Lipase-Mediated Dynamic Kinetic Resolution of 1-Phenylethanol Using Niobium Salts as Racemization Agents

Higa, Vanessa M.; Rocha, Willian S.; Sairre, Mirela Inês de; Omori, Álvaro T.

doi:10.21577/0103-5053.20210086

Acessibilidade / Reportar erro

Brasil

Journal of the Brazilian Chemical Society

Español English

Brasil

Español English

sumário « anterior atual seguinte »

Sumário

Article • J. Braz. Chem. Soc. 32 (10) • Oct 2021 • https://doi.org/10.21577/0103-5053.20210086 copy

Lipase-Mediated Dynamic Kinetic Resolution of 1-Phenylethanol Using Niobium Salts as Racemization Agents

Authorship SCIMAGO INSTITUTIONS RANKINGS

In this work, a racemization method of (S)-1-phenylethanol by niobium salts was developed. Among the salts available, the niobium phosphate hydrate (NbOPO₄.nH₂O) reduced the enantiomeric excess (ee) of the chiral alcohol from 95 to 0% after 24 h at 60 ºC in toluene. This new racemization agent was combined with a lipase (CALB) in order to achieve a chemoenzymatic dynamic kinetic resolution (DKR). Experiments demonstrated that the DKR process is feasible and the corresponding (R)-1-phenylethyl acetate was obtained with 92% conversion and 85% ee.

Keywords:
niobium; dynamic kinetic resolution; biocatalysis; racemization agent


entry	Nb salt	ee of 1 after 3 h^b b enantiomeric excess (ee) was determined by chiral GC analysis; / %	ee of 1 after 24 h^b b enantiomeric excess (ee) was determined by chiral GC analysis; / %
1	none	96	94
2	NbOPO₄.nH₂O	50	0
3	Nb₂O₅.nH₂O	96	94
4	NbCl₅	46	-^c c no peaksof 1-phenylethanol was detected.
5	NH₄[NbO(C₂O₄)(H₂O)_x].nH₂O	94	76


entry	NbOPO₄.nH₂O / mg	ee of 1 after 3 h^b b enantiomeric excess (ee) was determined by chiral GC analysis; / %	ee of 1 after 6 h^b b enantiomeric excess (ee) was determined by chiral GC analysis; / %	ee of 1 after 24 h^b b enantiomeric excess (ee) was determined by chiral GC analysis; / %
1	10	88	84	78
2	50	50	33	0
3	100	12	0	1^c c unknown byproduct formation.
4	150	6	2	6^c c unknown byproduct formation.
5	200	0	1	14^c c unknown byproduct formation.


entry	Temperature / °C	ee of 1 after 3 h^b b enantiomeric excess (ee) was determined by chiral GC analysis. / %	ee of 1 after 6 h^b b enantiomeric excess (ee) was determined by chiral GC analysis. / %	ee of 1 after 24 h^b b enantiomeric excess (ee) was determined by chiral GC analysis. / %
1	20	> 98	> 98	> 98
2	40	96	96	86
3	60	50	33	0


entry	Solvent	ee of 1 after 3 h^b b enantiomeric excess (ee) was determined by chiral GC analysis; / %	ee of 1 after 6 h^b b enantiomeric excess (ee) was determined by chiral GC analysis; / %	ee of 1 after 24 h^b b enantiomeric excess (ee) was determined by chiral GC analysis; / %
1	toluene	76	56	42
2	hexane	88	73	71
3	1,4-dioxane	> 98	> 98	> 98
4	diethyl ether	98	-^c c ee not measured due to evaporation. THF: tetrahydrofuran.	-^c c ee not measured due to evaporation. THF: tetrahydrofuran.
5	THF	> 98	-^c c ee not measured due to evaporation. THF: tetrahydrofuran.	-^c c ee not measured due to evaporation. THF: tetrahydrofuran.


No.	Reaction time / h	Reaction time duration in flask A / h	Reaction time duration in flask B / h	(R)-1 / %	(S)-1 / %	(S)-2 / %	(R)-2 / %	Byproduct / %
1	0-1	1	-	6	44	1	50	-
2	1-2	1	-	2	43	1	54	-
3	2-3	1	-	-	43	1	56	-
4	3-6	3	-	0	42	1	57	-
5	6-24	-	18	15	16	4	65	-
6	24-25	1	-	6	14	4	70	6
7	25-26	1	-	2	15	4	74	5
8	26-27	1	-	< 1	15	4	75	6
9	27-48	-	21	5	6	6	77	6
10	48-49	1	-	3	5	6	78	6
11	49-50	1	-	2	6	7	79	7
12	50-51	1	-	1	5	6	69	5
13	51-72	-	21	2.5	2.5	8	80	7
14	72-74	2	-	0.5	1.5	8	84	6


time / h	Flask	(R)-1 / %	(S)-1 / %	(S)-2 / %	(R)-2 / %	ee (R)-2 / %	Byproduct / %
1	A	37	50	1	9	80	2
1	B	18	45	1	33	94	2
2	A	30	46	1	19	90	4
2	B	9	43	1	45	> 95	2
4	A	16	39	2	41	91	2
4	B	4	42	1	51	> 95	1
6	A	6	28	3	59	90	2
6	B	2	38	2	56	93	3
24	A	< 1	7	7	85	85	2
24	B	< 1	18	5	75	88	2

Sociedade Brasileira de Química Instituto de Química - UNICAMP, Caixa Postal 6154, 13083-970 Campinas SP - Brazil, Tel./FAX.: +55 19 3521-3151 - São Paulo - SP - Brazil
E-mail: office@jbcs.sbq.org.br

Acompanhe os números deste periódico no seu leitor de RSS

[1] *e-mail: alvaro.omori@ufabc.edu.br