 12b −6.24 −0.64 +3.20 0

aThe energy difference between each tautomer related to tautomer D. bCalculated by using DFT B3LYP (6-31G*) in Spartan 02. cReported in our previous paper [10].