Method for preparing 5-substituted-2-thiazolidinone
A technology of thiazolidinone and alkyl, applied in the field of preparation of 5-substituted 2-thiazolidinone
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Embodiment 1
[0051] Preparation of methyl 3-(2-thiazolidinon-5-yl)propionate 3a
[0052] Add dithiocarbonic acid to a 50 mL three-neck flask O -Ethyl- S -(2-oxo-2-methoxyethyl) ester (388.3 mg, 2 mmol), tert-butyl N-allylcarbamate (345.8 mg, 2.2 mmol) and 2 mL of 1,2-dichloro Ethane (DCE), evacuated, N 2 under protection at 90 o Add lauroyl peroxide (DLP) (21 mg, 2.5 mol%) after reflux in C oil bath for 5 minutes, TLC detects the reaction, add DLP (11.5-84 mg, 1.25-10 mol%) every 45 minutes until the raw material is yellow The ortho ester completely disappeared and the reaction was stopped. After the reaction solution was spinned to remove the solvent, it was separated on a silica gel column (eluent petroleum ether: ethyl acetate = 15:1 to 3:1) to obtain dithiocarbonic acid O -Ethyl- S -(5-methoxy-1-tert-butoxycarbonylamino-5-oxopent-2-yl)ester.
[0053] Add the above addition product (351.5 mg, 1 mmol), 5 mL of acetonitrile and 88% formic acid (690 mg, 15 mmol) into a 25 mL round-b...
Embodiment 2
[0055] Preparation of Diethyl 2-[(2-thiazolidinon-5-yl)methyl]malonate 3b
[0056] According to the method described in Example 1, with dithiocarbonic acid O -Ethyl- S -(1,3-diethoxy-1,3-dioxopropan-2-yl] ester and tert-butyl N-allylcarbamate as raw materials to obtain 2-[(2-thiazolidinone-5 -yl)methyl]diethyl malonate, colorless solid 201 mg, yield 31%, melting point: 68-69 o c. 1 H NMR (CDCl 3 , 400 MHz) ( δ , ppm) 1.28 (t, J = 7.1 Hz, 3H, CH 3 ), 1.29 (t, J = 7.1 Hz, 3H, CH 3 ), 2.32 (ddd, J = 14.2, 9.2, 8.0 Hz, 1H in CH 2 ), 2.40 (ddd, J = 14.2, 9.2, 5.6 Hz, 1H in CH 2 ), 3.34 (ddd, J = 10.1, 5.6, 0.9 Hz, 1H in CH 2 ), 3.50 (dd, J = 9.2, 5.6 Hz, 1H, CH), 3.76 (dd, J = 10.1, 7.2 Hz, 1H in CH 2 ), 3.86 (dddd, J = 9.2, 8.0, 5.6, 5.6 Hz, 1H, CH), 4.17-4.26 (m, 4H, 2CH 2 ), 6.23 (s, 1H, NH). 13 C NMR (CDCl 3 , 101 MHz) ( δ , ppm) 13.9, 14.0, 34.4, 44.4, 48.7, 49.8, 61.8, 61.9, 168.4, 168.5, 174.7.
Embodiment 3
[0058] Preparation of 5-(3-oxobutyl)thiazolidin-2-one 3c
[0059] According to the method described in Example 1, with dithiocarbonic acid O -Ethyl- S -(2-oxopropyl) ester and tert-butyl N-allyl carbamate were used as raw materials to obtain 5-(3-oxobutyl)thiazolidin-2-one, colorless oily liquid 125 mg, yield 54%. 1 H NMR (CDCl 3 , 400 MHz) ( δ , ppm) 1.98 (dddd, J = 14.4, 7.6, 7.6, 6.0 Hz, 1H in CH 2 ), 2.11 (dddd, J = 14.4, 9.6, 7.6, 6.0 Hz, 1H in CH 2 ), 2.17 (s, 3H, CH 3 ), 2.56 (ddd, J = 16.4, 7.6, 6.0 Hz, 1H in CH 2 ), 2.63 (ddd, J = 16.4, 7.6, 6.0 Hz, 1H in CH 2 ), 3.31 (ddd, J = 10.1, 5.2, 1.2 Hz, 1H, CH), 3.73 (ddd, J = 10.1, 5.2, 0.8 Hz, 1H in CH 2 ), 3.88 (dddd, J = 9.6, 7.6, 5.2, 5.2 Hz, 1H, CH), 6.16 (s, 1H, NH). 13C NMR (CDCl 3 , 101 MHz) ( δ , ppm) 29.1, 30.0, 40.7, 46.1, 48.8, 175.0, 207.1.
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