. 2023 Dec 9;28(1):273–280. doi: 10.1021/acs.oprd.3c00353

Table 1. Direct Amidation of Diamine with (R)-Pantalactone^a.

graphic file with name op3c00353_0006.jpg

					HPLC (area %)^b		HILIC (area % ratio)^c
entry	solvent	volume (V)	base	T (h)	13	11 + 12	11:12
1	EtOH	10	Na₂CO₃	3	8	52	89:11
2	MeOH	10	Na₂CO₃	3	4	82	90:10
3	IPA	10	Na₂CO₃	72	8	41	90:10
4	THF	10	Na₂CO₃	3	--^e	--	--
5	CH₃CN	10	Na₂CO₃	3	--^e	--	--
6	DMF	10	Na₂CO₃	3	--^e	--	--
7	DMSO	10	Na₂CO₃	3	--^e	--	--
8	IPA/H₂O (7:3)^d	10	Na₂CO₃	3	5	86	91:09
9	IPA/H₂O (7:3)	5	Na₂CO₃	3	7	84	90:10
10	IPA/H₂O (7:3)	20	Na₂CO₃	3	6	84	92:08
11	IPA/H₂O (7:3)	10	Et₃N	3	6	88	91:09
12	IPA/H₂O (7:3)	10	NaHCO₃	3	--^e	--	--
13	IPA/H₂O (7:3)	10	NaOCH₃	6	45	55	90:10
14	IPA/H₂O (9:1)	10	Na₂CO₃	3	4	86	90:10
15^f	IPA/H₂O (9:1)	10	Na₂CO₃	6	11	86	90:10
16^g	IPA/H₂O (9:1)	10	Na₂CO₃	6	5	81	90:10
17^h	IPA/H₂O (9:1)	10	Na₂CO₃	6	6	83	90:10

All reactions were carried out with (S)-propane-1,2-diamine dihydrochloride 10 (1.0 g 1.0 equiv), (R)-3-hydroxy-4,4-dimethyldihydrofuran-2(3H)-one 4 (1.0 equiv), base (3,0 equiv), 25 °C, 10 V of solvent, unless otherwise stated.

LCAP at 210 nm.

HILIC ratio at 210 nm.

IPA: i-PrOH.

No reaction.

Reaction was carried out at 0 °C.

(2.0 equiv) of Na₂CO₃ was used.

(2.5 equiv) of Na₂CO₃ was used.

Table 1. Direct Amidation of Diamine with (R)-Pantalactonea.

Table 1. Direct Amidation of Diamine with (R)-Pantalactone^a.